This document describes a structural optimization of an S-type load cell design using a multi-objective optimization technique that incorporates reliability analysis. A reliability-related multi-factor optimization model is formulated to minimize stress, displacement, mass, and maximize reliability under a single loading case. Finite element analysis is used to model an initial S-type load cell design and evaluate structural responses. Parameter and case performance indices are developed to quantitatively evaluate and compare different load cell designs. The optimization aims to improve the overall performance index by varying design variables like width, height, and thickness to satisfy multiple objectives.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
Power system state estimation using teaching learning-based optimization algo...TELKOMNIKA JOURNAL
The main goal of this paper is to formulate power system state estimation (SE) problem as a constrained nonlinear programming problem with various constraints and boundary limits on the state variables. SE forms the heart of entire real time control of any power system. In real time environment, the state estimator consists of various modules like observability analysis, network topology processing, SE and bad data processing. The SE problem formulated in this work is solved using teaching leaning-based optimization (TLBO) technique. Difference between the proposed TLBO and the conventional optimization algorithms is that TLBO gives global optimum solution for the present problem. To show the suitability of TLBO for solving SE problem, IEEE 14 bus test system has been selected in this work. The results obtained with TLBO are also compared with conventional weighted least square (WLS) technique and evolutionary based particle swarm optimization (PSO) technique.
Electronics system thermal management optimization using finite element and N...TELKOMNIKA JOURNAL
The demand for high-performance, smaller-sized, and multi-functional electronics component
poses a great challenge to the thermal management issues in a printed circuit board (PCB)
design. Moreover, this thermal problem can affect the lifespan, performance, and the reliability of
the electronic system. This project presents the simulation of an optimal thermal distribution for various
samples of electronics components arrangement on PCB. The objectives are to find the optimum
components arrangement with minimal heat dissipation and cover small PCB area. Nelder-Mead
Optimization (NMO) with Finite Element method has been used to solve these multi-objective problems.
The results show that with the proper arrangement of electronics components, the area of PCB has been
reduced by 26% while the temperature of components is able to reduce up to 40%. Therefore, this study
significantly benefits for the case of thermal management and performance improvement onto the electronic
product and system.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
Power system state estimation using teaching learning-based optimization algo...TELKOMNIKA JOURNAL
The main goal of this paper is to formulate power system state estimation (SE) problem as a constrained nonlinear programming problem with various constraints and boundary limits on the state variables. SE forms the heart of entire real time control of any power system. In real time environment, the state estimator consists of various modules like observability analysis, network topology processing, SE and bad data processing. The SE problem formulated in this work is solved using teaching leaning-based optimization (TLBO) technique. Difference between the proposed TLBO and the conventional optimization algorithms is that TLBO gives global optimum solution for the present problem. To show the suitability of TLBO for solving SE problem, IEEE 14 bus test system has been selected in this work. The results obtained with TLBO are also compared with conventional weighted least square (WLS) technique and evolutionary based particle swarm optimization (PSO) technique.
Electronics system thermal management optimization using finite element and N...TELKOMNIKA JOURNAL
The demand for high-performance, smaller-sized, and multi-functional electronics component
poses a great challenge to the thermal management issues in a printed circuit board (PCB)
design. Moreover, this thermal problem can affect the lifespan, performance, and the reliability of
the electronic system. This project presents the simulation of an optimal thermal distribution for various
samples of electronics components arrangement on PCB. The objectives are to find the optimum
components arrangement with minimal heat dissipation and cover small PCB area. Nelder-Mead
Optimization (NMO) with Finite Element method has been used to solve these multi-objective problems.
The results show that with the proper arrangement of electronics components, the area of PCB has been
reduced by 26% while the temperature of components is able to reduce up to 40%. Therefore, this study
significantly benefits for the case of thermal management and performance improvement onto the electronic
product and system.
The article presents a new method of the optimal design of the electrical rotating machine based on the genetic algorithm which can used for all electrical rotating machine types and to predict their properties. The new method for optimal design allows obtaining the new electrical rotating machine which mass is lower than mass of the conventional electrical rotating machine by two times. As the result of optimal electrical rotating machine design by using the proposed method, the value of the rotor active length is lower by 2.37 times, and the current density is higher by 1.7 times in comparison with the initial electrical rotating machine. The losses are increased by only 25% (power, rotation and materials frequency of both electrical rotating machine are the same). It was also found that the optimality of a particular design scheme, including the rotor magnetic system or the groove type depends on the complex of sizes. Moreover, the change of this complex leads to a change in the optimum design scheme.
Applying of Double Seasonal ARIMA Model for Electrical Power Demand Forecasti...IJECEIAES
The prediction of the use of electric power is very important to maintain a balance between the supply and demand of electric power in the power generation system. Due to a fluctuating of electrical power demand in the electricity load center, an accurate forecasting method is required to maintain the efficiency and reliability of power generation system continuously. Such conditions greatly affect the dynamic stability of power generation systems. The objective of this research is to propose Double Seasonal Autoregressive Integrated Moving Average (DSARIMA) to predict electricity load. Half hourly load data for of three years period at PT. PLN Gresik Indonesia power plant unit are used as case study. The parameters of DSARIMA model are estimated by using least squares method. The result shows that the best model to predict these data is subset DSARIMA with order ( [ 1,2,7,16,18,35,46 ] , 1, [ 1,3,13,21,27,46 ] )( 1,1,1 ) 48 ( 0,0,1 ) 336 with MAPE about 2.06%. Thus, future research could be done by using these predictive results as models of optimal control parameters on the power system side.
Optimization of Surface Roughness Index for a Roller Burnishing Process Using...paperpublications3
Abstract: The main objective of this dissertation is to optimize the roughness index for a roller burnishing process. The factors have been identified from literature review. These barriers may be of market, cultural, human resource.management, financial, economical, attitudinal, environmental, geographical and technological type. Technology transfer barriers threats the movement of physical structure, knowledge, skills, organization value and capital from the developed to developing countries. Clear understanding of these barriers may help the practitioners to find out various ways to deal with them. This may further facilitate successful implementation of technology transfer. Technology transfer may be said to be successful if Transferor (seller) and the transferee (buyer) can effectively utilize the technology for business gain. The transfer involves cost and expenditure that should be agreed by the transferee and transferor. The process is affected by various factors that hinder Technology Transfer. These factors named Barriers. In the present work, Interpretive Structure Modeling (ISM) is used for the analysis and comparison of various factors important for Technology Transfer. The important parameters are identified and self-interaction matrixes proposed with the help of Interpretive Structure Modeling which evaluates the inhibiting power of these parameters. This index can be used in comparison of different factors responsible for Roller Burnishing Processes.
Multi Area Economic Dispatch Using Secant Method and Tie Line MatrixIJAPEJOURNAL
In this paper, Secant method and tie line matrix are proposed to solve multi area economic dispatch (MAED) problem with tie line loss. Generator limits of all generators in each area are calculated at given area power demands plus export (or import) using secant method and the generator limits of all generators are modified as modified generator limits. Central economic dispatch (CED) problem is used to determine the output powers of all generators and finally power flows in all tie lines are determined from tie line matrix. Here, Secant method is applied to solve the CED problem. A modified tie line matrix is used to find power flow in each tie line and then tie line loss is calculated from the power flow in each tie line. The proposed approach has been tested on two-area (two generators in each area) system and four-area (four generators in each area) system. It is observed from various cases that the proposed approach provides optimally best solution in terms of cost with tie line loss with less computational burden.
Power System Reliability Assessment in a Complex Restructured Power SystemIJECEIAES
The basic purpose of an electric power system is to supply its consumers with electric energy as parsimoniously as possible and with a sensible degree of continuity and quality. It is expected that the solicitation of power system reliability assessment in bulk power systems will continue to increase in the future especially in the newly deregulated power diligence. This paper presents the research conducted on the three areas of incorporating multi-state generating unit models, evaluating system performance indices and identifying transmission paucities in complex system adequacy assessment. The incentives for electricity market participants to endow in new generation and transmission facilities are highly influenced by the market risk in a complex restructured environment. This paper also presents a procedure to identify transmission deficiencies and remedial modification in the composite generation and transmission system and focused on the application of probabilistic techniques in composite system adequacy assessment
This paper presents the implementation of multiple distributed generations planning in distribution system using computational intelligence technique. A pre-developed computational intelligence optimization technique named as Embedded Meta EP-Firefly Algorithm (EMEFA) was utilized to determine distribution loss and penetration level for the purpose of distributed generation (DG) installation. In this study, the Artificial Neural Network (ANN) was used in order to solve the complexity of the multiple DG concepts. EMEFA-ANN was developed to optimize the weight of the ANN to minimize the mean squared error. The proposed method was validated on IEEE 69 Bus distribution system with several load variations scenario. The case study was conducted based on the multiple unit of DG in distribution system by considering the DGs are modeled as type I which is capable of injecting real power. Results obtained from the study could be utilized by the utility and energy commission for loss reduction scheme in distribution system.
