Abrasive jet micro-machining (AJM), in which abrasive particles are accelerated by air and directed toward a target, has been used to make components for micro-electro-mechanical (MEMS) and micro-fluidic capillary electrophoresis devices. One of the disadvantages of AJM is that the compressed air jet used to propel the erodent particles diverges significantly after the nozzle exit, increasing the size of the blast zone and the width of the smallest channel or hole that can be machined without the use of a patterned erosion-resistant mask that defines the micro-feature edges. Abrasive slurry jet micro-machining (ASJM) is similar to AJM except that pressurized water, instead of air, is used to accelerate the suspended abrasive particles such as garnet or alumina (Al2O3). In both AJM and ASJM, the material removal occurs by erosion. However, for the same jet dimension and low speed, slurry jets have a much lower divergence angle than air jets, allowing for the micro-machining of small features without the use of patterned masks.
1) The document analyzes the effect of nanocrystalline diamond (NCD) and microcrystalline diamond (MCD) coatings deposited via chemical vapor deposition (CVD) on cemented tungsten carbide (WC-Co) substrates.
2) Tribological tests were conducted using a ball-on-disc tribometer under dry conditions with an alumina ball, showing lower coefficients of friction for the diamond coatings compared to the uncoated WC-Co substrate.
3) Characterization of the coatings and wear tracks using Raman spectroscopy, SEM, EDS, and XRD showed the diamond coatings improved the tribological performance of the WC-Co substrates.
Influence of the speed in advance and the laser’s power on the zone affected ...IOSR Journals
Abstract: The Laser cutting is a very important manufacturing technology. But this method has some
disadvantages, among which we find the emergence of a Thermically Affected Zone ZAT can dramatically alter
the characteristics of the processed material which affects its behaviour during its use. For this, we have tried in
this article to study the effect of the forward speed and the laser power in this area (thickness, hardening). In
this context, tests were made on steel C45 where we relied on the method of experiment plans to create a
mathematical model Significant coefficients are obtained by carrying out a variance analysis ANOVA on the
level of 5% of significance. We find that the speed in advance and the power of the laser have a great effect on
the ZAT.
Keywords: Cutting, Laser CO2, Heat Affected Zone.
Prediction Models for Sliding Wear of AA3003/Al2O3 CompositesIJERA Editor
In the present work, the AA3003/Al2O3 metal matrix composites were manufactured at 10% and 30% volume
fractions of Al2O3. The composites were wear tested at different levels of normal load, sliding speed and sliding
distances. The microstructure of worn surfaces pertaining to AA3003/ Al2O3 composite reveals the fracture of
AA3033 alloy matrix as well as the detachment of Al2O3 particles from the matrix.
The Effect of Direct- and Cross-Rolling on Mechanical Properties and Microstr...Kaveh Rahimi Mamaghani
Severely deformed commercial pure aluminum sheets by constrained groove pressing are direct and crossrolled.
The grain size evolution and dislocation density during rolling are studied using Williamson-Hall
analysis on x-ray diffraction patterns of the deformed samples. These results and optical microscopy
observations show that subsequent direct or cross-rolling of constrained groove pressed aluminum can
produce elongated fine grains. The minimum crystallite size is achieved after cross-rolling of constrained
groove pressed samples. By direct-rolling or cross-rolling of annealed sheet, the maximum intensity in x-ray
diffraction patterns remains on (200) like annealed aluminum but direct-rolling or cross-rolling of constrained
groove pressed sheets changes the maximum intensity from (111) for constrained groove pressed
sheets to (220). Also, mechanical properties are studied using tensile test and hardness measurement. The
results show that cross-rolling on constrained groove pressed samples is more effective than direct-rolling in
mechanical properties improvement.
Laboratory experimental study and elastic wave velocity on physical propertie...HoangTienTrung1
Pressure grouting has gained popularity as a soil reinforcement method. However, the behavior of the interface between rock and grout is not well known. This study investigates the interaction of pressure grouting and rock, through a series of laboratory tests performed on specially designed and fabricated equipment and using standard testing methods. The test measures the density, compressional strength, and frictional resistance of grout relative to the applied pressure and curing time. Simultaneously, the velocities of the elastic wave traveling through the grout are obtained to develop correlations between the physical properties of the grout and the test conditions. The results of the tests show that the density, compressional strength, and frictional resistance of the grout increase with applied pressure and curing time. The strengths of the influencing factors are seen to be correlated within the range of the test conditions. Using the results of these tests, the potential development of a new method that requires less cement was discussed.
This document summarizes an XRD stress analysis of nano-diamond coatings deposited on WC-Co substrates. The key points are:
1. A compressive residual stress of 1.65GPa was measured in the nano-diamond coatings using the sin2ψ method with omega tilting mode.
2. "ψ-splitting" was observed, demonstrating the existence of non-zero shear stress normal to the coating surface, indicating a triaxial rather than biaxial stress state.
3. Various diffraction peaks and instrument settings were tested to obtain reliable stress measurements, with the (311) peak in omega mode providing the best results.
This document discusses a study on the effect of liquid additives on the strength and behavior of reinforced concrete model beams. Six model beams were tested with different proportions of high-range water reducing admixtures by weight of cement ranging from 0% to 2%. Compressive strength, modulus of elasticity, shear modulus, modulus of volume change, Poisson's ratio, deflection, and cracking were measured and calculated at 28 days. The best results were achieved using an admixture ratio of 1.6%, which improved compressive strength and modulus of elasticity but had no effect on cracking behavior. Control cube specimens were also tested to determine compressive strength at 7 and 28 days. The experimental results are presented in tables.
In the present study, coatings were deposited on CrC-NiCrFeSiBCoC(80%-20% )a
Fe based SS316 steel substrate to reduce the damage caused by erosion boiler
applications. Erosion studies were conducted on uncoated as well as HVOF coated steels.
The erosion experiments were carried out using an air-jet erosion test rig according to
ASTM G-76 standard at a velocity of 30 m/s and at different impingement angles of 30°,
60° and 90°. The HVOF spraying leads to a high retention of CrC in the coating matrix
accompanied with lower porosity The high velocity oxy-fuel (HVOF) sprayed CrCNiCrFeSiBCoC(
80%-20% )coatings on 316SS boiler tube steal exhibit composite ductile
or brittle modes of erosion under angular alumina sand erodent of size 50 impacted
at 30m/s. The HVOF spraying leads to a high retention of CrC in the coating matrix
accompanied with lower porosity.
1) The document analyzes the effect of nanocrystalline diamond (NCD) and microcrystalline diamond (MCD) coatings deposited via chemical vapor deposition (CVD) on cemented tungsten carbide (WC-Co) substrates.
2) Tribological tests were conducted using a ball-on-disc tribometer under dry conditions with an alumina ball, showing lower coefficients of friction for the diamond coatings compared to the uncoated WC-Co substrate.
3) Characterization of the coatings and wear tracks using Raman spectroscopy, SEM, EDS, and XRD showed the diamond coatings improved the tribological performance of the WC-Co substrates.
Influence of the speed in advance and the laser’s power on the zone affected ...IOSR Journals
Abstract: The Laser cutting is a very important manufacturing technology. But this method has some
disadvantages, among which we find the emergence of a Thermically Affected Zone ZAT can dramatically alter
the characteristics of the processed material which affects its behaviour during its use. For this, we have tried in
this article to study the effect of the forward speed and the laser power in this area (thickness, hardening). In
this context, tests were made on steel C45 where we relied on the method of experiment plans to create a
mathematical model Significant coefficients are obtained by carrying out a variance analysis ANOVA on the
level of 5% of significance. We find that the speed in advance and the power of the laser have a great effect on
the ZAT.
Keywords: Cutting, Laser CO2, Heat Affected Zone.
Prediction Models for Sliding Wear of AA3003/Al2O3 CompositesIJERA Editor
In the present work, the AA3003/Al2O3 metal matrix composites were manufactured at 10% and 30% volume
fractions of Al2O3. The composites were wear tested at different levels of normal load, sliding speed and sliding
distances. The microstructure of worn surfaces pertaining to AA3003/ Al2O3 composite reveals the fracture of
AA3033 alloy matrix as well as the detachment of Al2O3 particles from the matrix.
The Effect of Direct- and Cross-Rolling on Mechanical Properties and Microstr...Kaveh Rahimi Mamaghani
Severely deformed commercial pure aluminum sheets by constrained groove pressing are direct and crossrolled.
The grain size evolution and dislocation density during rolling are studied using Williamson-Hall
analysis on x-ray diffraction patterns of the deformed samples. These results and optical microscopy
observations show that subsequent direct or cross-rolling of constrained groove pressed aluminum can
produce elongated fine grains. The minimum crystallite size is achieved after cross-rolling of constrained
groove pressed samples. By direct-rolling or cross-rolling of annealed sheet, the maximum intensity in x-ray
diffraction patterns remains on (200) like annealed aluminum but direct-rolling or cross-rolling of constrained
groove pressed sheets changes the maximum intensity from (111) for constrained groove pressed
sheets to (220). Also, mechanical properties are studied using tensile test and hardness measurement. The
results show that cross-rolling on constrained groove pressed samples is more effective than direct-rolling in
mechanical properties improvement.
Laboratory experimental study and elastic wave velocity on physical propertie...HoangTienTrung1
Pressure grouting has gained popularity as a soil reinforcement method. However, the behavior of the interface between rock and grout is not well known. This study investigates the interaction of pressure grouting and rock, through a series of laboratory tests performed on specially designed and fabricated equipment and using standard testing methods. The test measures the density, compressional strength, and frictional resistance of grout relative to the applied pressure and curing time. Simultaneously, the velocities of the elastic wave traveling through the grout are obtained to develop correlations between the physical properties of the grout and the test conditions. The results of the tests show that the density, compressional strength, and frictional resistance of the grout increase with applied pressure and curing time. The strengths of the influencing factors are seen to be correlated within the range of the test conditions. Using the results of these tests, the potential development of a new method that requires less cement was discussed.
