1. The document presents a finite element analysis of buckling in stiffened plates. Stiffened plates are widely used in shipbuilding and offshore structures to increase strength and stability.
2. A finite element model was created in NISA software to analyze buckling in stiffened plates. Both discrete stiffener modeling and rigorous modeling techniques were used.
3. The results found that rigorous modeling, which models both the plate and stiffeners with shell elements, produced buckling loads that were 8-13% lower but were considered more accurate. Discrete stiffener modeling, which uses beam elements for stiffeners, can also provide adequate results with less computational requirements.
Three dimensional static analysis of two dimensional functionally graded platesijmech
In this paper, static analysis of two dimensional functionally graded plates based on three dimensional theory of elasticity is investigated. Graded finite element method has been used to solve the problem. The effects of power law exponents on static behavior of a fully clamped 2D-FGM plate have been investigated. The model has been compared with result of a 1D-FGM plate for different boundary conditions, and it shows very good agreement.
Three dimensional static analysis of two dimensional functionally graded platesrtme
In this paper, static analysis of two dimensional functionally graded plates based on three dimensional
theory of elasticity is investigated. Graded finite element method has been used to solve the problem. The
effects of power law exponents on static behavior of a fully clamped 2D-FGM plate have been investigated.
The model has been compared with result of a 1D-FGM plate for different boundary conditions, and it
shows very good agreement
Experimental and numerical analysis of elasto-plastic behaviour of notched sp...IJERA Editor
The objective of the work was to estimate the elasto-plastic stress and strain behaviour at the root of the notch of
an Al 6061 plate undergoing tensile and compressive cyclic loading by both experimental and numerical
methods. This attempt to measured initial elasto-plastic stresses experimentally then verified by numerically.
The various Kt values such as 2, 4 and 6 specimens were subjected to tensile test using a computerised universal
testing machine. Numerical approach associated with body discretization and developed finite element model
with sufficient degree of freedom to analyses elasto-plastic analysis of notched specimen. Experimental results
show that analysis of three Kt notched specimens had similar behaviour of elasto-plastic behaviour but different
magnitude. The experimental results compare well with the numerical results which are obtained during finite
element analysis of notched specimens.
Predicting the Nonlinear Material Behaviour under Monotonic and Cyclic loadin...IJERA Editor
Nonlinearity naturally arises in a true, rigorous mathematical formulation of physical problems. One of the most
common nonlinearity is the material nonlinearity where the stress-strain response behaves nonlinearly. The main
objective of this paper is to predict the material nonlinearity with the use of constitutive material model. To this
end, the specimen is modeled with the eight nodded solid elements. One end of the specimen is fixed while the
prescribed displacement is specified at the other end. The Chaboche model parameters are fitted first by
matching the experimental stress-strain curve [4] with the finite element simulations. After that the response of
the specimen is predicted when subjected to different displacement amplitudes i.e. completely reversed loading,
cyclic tension loading and fluctuating ramp loading
Three dimensional static analysis of two dimensional functionally graded platesijmech
In this paper, static analysis of two dimensional functionally graded plates based on three dimensional theory of elasticity is investigated. Graded finite element method has been used to solve the problem. The effects of power law exponents on static behavior of a fully clamped 2D-FGM plate have been investigated. The model has been compared with result of a 1D-FGM plate for different boundary conditions, and it shows very good agreement.
Three dimensional static analysis of two dimensional functionally graded platesrtme
In this paper, static analysis of two dimensional functionally graded plates based on three dimensional
theory of elasticity is investigated. Graded finite element method has been used to solve the problem. The
effects of power law exponents on static behavior of a fully clamped 2D-FGM plate have been investigated.
The model has been compared with result of a 1D-FGM plate for different boundary conditions, and it
shows very good agreement
Experimental and numerical analysis of elasto-plastic behaviour of notched sp...IJERA Editor
The objective of the work was to estimate the elasto-plastic stress and strain behaviour at the root of the notch of
an Al 6061 plate undergoing tensile and compressive cyclic loading by both experimental and numerical
methods. This attempt to measured initial elasto-plastic stresses experimentally then verified by numerically.