Optimum reactive power compensation for distribution system using dolphin alg...IJECEIAES
The distribution system represents the connection between the consumers and entire power network. The radial structure is preferred for distribution system due to its simple design and low cost. It suffers from problems of rising power losses higher than the transmission system and voltage drop. One of the important solutions to evolve the system voltage profile and to lower system losses is the reactive power compensation which is based on the optimum choice of position and capacitor size in the network. Different models of loads such as constant power (P), constant current (I), constant impedance (Z), and composite (ZIP) are implemented with comparisons among them in order to identify the most effective load type that produces the optimal settlement for minimization loss reduction, voltage profile enhancement and cost savings. Dolphin Optimization Algorithm (DOA) is applied for selecting the sizes and locations of capacitors. Two case studies (IEEE 16-bus and 33-bus) are employed to evaluate the different load models with optimal reactive power compensation. The results show that ZIP model is the best to produce the optimal solution for capacitors position and sizes. Comparison of results with literature works shows that DOA is the most robust among the other algorithms.
Optimal Placement and Sizing of Distributed Generation Units Using Co-Evoluti...Radita Apriana
Today, with the increase of distributed generation sources in power systems, it’s important to
optimal location of these sources. Determine the number, location, size and type of distributed generation
(DG) on Power Systems, causes the reducing losses and improving reliability of the system. In this paper
is used Co-evolutionary particle swarm optimization algorithm (CPSO) to determine the optimal values of
the listed parameters. Obtained results through simulations are done in MATLAB software is presented in
the form of figure and table in this paper. These tables and figures, show how to changes the system
losses and improving reliability by changing parameters such as location, size, number and type of DG.
Finally, the results of this method are compared with the results of the Genetic algorithm (GA) method, to
determine the performance of each of these methods.
ASSESSMENT OF INTRICATE DG PLANNING WITH PRACTICAL LOAD MODELS BY USING PSO ecij
This paper presents the optimal sizing and placement of DG by assuming practical load models. The particle swarm optimization technique is used to minimize the multi-objective fitness function (MOFF). This MOFF has considered the performance indices such as a voltage difference index, active power loss index and reactive power loss index. Most of the studies have considered the constant load for distribution system planning which may mislead the exact assessment of the system performance. Thus the voltage dependency of load models is found in a highly demanding issue in updating researches. Keeping in view the urgent need of precise and flawless distribution system planning the effect of different load models on the total load, voltage profile, active and reactive power loss has been evaluated and presented in this paper. The efficacy of the proposed method has been executed by implementing it on the 33-bus radial test system.
SOLVING A MULTI-OBJECTIVE REACTIVE POWER MARKET CLEARING MODEL USING NSGA-IIijait
This paper presents an application of elitist non-dominated sorting genetic algorithm (NSGA-II) for solving a multi-objective reactive power market clearing (MO-RPMC) model. In this MO-RPMC model, two objective functions such as total payment function (TPF) for reactive power support from generators/synchronous condensers and voltage stability enhancement index (VSEI) are optimized
simultaneously while satisfying various system equality and inequality constraints in competitive electricity markets which forms a complex mixed integer nonlinear optimization problem with binary variables. The proposed NSGA-II based MO-RPMC model is tested on standard IEEE 24 bus reliability test system. The results obtained in NSGA-II based MO- RPMC model are also compared with the results obtained in real coded genetic algorithm (RCGA) based single-objective RPMC models.
The article presents a new method of the optimal design of the electrical rotating machine based on the genetic algorithm which can used for all electrical rotating machine types and to predict their properties. The new method for optimal design allows obtaining the new electrical rotating machine which mass is lower than mass of the conventional electrical rotating machine by two times. As the result of optimal electrical rotating machine design by using the proposed method, the value of the rotor active length is lower by 2.37 times, and the current density is higher by 1.7 times in comparison with the initial electrical rotating machine. The losses are increased by only 25% (power, rotation and materials frequency of both electrical rotating machine are the same). It was also found that the optimality of a particular design scheme, including the rotor magnetic system or the groove type depends on the complex of sizes. Moreover, the change of this complex leads to a change in the optimum design scheme.
Applying of Double Seasonal ARIMA Model for Electrical Power Demand Forecasti...IJECEIAES
The prediction of the use of electric power is very important to maintain a balance between the supply and demand of electric power in the power generation system. Due to a fluctuating of electrical power demand in the electricity load center, an accurate forecasting method is required to maintain the efficiency and reliability of power generation system continuously. Such conditions greatly affect the dynamic stability of power generation systems. The objective of this research is to propose Double Seasonal Autoregressive Integrated Moving Average (DSARIMA) to predict electricity load. Half hourly load data for of three years period at PT. PLN Gresik Indonesia power plant unit are used as case study. The parameters of DSARIMA model are estimated by using least squares method. The result shows that the best model to predict these data is subset DSARIMA with order ( [ 1,2,7,16,18,35,46 ] , 1, [ 1,3,13,21,27,46 ] )( 1,1,1 ) 48 ( 0,0,1 ) 336 with MAPE about 2.06%. Thus, future research could be done by using these predictive results as models of optimal control parameters on the power system side.
Optimization of Surface Roughness Index for a Roller Burnishing Process Using...paperpublications3
Abstract: The main objective of this dissertation is to optimize the roughness index for a roller burnishing process. The factors have been identified from literature review. These barriers may be of market, cultural, human resource.management, financial, economical, attitudinal, environmental, geographical and technological type. Technology transfer barriers threats the movement of physical structure, knowledge, skills, organization value and capital from the developed to developing countries. Clear understanding of these barriers may help the practitioners to find out various ways to deal with them. This may further facilitate successful implementation of technology transfer. Technology transfer may be said to be successful if Transferor (seller) and the transferee (buyer) can effectively utilize the technology for business gain. The transfer involves cost and expenditure that should be agreed by the transferee and transferor. The process is affected by various factors that hinder Technology Transfer. These factors named Barriers. In the present work, Interpretive Structure Modeling (ISM) is used for the analysis and comparison of various factors important for Technology Transfer. The important parameters are identified and self-interaction matrixes proposed with the help of Interpretive Structure Modeling which evaluates the inhibiting power of these parameters. This index can be used in comparison of different factors responsible for Roller Burnishing Processes.
Multi Area Economic Dispatch Using Secant Method and Tie Line MatrixIJAPEJOURNAL
In this paper, Secant method and tie line matrix are proposed to solve multi area economic dispatch (MAED) problem with tie line loss. Generator limits of all generators in each area are calculated at given area power demands plus export (or import) using secant method and the generator limits of all generators are modified as modified generator limits. Central economic dispatch (CED) problem is used to determine the output powers of all generators and finally power flows in all tie lines are determined from tie line matrix. Here, Secant method is applied to solve the CED problem. A modified tie line matrix is used to find power flow in each tie line and then tie line loss is calculated from the power flow in each tie line. The proposed approach has been tested on two-area (two generators in each area) system and four-area (four generators in each area) system. It is observed from various cases that the proposed approach provides optimally best solution in terms of cost with tie line loss with less computational burden.