This document summarizes an XRD stress analysis of nano-diamond coatings deposited on WC-Co substrates. The key points are:
1. A compressive residual stress of 1.65GPa was measured in the nano-diamond coatings using the sin2ψ method with omega tilting mode.
2. "ψ-splitting" was observed, demonstrating the existence of non-zero shear stress normal to the coating surface, indicating a triaxial rather than biaxial stress state.
3. Various diffraction peaks and instrument settings were tested to obtain reliable stress measurements, with the (311) peak in omega mode providing the best results.
This document discusses a study on the effect of liquid additives on the strength and behavior of reinforced concrete model beams. Six model beams were tested with different proportions of high-range water reducing admixtures by weight of cement ranging from 0% to 2%. Compressive strength, modulus of elasticity, shear modulus, modulus of volume change, Poisson's ratio, deflection, and cracking were measured and calculated at 28 days. The best results were achieved using an admixture ratio of 1.6%, which improved compressive strength and modulus of elasticity but had no effect on cracking behavior. Control cube specimens were also tested to determine compressive strength at 7 and 28 days. The experimental results are presented in tables.
In the present study, coatings were deposited on CrC-NiCrFeSiBCoC(80%-20% )a
Fe based SS316 steel substrate to reduce the damage caused by erosion boiler
applications. Erosion studies were conducted on uncoated as well as HVOF coated steels.
The erosion experiments were carried out using an air-jet erosion test rig according to
ASTM G-76 standard at a velocity of 30 m/s and at different impingement angles of 30°,
60° and 90°. The HVOF spraying leads to a high retention of CrC in the coating matrix
accompanied with lower porosity The high velocity oxy-fuel (HVOF) sprayed CrCNiCrFeSiBCoC(
80%-20% )coatings on 316SS boiler tube steal exhibit composite ductile
or brittle modes of erosion under angular alumina sand erodent of size 50 impacted
at 30m/s. The HVOF spraying leads to a high retention of CrC in the coating matrix
accompanied with lower porosity.
ICMCTF2011: Micro-scratch testing for interface characterizations of diamond-...The University of Alabama
This document summarizes research on characterizing the adhesion of diamond coatings on tungsten carbide substrates through scratch testing and finite element modeling. Key findings include:
1) Scratch testing identified a critical load range of 4-6N for delamination initiation, detected by increased acoustic emission and tangential force.
2) Finite element modeling of the scratch process, using a cohesive zone model at the interface, produced stress distributions consistent with experimental observations of delamination.
3) Both experiments and simulations provide methods to evaluate coating/substrate interface properties relevant to delamination behavior.
This document summarizes research on the wrinkling behavior of pure aluminum, copper, and steel sheets during deep drawing processes. Tests were conducted using conical and tractrix dies on commercially pure aluminum grades annealed at different temperatures. Results show the aluminum grade ISS 19660 exhibited the best wrinkling resistance, while ISS 19000 showed the lowest. Higher annealing temperatures improved wrinkling resistance for all grades. The tractrix die also demonstrated better wrinkling suppression compared to the conical die. Charts and diagrams are presented comparing strain and stress ratios at wrinkling onset between die types and aluminum grades.
1) The document outlines applications of terahertz spectrometry, reflectometry, and sub-surface imaging for semiconductor wafer testing to minimize wafer rejects.
2) Exemplary results are analyzed from scanning a wafer to determine defects. Terahertz reflectometry is also shown to effectively control wafer polishing by precisely monitoring thickness.
3) The technique can also identify different self-assembled monolayer coatings on wafers by analyzing their terahertz absorption spectra signatures.
This document summarizes a study on the friction mechanisms of fresh concrete under pressure. It discusses how friction occurs in many civil engineering applications and influences concrete pressure on formwork. Tribometer tests were conducted on different concrete mixes to study how parameters like plate roughness, sliding velocity, concrete mix design, grain size, and water reducers influence friction stress. The concrete mixes tested ranged from normal concrete to self-compacting concrete. Test results provide insight into adapting mix designs for applications and developing friction models for fresh concrete.
System shear connector jakarta digunakan sebagai aplikasi dalam konstruksi bangunan untuk menghasilkan kekuatan coran beton lebih kuat dan stabil sesuai dengan perhitungan engineering civil. Dalam hal ini ada 2 hal perhitungan kekuatan secara umum yaitu kekuatan kelengketan stud pada batang baja sesudah dilas. Dan yang kedua adalah kekuatan stud bolt yang digunakan.
Tichomir G. Vasilev, Wear of bronze bearing bushes after finishing with burni...Tihomir Vasilev
The article published results of experimental studies of wear of bronze bearings bushes, after finishing with burnishing.
Research addresses two types of bronze alloys widely used in practice for making bronze bearings operate under boundary or mixed film friction.
This document summarizes an experimental study on the abrasion and drop weight impact resistance of concrete with coconut shell ash (CSA) as a partial replacement for cement. Cement was replaced with 10-50% CSA in concrete mixes. Compressive strength was found to initially increase and then decrease with higher CSA content. Abrasion resistance and impact resistance were highest for 10-20% CSA replacement, with lower wear loss and higher numbers of impacts before cracking. The study concluded that CSA concrete can be used in applications like highways and industrial floors that involve abrasion or impact loads, with up to 10% CSA replacement providing good performance.
An Experimental Investigation into the Grindability Aspects of Newly Develope...IDES Editor
The document summarizes an experimental investigation into the grindability of a newly developed ceramic composite material called AlSiTi. The study analyzed the effects of grinding wheel speed, table feed rate, and depth of cut on grinding forces, specific energy, surface roughness, and subsurface damage using Taguchi's experimental design method. Scanning electron microscopy revealed that higher grinding forces led to greater subsurface damage. Optimizing grinding parameters and using coolants could help improve the grindability of this composite ceramic material by reducing forces and specific energy, thereby minimizing subsurface defects.
Vibrational Analysis Of Cracked Rod Having Circumferential Crack IDES Editor
The frequency ratio of torsional vibration of a rod without crack and of rod with crack subjected to torque at the free end for various crack depth and varying crack location is investigated. It is found that even a cracked of small depth is
dangerous at the fixed end, also as the crack depth is increases more than 50% of diameter of rod there is a considerable drop in natural frequency of the rod .
SLIDING WEAR OF AA6061/CARBON BLACK METAL MATRIX COMPOSITESIAEME Publication
In this study, the effects of carbon black amount on fracture and wear behaviors of AA6061-carbon black metal matrix composites produced by stir casting route were investigated. Wear tests were performed in a pin on type wear apparatus under different loads of 10, 20, 30 N with different sliding speeds of 2, 3 and 4 m/s, at three different sliding distances of 500, 750 and 1000 m. The design of experiments was carried out as per Taguchi technique. Wear rate function was determined in terms of volume fraction, normal load, sliding speed and sliding distance. It was found that there was a good agreement between the theoretical and the experimental value of wear rate. Maximum sliding wear of 68.72% was attributed sliding distance. Sliding wear resistance increases by 42.56% for AA6061/30%CB metal matrix composites as compared to the matrix alloy AA6061
Busef, Sarah 9835048 Project Poster 2016Sarah Busef
This document summarizes a research project investigating stress corrosion cracking (SCC) in the aluminium alloy AA7032. The project aims to correlate grain boundary character observed in AA7032 with the SCC weakening mechanism through a multi-scale analysis combining microstructural examination, serial sectioning, and X-ray computed tomography. The susceptibility of aluminium alloys to SCC depends on factors like grain size and distribution, grain boundary chemistry and precipitates. The analysis seeks to determine the active SCC mechanism by studying crack tip behaviour in relation to the underlying 2D and 3D grain boundary microstructure.
Investigation of Extrusion of Lead experimentally from Round section through ...inventy
ABSTRACT :The changes of die angle, area reduction in dies, loading rate on the final extruded products, extrusion pressures of lead of circular cross sections has been investigated experimentally. The proposed method is successfully adapted to the forward extrusion of the equilateral triangular section from round billet through converging dies of different area reductions. Computation of extrusion pressure at various area reductions and calculations of different parameters (stress, strain etc.) in wet condition.
Keywords - Extrusion of Triangular section, Converging Dies at different area reductions, Friction Factor, Extrusion Pressure
AJK2011-03023 (Conference Paper DR) Modelling Multiphase Jet Flows for High V...David Ryan
This document summarizes CFD simulations of flow inside an industrial static mixer called a Sonolator. Single-phase steady-state simulations were performed for three mass flow rates through a fixed nozzle orifice. Streamline data was used to calculate residence times and turbulent energy dissipation rates, which can provide insight into droplet breakup for emulsification processes. Validation was done against experimental discharge coefficients and predicted droplet sizes may depend on inlet conditions for multiphase mixtures.
The document discusses cavitation erosion testing of stellite alloy weld overlays. It conducted tests using a vibratory method and cavitating liquid jet method to evaluate the erosion resistance of weld overlays made of ST6 and ST21 alloys. The results found that the grain size of the cobalt matrix in ST6 overlays affected their cavitation erosion resistance. ST6 overlays showed erosion rates about 1/13 to 1/7 times lower than SUS304 steel. Examination with SEM clarified the erosion mechanisms of SUS304 and ST6. Erosion rates from the cavitating liquid jet method correlated well with those from the vibratory method.