The various Kt values such as 2, 4 and 6 specimens were subjected to tensile test using a computerised universal
testing machine. Numerical approach associated with body discretization and developed finite element model
with sufficient degree of freedom to analyses elasto-plastic analysis of notched specimen. Experimental results
show that analysis of three Kt notched specimens had similar behaviour of elasto-plastic behaviour but different
magnitude. The experimental results compare well with the numerical results which are obtained during finite
element analysis of notched specimens.
Predicting the Nonlinear Material Behaviour under Monotonic and Cyclic loadin...IJERA Editor
Nonlinearity naturally arises in a true, rigorous mathematical formulation of physical problems. One of the most
common nonlinearity is the material nonlinearity where the stress-strain response behaves nonlinearly. The main
objective of this paper is to predict the material nonlinearity with the use of constitutive material model. To this
end, the specimen is modeled with the eight nodded solid elements. One end of the specimen is fixed while the
prescribed displacement is specified at the other end. The Chaboche model parameters are fitted first by
matching the experimental stress-strain curve [4] with the finite element simulations. After that the response of
the specimen is predicted when subjected to different displacement amplitudes i.e. completely reversed loading,
cyclic tension loading and fluctuating ramp loading
Analysis Of Laminated and Sandwich Composites by A Zig-Zag Plate Element with...IJERA Editor
A C° layerwise plate element with standard nodal d.o.f. and serendipity interpolation functions is applied to the analysis of laminates and sandwiches giving rise to strong layerwise effects. The element is obtained using an energy updating technique and symbolic calculus starting from a physically-based zig-zag model with variable kinematics and fixed d.o.f. able to a priori satisfy to displacement and stress continuity at the material interfaces. Non classical feature, a high-order piecewise zig-zag variation of the transverse displacement is assumed as it helps keeping equilibrium. Crushing of core is studied carrying apart a detailed 3D modelling of the honeycomb structure discretizing the cell walls with plate elements, with the aim of obtaining apparent elastic moduli at each load level. Using such apparent moduli, a 2D homogenized analysis is carried out simulating sandwiches as multi-layered structures Applications are presented to plates undergoing impulsive loading incorporating plies with spatially variable stiffness properties. It is shown that accurate predictions are always obtained in in the numerical applications with a very low computational effort. Compared to kinematically based zig-zag models, present physically based one is proven to more accurate, being always in a good agreement with exact 3D solutions.
Analysis of Isotropic Perforated Stiffened Plate Using FEMIJERA Editor
In this paper, studied the structural instability caused by circular and square perforated plate having all round simply supported and clamped plate boundary conditions subjected to inplane uniaxial compression loading and also the strengthening effect of the stiffeners when they are reinforced to the unperforated and perforated plate in longitudinal and transverse directions. The area ratios, aspect ratios and types of stiffeners are the parameters considered. A general purpose finite element analysis software ANSYS is used to carry out the study. Results show that the presence of a central circular and square perforations causes reduction in buckling strength of plate and stiffeners can be used to compensate this reduction before it can be used to its best advantage. It is also observed that the plate strengthening effect of longitudinal stiffener is more than that of transverse stiffener for both unperforated and perforated plate. An economical design is possible by introducing stiffeners of optimum size.
Expositions on the Variation of Torsional-Distortional Stresses and Deformati...IJERD Editor
- In this work a single cell and a double cell mono symmetric box girder study profile with the same
cross sectional (enclosed) area and same material thickness were used to obtain the effect of sectorial properties
on the distortional bending stresses and deformation of mono-symmetric box girders. The principles of Vlasov’s
theory of thin walled plates were used to obtain the torsional-distortional equilibrium equation for the analysis
of the study profiles. The distortional bending stresses for the profiles were obtained by numerical
differentiation of the warping function to obtain the distortion diagrasm which formed the base system for
evaluation of the distortional bending moments. By solving the fourth order differential equations for torsionaldistortional
equilibrium the deformations of the study profiles were obtained. The warping functions, the
distortion diagrams, the distortional bending moments and the torsional and distortional deformations of the
study profiles were critically examined and conclusions were made.