Power System Reliability Assessment in a Complex Restructured Power SystemIJECEIAES
The basic purpose of an electric power system is to supply its consumers with electric energy as parsimoniously as possible and with a sensible degree of continuity and quality. It is expected that the solicitation of power system reliability assessment in bulk power systems will continue to increase in the future especially in the newly deregulated power diligence. This paper presents the research conducted on the three areas of incorporating multi-state generating unit models, evaluating system performance indices and identifying transmission paucities in complex system adequacy assessment. The incentives for electricity market participants to endow in new generation and transmission facilities are highly influenced by the market risk in a complex restructured environment. This paper also presents a procedure to identify transmission deficiencies and remedial modification in the composite generation and transmission system and focused on the application of probabilistic techniques in composite system adequacy assessment
This paper presents the implementation of multiple distributed generations planning in distribution system using computational intelligence technique. A pre-developed computational intelligence optimization technique named as Embedded Meta EP-Firefly Algorithm (EMEFA) was utilized to determine distribution loss and penetration level for the purpose of distributed generation (DG) installation. In this study, the Artificial Neural Network (ANN) was used in order to solve the complexity of the multiple DG concepts. EMEFA-ANN was developed to optimize the weight of the ANN to minimize the mean squared error. The proposed method was validated on IEEE 69 Bus distribution system with several load variations scenario. The case study was conducted based on the multiple unit of DG in distribution system by considering the DGs are modeled as type I which is capable of injecting real power. Results obtained from the study could be utilized by the utility and energy commission for loss reduction scheme in distribution system.
Optimum reactive power compensation for distribution system using dolphin alg...IJECEIAES
The distribution system represents the connection between the consumers and entire power network. The radial structure is preferred for distribution system due to its simple design and low cost. It suffers from problems of rising power losses higher than the transmission system and voltage drop. One of the important solutions to evolve the system voltage profile and to lower system losses is the reactive power compensation which is based on the optimum choice of position and capacitor size in the network. Different models of loads such as constant power (P), constant current (I), constant impedance (Z), and composite (ZIP) are implemented with comparisons among them in order to identify the most effective load type that produces the optimal settlement for minimization loss reduction, voltage profile enhancement and cost savings. Dolphin Optimization Algorithm (DOA) is applied for selecting the sizes and locations of capacitors. Two case studies (IEEE 16-bus and 33-bus) are employed to evaluate the different load models with optimal reactive power compensation. The results show that ZIP model is the best to produce the optimal solution for capacitors position and sizes. Comparison of results with literature works shows that DOA is the most robust among the other algorithms.
Optimal Placement and Sizing of Distributed Generation Units Using Co-Evoluti...Radita Apriana
Today, with the increase of distributed generation sources in power systems, it’s important to
optimal location of these sources. Determine the number, location, size and type of distributed generation
(DG) on Power Systems, causes the reducing losses and improving reliability of the system. In this paper
is used Co-evolutionary particle swarm optimization algorithm (CPSO) to determine the optimal values of
the listed parameters. Obtained results through simulations are done in MATLAB software is presented in
the form of figure and table in this paper. These tables and figures, show how to changes the system
losses and improving reliability by changing parameters such as location, size, number and type of DG.
Finally, the results of this method are compared with the results of the Genetic algorithm (GA) method, to
determine the performance of each of these methods.
ASSESSMENT OF INTRICATE DG PLANNING WITH PRACTICAL LOAD MODELS BY USING PSO ecij
This paper presents the optimal sizing and placement of DG by assuming practical load models. The particle swarm optimization technique is used to minimize the multi-objective fitness function (MOFF). This MOFF has considered the performance indices such as a voltage difference index, active power loss index and reactive power loss index. Most of the studies have considered the constant load for distribution system planning which may mislead the exact assessment of the system performance. Thus the voltage dependency of load models is found in a highly demanding issue in updating researches. Keeping in view the urgent need of precise and flawless distribution system planning the effect of different load models on the total load, voltage profile, active and reactive power loss has been evaluated and presented in this paper. The efficacy of the proposed method has been executed by implementing it on the 33-bus radial test system.
SOLVING A MULTI-OBJECTIVE REACTIVE POWER MARKET CLEARING MODEL USING NSGA-IIijait
This paper presents an application of elitist non-dominated sorting genetic algorithm (NSGA-II) for solving a multi-objective reactive power market clearing (MO-RPMC) model. In this MO-RPMC model, two objective functions such as total payment function (TPF) for reactive power support from generators/synchronous condensers and voltage stability enhancement index (VSEI) are optimized
simultaneously while satisfying various system equality and inequality constraints in competitive electricity markets which forms a complex mixed integer nonlinear optimization problem with binary variables. The proposed NSGA-II based MO-RPMC model is tested on standard IEEE 24 bus reliability test system. The results obtained in NSGA-II based MO- RPMC model are also compared with the results obtained in real coded genetic algorithm (RCGA) based single-objective RPMC models.
Tuning PID Controller Parameters for Load Frequency Control Considering Syste...IJERA Editor
In this paper, parameters of PID controller and bias coefficient for Load Frequency Control (LFC) are designed using a new approach. In the proposed method, the power system uncertainties and nonlinear limitations of governors and turbines ,i.e. Valve Speed Limit (VSL)and Generation Rate Constraint (GRC), are taken into account in designing. Variations of uncertain parameters are considered between -40% and +40% of nominal values with 5% step .In order to design the proposed PID controller ,a new objective function is defined. MATLAB codes are developed for GA based PID controller tuning, the results of which are used to study the system step response. All these are through in Simulink based background.
Software cost estimation is a key open issue for the software industry, which
suffers from cost overruns frequently. As the most popular technique for object-oriented
software cost estimation is Use Case Points (UCP) method, however, it has two major
drawbacks: the uncertainty of the cost factors and the abrupt classification. To address
these two issues, refined the use case complexity classification using fuzzy logic theory which
mitigate the uncertainty of cost factors and improve the accuracy of classification.
Software estimation is a crucial task in software engineering. Software estimation
encompasses cost, effort, schedule, and size. The importance of software estimation becomes
critical in the early stages of the software life cycle when the details of software have not
been revealed yet. Several commercial and non-commercial tools exist to estimate software
in the early stages. Most software effort estimation methods require software size as one of
the important metric inputs and consequently, software size estimation in the early stages
becomes essential.
The proposed method presents a techniques using fuzzy logic theory to improve the
accuracy of the use case points method by refining the use case classification.
Multi-Objective Optimization Based Design of High Efficiency DC-DC Switching ...IJPEDS-IAES
In this paper we explore the feasibility of applying multi objective stochastic
optimization algorithms to the optimal design of switching DC-DC
converters, in this way allowing the direct determination of the Pareto
optimal front of the problem. This approach provides the designer, at
affordable computational cost, a complete optimal set of choices, and a more
general insight in the objectives and parameters space, as compared to other
design procedures. As simple but significant study case we consider a low
power DC-DC hybrid control buck converter. Its optimal design is fully
analyzed basing on a Matlab public domain implementations for the
considered algorithms, the GODLIKE package implementing Genetic
Algorithm (GA), Particle Swarm Optimization (PSO) and Simulated
Annealing (SA). In this way, in a unique optimization environment, three
different optimization approaches are easily implemented and compared.
Basic assumptions for the Matlab model of the converter are briefly
discussed, and the optimal design choice is validated “a-posteriori” with
SPICE simulations.
Mechanical properties of hybrid fiber reinforced concrete for pavementseSAT Journals
Abstract
The effect of addition of mono fibers and hybrid fibers on the mechanical properties of concrete mixture is studied in the present
investigation. Steel fibers of 1% and polypropylene fibers 0.036% were added individually to the concrete mixture as mono fibers and
then they were added together to form a hybrid fiber reinforced concrete. Mechanical properties such as compressive, split tensile and
flexural strength were determined. The results show that hybrid fibers improve the compressive strength marginally as compared to
mono fibers. Whereas, hybridization improves split tensile strength and flexural strength noticeably.
Keywords:-Hybridization, mono fibers, steel fiber, polypropylene fiber, Improvement in mechanical properties.
Material management in construction – a case studyeSAT Journals
Abstract
The objective of the present study is to understand about all the problems occurring in the company because of improper application
of material management. In construction project operation, often there is a project cost variance in terms of the material, equipments,
manpower, subcontractor, overhead cost, and general condition. Material is the main component in construction projects. Therefore,
if the material management is not properly managed it will create a project cost variance. Project cost can be controlled by taking
corrective actions towards the cost variance. Therefore a methodology is used to diagnose and evaluate the procurement process
involved in material management and launch a continuous improvement was developed and applied. A thorough study was carried
out along with study of cases, surveys and interviews to professionals involved in this area. As a result, a methodology for diagnosis
and improvement was proposed and tested in selected projects. The results obtained show that the main problem of procurement is
related to schedule delays and lack of specified quality for the project. To prevent this situation it is often necessary to dedicate
important resources like money, personnel, time, etc. To monitor and control the process. A great potential for improvement was
detected if state of the art technologies such as, electronic mail, electronic data interchange (EDI), and analysis were applied to the
procurement process. These helped to eliminate the root causes for many types of problems that were detected.