This document discusses two damage models for predicting ductile fracture initiation: 1) the Rice and Tracey cavity growth model, which relates cavity growth rate to stress triaxiality and plastic strain increment, and predicts initiation when cavity radius reaches a critical value. 2) A damage work model, which combines plastic strain work with a term accounting for cavity growth related to hydrostatic stress, predicting initiation when damage work reaches a critical value. Finite element simulations of notched tensile specimens of two steel materials were performed to evaluate these models based on experimental crack initiation locations and steps. Both models were able to predict initiation location and step for a relatively constant critical damage value.
This study used finite element modeling to analyze swelling behavior in a tunnel excavated through marl rock. Laboratory tests on marl rock samples were used to calibrate two finite element programs, FISS and Nisa-II. FISS modeled the tunnel using the laboratory swelling test results. Nisa-II modeled time-dependent creep behavior by defining a creep function relating stress, strain, and time. Both programs analyzed stresses around the tunnel and indicated higher stresses in the sidewalls compared to the roof and floor. The study demonstrated a method to numerically model swelling behavior in tunnels using laboratory test data.
Implementation of 1D Brinson model in 3D SMA specimens Influenced by stress c...irjes
The application of small-size SMA components has grown rapidly in various industries over the last
few years. Due to their complex nature, local constitutive models for those components have proven somehow
impractical; whereas global models have been unable to take the stress concentration into consideration and
hence cannot predict the nucleation and stress patterns accurately, especially in small samples. Moreover, FE
analyses are impossible to conduct in cases where a large number of evaluations are required to design a suitable
SMA sample. This paper proposes a new iterative method to accurately calculate the stress and martensitic
volume fraction in samples with stress concentration using 1D Brinson model. The method is implemented in
the form of a computer code which is then refined iteratively using FEM model which is validated based on
experimental data. Final assessments show that the proposed method could predict the stress values accurately
at negligible computational costs.
The influence of silicon carbide SiC abrasive particles of 20, 30, 40, 50 and 60 size on carburized digger tooth steel was studied. Four types of steel, with different hardness, were tested at two constant linear sliding speeds and under various loads of 10, 20, 30, 40 and 50N. Tests were carried out for sliding time of 0.5, 1.0, 1.5, 2.0 and 2.5min. Experimental results showed that there was consistent reduction in abrasive wear as the hardness of the materials was increased. It was found that wear increased with the increase of applied load, linear sliding speed and sliding time. Also, it was noticed that the wear increased with increase in abrasive particle size, and the most effective size was 40 . SEM observations of the worm surface showed that the cutting and ploughing were the dominant abrasive wear mechanisms.
This document discusses using acoustic emission (AE) techniques to non-destructively evaluate the properties of concrete and mortar, including compressive strength, flexural strength, and moisture content. Tests were conducted on concrete cubes and mortar cubes and beams with varying water-to-cement ratios. Results showed that the AE amplitude attenuated with increasing distance from the source, and that the attenuation factor correlated strongly with compressive strength, flexural strength, and moisture content - providing a way to predict these properties using a non-destructive AE method.
B 748 90 r01 espeso r.m microscopia electronicaLPELABORATORIO
1) This document describes a standard test method for measuring the thickness of metallic coatings using a scanning electron microscope to examine a cross section.
2) A test specimen is cut, ground, and polished to create a cross section for examination under the SEM. The coating thickness is measured directly from micrographs or video waveform scans.
3) Many factors can affect the accuracy of measurements, including surface roughness, taper of the cross section, specimen tilt, magnification calibration, and clarity of coating boundaries after preparation. Careful preparation and calibration are required to achieve repeatable results within 10% uncertainty or 0.1 μm, whichever is greater.
A model for abrasive waterjet (awj) machiningHung BUI Van
This document presents a model for predicting the depth of cut of abrasive waterjets in different metals. The model is based on an improved erosion model that accounts for the physical and geometrical characteristics of eroding particles. The erosion model yields a velocity exponent of 2.5, which agrees with erosion data. The erosion model is combined with a kinematic jet penetration model to determine expressions for depth of cut according to different erosion modes along the cutting kerf. The depth of cut consists of cutting wear at shallow impact angles and deformation wear at large angles. The model predictions agree well with experimental cutting results for various metals, with correlation coefficients over 0.9.
This document summarizes deburring techniques for small intersecting holes. It discusses how hole size, tolerance, depth of intersection, and other factors impact the deburring process selection. Only 5 of the 37 major deburring processes are normally suitable for small holes. These include thermal energy method, abrasive jet, abrasive flow, electropolish, and manual methods. The document provides tables comparing deburring process capabilities based on hole size change, edge condition, and other criteria.
ICMCTF2011: Micro-scratch testing for interface characterizations of diamond-...The University of Alabama
This document summarizes research on characterizing the adhesion of diamond coatings on tungsten carbide substrates through scratch testing and finite element modeling. Key findings include:
1) Scratch testing identified a critical load range of 4-6N for delamination initiation, detected by increased acoustic emission and tangential force.
2) Finite element modeling of the scratch process, using a cohesive zone model at the interface, produced stress distributions consistent with experimental observations of delamination.
3) Both experiments and simulations provide methods to evaluate coating/substrate interface properties relevant to delamination behavior.
This document summarizes research on the wrinkling behavior of pure aluminum, copper, and steel sheets during deep drawing processes. Tests were conducted using conical and tractrix dies on commercially pure aluminum grades annealed at different temperatures. Results show the aluminum grade ISS 19660 exhibited the best wrinkling resistance, while ISS 19000 showed the lowest. Higher annealing temperatures improved wrinkling resistance for all grades. The tractrix die also demonstrated better wrinkling suppression compared to the conical die. Charts and diagrams are presented comparing strain and stress ratios at wrinkling onset between die types and aluminum grades.
1) The document outlines applications of terahertz spectrometry, reflectometry, and sub-surface imaging for semiconductor wafer testing to minimize wafer rejects.
2) Exemplary results are analyzed from scanning a wafer to determine defects. Terahertz reflectometry is also shown to effectively control wafer polishing by precisely monitoring thickness.
3) The technique can also identify different self-assembled monolayer coatings on wafers by analyzing their terahertz absorption spectra signatures.
This document summarizes a study on the friction mechanisms of fresh concrete under pressure. It discusses how friction occurs in many civil engineering applications and influences concrete pressure on formwork. Tribometer tests were conducted on different concrete mixes to study how parameters like plate roughness, sliding velocity, concrete mix design, grain size, and water reducers influence friction stress. The concrete mixes tested ranged from normal concrete to self-compacting concrete. Test results provide insight into adapting mix designs for applications and developing friction models for fresh concrete.
System shear connector jakarta digunakan sebagai aplikasi dalam konstruksi bangunan untuk menghasilkan kekuatan coran beton lebih kuat dan stabil sesuai dengan perhitungan engineering civil. Dalam hal ini ada 2 hal perhitungan kekuatan secara umum yaitu kekuatan kelengketan stud pada batang baja sesudah dilas. Dan yang kedua adalah kekuatan stud bolt yang digunakan.
Tichomir G. Vasilev, Wear of bronze bearing bushes after finishing with burni...Tihomir Vasilev
The article published results of experimental studies of wear of bronze bearings bushes, after finishing with burnishing.
Research addresses two types of bronze alloys widely used in practice for making bronze bearings operate under boundary or mixed film friction.
This document summarizes an experimental study on the abrasion and drop weight impact resistance of concrete with coconut shell ash (CSA) as a partial replacement for cement. Cement was replaced with 10-50% CSA in concrete mixes. Compressive strength was found to initially increase and then decrease with higher CSA content. Abrasion resistance and impact resistance were highest for 10-20% CSA replacement, with lower wear loss and higher numbers of impacts before cracking. The study concluded that CSA concrete can be used in applications like highways and industrial floors that involve abrasion or impact loads, with up to 10% CSA replacement providing good performance.
An Experimental Investigation into the Grindability Aspects of Newly Develope...IDES Editor
The document summarizes an experimental investigation into the grindability of a newly developed ceramic composite material called AlSiTi. The study analyzed the effects of grinding wheel speed, table feed rate, and depth of cut on grinding forces, specific energy, surface roughness, and subsurface damage using Taguchi's experimental design method. Scanning electron microscopy revealed that higher grinding forces led to greater subsurface damage. Optimizing grinding parameters and using coolants could help improve the grindability of this composite ceramic material by reducing forces and specific energy, thereby minimizing subsurface defects.
Vibrational Analysis Of Cracked Rod Having Circumferential Crack IDES Editor
The frequency ratio of torsional vibration of a rod without crack and of rod with crack subjected to torque at the free end for various crack depth and varying crack location is investigated. It is found that even a cracked of small depth is
dangerous at the fixed end, also as the crack depth is increases more than 50% of diameter of rod there is a considerable drop in natural frequency of the rod .
SLIDING WEAR OF AA6061/CARBON BLACK METAL MATRIX COMPOSITESIAEME Publication
In this study, the effects of carbon black amount on fracture and wear behaviors of AA6061-carbon black metal matrix composites produced by stir casting route were investigated. Wear tests were performed in a pin on type wear apparatus under different loads of 10, 20, 30 N with different sliding speeds of 2, 3 and 4 m/s, at three different sliding distances of 500, 750 and 1000 m. The design of experiments was carried out as per Taguchi technique. Wear rate function was determined in terms of volume fraction, normal load, sliding speed and sliding distance. It was found that there was a good agreement between the theoretical and the experimental value of wear rate. Maximum sliding wear of 68.72% was attributed sliding distance. Sliding wear resistance increases by 42.56% for AA6061/30%CB metal matrix composites as compared to the matrix alloy AA6061
Busef, Sarah 9835048 Project Poster 2016Sarah Busef
This document summarizes a research project investigating stress corrosion cracking (SCC) in the aluminium alloy AA7032. The project aims to correlate grain boundary character observed in AA7032 with the SCC weakening mechanism through a multi-scale analysis combining microstructural examination, serial sectioning, and X-ray computed tomography. The susceptibility of aluminium alloys to SCC depends on factors like grain size and distribution, grain boundary chemistry and precipitates. The analysis seeks to determine the active SCC mechanism by studying crack tip behaviour in relation to the underlying 2D and 3D grain boundary microstructure.