EFFECT OF SURFACE ROUGHNESS ON CHARACTERISTICS OF SQUEEZE FILM BETWEEN POROUS...IAEME Publication
In investigation aims to analyse the effect of transverse surface roughness on the squeeze film performance between porous rectangular plates. The associated differential equation is stochastically averaged making use of stochastic averaging method of Christensen and Tonder for transverse surface roughness. The equation is solved with appropriate boundary conditions to obtain the pressure and consequentlythe load bearing. The graphical results suggest that the bearing suffers because of transverse surface roughness. However the situation is slightly better in the case of
negatively skew roughness. Further variance (-ve) makes the situation furtherimproved even if moderate values of porosity are involved
Probabilistic Design of Hollow Circular Composite Structure by using Finite E...IJERA Editor
This study represents simulation of hollow circular composite beam by using Monte Carlo method .A three
dimensional static analysis of large displacement type has been carried out. Finite element analysis of hollow
circular composite structure has been carried out and uncertainty in bending stress is analyzed. Bending stress
was objective function. Beam length, beam radius, elastic modulus, shear modulus and Poisson ratio of epoxy
graphite, ply angles of hollow circular section, radius and force are randomly varied within effective range and
their effect on bending stress has been analyzed. In order to validate the results, one loop of simulation is
benchmarked from results in literature. Ultimately, best set of probabilistic design variable is proposed to reduce
bending stress under static loading condition.
Improvement of the Shell Element Implemented in FEASTSMTiosrjce
The paper deals with shear locking problem in shell element. Shear locking does not mean complete
rigidity, it refers to unwanted high-stiffness behavior that influences the solution but does not over whelm it, so
that convergence with mesh refinement is slowed but not prevented. In the present study the Bilinear
Degenerated Shell (BDS) element model is improved based on the bubble function for membrane strain energy
and selective integration for the shear energy. After formulation of the shell element, implementation is carried
out in FEASTSMT (FINITE ELEMENT ANALYSIS OF STRUCTURES). Result of the shell element without any
bubble function terms showed sensitivity to shear locking problem. Use of bubble functions and selective
integration greatly improves the element performance. The results were compared with those available in
literatures.
A comprehensive literature review on different theories of laminated plates have been
reviewed and discussed thoroughly. It has been found that there are two main theories of
laminated plates which are known as linear and nonlinear theories. The two theories are
depending on the magnitude of deformation resulting from loading the given plates. The
difference between the two theories is that the deformations are small in the linear theory,
whereas they are finite or large in the nonlinear theory.
In comparisons between FEM and different numerical methods it has been found that
FEM can be considered of acceptable accuracy, and can also be applied to different
complicated geometries and shapes.
Dynamic Relaxation (DR) method is presented for the analysis of geometrically linear laterally loaded, rectangular laminated plates. The analysis uses the Mindlin plate theory which accounts for transverse shear deformations. A computer program has been compiled. The convergence and accuracy of the DR solutions of isotropic, orthotropic, and laminated plates for elastic small deflection response are established by comparison with different exact and approximate solutions. The present Dynamic Relaxation (DR) method shows a good agreement with other analytical and numerical methods used in the verification scheme. It was found that: The convergence and accuracy of the DR solution were dependent on several factors which include boundary conditions, mesh size and type, fictitious densities, damping coefficients, time increment and applied load. Also, the DR small deflection program using uniform meshes can be employed in the analysis of different thicknesses for isotropic, orthotropic or laminated plates under uniform loads in a fairly good accuracy.