Managing drought short term strategies in semi arid regions a case studyeSAT Journals
Abstract
Drought management needs multidisciplinary action. Interdisciplinary efforts among the experts in various fields of the droughts
prone areas are helpful to achieve tangible and permanent solution for this recurring problem. The Gulbarga district having the total
area around 16, 240 sq.km, and accounts 8.45 per cent of the Karnataka state area. The district has been situated with latitude 17º 19'
60" North and longitude of 76 º 49' 60" east. The district is situated entirely on the Deccan plateau positioned at a height of 300 to
750 m above MSL. Sub-tropical, semi-arid type is one among the drought prone districts of Karnataka State. The drought
management is very important for a district like Gulbarga. In this paper various short term strategies are discussed to mitigate the
drought condition in the district.
Keywords: Drought, South-West monsoon, Semi-Arid, Rainfall, Strategies etc.
Life cycle cost analysis of overlay for an urban road in bangaloreeSAT Journals
Abstract
Pavements are subjected to severe condition of stresses and weathering effects from the day they are constructed and opened to traffic
mainly due to its fatigue behavior and environmental effects. Therefore, pavement rehabilitation is one of the most important
components of entire road systems. This paper highlights the design of concrete pavement with added mono fibers like polypropylene,
steel and hybrid fibres for a widened portion of existing concrete pavement and various overlay alternatives for an existing
bituminous pavement in an urban road in Bangalore. Along with this, Life cycle cost analyses at these sections are done by Net
Present Value (NPV) method to identify the most feasible option. The results show that though the initial cost of construction of
concrete overlay is high, over a period of time it prove to be better than the bituminous overlay considering the whole life cycle cost.
The economic analysis also indicates that, out of the three fibre options, hybrid reinforced concrete would be economical without
compromising the performance of the pavement.
Keywords: - Fatigue, Life cycle cost analysis, Net Present Value method, Overlay, Rehabilitation
Laboratory studies of dense bituminous mixes ii with reclaimed asphalt materialseSAT Journals
Abstract
The issue of growing demand on our nation’s roadways over that past couple of decades, decreasing budgetary funds, and the need to
provide a safe, efficient, and cost effective roadway system has led to a dramatic increase in the need to rehabilitate our existing
pavements and the issue of building sustainable road infrastructure in India. With these emergency of the mentioned needs and this
are today’s burning issue and has become the purpose of the study.
In the present study, the samples of existing bituminous layer materials were collected from NH-48(Devahalli to Hassan) site.The
mixtures were designed by Marshall Method as per Asphalt institute (MS-II) at 20% and 30% Reclaimed Asphalt Pavement (RAP).
RAP material was blended with virgin aggregate such that all specimens tested for the, Dense Bituminous Macadam-II (DBM-II)
gradation as per Ministry of Roads, Transport, and Highways (MoRT&H) and cost analysis were carried out to know the economics.
Laboratory results and analysis showed the use of recycled materials showed significant variability in Marshall Stability, and the
variability increased with the increase in RAP content. The saving can be realized from utilization of recycled materials as per the
methodology, the reduction in the total cost is 19%, 30%, comparing with the virgin mixes.
Keywords: Reclaimed Asphalt Pavement, Marshall Stability, MS-II, Dense Bituminous Macadam-II
Laboratory investigation of expansive soil stabilized with natural inorganic ...eSAT Journals
Abstract
Soil stabilization has proven to be one of the oldest techniques to improve the soil properties. Literature review conducted revealed
that uses of natural inorganic stabilizers are found to be one of the best options for soil stabilization. In this regard an attempt has
been made to evaluate the influence of RBI-81 stabilizer on properties of black cotton soil through laboratory investigations. Black
cotton soil with varying percentages of RBI-81 viz., 0, 0.5, 1, 1.5, 2, and 2.5 percent were studied for moisture density relationships
and strength behaviour of soils. Also the effect of curing period was evaluated as literature review clearly emphasized the strength
gain of soils stabilized with RBI-81 over a period of time. The results obtained shows that the unconfined compressive strength of
specimens treated with RBI-81 increased approximately by 250% for a curing period of 28 days as compared to virgin soil. Further
the CBR value improved approximately by 400%. The studies indicated an increasing trend for soil strength behaviour with
increasing percentage of RBI-81 suggesting its potential applications in soil stabilization.
Influence of reinforcement on the behavior of hollow concrete block masonry p...eSAT Journals
Abstract
Reinforced masonry was developed to exploit the strength potential of masonry and to solve its lack of tensile strength. Experimental
and analytical studies have been carried out to investigate the effect of reinforcement on the behavior of hollow concrete block
masonry prisms under compression and to predict ultimate failure compressive strength. In the numerical program, three dimensional
non-linear finite elements (FE) model based on the micro-modeling approach is developed for both unreinforced and reinforced
masonry prisms using ANSYS (14.5). The proposed FE model uses multi-linear stress-strain relationships to model the non-linear
behavior of hollow concrete block, mortar, and grout. Willam-Warnke’s five parameter failure theory has been adopted to model the
failure of masonry materials. The comparison of the numerical and experimental results indicates that the FE models can successfully
capture the highly nonlinear behavior of the physical specimens and accurately predict their strength and failure mechanisms.
Keywords: Structural masonry, Hollow concrete block prism, grout, Compression failure, Finite element method,
Numerical modeling.
Influence of compaction energy on soil stabilized with chemical stabilizereSAT Journals
Abstract
Increase in traffic along with heavier magnitude of wheel loads cause rapid deterioration in pavements. There is a need to improve
density, strength of soil subgrade and other pavement layers. In this study an attempt is made to improve the properties of locally
available loamy soil using twin approaches viz., i) increasing the compaction of soil and ii) treating the soil with chemical stabilizer.
Laboratory studies are carried out on both untreated and treated soil samples compacted by different compaction efforts. Studies
show that increase in compaction effort results in increase in density of soil. However in soil treated with chemical stabilizer, rate of
increase in density is not significant. The soil treated with chemical stabilizer exhibits improvement in both strength and performance
properties.
Keywords: compaction, density, subgradestabilization, resilient modulus
Geographical information system (gis) for water resources managementeSAT Journals
Abstract
Water resources projects are inherited with overlapping and at times conflicting objectives. These projects are often of varied sizes
ranging from major projects with command areas of millions of hectares to very small projects implemented at the local level. Thus,
in all these projects there is seldom proper coordination which is essential for ensuring collective sustainability.
Integrated watershed development and management is the accepted answer but in turn requires a comprehensive framework that can
enable planning process involving all the stakeholders at different levels and scales is compulsory. Such a unified hydrological
framework is essential to evaluate the cause and effect of all the proposed actions within the drainage basins.
The present paper describes a hydrological framework developed in the form of a Hydrologic Information System (HIS) which is
intended to meet the specific information needs of the various line departments of a typical State connected with water related aspects.
The HIS consist of a hydrologic information database coupled with tools for collating primary and secondary data and tools for
analyzing and visualizing the data and information. The HIS also incorporates hydrological model base for indirect assessment of
various entities of water balance in space and time. The framework would be maintained and updated to reflect fully the most
accurate ground truth data and the infrastructure requirements for planning and management.