Investigation of Extrusion of Lead experimentally from Round section through ...inventy
ABSTRACT :The changes of die angle, area reduction in dies, loading rate on the final extruded products, extrusion pressures of lead of circular cross sections has been investigated experimentally. The proposed method is successfully adapted to the forward extrusion of the equilateral triangular section from round billet through converging dies of different area reductions. Computation of extrusion pressure at various area reductions and calculations of different parameters (stress, strain etc.) in wet condition.
Keywords - Extrusion of Triangular section, Converging Dies at different area reductions, Friction Factor, Extrusion Pressure
AJK2011-03023 (Conference Paper DR) Modelling Multiphase Jet Flows for High V...David Ryan
This document summarizes CFD simulations of flow inside an industrial static mixer called a Sonolator. Single-phase steady-state simulations were performed for three mass flow rates through a fixed nozzle orifice. Streamline data was used to calculate residence times and turbulent energy dissipation rates, which can provide insight into droplet breakup for emulsification processes. Validation was done against experimental discharge coefficients and predicted droplet sizes may depend on inlet conditions for multiphase mixtures.
The document discusses cavitation erosion testing of stellite alloy weld overlays. It conducted tests using a vibratory method and cavitating liquid jet method to evaluate the erosion resistance of weld overlays made of ST6 and ST21 alloys. The results found that the grain size of the cobalt matrix in ST6 overlays affected their cavitation erosion resistance. ST6 overlays showed erosion rates about 1/13 to 1/7 times lower than SUS304 steel. Examination with SEM clarified the erosion mechanisms of SUS304 and ST6. Erosion rates from the cavitating liquid jet method correlated well with those from the vibratory method.
This document discusses two damage models for predicting ductile fracture initiation: 1) the Rice and Tracey cavity growth model, which relates cavity growth rate to stress triaxiality and plastic strain increment, and predicts initiation when cavity radius reaches a critical value. 2) A damage work model, which combines plastic strain work with a term accounting for cavity growth related to hydrostatic stress, predicting initiation when damage work reaches a critical value. Finite element simulations of notched tensile specimens of two steel materials were performed to evaluate these models based on experimental crack initiation locations and steps. Both models were able to predict initiation location and step for a relatively constant critical damage value.
This study used finite element modeling to analyze swelling behavior in a tunnel excavated through marl rock. Laboratory tests on marl rock samples were used to calibrate two finite element programs, FISS and Nisa-II. FISS modeled the tunnel using the laboratory swelling test results. Nisa-II modeled time-dependent creep behavior by defining a creep function relating stress, strain, and time. Both programs analyzed stresses around the tunnel and indicated higher stresses in the sidewalls compared to the roof and floor. The study demonstrated a method to numerically model swelling behavior in tunnels using laboratory test data.
Implementation of 1D Brinson model in 3D SMA specimens Influenced by stress c...irjes
The application of small-size SMA components has grown rapidly in various industries over the last
few years. Due to their complex nature, local constitutive models for those components have proven somehow
impractical; whereas global models have been unable to take the stress concentration into consideration and
hence cannot predict the nucleation and stress patterns accurately, especially in small samples. Moreover, FE
analyses are impossible to conduct in cases where a large number of evaluations are required to design a suitable
SMA sample. This paper proposes a new iterative method to accurately calculate the stress and martensitic
volume fraction in samples with stress concentration using 1D Brinson model. The method is implemented in
the form of a computer code which is then refined iteratively using FEM model which is validated based on
experimental data. Final assessments show that the proposed method could predict the stress values accurately
at negligible computational costs.
The influence of silicon carbide SiC abrasive particles of 20, 30, 40, 50 and 60 size on carburized digger tooth steel was studied. Four types of steel, with different hardness, were tested at two constant linear sliding speeds and under various loads of 10, 20, 30, 40 and 50N. Tests were carried out for sliding time of 0.5, 1.0, 1.5, 2.0 and 2.5min. Experimental results showed that there was consistent reduction in abrasive wear as the hardness of the materials was increased. It was found that wear increased with the increase of applied load, linear sliding speed and sliding time. Also, it was noticed that the wear increased with increase in abrasive particle size, and the most effective size was 40 . SEM observations of the worm surface showed that the cutting and ploughing were the dominant abrasive wear mechanisms.
This document discusses using acoustic emission (AE) techniques to non-destructively evaluate the properties of concrete and mortar, including compressive strength, flexural strength, and moisture content. Tests were conducted on concrete cubes and mortar cubes and beams with varying water-to-cement ratios. Results showed that the AE amplitude attenuated with increasing distance from the source, and that the attenuation factor correlated strongly with compressive strength, flexural strength, and moisture content - providing a way to predict these properties using a non-destructive AE method.
B 748 90 r01 espeso r.m microscopia electronicaLPELABORATORIO
1) This document describes a standard test method for measuring the thickness of metallic coatings using a scanning electron microscope to examine a cross section.
2) A test specimen is cut, ground, and polished to create a cross section for examination under the SEM. The coating thickness is measured directly from micrographs or video waveform scans.
3) Many factors can affect the accuracy of measurements, including surface roughness, taper of the cross section, specimen tilt, magnification calibration, and clarity of coating boundaries after preparation. Careful preparation and calibration are required to achieve repeatable results within 10% uncertainty or 0.1 μm, whichever is greater.
A model for abrasive waterjet (awj) machiningHung BUI Van
This document presents a model for predicting the depth of cut of abrasive waterjets in different metals. The model is based on an improved erosion model that accounts for the physical and geometrical characteristics of eroding particles. The erosion model yields a velocity exponent of 2.5, which agrees with erosion data. The erosion model is combined with a kinematic jet penetration model to determine expressions for depth of cut according to different erosion modes along the cutting kerf. The depth of cut consists of cutting wear at shallow impact angles and deformation wear at large angles. The model predictions agree well with experimental cutting results for various metals, with correlation coefficients over 0.9.
This document summarizes deburring techniques for small intersecting holes. It discusses how hole size, tolerance, depth of intersection, and other factors impact the deburring process selection. Only 5 of the 37 major deburring processes are normally suitable for small holes. These include thermal energy method, abrasive jet, abrasive flow, electropolish, and manual methods. The document provides tables comparing deburring process capabilities based on hole size change, edge condition, and other criteria.
Modeling of Rough Surface and Contact Simulationijsrd.com
As a result of limitation of manufacturing processes, real surfaces always have some roughness and surface curvature. In many heat transfer applications, the perfectly smooth surfaces are necessary to transmit the heat. Due to the surface curvature of contacting bodies, the macro-contact area is formed, the area where micro-contacts are distributed randomly. The real contact occurs only over microscopic contacts. The heat flow must pass through the macro-contact and then micro-contacts to transfer from one body to another to form heat conductance. This phenomenon leads to a relatively high temperature drop across the interface. Thermal contact resistance (TCR) is a complex interdisciplinary problem, which includes geometrical, mechanical, and thermal analyses. In this paper, geometric modeling of asperities of rough surface 2 μm, 3.2 μm and 15μm surface roughness's is done in ANSYS and the number of asperities and areal contact area is found. The simulation is done with 1.8MPa pressure and with SS 304 as material for all above mentioned surface roughness's. The contacting bodies are kept at LN2 temperature and atmospheric temperature.
This document provides an overview of abrasive jet machining (AJM). It discusses the basic components and process of AJM. Key points include:
- AJM uses a high-velocity stream of abrasive particles carried by a gas to erode material from a workpiece. It can machine hard, brittle materials without generating heat.
- The document outlines the typical components of an AJM system including a compressor, mixing chamber, nozzle, and working chamber. It also discusses common process parameters like carrier gas, abrasives, velocity, work material, and nozzle tip distance.
- Chapters 2 and 3 will review literature on AJM and discuss the project methodology for experiments to evaluate how process parameters
The document summarizes a study investigating the microstructure and mechanical properties of commercially pure aluminum produced using the Repetitive Corrugation and Straightening (RCS) severe plastic deformation (SPD) process. The study examined the effects of RCS process parameters like strain rate, number of passes, and plate thickness on the grain size, microhardness, and tensile strength of RCS aluminum specimens. Optical microscopy images showed that increasing the number of RCS passes led to finer grain refinement down to 3.1-4.7 microns, with the number of passes having the greatest influence followed by plate thickness and strain rate. The study provides insight into optimizing RCS parameters to develop ultrafine grain structures and
The document describes characterizing wafer geometry and overlay error on silicon wafers with nonuniform stress. It discusses measuring wafer geometry using an optical metrology tool to characterize nonuniform stress-induced wafer distortions. A metric called the predicted in-plane distortion residual (PIR), derived from wafer geometry measurements, is shown to strongly correlate with measured overlay error. The relationship between wafer geometry, in-plane distortion when the wafer is chucked, and resulting overlay error is explored through finite element models. Engineered stress monitor wafers with deliberate variations in nonuniform stress are used to further study this relationship and correlations between PIR and measured overlay error.
Experimental Analysis on Surface Roughness of Abrasive Magnetic Particle Usin...IJSRD
This document presents an experimental analysis of surface roughness when using abrasive magnetic particles on EN8 steel. Nine experiments were conducted using Taguchi's design of experiments method to determine the optimal levels of four factors (current, grit size, iron percentage, and speed). The order of significance for the factors was found to be current > grit size > iron percentage > speed. Across all experiments, surface roughness improved by 33.5-60.5% compared to the initial roughness, with higher currents, finer grit sizes, higher iron percentages, and faster speeds generally producing better surface finishes.