TRANSIENT ANALYSIS OF PIEZOLAMINATED COMPOSITE PLATES USING HSDTP singh
Piezoelectric materials have excellent sensing and actuating capabilities have made them the most practical smart materials to integrate with laminated structures. Integrated structure system can be called a smart structure because of its ability to perform self-diagnosis and quick adaption to environment changes. An analytical procedure has been developed in the work based on higher order shear deformation theory subjected to electromechanical loading for investigating transient characteristics of smart material plates. For analysis two displacement models are to be considered i.e., model-1 accounts for strain in thickness direction is zero whereas in model-2 in-plane displacements are expanded as cubic functions of the thickness coordinate. Navier’s technique has been adopted for obtaining solutions of anti-symmetric cross–ply and angle-ply laminates of both model-1 and model-2 with simply supported boundary conditions. For obtaining transient response of a laminated composite plate attached with piezoelectric layer Newmark’s method has been used. Effect of thickness coordinate of composite laminated plates attached with piezoelectric layer subjected to electromechanical loadings is studied.
“Investigation of Structural Analysis of Composite Beam Having I- Cross Secti...IOSR Journals
Abstract: - In structural applications, beam is one of the most common structural members that have been
considered in design. This paper is intended to provide tools that ensure better designing options for composite
laminates of I -beam. In this Paper an analytical method & FEM approach calculating axial stiffness , Axial
stress ,Axial strain of flange and web laminates. The results show the stacking sequence and fiber angle
orientation strongly affects strength of composite I-beam.
Analysis of Cross-ply Laminate composite under UD load based on CLPT by Ansys...IJERA Editor
In current study the strength of composite material configuration is obtained from the properties of constituent
laminate by using classical laminate plate theory. For the purpose of analysis various configurations of 2 layered
and 4 layered cross ply laminates are used. The material of laminate is supposed to be boron/epoxy having
orthotropic properties. The loading in current study is supposed to be of uniformly distributed load type. For the
analysis purpose software working on finite element analysis logics i.e. Ansys mechanical APDL is used. By the
help of Ansys mechanical APDL the deflection and stress intensity is found out. The effect of variation of
laminate layers is also studied in current study along with the effect of variation of stacking patterns. The current
study will also help to conclude which stacking pattern is best in 2 layered and 4 layered cross ply laminate.
Effect of lamination angle on maximum deflection of simply supported composit...RAVI KUMAR
In this project a composite laminated beam is studied with glass-epoxy and graphite-epoxy combination. The beam is composed of four layers of different combination of composite material (glass epoxy and graphite epoxy composite). The beam is simply supported at both the ends and is subjected to uniformly distributed load along the length. Transverse deflection is computed for different lamination angle (0^0-〖90〗^0) by using Euler- Bernoulli’s theory (or CLPT). Maximum transverse deflection analysis is carried out using derived analytical expressions. The research carried out in this project will enable to determine the beam strength due to bending loads. The importance of fibre reinforcement in the manufacturing of the beam is studied in terms of bending strength of the beam. MATLAB codes are generated to implement analytical expiations of the composite beam.
The main objective of the paper is to find out the lamination angle at which minimum deflection is obtained & to find out the effect of lamination angle on maximum transverse deflection of the beam.
Analysis Of Laminated and Sandwich Composites by A Zig-Zag Plate Element with...IJERA Editor
A C° layerwise plate element with standard nodal d.o.f. and serendipity interpolation functions is applied to the analysis of laminates and sandwiches giving rise to strong layerwise effects. The element is obtained using an energy updating technique and symbolic calculus starting from a physically-based zig-zag model with variable kinematics and fixed d.o.f. able to a priori satisfy to displacement and stress continuity at the material interfaces. Non classical feature, a high-order piecewise zig-zag variation of the transverse displacement is assumed as it helps keeping equilibrium. Crushing of core is studied carrying apart a detailed 3D modelling of the honeycomb structure discretizing the cell walls with plate elements, with the aim of obtaining apparent elastic moduli at each load level. Using such apparent moduli, a 2D homogenized analysis is carried out simulating sandwiches as multi-layered structures Applications are presented to plates undergoing impulsive loading incorporating plies with spatially variable stiffness properties. It is shown that accurate predictions are always obtained in in the numerical applications with a very low computational effort. Compared to kinematically based zig-zag models, present physically based one is proven to more accurate, being always in a good agreement with exact 3D solutions.