Keywords: Hydrological Information System (HIS); WebGIS; Data Model; Web Mapping Services
Forest type mapping of bidar forest division, karnataka using geoinformatics ...eSAT Journals
Abstract
The study demonstrate the potentiality of satellite remote sensing technique for the generation of baseline information on forest types
including tree plantation details in Bidar forest division, Karnataka covering an area of 5814.60Sq.Kms. The Total Area of Bidar
forest division is 5814Sq.Kms analysis of the satellite data in the study area reveals that about 84% of the total area is Covered by
crop land, 1.778% of the area is covered by dry deciduous forest, 1.38 % of mixed plantation, which is very threatening to the
environmental stability of the forest, future plantation site has been mapped. With the use of latest Geo-informatics technology proper
and exact condition of the trees can be observed and necessary precautions can be taken for future plantation works in an appropriate
manner
Keywords:-RS, GIS, GPS, Forest Type, Tree Plantation
Factors influencing compressive strength of geopolymer concreteeSAT Journals
Abstract
To study effects of several factors on the properties of fly ash based geopolymer concrete on the compressive strength and also the
cost comparison with the normal concrete. The test variables were molarities of sodium hydroxide(NaOH) 8M,14M and 16M, ratio of
NaOH to sodium silicate (Na2SiO3) 1, 1.5, 2 and 2.5, alkaline liquid to fly ash ratio 0.35 and 0.40 and replacement of water in
Na2SiO3 solution by 10%, 20% and 30% were used in the present study. The test results indicated that the highest compressive
strength 54 MPa was observed for 16M of NaOH, ratio of NaOH to Na2SiO3 2.5 and alkaline liquid to fly ash ratio of 0.35. Lowest
compressive strength of 27 MPa was observed for 8M of NaOH, ratio of NaOH to Na2SiO3 is 1 and alkaline liquid to fly ash ratio of
0.40. Alkaline liquid to fly ash ratio of 0.35, water replacement of 10% and 30% for 8 and 16 molarity of NaOH and has resulted in
compressive strength of 36 MPa and 20 MPa respectively. Superplasticiser dosage of 2 % by weight of fly ash has given higher
strength in all cases.
Keywords: compressive strength, alkaline liquid, fly ash
Experimental investigation on circular hollow steel columns in filled with li...eSAT Journals
Abstract
Composite Circular hollow Steel tubes with and without GFRP infill for three different grades of Light weight concrete are tested for
ultimate load capacity and axial shortening , under Cyclic loading. Steel tubes are compared for different lengths, cross sections and
thickness. Specimens were tested separately after adopting Taguchi’s L9 (Latin Squares) Orthogonal array in order to save the initial
experimental cost on number of specimens and experimental duration. Analysis was carried out using ANN (Artificial Neural
Network) technique with the assistance of Mini Tab- a statistical soft tool. Comparison for predicted, experimental & ANN output is
obtained from linear regression plots. From this research study, it can be concluded that *Cross sectional area of steel tube has most
significant effect on ultimate load carrying capacity, *as length of steel tube increased- load carrying capacity decreased & *ANN
modeling predicted acceptable results. Thus ANN tool can be utilized for predicting ultimate load carrying capacity for composite
columns.
Keywords: Light weight concrete, GFRP, Artificial Neural Network, Linear Regression, Back propagation, orthogonal
Array, Latin Squares
Experimental behavior of circular hsscfrc filled steel tubular columns under ...eSAT Journals
Abstract
This paper presents an outlook on experimental behavior and a comparison with predicted formula on the behaviour of circular
concentrically loaded self-consolidating fibre reinforced concrete filled steel tube columns (HSSCFRC). Forty-five specimens were
tested. The main parameters varied in the tests are: (1) percentage of fiber (2) tube diameter or width to wall thickness ratio (D/t
from 15 to 25) (3) L/d ratio from 2.97 to 7.04 the results from these predictions were compared with the experimental data. The
experimental results) were also validated in this study.
Keywords: Self-compacting concrete; Concrete-filled steel tube; axial load behavior; Ultimate capacity.
Evaluation of punching shear in flat slabseSAT Journals
Abstract
Flat-slab construction has been widely used in construction today because of many advantages that it offers. The basic philosophy in
the design of flat slab is to consider only gravity forces; this method ignores the effect of punching shear due to unbalanced moments
at the slab column junction which is critical. An attempt has been made to generate generalized design sheets which accounts both
punching shear due to gravity loads and unbalanced moments for cases (a) interior column; (b) edge column (bending perpendicular
to shorter edge); (c) edge column (bending parallel to shorter edge); (d) corner column. These design sheets are prepared as per
codal provisions of IS 456-2000. These design sheets will be helpful in calculating the shear reinforcement to be provided at the
critical section which is ignored in many design offices. Apart from its usefulness in evaluating punching shear and the necessary
shear reinforcement, the design sheets developed will enable the designer to fix the depth of flat slab during the initial phase of the
design.
Keywords: Flat slabs, punching shear, unbalanced moment.
Evaluation of performance of intake tower dam for recent earthquake in indiaeSAT Journals
Abstract
Intake towers are typically tall, hollow, reinforced concrete structures and form entrance to reservoir outlet works. A parametric
study on dynamic behavior of circular cylindrical towers can be carried out to study the effect of depth of submergence, wall thickness
and slenderness ratio, and also effect on tower considering dynamic analysis for time history function of different soil condition and
by Goyal and Chopra accounting interaction effects of added hydrodynamic mass of surrounding and inside water in intake tower of
dam
Key words: Hydrodynamic mass, Depth of submergence, Reservoir, Time history analysis,
Evaluation of operational efficiency of urban road network using travel time ...eSAT Journals
Abstract
Efficiency of the road network system is analyzed by travel time reliability measures. The study overlooks on an important measure of
travel time reliability and prioritizing Tiruchirappalli road network. Traffic volume and travel time were collected using license plate
matching method. Travel time measures were estimated from average travel time and 95th travel time. Effect of non-motorized vehicle
on efficiency of road system was evaluated. Relation between buffer time index and traffic volume was created. Travel time model has
been developed and travel time measure was validated. Then service quality of road sections in network were graded based on
travel time reliability measures.
Keywords: Buffer Time Index (BTI); Average Travel Time (ATT); Travel Time Reliability (TTR); Buffer Time (BT).
Estimation of surface runoff in nallur amanikere watershed using scs cn methodeSAT Journals
Abstract
The development of watershed aims at productive utilization of all the available natural resources in the entire area extending from
ridge line to stream outlet. The per capita availability of land for cultivation has been decreasing over the years. Therefore, water and
the related land resources must be developed, utilized and managed in an integrated and comprehensive manner. Remote sensing and
GIS techniques are being increasingly used for planning, management and development of natural resources. The study area, Nallur
Amanikere watershed geographically lies between 110 38’ and 110 52’ N latitude and 760 30’ and 760 50’ E longitude with an area of
415.68 Sq. km. The thematic layers such as land use/land cover and soil maps were derived from remotely sensed data and overlayed
through ArcGIS software to assign the curve number on polygon wise. The daily rainfall data of six rain gauge stations in and around
the watershed (2001-2011) was used to estimate the daily runoff from the watershed using Soil Conservation Service - Curve Number
(SCS-CN) method. The runoff estimated from the SCS-CN model was then used to know the variation of runoff potential with different
land use/land cover and with different soil conditions.
Keywords: Watershed, Nallur watershed, Surface runoff, Rainfall-Runoff, SCS-CN, Remote Sensing, GIS.
Estimation of morphometric parameters and runoff using rs & gis techniqueseSAT Journals
Abstract
Land and water are the two vital natural resources, the optimal management of these resources with minimum adverse environmental
impact are essential not only for sustainable development but also for human survival. Satellite remote sensing with geographic
information system has a pragmatic approach to map and generate spatial input layers of predicting response behavior and yield of
watershed. Hence, in the present study an attempt has been made to understand the hydrological process of the catchment at the
watershed level by drawing the inferences from moprhometric analysis and runoff. The study area chosen for the present study is
Yagachi catchment situated in Chickamaglur and Hassan district lies geographically at a longitude 75⁰52’08.77”E and
13⁰10’50.77”N latitude. It covers an area of 559.493 Sq.km. Morphometric analysis is carried out to estimate morphometric
parameters at Micro-watershed to understand the hydrological response of the catchment at the Micro-watershed level. Daily runoff
is estimated using USDA SCS curve number model for a period of 10 years from 2001 to 2010. The rainfall runoff relationship of the
study shows there is a positive correlation.