The document discusses a new material removal process called arc ablation. Preliminary results show it can remove materials like hardened steel, Inconel, and titanium at rates far exceeding plasma cutting for the same power levels. Arc ablation uses an electric arc to melt material, which is then removed by a rotating copper tool. Tests achieved removal rates up to 97 mm3/sec at 4kW on steel. Challenges include extending it to hole making and achieving removal rates of 1000 mm3/sec at 40kW. The document describes experimental setup, parameters tested, and results obtained, finding arc ablation has potential for fast, low-cost material removal.
STUDY OF RECAST LAYERS AND SURFACE ROUGHNESS ON AL-7075 METAL MATRIX COMPOSIT...ijmech
Demand for low weight to strength ratio for exclusive application in automobile and aerospace components created scope for advance studies on Metal Matrix Composites (MMCs). However, machining of MMCs challenges for conventional machining processes due to uneven hardness, matrix of composites and undesired tool life. Electric Discharge Machining (EDM) is one of the unconventional material removal process, which offers alternatives for machining of MMCs because, being a non-contact process it can be machine excessive harder material, intricate shape with better surface finish and tool life. The evolved heat during EDM process and subsequent flushing of machined debris and rapidly resolidified layer is formed by the re-solidification of residual molten material on the machined surface during the EDM process leaves behind recast layers which is extremely hard and brittle. In the presents study optimization of process parameters to minimize the surface roughness of the rapidly resolidified layer of Al 7075 MMC while
machining using EDM process is carried out using the Taguchi tequniues. The gap current, pulse on-time and pulse off-time were considered as process parameters. The formation of resolidified layers is investigated in terms of the surface roughness as response variables inside the hole and near the hole while EDM drilling.
In the present work micromachining of PMMA was carried out using KrF excimer laser. Excimer laser pulse with a wavelength of 248 nm was generated with a coherent COMPexPro 110 excimer laser system.
A micro-hole of Ø150 μm was machined on PMMA substrate during the experimentation. The PMMA substrate was mounted on the translation stage. The PMMA substrates were ex-posed to different number of pulses (1, 2, 5, 10, 20, 50 and 100) at repetition rate of 2, 5 and 10 Hz respectively by keeping the pulse energy unchanged at 200 mJ. In the present experimentation, the effect of pulse repetition rate and
number of pulses on ablation depth has been investigated. The experimental results for micromachining
demonstrate ablation process as a photo-chemical mechanism. The results of the experimentation have
revealed that, ablation depth is directly proportional to pulse number & pulse repetition rate has no significant effects on the ablation depth.
This document summarizes a study on WC-Co coatings produced by HVOF spray technique on stainless steel substrates. Three coatings were produced with varying WC particle size ranges. SEM analysis showed uniform distribution of WC particles in the coatings. XRD analysis identified WC and Co phases in the coatings. Hardness testing and pin-on-disc wear testing was conducted under varying loads and speeds. The coating with larger WC particle size (45-90μm) exhibited the lowest wear rate, indicating improved wear resistance with larger WC particle size. SEM of the worn surfaces showed grooves, pulled out particles and cracks formed during wear testing.
Interface characterizations of diamond coated tools by scratch testing and si...The University of Alabama
1. Micro-scratch tests were conducted on diamond-coated tungsten-carbide substrates to investigate coating adhesion. Acoustic emission signals and fluctuations in tangential force indicated when coating delamination occurred, around a critical normal load of 4-6 Newtons.
2. A finite element model with a cohesive interface was developed to simulate the scratch process and evaluate interface properties based on the experimental critical load. Adjusting the cohesive properties approximated the measured critical load.
3. Scratch simulations showed high compressive and tensile stresses developed in the coating near the slider at delamination onset, around 4 Newtons normal load, consistent with experimental observations. The model can be used to evaluate adhesion of different diamond
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
MICROSTRUCTURAL STUDY AND TRIBOLOGICAL BEHAVIOR OF WC-Co COATINGS ON STAINLES...IAEME Publication
Tungsten Carbide (WC) coatings exhibit high wear resistance at low and high temperatures,WC - Cobalt coatings will demonstrate anti-resistive and wear characteristics better than those of conventional materials. Research in this area has shown that the service life of the WC-Co coatings
depended on varying compositions of tungsten and cobalt.
Dry Sliding Wear Behaviour of Rheocat Al-5.7Si-2Cu-0.3Mg AlloyDr. Manal Abdullatif
In this study, the effect of improved microstructure of Al-5.7Si-2Cu-0.3Mg alloys by using semisolid process on hardness and dry sliding wear behaviour were investigated. The microstructures of conventional cast alloy were totally dendritic, while in rheocasting the dendrit-ic transfer to fine globular microstructures after using cooling slope casting. Tribological tests were carried out by using a pin-on-disc apparatus in dry sliding conditions. Wear tests were at low sliding speed 1ms-1 ,applied load at 50N and three different sliding distance (i.e., 1.8Km, 5.4Km and 9Km) respectively. An optical microscope and a scanning electron microscope were used to examine the micro-structure and to understand the wear mechanism on the worn surface of both samples. The results showed that, the wear resistance of rheocast alloy was improved and higher than that those produce by conventional casting. The volume loss of rheocast alloy show reduc-tion more than 18% at 1.8Km and 10% at 9Km compared to as-cast alloy. Moderate wear regimes were appeared in both alloys, accord-ing to the range of wear rate. The friction coefficient had increased due to increase in the contact point between pin and disc materials. The dominant wear mechanism for conventional and rheocasting alloys was adhesion wear and abrasive wear respectively.
ANALYSIS OF THE EFFECT OF ULTRASONIC VIBRATIONS ON THE PERFORMANCE OF MICROEL...ijmech
The document analyzes the effect of ultrasonic vibrations on the performance of micro-electrical discharge machining (micro-EDM) of A2 tool steel. It first discusses challenges with micro-EDM at low discharge energies and how ultrasonic vibration-assisted micro-EDM helps address these challenges by improving flushing of debris from the gap. The document then analyzes experimental data on material removal rate (MRR) and tool wear rate (TWR) under different processing conditions. Analysis of means plots and interaction plots show that MRR increases with capacitance, vibration power, and feed rate, but decreases with machining time, while TWR generally decreases with capacitance but increases with vibration power. Regression equations
Design of Equal Channel Angular Extrusion For Grain Refinement Pratik Saxena
Equal Channel Angular Extrusion Grain refinement by severe deformation and FEA of ECAE deformation was carried out using Hyper mesh, Abaqus for optimization of Billet.
Tasks Performed
Effect of friction on Strain
Effect of die angle on Strain
Effect of Fillet radius on Strain
Effect of Thickness on Strain
This document discusses modeling abrasive flow machining (AFM) to determine stress levels, depth of indentation, and material removal rate. AFM uses an abrasive particle-filled viscoelastic polymer that is forced through a workpiece to improve its surface finish. The summary is as follows:
(1) Computational fluid dynamics (CFD) analysis using ANSYS software was used to model AFM of mild steel with a convergent-divergent nozzle.
(2) The CFD simulation results provided values for axial stress, radial stress, normal stress, depth of indentation, and material removal rate.
(3) Modeling equations were presented for calculating the normal force on abrasive particles
Improvement of Surface Roughness of Nickel Alloy Specimen by Removing Recast ...IJMER
In this investigation, experimental work and computational work are combined to obtain
improvement in the surface roughness of nickel alloy specimen, the machining is carried out by means
of CNC wire electric discharge machining (WEDM). Brass wire is used as the tool electrode and nickel
alloy (Inconel600) is used as the work piece material. The machining parameters such as Pulse-On time
(Ton), Pulse-Off time (Toff), Peak Current (Ip), and Bed speed are considered as input parameters for this
project. Surface roughness and Recast layer are considered the output parameters. The experiments
with the pre-planned set of input parameters are designed based on Taguchi’s orthogonal array. The
surface roughness is measured using stylus type roughness tester and the thickness of the Recast layer
is measured using Scanning Electron Microscope (SEM). The results obtained from the experiments are
fed to the Minitab software and optimum input parameters for the desired output parameters are
identified. The software uses the concept of analysis of variance (ANOVA) and indicates the nature of
effect of input parameters on the output parameters and confirmation is done by validation
experiments. Once the recast layer thickness is obtained Chemical Etching and abrasive blasting is
performed in order to remove the recast layer and again the surface roughness is measured by using
stylus type roughness tester. Finally from the obtained results it was found that there was significant
improvement in the Surface roughness of the nickel alloy material. In addition using regression
analysis this work is stimulated by computational method and the results are obtained.
COMPLAINTS AND APPEALS in Research examples from abroadtp jayamohan
The document discusses several topics related to research misconduct allegations and whistleblowing. It provides guidance for complainants on carefully preparing allegations, protections for complainants, and reporting allegations to the appropriate institutional official. It also discusses cases where whistleblowers uncovered misconduct through diligent analysis of data, but faced resistance, and a case where a complainant was found to have defamed and invaded the privacy of the researcher through improper public disclosure of unproven allegations.
There are several ways to identify research gaps including reviewing literature, discussions with colleagues, reviewing digital platforms, analyzing issues raised by organizations, examining highly cited research, and questioning aspects of previous research works. Some challenges in identifying gaps are the large number of unsolved issues to analyze, unorganized literature reviews, hesitation to question existing works, and lack of skills like curiosity and imagination.
prevention of flood using reataining walltp jayamohan
This document discusses the application of a retaining wall with a relief shelf for flood control in Kuttanad, Kerala. Kuttanad frequently experiences severe flooding, with water levels rising over 5 feet in many areas. The study aims to analyze how incorporating a retaining wall with a relief shelf can help control floods in the region. Retaining walls are commonly used in engineering, but adding a relief shelf can increase the stability of taller walls by decreasing lateral earth pressures. The document provides background on retaining walls and discusses software used for the finite element analysis. It also lists several references on retaining wall design and the impacts of flooding in Kuttanad.