Analysis of Isotropic Perforated Stiffened Plate Using FEMIJERA Editor
In this paper, studied the structural instability caused by circular and square perforated plate having all round simply supported and clamped plate boundary conditions subjected to inplane uniaxial compression loading and also the strengthening effect of the stiffeners when they are reinforced to the unperforated and perforated plate in longitudinal and transverse directions. The area ratios, aspect ratios and types of stiffeners are the parameters considered. A general purpose finite element analysis software ANSYS is used to carry out the study. Results show that the presence of a central circular and square perforations causes reduction in buckling strength of plate and stiffeners can be used to compensate this reduction before it can be used to its best advantage. It is also observed that the plate strengthening effect of longitudinal stiffener is more than that of transverse stiffener for both unperforated and perforated plate. An economical design is possible by introducing stiffeners of optimum size.
Expositions on the Variation of Torsional-Distortional Stresses and Deformati...IJERD Editor
- In this work a single cell and a double cell mono symmetric box girder study profile with the same
cross sectional (enclosed) area and same material thickness were used to obtain the effect of sectorial properties
on the distortional bending stresses and deformation of mono-symmetric box girders. The principles of Vlasov’s
theory of thin walled plates were used to obtain the torsional-distortional equilibrium equation for the analysis
of the study profiles. The distortional bending stresses for the profiles were obtained by numerical
differentiation of the warping function to obtain the distortion diagrasm which formed the base system for
evaluation of the distortional bending moments. By solving the fourth order differential equations for torsionaldistortional
equilibrium the deformations of the study profiles were obtained. The warping functions, the
distortion diagrams, the distortional bending moments and the torsional and distortional deformations of the
study profiles were critically examined and conclusions were made.
EFFECT OF SURFACE ROUGHNESS ON CHARACTERISTICS OF SQUEEZE FILM BETWEEN POROUS...IAEME Publication
In investigation aims to analyse the effect of transverse surface roughness on the squeeze film performance between porous rectangular plates. The associated differential equation is stochastically averaged making use of stochastic averaging method of Christensen and Tonder for transverse surface roughness. The equation is solved with appropriate boundary conditions to obtain the pressure and consequentlythe load bearing. The graphical results suggest that the bearing suffers because of transverse surface roughness. However the situation is slightly better in the case of
negatively skew roughness. Further variance (-ve) makes the situation furtherimproved even if moderate values of porosity are involved
Probabilistic Design of Hollow Circular Composite Structure by using Finite E...IJERA Editor
This study represents simulation of hollow circular composite beam by using Monte Carlo method .A three
dimensional static analysis of large displacement type has been carried out. Finite element analysis of hollow
circular composite structure has been carried out and uncertainty in bending stress is analyzed. Bending stress
was objective function. Beam length, beam radius, elastic modulus, shear modulus and Poisson ratio of epoxy
graphite, ply angles of hollow circular section, radius and force are randomly varied within effective range and
their effect on bending stress has been analyzed. In order to validate the results, one loop of simulation is
benchmarked from results in literature. Ultimately, best set of probabilistic design variable is proposed to reduce
bending stress under static loading condition.
Improvement of the Shell Element Implemented in FEASTSMTiosrjce
The paper deals with shear locking problem in shell element. Shear locking does not mean complete
rigidity, it refers to unwanted high-stiffness behavior that influences the solution but does not over whelm it, so
that convergence with mesh refinement is slowed but not prevented. In the present study the Bilinear
Degenerated Shell (BDS) element model is improved based on the bubble function for membrane strain energy
and selective integration for the shear energy. After formulation of the shell element, implementation is carried
out in FEASTSMT (FINITE ELEMENT ANALYSIS OF STRUCTURES). Result of the shell element without any
bubble function terms showed sensitivity to shear locking problem. Use of bubble functions and selective
integration greatly improves the element performance. The results were compared with those available in
literatures.
A comprehensive literature review on different theories of laminated plates have been
reviewed and discussed thoroughly. It has been found that there are two main theories of
laminated plates which are known as linear and nonlinear theories. The two theories are
depending on the magnitude of deformation resulting from loading the given plates. The
difference between the two theories is that the deformations are small in the linear theory,
whereas they are finite or large in the nonlinear theory.