Keywords: morphometric analysis, runoff, remote sensing and GIS, SCS - method
-
Effect of variation of plastic hinge length on the results of non linear anal...eSAT Journals
Abstract The nonlinear Static procedure also well known as pushover analysis is method where in monotonically increasing loads are applied to the structure till the structure is unable to resist any further load. It is a popular tool for seismic performance evaluation of existing and new structures. In literature lot of research has been carried out on conventional pushover analysis and after knowing deficiency efforts have been made to improve it. But actual test results to verify the analytically obtained pushover results are rarely available. It has been found that some amount of variation is always expected to exist in seismic demand prediction of pushover analysis. Initial study is carried out by considering user defined hinge properties and default hinge length. Attempt is being made to assess the variation of pushover analysis results by considering user defined hinge properties and various hinge length formulations available in literature and results compared with experimentally obtained results based on test carried out on a G+2 storied RCC framed structure. For the present study two geometric models viz bare frame and rigid frame model is considered and it is found that the results of pushover analysis are very sensitive to geometric model and hinge length adopted. Keywords: Pushover analysis, Base shear, Displacement, hinge length, moment curvature analysis
Effect of use of recycled materials on indirect tensile strength of asphalt c...eSAT Journals
Abstract
Depletion of natural resources and aggregate quarries for the road construction is a serious problem to procure materials. Hence
recycling or reuse of material is beneficial. On emphasizing development in sustainable construction in the present era, recycling of
asphalt pavements is one of the effective and proven rehabilitation processes. For the laboratory investigations reclaimed asphalt
pavement (RAP) from NH-4 and crumb rubber modified binder (CRMB-55) was used. Foundry waste was used as a replacement to
conventional filler. Laboratory tests were conducted on asphalt concrete mixes with 30, 40, 50, and 60 percent replacement with RAP.
These test results were compared with conventional mixes and asphalt concrete mixes with complete binder extracted RAP
aggregates. Mix design was carried out by Marshall Method. The Marshall Tests indicated highest stability values for asphalt
concrete (AC) mixes with 60% RAP. The optimum binder content (OBC) decreased with increased in RAP in AC mixes. The Indirect
Tensile Strength (ITS) for AC mixes with RAP also was found to be higher when compared to conventional AC mixes at 300C.
Keywords: Reclaimed asphalt pavement, Foundry waste, Recycling, Marshall Stability, Indirect tensile strength.
We have compiled the most important slides from each speaker's presentation. This year’s compilation, available for free, captures the key insights and contributions shared during the DfMAy 2024 conference.
Overview of the fundamental roles in Hydropower generation and the components involved in wider Electrical Engineering.
This paper presents the design and construction of hydroelectric dams from the hydrologist’s survey of the valley before construction, all aspects and involved disciplines, fluid dynamics, structural engineering, generation and mains frequency regulation to the very transmission of power through the network in the United Kingdom.
Author: Robbie Edward Sayers
Collaborators and co editors: Charlie Sims and Connor Healey.
(C) 2024 Robbie E. Sayers
Using recycled concrete aggregates (RCA) for pavements is crucial to achieving sustainability. Implementing RCA for new pavement can minimize carbon footprint, conserve natural resources, reduce harmful emissions, and lower life cycle costs. Compared to natural aggregate (NA), RCA pavement has fewer comprehensive studies and sustainability assessments.
Forklift Classes Overview by Intella PartsIntella Parts
Discover the different forklift classes and their specific applications. Learn how to choose the right forklift for your needs to ensure safety, efficiency, and compliance in your operations.
For more technical information, visit our website https://intellaparts.com
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NUMERICAL SIMULATIONS OF HEAT AND MASS TRANSFER IN CONDENSING HEAT EXCHANGERS...ssuser7dcef0
Power plants release a large amount of water vapor into the
atmosphere through the stack. The flue gas can be a potential
source for obtaining much needed cooling water for a power
plant. If a power plant could recover and reuse a portion of this
moisture, it could reduce its total cooling water intake
requirement. One of the most practical way to recover water
from flue gas is to use a condensing heat exchanger. The power
plant could also recover latent heat due to condensation as well
as sensible heat due to lowering the flue gas exit temperature.
Additionally, harmful acids released from the stack can be
reduced in a condensing heat exchanger by acid condensation. reduced in a condensing heat exchanger by acid condensation.
Condensation of vapors in flue gas is a complicated
phenomenon since heat and mass transfer of water vapor and
various acids simultaneously occur in the presence of noncondensable
gases such as nitrogen and oxygen. Design of a
condenser depends on the knowledge and understanding of the
heat and mass transfer processes. A computer program for
numerical simulations of water (H2O) and sulfuric acid (H2SO4)
condensation in a flue gas condensing heat exchanger was
developed using MATLAB. Governing equations based on
mass and energy balances for the system were derived to
predict variables such as flue gas exit temperature, cooling
water outlet temperature, mole fraction and condensation rates
of water and sulfuric acid vapors. The equations were solved
using an iterative solution technique with calculations of heat
and mass transfer coefficients and physical properties.
Welcome to WIPAC Monthly the magazine brought to you by the LinkedIn Group Water Industry Process Automation & Control.
In this month's edition, along with this month's industry news to celebrate the 13 years since the group was created we have articles including
A case study of the used of Advanced Process Control at the Wastewater Treatment works at Lleida in Spain
A look back on an article on smart wastewater networks in order to see how the industry has measured up in the interim around the adoption of Digital Transformation in the Water Industry.
About
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
• Compatible with IDM8000 CCR.
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
• Easy in configuration using DIP switches.
Technical Specifications
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
Key Features
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface
• Compatible with MAFI CCR system
• Copatiable with IDM8000 CCR
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
Application
• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
• Compatible with IDM8000 CCR.
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
• Easy in configuration using DIP switches.
Governing Equations for Fundamental Aerodynamics_Anderson2010.pdf
Structural sizing and shape optimisation of a load cell
1. IJRET: International Journal of Research in Engineering and Technology e-ISSN: 2319-1163 | p-ISSN: 2321-7308
__________________________________________________________________________________________
Volume: 02 Issue: 07 | Jul-2013, Available @ http://www.ijret.org 196
STRUCTURAL SIZING AND SHAPE OPTIMISATION OF A LOAD CELL
Chung Ket TheinC K Thein1
1
School of Engineering, Taylor’s University, Selangor, Malaysia, ckthein@yahoo.com
Abstract
This paper presents a structural application of a sizing and shape based on a reliability-related multi-factor optimisation. The
application to a load cell design confirmed that this method is highly effective and efficient in terms of sizing and shape optimisation.
A simple model of the S-type load cell is modelled in finite element analysis software and the systematic optimisation method is
applied. Structural responses and geometrical sensitivities are analysed by a FE method, and reliability performance is calculated by
a reliability loading-case index (RLI). The evaluation indices of performances and loading cases are formulated, and an overall
performance index is presented to quantitatively evaluate a design.
Index Terms: Multifactor optimisation, Finite element analysis, Load cell
-------------------------------------------------------------------------------***------------------------------------------------------------------------------
1. INTRODUCTION
Rapid advances in multi-objective and multi-disciplinary
optimisation related to component designs as a tool in solving
engineering design problems. Multi-objective optimisation
that incorporates reliability assessment is presented [1]. This
research addresses a design optimisation problem in which the
load cell design is required to satisfy multiple criteria such as
mechanical strength and stiffness, mass, and reliability feature
under a single loading case.
Load cell is a device normally use in weighing industrial. The
capacity of load cell is vary from 25 kg up to 20 tons. One of
the most popular types of load cell is S-type load cell. It was
originally designed for in-line applications to convert
mechanical scale to digital by replacing the spring. A load cell
is a transducer that converts a force into electrical signal. The
force is sensed by a strain gauge that will be converted into
electrical signals.
The main objective of this paper is to design an S-type load
cell. Multi-objective and multi-disciplinary optimisation
technique and reliability analyses is applied in order to
minimise stress and displacement, mass, and to maximise the
reliability index simultaneously.
2. OPTIMISATION METHDOLOGY
This section deals with the combination of reliability analysis
and the Multifactor Optimisation of Structures Techniques
(MOST) [1] [2], as adopted in part of this paper.
2.1 Formulation of the optimization model
The requirements for a load cell design indicate that the
optimisation must involve multiple objectives and a number of
design variables. Thus, an optimisation procedure is to
establish a suitable method for evaluating this process;
however, complex cross-relationships make it difficult to
suitably appraise the design in order to yield an overall
quantitative performance index which truly represents the
character of the system. The optimisation tackles this problem
by employing a systematic method for evaluation based on the
concept of parameter profiles analysis [3]. This method
evaluates a load cell design by considering many individual
performance parameters for a single loading case, while also
considering cost and performance.