This document discusses flood modelling and prediction in Kerala using GIS and remote sensing. It provides background on Kerala's geography and climate, which causes frequent flooding. It then describes how GIS and remote sensing tools like digital elevation models, land use data, and rainfall data can be used as inputs to model flood inundation areas and predict future flooding. The outputs of these models, like flood extent maps, can help with disaster management and planning flood prevention measures.
This document provides an overview of a project report on designing a multi-storied reinforced concrete building using ETABS software. The objectives are to analyze, design, and detail the structural components of the building. The methodology involves preparing CAD drawings, calculating loads, analyzing the structure, and designing and detailing structural elements. The building to be designed is a residential building with ground + 5 floors located in Chalikkavattom. Loads like dead, live, wind, and seismic loads will be calculated according to Indian codes and applied in the ETABS analysis model.
This document provides an overview of berth development projects at several ports. It discusses the scope of improving existing berths at Morehead Port in North Carolina and the Panama Canal by strengthening structures, increasing dredge depth, and adding new finger piers for larger ships. It also reviews a project to monitor lateral soil movement during dredging near berths constructed with diaphragm walls and piles at Jawaharlal Nehru Port in Mumbai. Geotechnical site investigations including testing were important for understanding soil conditions and designing stable berth structures.
This document discusses precautions taken for concreting in sub-zero temperatures. It recommends selecting cement that hydrates fast to generate early heat, using admixtures like calcium chloride or sodium chloride to lower the freezing point of water and accelerate hydration, insulating concrete to preserve heat during curing, and employing air entraining agents to increase durability against frost damage by modifying the pore structure. Heating materials like aggregates and mixing water is also suggested to maintain the concrete above freezing during the pre-hardening period.
The document contains floor plans for a two story building. The ground floor includes a 5x4 verandah, 3x4.2 store, 5x3 dining area, 4x2 car porch, 4x5 living room, 4x2 kitchen, and 1.8x4.2 toilet. The first floor contains a master bedroom, work area, two bedrooms, two toilets, and windows and doors labeled on the plans. Dimensions are provided for all rooms and building elements in meters. The plans were created by student Gayathry.T.J with roll number 27.
This engineering drawing shows elevation section A-A with various dimensions in meters. It includes dimensions for the overall height of 2.9 meters and widths of 0.12, 0.9, 1.2, 0.45 and 0.45 meters. Smaller dimensions shown are 0.1, 1.38, 0.13 and 0.6 meters.
The document contains a floor plan layout for a house with dimensions for various rooms and features. It includes a kitchen, two bedrooms, a dining/living area, verandah, toilet, and car porch. The bedrooms are labeled Bedroom-1 and Bedroom-2 and measure 3x4 meters and 4x5.3 meters respectively. An index provides labels and dimensions for doors, windows, and ventilators used in the plan.
Internship front pages (3 files merged)tp jayamohan
This report summarizes the internship of the author at a construction site in South Kalamassery, Ernakulam. The five-day internship involved observing the reinforcement and concreting of the basement slab, and formwork of retaining walls. The project site is a five-story residential and commercial building. On the first day, reinforcement was placed for the basement slab. On the second day, the basement slab was concreted. The last two days focused on the formwork of retaining walls. The report also discusses soil testing, foundation design using a reinforced concrete raft, and concrete mixing and placement.
1. Water resources are essential for development but face increasing challenges from climate change, demand, and sedimentation. Reservoirs constructed on rivers are prone to sedimentation over time, reducing their storage capacity.
2. Sedimentation in reservoirs occurs as sediment particles from the watershed settle in the reservoir due to decreased flow speeds. This reduces the reservoir's storage potential and can impact downstream soil fertility and biodiversity. Assessing sedimentation is important for reservoir management.
3. Remote sensing techniques provide an alternative method for assessing reservoir sedimentation that is more expedient and efficient than traditional surveys. Satellite imagery can be used to measure changes in reservoir water spreads at different elevations over time, indicating loss of storage capacity
William John Macquorn Rankine, (born July 5, 1820, Edinburgh, Scot.—died Dec. 24, 1872, Glasgow), Scottish engineer and physicist and one of the founders of the science of thermodynamics, particularly in reference to steam-engine theory.
Trained as a civil engineer under Sir John Benjamin MacNeill, Rankine was appointed to the Queen Victoria chair of civil engineering and mechanics at the University of Glasgow (1855). One of Rankine’s first scientific works, a paper on fatigue in metals of railway axles (1843), led to new methods of construction. His Manual of Applied Mechanics (1858) was of considerable help to designing engineers and architects. His classic Manual of the Steam Engine and Other Prime Movers (1859) was the first attempt at a systematic treatment of steam-engine theory. Rankine worked out a thermodynamic cycle of events (the so-called Rankine cycle) used as a standard for the performance of steam-power installations in which a condensable vapour provides the working fluid.
William John Macquorn Rankine, (born July 5, 1820, Edinburgh, Scot.—died Dec. 24, 1872, Glasgow), Scottish engineer and physicist and one of the founders of the science of thermodynamics, particularly in reference to steam-engine theory.
Trained as a civil engineer under Sir John Benjamin MacNeill, Rankine was appointed to the Queen Victoria chair of civil engineering and mechanics at the University of Glasgow (1855). One of Rankine’s first scientific works, a paper on fatigue in metals of railway axles (1843), led to new methods of construction. His Manual of Applied Mechanics (1858) was of considerable help to designing engineers and architects. His classic Manual of the Steam Engine and Other Prime Movers (1859) was the first attempt at a systematic treatment of steam-engine theory. Rankine worked out a thermodynamic cycle of events (the so-called Rankine cycle) used as a standard for the performance of steam-power installations in which a condensable vapour provides the working fluid.
Utilization of jarosite generated from leadtp jayamohan
Large quantities of industrial waste by-products are produced in India by different type of industries viz. Jarosite, Jarofix, Copper slag, Zinc slag, Red mud, Steel slag and Coal ash. For many years these materials were considered as waste and were dumped haphazardly near the producing plants. Efforts are being carried out by research studies to utilize these materials in embankment, sub base and base layers of road construction. Experimental studies have been also carried out to investigate their feasibility as an additive in cement concrete. Jarosite material is produced during extraction of zinc ore concentrate by hydrometallurgy operation. When zinc ore concentrate is roasted at 9000 C and subjected to leaching, Jarosite is formed as a waste material. The Jarosite material is mixed with 2 % lime and 10 % cement and transported to the disposal area as a Jarofix material.
Tall structures are ;
Flexible, low in damping, slender and light in weight.
Sensitive to dynamic wind loads.
Adversely affect the serviceability and occupant comfort.
Oscillations are observed in the along-wind and crosswind directions and in torsional mode.
Behaviour of wind response is largely determined by building shapes.
Aerodynamic optimization of building shapes is the most efficient way to achieve wind resistant design.
In ancient China, tall buildings appear to be those of traditional pagodas.
Abrasive jet micro-machining (AJM), in which abrasive parti-cles are accelerated by air and directed toward a target, has beenused to make components for micro-electromechanical (MEMS) and micro-fluidic capillary electrophoresis devices . One ofthe disadvantages of AJM is that the compressed air jet used topropel the erodent particles diverges significantly after the noz-zle exit, increasing the size of the blast zone and the width of thesmallest channel or hole that can be machined without the use of a patterned erosion-resistant mask that defines the micro-featureedges . Abrasive slurry jet micro-machining (ASJM) is similar to AJM except that pressurized water, instead of air, is used to accel-erate the suspended abrasive particles such as garnet or alumina(Al2O3). In both AJM and ASJM, the material removal occurs by ero-sion. However, for the same jet dimension and flow speed, slurryjets have a much lower divergence angle than air jets , allow-ing for the micro-machining of small features without the use ofpatterned masks.
This document discusses a novel direct-injection system for 2-stroke engines that uses LPG as fuel. It aims to increase fuel efficiency by reducing fuel spillage and fresh charge losses. CFD simulations analyze different injector positions and their effects. Graphs of mass flow rate and combustion chamber pressure show the best position is at the transfer port. Emission levels are also studied and compared to a conventional engine. The ignition system is recommended to use a fast-response inductive ignition to suit the direct-injection setup, though it can still work with the existing ignition.
This document discusses dynamic analysis of soil structure interaction on gravity dams. It first provides background on dynamic analysis and how the behavior of dams is influenced by foundation conditions. It then reviews literature showing that considering soil stiffness, mass, and soil-structure interaction leads to higher displacements and stresses in dams compared to models without these factors. The document outlines a methodology to model different soil types, analyze soil-structure interaction, and conduct dynamic analysis. It provides a time schedule and expected outcomes of discovering displacement based on soil-structure interaction and seismic response of the structure. Finally, it lists references on this topic.
• Considering soil-structure interaction makes a structure more flexible and thus, increasing the natural period of the structure compared to the corresponding rigidly supported structure
Introduction- e - waste – definition - sources of e-waste– hazardous substances in e-waste - effects of e-waste on environment and human health- need for e-waste management– e-waste handling rules - waste minimization techniques for managing e-waste – recycling of e-waste - disposal treatment methods of e- waste – mechanism of extraction of precious metal from leaching solution-global Scenario of E-waste – E-waste in India- case studies.