In comparisons between FEM and different numerical methods it has been found that
FEM can be considered of acceptable accuracy, and can also be applied to different
complicated geometries and shapes.
Dynamic Relaxation (DR) method is presented for the analysis of geometrically linear laterally loaded, rectangular laminated plates. The analysis uses the Mindlin plate theory which accounts for transverse shear deformations. A computer program has been compiled. The convergence and accuracy of the DR solutions of isotropic, orthotropic, and laminated plates for elastic small deflection response are established by comparison with different exact and approximate solutions. The present Dynamic Relaxation (DR) method shows a good agreement with other analytical and numerical methods used in the verification scheme. It was found that: The convergence and accuracy of the DR solution were dependent on several factors which include boundary conditions, mesh size and type, fictitious densities, damping coefficients, time increment and applied load. Also, the DR small deflection program using uniform meshes can be employed in the analysis of different thicknesses for isotropic, orthotropic or laminated plates under uniform loads in a fairly good accuracy.
TRANSIENT ANALYSIS OF PIEZOLAMINATED COMPOSITE PLATES USING HSDTP singh
Piezoelectric materials have excellent sensing and actuating capabilities have made them the most practical smart materials to integrate with laminated structures. Integrated structure system can be called a smart structure because of its ability to perform self-diagnosis and quick adaption to environment changes. An analytical procedure has been developed in the work based on higher order shear deformation theory subjected to electromechanical loading for investigating transient characteristics of smart material plates. For analysis two displacement models are to be considered i.e., model-1 accounts for strain in thickness direction is zero whereas in model-2 in-plane displacements are expanded as cubic functions of the thickness coordinate. Navier’s technique has been adopted for obtaining solutions of anti-symmetric cross–ply and angle-ply laminates of both model-1 and model-2 with simply supported boundary conditions. For obtaining transient response of a laminated composite plate attached with piezoelectric layer Newmark’s method has been used. Effect of thickness coordinate of composite laminated plates attached with piezoelectric layer subjected to electromechanical loadings is studied.
“Investigation of Structural Analysis of Composite Beam Having I- Cross Secti...IOSR Journals
Abstract: - In structural applications, beam is one of the most common structural members that have been
considered in design. This paper is intended to provide tools that ensure better designing options for composite
laminates of I -beam. In this Paper an analytical method & FEM approach calculating axial stiffness , Axial
stress ,Axial strain of flange and web laminates. The results show the stacking sequence and fiber angle
orientation strongly affects strength of composite I-beam.
Analysis of Cross-ply Laminate composite under UD load based on CLPT by Ansys...IJERA Editor
In current study the strength of composite material configuration is obtained from the properties of constituent
laminate by using classical laminate plate theory. For the purpose of analysis various configurations of 2 layered
and 4 layered cross ply laminates are used. The material of laminate is supposed to be boron/epoxy having
orthotropic properties. The loading in current study is supposed to be of uniformly distributed load type. For the
analysis purpose software working on finite element analysis logics i.e. Ansys mechanical APDL is used. By the
help of Ansys mechanical APDL the deflection and stress intensity is found out. The effect of variation of
laminate layers is also studied in current study along with the effect of variation of stacking patterns. The current
study will also help to conclude which stacking pattern is best in 2 layered and 4 layered cross ply laminate.
Effect of lamination angle on maximum deflection of simply supported composit...RAVI KUMAR
In this project a composite laminated beam is studied with glass-epoxy and graphite-epoxy combination. The beam is composed of four layers of different combination of composite material (glass epoxy and graphite epoxy composite). The beam is simply supported at both the ends and is subjected to uniformly distributed load along the length. Transverse deflection is computed for different lamination angle (0^0-〖90〗^0) by using Euler- Bernoulli’s theory (or CLPT). Maximum transverse deflection analysis is carried out using derived analytical expressions. The research carried out in this project will enable to determine the beam strength due to bending loads. The importance of fibre reinforcement in the manufacturing of the beam is studied in terms of bending strength of the beam. MATLAB codes are generated to implement analytical expiations of the composite beam.