An m n matrix (dij
)—the so-called performance data matrix
(PDM)—is defined by a set of performance parameters Pi
(i =
1, 2,…, m) and loading case parameters Cj
(j = 1, 2,…, n),
respectively. The PDM is a schematic representation of a
collection of data as shown in Table 1. Thus, the data point dij
is the i-th performance Pi
of the structure at the loading case
Cj
. The data points of the matrix are obtained by a finite
element analysis and a reliability analysis of the structure. The
matrix lists every performance of the structure at every
individual loading case.
Table -1: Performance data matrix
C1 C2 ⋯ Cn
P1 d11 d12 ⋯ d1n
P2 d21 d22 ⋯ d2n
⋮ ⋮ ⋮ ⋮
Pm dm1 dm2 ⋯ dmn
A parameter profile matrix (PPM) is created to review the
profile of the performances for different loading cases (Table
2). The data point Dij
in the PPM is a non-dimensional number
with a range of 0–10. The PPM assesses the characteristic of
the structure with respect to the actual performances at their
worst acceptable limits and the best expected values of the
performances.
2. IJRET: International Journal of Research in Engineering and Technology e-ISSN: 2319-1163 | p-ISSN: 2321-7308
__________________________________________________________________________________________
Volume: 02 Issue: 07 | Jul-2013, Available @ http://www.ijret.org 197
Table -2: Parameter profile matrix
C1 C2 ⋯ Cn
P1 D11 D12 ⋯ D1n
P2 D21 D22 ⋯ D2n
⋮ ⋮ ⋮ ⋮
Pm Dm1 Dm2 ⋯ Dmn
The data point Dij
for the one acceptable limit (e.g., lower
limit) is calculated as follows:
10
ijij
ijij
ij
lb
ld
D (1)
where dij
is the actual value of the performance obtained from
the PDM, and lij
and bij
are the lower acceptable limit and the
best expected value, respectively. Equation (1) is valid for lij
<
dij
< bij; for dij
> bij
, Dij
= 10; and for dij
< lij
, Dij
= 0. The data
point for the cases of acceptable upper limit and double
acceptable limits can be calculated in a similar way.
In the optimisation model proposed, all the performance
parameters, no matter whether they are considered as
objectives or constraints, are collected into the PDM (Table 1).
By introducing acceptable limits and best level values for each
performance, a PPM (Table 2) can be founded. This procedure
transforms every performance parameter into a set of goal
functions in connection with loading cases. These goal
functions are the elements of the PPM. In this way, a goal
system is established and it brings all the performance data
into the range of 0-10. For every performance parameter, the
best goal is the same and its value is set to be 10. The goal
functions represent closenesses to the predetermined targets
(best level values of the performances). The closeness value
for each parameter is an adjustable quantity related to the
acceptable limit(s) and best level value of the performance.
Hence, the original optimisation problem is converted to the
problem of minimising the deviations between all these goal
functions and their pseudo targets quantitative value 10.
The mean and standard deviation (SD) are calculated for each
parameter and loading case in each column and row in the
PPM. A well-designed system should have low SDs and high
mean values (close to 10). The existence of high SDs signifies
that the system is likely to have significant problematic areas.
Therefore, a high SD for a row indicates variable system
performance at different loading cases for a particular
parameter. Conversely, a high SD for a column indicates that
the system is likely to have significant problematic
performance for the specific loading case.
The system can be further analysed using a parameter
performance index (PPI) and a case performance index (CPI),
which are defined as follows:
n
j ij
i
D
n
1
1
PPI , mi ,,2,1 and
m
i ij
j
D
m
1
1
CPI , nj ,,2,1 (2)
When i-th parameter is very vulnerable, some data points Dij
of the PPM will have values close to 0 and hence the PPIi will
also close to 0. Similarly, when the system is vulnerable at the
j-th loading case, CPIj will be close to 0. The highest values
for PPI and CPI are 10. PPI and CPI values that are close to 10
indicate good design, whereas values close to zero indicate
poor design. The system may be reviewed by using the
information in the indices, as follows:
A comparison of PPIs indicates whether the system
performs better with respect to some performances
than to others.
A comparison of CPIs shows whether the system
performs better under certain loading cases than
under others.
The mean values, CPIs, PPIs, and SDs provide an overall
performance assessment for the system and loading cases.
These indices are calculated by summing the inverse of the
data points as a performance rating to avoid the effect
associated with low scores being hidden by high scores. The
mean values are not used directly to rate the performance. To
simplify the calculations, the performance indices are
categorized into the range 0–10. This enables different loading
cases and parameters to be compared in order to gain an
overall perspective of the characteristics of the system.
According to the matrix profile analysis, PPI and CPI are
measures of the vulnerability of each performance parameter
and each loading case, respectively. Hence, the integration of
PPI and CPI indicates the vulnerability of a particular
parameter/loading case combination. The above design
synthesis concept provides a framework for formulating the
quantifiable portion of a system design, from which advanced
optimisation techniques can be developed. The optimisation
objective function should be an overall measurement of design
quality of a structural system. An overall performance index
(OPI) is used to develop the overall objective function. The
OPI, which takes the form of a qualitative score, can be
established for the system by considering all the performances
and all the loading cases. The OPI function lies in the range of
0–100. Each performance parameter and each loading case is
given a weighting value according to its importance. The OPI
can be expressed as follows (for the un-weighted case):
m
i
n
j
ji
nm 1 1
CPIPPI
100
OPI (3)
3. IJRET: International Journal of Research in Engineering and Technology e-ISSN: 2319-1163 | p-ISSN: 2321-7308
__________________________________________________________________________________________
Volume: 02 Issue: 07 | Jul-2013, Available @ http://www.ijret.org 198
},,2,1,{ maxmin
kixxx iii
The OPI can be used to compare the performances of different
designs under a same weighting system. The higher the OPI
score, the more reliable the design would be. The OPI reflects
the optimisation model (Eqn. (5) (see section 2.3)) and
assembles all the objectives in the model. The overall
objective function is maximised using the effective zero-order
method, employing conjugate search directions [2]. The OPI is
of great significance because it integrates all optimisation
objectives with all design constraints in such a way that all the
system performances are treated as objectives in the
optimisation. Once some of the performances are improved up
to their best levels, these performances will be transformed
into constraints until all the performances reach their best
levels or cannot be improved any more (convergence).
2.2 Reliability Analysis
A reliability loading-case index (RLI) is proposed which is a
new development of first-order reliability-related method [1].
This method is based on the FORM developed by Hasofer and
Lind (H–L) [4] and later extended by Rackwitz and Fiessler
(R–F) [5]. However, in the present approach a different
method is presented involving the evaluation of the RLI. The
RLI reflects all the possible outcomes such as the
performances and cost of the design and it can be formulated
as:
i
ij
d
Pj
d
WWRLI i
i
2
)(max
(4)
mi ,,2,1 and nj ,,2,1
where WPi
is a weighting factor (range, 0–1) which reflects
performance, dij
is a data point which indicates the
performance parameters and loading case, σdi
is the standard
deviation of the performances, and W is the magnification
factor applied to a particular parameter. i indicates the i-th
performance, and j indicates the j-th loading case.
W is used to amplify the MSNS values to ensure they are
significant when the design variable is changed, thereby
enabling the results to be easily assessed. It is assumed that W
cannot be equal to 0. Preliminary calculations indicate that this
factor should have a value in the range of 5–7.
2.3 A reliability-related multifactor optimization model
An optimisation method ―Multifactor Optimisation of
Structure Techniques‖ (MOST) has been incorporate with
reliability loading-case index (RLI) to execute a multi-factor
sizing optimisation. The design problem is to minimise the
structural mass, minimise the maximum stress minimise the
maximum displacement, and simultaneously maximise the
reliability loading-case index, subject to the design constraints
under single loading case. The optimisation problem to be
solved can be stated as follows:
find X = (x1, x2, …, xk)
min {M(X), σmax,j(X), and δmax,j(X) } and
max {RLIj(X)} (5)
s.t. {σmax,j ≤ σlim ; δmax,j ≤ δlim ; M ≤ Mlim ; RLIj ≥ RLIlim }
j = 1, 2, …, n
where k is the number of design variables, M is the structural
mass, σmax is the maximum stress of the structure, δmax is the
maximum displacement of the structure, RLI is the reliability
loading-case index, the subscript ‗lim‘ indicates a specified
performance limit for the structure, and n is the number of
loading cases. min
ix and max
ix are the lower and upper bounds
of the design variables of xi, respectively.