Discover the latest insights on Data Driven Maintenance with our comprehensive webinar presentation. Learn about traditional maintenance challenges, the right approach to utilizing data, and the benefits of adopting a Data Driven Maintenance strategy. Explore real-world examples, industry best practices, and innovative solutions like FMECA and the D3M model. This presentation, led by expert Jules Oudmans, is essential for asset owners looking to optimize their maintenance processes and leverage digital technologies for improved efficiency and performance. Download now to stay ahead in the evolving maintenance landscape.
Rainfall intensity duration frequency curve statistical analysis and modeling...bijceesjournal
Using data from 41 years in Patna’ India’ the study’s goal is to analyze the trends of how often it rains on a weekly, seasonal, and annual basis (1981−2020). First, utilizing the intensity-duration-frequency (IDF) curve and the relationship by statistically analyzing rainfall’ the historical rainfall data set for Patna’ India’ during a 41 year period (1981−2020), was evaluated for its quality. Changes in the hydrologic cycle as a result of increased greenhouse gas emissions are expected to induce variations in the intensity, length, and frequency of precipitation events. One strategy to lessen vulnerability is to quantify probable changes and adapt to them. Techniques such as log-normal, normal, and Gumbel are used (EV-I). Distributions were created with durations of 1, 2, 3, 6, and 24 h and return times of 2, 5, 10, 25, and 100 years. There were also mathematical correlations discovered between rainfall and recurrence interval.
Findings: Based on findings, the Gumbel approach produced the highest intensity values, whereas the other approaches produced values that were close to each other. The data indicates that 461.9 mm of rain fell during the monsoon season’s 301st week. However, it was found that the 29th week had the greatest average rainfall, 92.6 mm. With 952.6 mm on average, the monsoon season saw the highest rainfall. Calculations revealed that the yearly rainfall averaged 1171.1 mm. Using Weibull’s method, the study was subsequently expanded to examine rainfall distribution at different recurrence intervals of 2, 5, 10, and 25 years. Rainfall and recurrence interval mathematical correlations were also developed. Further regression analysis revealed that short wave irrigation, wind direction, wind speed, pressure, relative humidity, and temperature all had a substantial influence on rainfall.
Originality and value: The results of the rainfall IDF curves can provide useful information to policymakers in making appropriate decisions in managing and minimizing floods in the study area.
Advanced control scheme of doubly fed induction generator for wind turbine us...IJECEIAES
This paper describes a speed control device for generating electrical energy on an electricity network based on the doubly fed induction generator (DFIG) used for wind power conversion systems. At first, a double-fed induction generator model was constructed. A control law is formulated to govern the flow of energy between the stator of a DFIG and the energy network using three types of controllers: proportional integral (PI), sliding mode controller (SMC) and second order sliding mode controller (SOSMC). Their different results in terms of power reference tracking, reaction to unexpected speed fluctuations, sensitivity to perturbations, and resilience against machine parameter alterations are compared. MATLAB/Simulink was used to conduct the simulations for the preceding study. Multiple simulations have shown very satisfying results, and the investigations demonstrate the efficacy and power-enhancing capabilities of the suggested control system.
1. DEPT. OF MECHANICAL ENGINEERING 1
CHAPTER 1
INTRODUCTION
Abrasive jet micro-machining (AJM), in which abrasive particles are accelerated by
air and directed toward a target, has been used to make components for micro-electro-
mechanical (MEMS) and micro-fluidic capillary electrophoresis devices. One of the
disadvantages of AJM is that the compressed air jet used to propel the erodent particles
diverges significantly after the nozzle exit, increasing the size of the blast zone and the width
of the smallest channel or hole that can be machined without the use of a patterned erosion-
resistant mask that defines the micro-feature edges. Abrasive slurry jet micro-machining
(ASJM) is similar to AJM except that pressurized water, instead of air, is used to accelerate
the suspended abrasive particles such as garnet or alumina (Al2O3). In both AJM and ASJM,
the material removal occurs by erosion. However, for the same jet dimension and low speed,
slurry jets have a much lower divergence angle than air jets, allowing for the micro-
machining of small features without the use of patterned masks.
High pressure ASJM was investigated by Miller, who demonstrated its use for the
cutting of micro-slots at 70 MPa through the thickness of thin sheets of metals, glass,
ceramics, and polymer sand composite materials. Further studies demonstrated that relatively
low pressure ASJM (214 MPa) is a practical process not only for cutting, but also for the
milling or etching of materials. Using dimensional analysis and multi-variable regression of
experimental data, Pang et al. modelled the erosion rate, opening width and wall slope of
machined channels in glass. They found that the channels suffered from waviness due to the
mechanical vibration of the equipment. The roughness of micro-channels can affect fluid low
phenomena such as electro-osmotic mobility, separation efficiency and solute dispersion in
micro-fluidic applications, which makes it essential to develop models in order to predict the
roughness of micro-channels for a variety of machining conditions.
2. DEPT. OF MECHANICAL ENGINEERING 2
CHAPTER 2
LITERATURE SURVEY
Miller [2004], who demonstrated high pressure ASJM for the cutting of micro-slots
at 70 MPa through the thickness of thin sheets of metals, ceramics composite materials.
Jafar [2013], developed a numerical model to simulate the brittle erosion process in
AJM and predict the steady-state roughness and erosion rate of channels in borosilicate glass.
3. DEPT. OF MECHANICAL ENGINEERING 3
CHAPTER 3
OBJECTIVES
The aim of the present paper was to develop a model to predict the roughness and
erosion rate of unmasked channels machined with abrasive liquid slurry jets in borosilicate
glass. The models that were previously developed for abrasive air-jet machining formed the
starting point for the work.
4. DEPT. OF MECHANICAL ENGINEERING 4
CHAPTER 4
METHODOLOGY
4.1 EXPERIMENTAL SETUP
All the experiments were conducted using the low-pressure ASJM system, which is
capable of micro-machining channels and holes with a high degree of repeat-ability and a low
waviness. As shown in Fig. 1, the main components of the system are an open-reservoir
slurry mixing tank, a positive displacement slurry pump with pulsation damper, a 180
sapphire orifice, and a computer controlled linear stage to control movement of the target
relative to the stationary nozzle. The linear stage was capable of speeds up to 7 mm/s with a
step size of 0.047 producing a smooth, repeatable motion. For all experiments, the orifice to
target standoff distance, do, along the orifice centre-line was maintained constant at 20 mm,
and 25 percentage nominal diameter alumina (Al2O3) particles were mixed with water at
various concentrations to form the slurry.
Fig. 4.1: Schematic of the abrasive slurry jet apparatus
All micro-machining was conducted on 100 mm 50 mm 3 mm thick borosilicate glass
plates having a Young’s modulus (E) of 63 GPa, Poisson’s ratio of 0.2, fracture toughness
(Kc) of 0.76 MPa, and a Vickers hardness (H) of 5.4 GPa. Straight, unmasked channels were
machined at various nozzle pressures, P, using two targets traverse speeds, versus and six jet
5. DEPT. OF MECHANICAL ENGINEERING 5
impact angles, (Fig. 2) at each pressure, as shown in Table 4.1. The orifice discharge
coefficient (ratio of the actual mass low rate at the orifice exit to that of an ideal orifice) was
measured to be 0.60 0.03 which reduced the actual jet diameter to 140.Table 4.2 gives the
measured jet low rates and the calculated velocities used in the channel machining and single
impact experiments.
Fig. 4.2: Schematic of jet orientation during erosion rate measurements
Table 4.1: Process parameters used in the machining of the channels and the single impact
experiment.
PARAMETERS CHANNEL MACHINING SINGLE IMPACT
EXPERIMENT
Pressure, P (MPa) 6.1,4.7,3.6,3.0,2.6,2.1 4.7
Traverse speed, vs (mm/s) 0.2,0.3 3.5
Mixing tank particle
concentration, C (wt%)
0.25 0.01
Jet Impact angle, θ (deg) 15,30,45,60,75,90 90
Table 4.2: Slurry flow rate and jet velocities based on the applied pressure.
PARAMETERS CHANNEL MACHINING SINGLE IMPACT
EXPERIMENT
Pressure, P (MPa) 6.1,4.7,3.6,3.0,2.6,2.1 4.7
Slurry flow rate, Q (mL/s) 1.7,1.5,1.3,1.2,1.1,1.0 1.5
Jet velocity, vf (m/s) 110,96,89,78,72,65 97
6. DEPT. OF MECHANICAL ENGINEERING 6
CHAPTER 5
RESULTS AND DISCUSSIONS
5.1 SINGLE IMPACT EXPERIMENTS AT 90 DEGREE
Individual craters on borosilicate glass after blasting 25 mu particles at P= 4.7 MPa
and 90 Degree incidence using a scanning speed of 3.5 mm/s and a low slurry particle
concentration of 0.01 wt Percentage is shown in the figure given below.
Fig. 5.1: Individual craters on borosilicate glass
An area of 0.5 mm X 2 mm of the surface subjected to sparse single impacts at a
pressure of 4.7 MPa (Table 1) was scanned using the optical profilometer, and 986 craters
were counted and measured within the scanned area, implying that about 40 Percentage of the
incoming particles damaged the target. Fig. 9 illustrates a typical 3D scan of the surface after
the single particle impact tests. The shapes of the craters were similar to those found using air
jets, suggesting that brittle erosion was also the dominant damage mechanism in the slurry
jet. Based on the theoretical threshold (38.8 nJ), 28 Percentage of the particles in the
distribution should have initiated lateral cracks in target, while if the lower apparent threshold
7. DEPT. OF MECHANICAL ENGINEERING 7
based on Wensinks work was used (19.4 nJ), the percentage increased to 58Percentage.
Therefore, these two estimates of the fraction of incident particles with sufficient energy to
generate craters bound the measured value of 40 percentages.