The implementation flowchart of the reliability-related
multifactor optimisation is illustrated in Fig. 1.
Fig -1: Implementation flow chart of the multifactor
optimisation methodology
3. NUMERICAL EXAMPLE
Consider a three dimensional structural S-Type load cell with
9 nodal points are given in Table 3. The initial structure has a
width (A1) of 50 mm and a height (A2) of 62 mm with the
volume of 27492 mm3
, as shown in Fig. 2. The structural
model annotated with 4 design variables which include width
(A1), height (A2), and thickness (A3 and A4). The centre hole
with ϕ16.5 mm is fixed in the optimisation process where an
electronic device is placed to take the strain deformation. Fig.
3 show that two M6 × 1 thread are taped at the centre of the
load cell and a M6 hole is drilled toward the centre of the hole
(see Fig. 3 – No.9). Since there are three M6 hole and thread
in the load cell where a minimum clearance of 3 mm must be
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Volume: 02 Issue: 07 | Jul-2013, Available @ http://www.ijret.org 199
kept, the thickness of the load cell is keep constant as 12.5
mm.
Table -3: Coordinates of nodal point of initial structure
X (mm) Y (mm) Z (mm)
1 0.0 0.0 0.0
2 50.0 0.0 0.0
3 50.0 43.0 0.0
4 50.0 52.0 0.0
5 50.0 62.0 0.0
6 0.0 62.0 0.0
7 0.0 19.0 0.0
8 0.0 10.0 0.0
9 25.0 31.0 0.0
Fig -2: S-type load cell (initial design)
Fig -3: Initial layout of the S-type load cell structure
The initial structure of S-type load cell is modelled using finite
element software in conjunction with MOST. The ANSYS
SOLID92 element is used to generate the finite element
model, which consists of 8407 quadrilateral elements, as
shown in Fig. 4. MOST uses the ‗input file‘ method in
ANSYS to perform the optimisation process until
convergence. In the optimization process, the finite element
modelling is executed using ANSYS command. The ‗input
file‘ is updated the improved design during each iteration
which is required by the finite element code during the
optimisation.
Fig -4: Finite element model of initial structure
In terms of boundary conditions, the areas of the bottom in all
directions are fixed to be zero. The S-type load cell is make up
of steel EN 24 with a load maximum is 2500 N (i.e., the safety
of factor is up to 2.5). The S-load cell is considered at a single
loading case, i.e. a uniform distributed load of P N/m2
. The
uniform distribution load is defined as:
𝑃 =
𝐹𝑜𝑟𝑐𝑒
𝑤𝑖𝑑𝑡 ℎ ×𝑡ℎ𝑖𝑐𝑘𝑛𝑒𝑠𝑠 𝑜𝑓 𝑙𝑜𝑎𝑑 𝑐𝑒𝑙𝑙
(5)
The material density is 7840 kg/m3
, the Young‘s modulus is
210 GPa, the yield stress is 600 MPa, and the Poisson‘s ratio
is 0.3. The overall objective of the design problem is to
minimise the stress (consequently to minimise the maximum
strain), the maximum displacement, and the structural mass,
and to maximise the reliability loading-case index (RLI).
Table 4 lists the standard deviation (σdi
) and weighting factor
(WPi
) (see Eqn. 4) of the maximum stress, maximum
displacement, structural mass, and the RLI. In this example,
the magnification factor is set to be 6.67.
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Volume: 02 Issue: 07 | Jul-2013, Available @ http://www.ijret.org 200
Table -4: The RLI design variables of individual weighing
factor and standard deviation
Performances
Standard
deviation (σdi
)
Weighting
factor (WPi
)
Maximum stress (MPa) 5 0.01
Maximum displacement (µm) 0.5 0.01
Mass (g) 50 0.88
RLI - 0.10
The design is subjected to a maximum strain of 980 µ,
maximum displacement of 60 µm is imposed on all nodes in
all direction (x, y and z) and the structural mass is required to
be less than 160 grams. From these values (980 µ, 60 µm, and
160 grams) and the equation (4), the minimum acceptable
value for reliability-loading case index is calculated to be
1.834.
The optimisation of the S-load cell required ni = 36 iterations
to converge. The initial and optimised are shown in Fig. 5.
The attributes of the initial and optimised designs are given in
Table 5. The optimum design yields a minimal structural mass
of 143 grams and a RLI of 1.365. The maximum displacement
showed marked reductions from 159 to 53.3 µm. The
maximum von-Mises stress also remarkably reduced from 241
to 203 MPa, in the optimised design, thereby increasing the
safety of factor to ~3. Post-RLI calculations of initial and
optimised designs are given in Fig. 6 – 8.
Fig -5: Distribution of von-Mises Stress (Pa) of initial (left)
and optimised designs (right)
Table -5: Attributes of the initial and optimized designs of the
S-type load cell
Loading case 1
Initial Optimised
Maximum von Mises stress (MPa) 241 203
Maximum displacement (µm) 159 53.3
Maximum strain (µ) 1150 974
Mass (g) 215 143
Reliability loading-case index RLI 1.365 2.052
Fig -6: RLI calculations – preliminary data
Fig -7: RLI calculation – results from ANSYS simulation
Fig -8: RLI calculation – post-result
In the S-type load cell design, a single loading case is
considered. The convergence histories in Chart 1 and Chart 2
show that the trends in maximum displacement and maximum
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__________________________________________________________________________________________
Volume: 02 Issue: 07 | Jul-2013, Available @ http://www.ijret.org 201
stress. Charts 1 and 2 shows that an initially sharp decrease
(first iteration) in maximum displacement and maximum
stress. This is because the reduction of width and height of the
load cell which have a least impact on the stress and
displacement. As a result, the structural mass is reduced by
approximately 29% (see Chart 3). To attain convergence, the
height and width of the load cell shows a marked decrease by
approximately 4% and 30%, respectively.
The centre hole, ϕ16.5 mm, is fixed in the optimisation
process. Fig. 9 shows that the maximum strain distribution
across the width is increased by approximately 23%.
Chart -1: Optimisation convergence history of maximum
displacement
Chart -2: Optimisation convergence history of maximum
stress
Chart -3: Optimisation convergence history of mass and
design variables
Fig -9: Strain distribution of initial and optimised structure
across the width of load cell
CONCLUSIONS
A sizing and shape optimisation was presented that combines
a multifactor shape optimisation with a reliability loading-case
index using a parametric finite element model. The application
of this method to an S-type load cell was showed an
improvement of the structural performance and also indirectly
increased the profit by at least 30% (i.e., reducing the mass by
30%).
Future different shape optimisation on this S-type load cell
will be further analysing in order to withstand a maximum
load capacity at a minimum volume.
REFERENCES
[1]. Chung Ket Thein, Jing-Sheng Liu. Effective structural
sizing/shape optimisation through a reliability-related
multifactor optimisation approach. Multidiscipline Modeling
in Materials and Structures. 8(2)(2012): pp. 159 - 177
[2]. Liu, J.S. and Hollaway, L. Design optimisation of
composite panel structures with stiffening ribs under multiple
loading case. Computers & Structures. 78(4)(2000): pp. 637-
647.
[3]. Liu, J.S. and Thompson, G. The multi-factor design
evaluation of antenna structures by parameters profile
analysis. J. Engng Manufac. Proc Inst. Mech. Eng.
210(B5)(1996): pp. 449-456.
[4]. Hasofer, A.M. and Lind, N.C. Exact and invariant second-
moment code format. J. Eng MEch. Div. ASCE, 100(1)(1974):
pp. 111-121.
[5]. Rackwitz, R. and Fiessler, B. Structural reliability under
combined load sequences. Computers & Structures. 9(1978):
pp. 489-494.
BIOGRAPHIES
Chung Ket Thein was born in Malaysia. He
obtained his Bachelors and PhD in
Mechanical Engineering from University of
Hull, United Kingdom. His research
interests are the development of reliability
assessment and engineering design
optimisation using finite element method.