5.2 OBLIQUE BLASTING
Measured channel centreline roughness and erosion rate of borosilicate glass as a
function of impact angle at P = 4.7 MPa as shown in the below figure. The error bars show
the absolute range of the data over three measurements.
Fig.5.2: Measured channel centreline roughness and erosion rate of borosilicate glass
The above Fig. 5.2 shows the measured erosion rates and average roughness for P =
4.7 MPa and the experimental conditions given in Table 1. It is seen that the erosion rate
increased with the nominal impact angle (angle of the free jet relative to the target),
exhibiting a maximum at 90, which is characteristic of brittle erosion Similar trends were
found for the other pressures and conditions in Table 1. Increases in the impact angle resulted
in higher normal impact forces, leading to larger chips being removed, and ultimately higher
erosion rates and rougher channels.
8. DEPT. OF MECHANICAL ENGINEERING 8
5.3 COMPARISON OF THE ANALYTICAL MODELS
The comparison of the analytical models with the experiments is as
follows:
5.3.1 COMPARISON OF THE ANALYTICAL MODELS WITH SURFACE
ROUGHNESS AT NORMAL INCIDENCE
The below Fig. 5.3 shows the measured roughness of the ASJM channels as a
function of the incident effective average particle kinetic energy at normal incidence rougher
channels were produced when particles of higher average normal kinetic energy impacted the
surface, since they produced larger chips. The middle solid line in Fig. 5.3 shows the least-
squares power law _t of the experimental data for all the conditions of Table 1 (Ra =
0.43U0.20 with a coefficient of determination (Square of R) of 0.97) and the dashed line is
the equivalent trend line through the AJM experimental data of (Ra = 0.42U0.20 where U is
in nJ). U for the AJM data trend line was found using the average particle size and average
velocity of all particles in the jet, since the kinetic energy of all the particles was above the
apparent threshold. The difference between these two trend lines is only 2 Percentage,
confirming that, despite the differences in particle trajectories and ow patterns between
ASJM and AJM, the resulting roughness was governed only by the normal kinetic energy of
the incident particles above the threshold for lateral cracking, as was found for AJM. Fig. 5.3
also shows that the analytical model I overestimated the roughness with an average
error of 122 Percentage, but that model II, which assumed crack initiation at a depth.
a, resulted in a better agreement with the measured Ra, underestimating with an average error
of 42 Percentage over the entire range of studied kinetic energies. As discussed in the context
of AJM, this underestimation was likely due to the assumption of the crater depth a used in
the model. Although the measured crater depth was indeed closer to location a than b, it was
nevertheless about 22 Percentage larger than the measured indentation depth. Increasing a by
22 Percentage in model II increased the roughness (not shown in Fig.5.3) and lowered the
average error in the predicted roughness to 17 Percentage.
9. DEPT. OF MECHANICAL ENGINEERING 9
Fig. 5.3: Measured steady-state roughness of borosilicate glass channels machined using
ASJM compared to predictions of the analytical models
5.3.2 EROSION RATE AT NORMAL INCIDENCE
The below figure 5.4 shows that, as expected, the erosion rate increased with
increasing Ueff. As with the roughness predictions, model II agreed better with the data than
model I, having an average error of 41 Percentage compared with 232 Percentage for model
I. Just as with the underestimate of roughness, model II underestimated the erosion rate,
probably because the predicted crater depth was too small. For example, increasing the crater
depth a by 22 Percentage in model II to match the experimental measurements, reduced the
average error in the predicted erosion rate to 12 Percentage.
10. DEPT. OF MECHANICAL ENGINEERING 10
Fig. 5.4: Erosion rate of borosilicate glass as a function of average effective particle and
normal kinetic energy
5.3.3 OBLIQUE BLASTING RESULTS
The experimental data are reproduced from Fig. 5.1 and the predictions at 90 degree
are reproduced from Figs. 5.3 and 5.4. The predictions at 30 Degree and 60 degree were very
similar to those at 90 Degree (Figs. 5.3 and 5.4) in that model I overestimated the roughness
and erosion rate while model II underestimated those parameters although with a lower
average error. The errors in roughness prediction for 30 Degree and 60 Degree were 49
Percentage and 41 Percentage in Model I and 101 Percentage and 126 Percentage in Model
II, respectively. Similarly, the errors pertaining to the predictions of erosion rate for 30
Degree and 60 Degree were 48 Percentage and 27 Percentage in Model I and 292 Percentage
and 231 Percentage in Model II, respectively.
11. DEPT. OF MECHANICAL ENGINEERING 11
Fig. 5.5: Measured and predicted centreline channel roughness and (b) erosion rate of
borosilicate glass
5.3.4 CFD MODEL RESULTS
The CFD models were validated by comparing with published experimental data for
the velocity of free water jets and the pressure distribution on a target surface under an
impacting jet. In all cases, the agreement was very good. The CFD model was executed for
30 Degree and 90 Degree global impact angles, and in each case, separate simulations were
conducted over the range of applied pressures (e.g. 2.1, 2.6, 3.1, 3.6, 4.7 and 6.1 MPa). Fig.
5.6 and 5.7 illustrate the water velocity and particle trajectories distributions close to the
target in the 90 Degree orientation for 25 mu meter particle at a jet velocity of 89 m/s (i.e. P =
3.6 MPa, Table 4.2). Particle and fluid velocities were equal from the inlet of the domain to
within 1 mm of the target wall, where the stagnation zone quickly decreased the particle
velocity. The 25 mu meter particles, regardless of their position in the jet, impacted the target,
rebounded, were entrained by the lateral low parallel to the target and carried away from the
jet footprint. The variation of the drag force within the stagnation zone caused the particle
impact velocity and angle to be 49 m/s and 90 Degree at the centre of the jet, and 55 m/s and
43 Degree at the edge of the jet, as shown in Fig. 5.6. When applied to the present situation,
the analysis of Humphrey predicts such behaviour for most particles that are less than
approximately 10 mu meter in diameter. An increase in the viscosity of the slurry would
12. DEPT. OF MECHANICAL ENGINEERING 12
increase the momentum equilibration number, as defined by Humphrey, causing a greater
tendency for particles to follow the streamlines. This in turn would decrease the local impact
angle at the bottom of the channel and reduce the amount of erosion. The erosion rate would
also be decreased by the greater drag on particles in the stagnation zone. It was observed that
10 Percentage increase in the slurry viscosity (by adding glycerine to water) resulted in 19
Percentage reductions in channel depth.
Fig.5.6: Slurry jet velocity distribution at 90 Degree
Fig. 5.7: Slurry jet velocity distribution at 30 Degree
The above Fig. 5.7 shows that in the case of oblique jet blasting (less than 90 Degree), the
stagnation zone (i.e. the region where the velocity of the water was less than 10 Percentage of
the incident jet velocity) shifted away from the centreline of the jet. This contributed to an
13. DEPT. OF MECHANICAL ENGINEERING 13
asymmetric variation of the drag force that decelerated the incoming particles prior to impact.
Accordingly, the particle impact velocities varied significantly along the jet footprint. Table
4.3 gives the normal impact velocity ranges and their averages for the different particle sizes
at global impact angles of 30 Degree and 60 Degree.
Table 5.1: CFD predictions of the normal component of impact velocity for particles
PARTICLE
SIZE (µM)
IMPACT
ANGLE
(DEG)
NORMAL
IMPACT
VELOCITY
RANGE (M/S)
AVERAGE
NORMAL
IMPACT
VELOCITY
(M/S)
AVERAGE
NORMAL
KINETIC
ENERGY (NJ)
25 30 26-42 37 22
25 60 17-49 39 24
30 30 27-43 39 42
30 60 22-49 41 46
35 30 27-44 40 70
35 60 27-50 43 81
40 30 29-45 41 110
40 60 28-51 45 130
45 30 30-47 42 160
45 60 30-53 47 200
The above table shows the CFD predictions of the normal component of impact
velocity of the particles.
14. DEPT. OF MECHANICAL ENGINEERING 14
CHAPTER 6
CONCLUSION
The roughness and erosion rate of ASJM channels in borosilicate glass were measured
and predicted using existing analytical and numerical models developed for the AJM of
brittle materials. A brittle erosion mechanism was confirmed using an analysis of single
impact sites obtained with a dilute slurry at a high scan speed, and from the measurements of
erosion rate versus angle of the incident slurry jet. The presence of water was found to have a
negligible effect on the formation of chips in borosilicate glass. As with AJM, the particle
kinetic energy due to the normal component of the velocity was the only parameter which
governed the roughness and erosion rate. Slurry jets of higher normal kinetic energy
produced deeper and rougher channels, since they generated greater damage on the target and
removed larger chips from the surface. Decreasing the impact angle (reducing the normal
impact force on the target) resulted in a smoother channel and lower erosion rates, as
expected. As compared to AJM, ASJM Micro machining is faster and simple. Therefore
ASJM is used in machining of metals, glass, ceramics, laboratory instruments etc
15. DEPT. OF MECHANICAL ENGINEERING 15
REFERENCES
[1] Jafar RHM, Papini M, Spelt JK. ‘Simulation of erosive smoothing in abrasive jet
micro-machining of glass’- J Mater Process Technol (2013).
[2] N, Getu H, Sadeghian A, Papini M. ‘Computer simulation of developing abrasive jet
machined pro_les including particle interference’- J Mater Process Technol (2009).
[3] Miller DS. ‘Micro-machining with abrasive water jets’ -J MaterProcess Technol
(2004).
[4] E, Thurre S, Walchiers E, Sayah A, Gijs MAM. ‘The introduction of powder blasting for
sensor and micro system applications’ -Sens Actuators (2000)
[5] Humphrey J. ‘Fundamentals of uid motion in erosion by solid particle impact’- Int J Heat
Fluid Flow (1990)