The main objective of the paper is to find out the lamination angle at which minimum deflection is obtained & to find out the effect of lamination angle on maximum transverse deflection of the beam.
Analysis of stiffened plate using FE ApproachIJMER
The objective of the present investigation is to study the strengthening effect of the stiffeners
on the buckling of unperforated and perforated plate when they are reinforced in longitudinal and
transverse directions. The plate is subjected to inplane uniform uniaxial end compression load having
simply supported plate boundary condition. The parameters considered are plate aspect ratio, area ratio and types of stiffeners. The analysis has been carried out using ANSYS finite element software. The buckling analysis shows that the influence of transverse stiffener is less when compared to longitudinal stiffener
International Journal of Engineering Research and DevelopmentIJERD Editor
Electrical, Electronics and Computer Engineering,
Information Engineering and Technology,
Mechanical, Industrial and Manufacturing Engineering,
Automation and Mechatronics Engineering,
Material and Chemical Engineering,
Civil and Architecture Engineering,
Biotechnology and Bio Engineering,
Environmental Engineering,
Petroleum and Mining Engineering,
Marine and Agriculture engineering,
Aerospace Engineering.
In this study, Non-linear response of concrete with differential value of Young’s Modulus is determined by the stress strain expression. The modulus of elasticity is varied throughout to evaluate the non-linear response of concrete structure at a constant load. The modeling of structure is done in STAAD PRO Vi8 software. In this study, single storey-single bay frame is modeled which is subjected to dead load and uniform loads, has been considered for the non-linear response of concrete structures. A structural element such as Column is used for evaluation of the non-linear response of concrete material. From this, deflection of the column element is carried out by using STAAD PRO software with different initial tangent modulus of elasticity at a constant loading.
A review and buckling analysis of stiffened plateeSAT Journals
Abstract It happens many times that the structure is safe in normal stress and deflection but fails in buckling. Buckling analysis is one of the method to go for such type of analysis.It predicts various modes of buckling. Plates are used in many applications such as structures, aerospace, automobile etc. Such structures are subjected to heavy uniformly distributed load and concentrated load many times over it’s life span. Strength of these structures are increased by adding stiffeners to its plate. This paper deals with the analysis of rectangular stiffened plates which forms the basis of structures. A comparison of stiffened plate and unstiffened plate is done for the same dimensions. In order to continue this analysis various research papers were studied to understand the previous tasks done for stiffened plate. Hyper mesh and Nastran is used in this research work.Buckling analysis is performed for the component with aspect ratio of 2.Rectangular flat bar is used as stiffener Keywords: Stiffened Plate; Dynamic load; Buckling; Aspect ratio;Buckling Analysis.
Deformation Analysis of a Triangular Mild Steel Plate Using CST as Finite Ele...IJMER
International Journal of Modern Engineering Research (IJMER) is Peer reviewed, online Journal. It serves as an international archival forum of scholarly research related to engineering and science education.
International Journal of Modern Engineering Research (IJMER) covers all the fields of engineering and science: Electrical Engineering, Mechanical Engineering, Civil Engineering, Chemical Engineering, Computer Engineering, Agricultural Engineering, Aerospace Engineering, Thermodynamics, Structural Engineering, Control Engineering, Robotics, Mechatronics, Fluid Mechanics, Nanotechnology, Simulators, Web-based Learning, Remote Laboratories, Engineering Design Methods, Education Research, Students' Satisfaction and Motivation, Global Projects, and Assessment…. And many more.
Non Linear Analysis of Composite Beam Slab Junction with Shear Connectors usi...inventionjournals
Frame finite-element models permit obtaining, at moderate computational cost, significant information on the dynamic response behavior of steel–concrete composite beam frame structures. As an extension of conventional monolithic beam models, composite beams with deformable shear connection were specifically introduced and adopted for the analysis of composite beams, in which the flexible shear connection allows development of partial composite action influencing structural deformation and distribution of stresses. The use of beams with deformable shear connection in the analysis of frame structures raises very specific modeling issues, such as the characterization of the cyclic behavior of the deformable shear connection and the assembly of composite beam elements with conventional beam–column elements. In addition, the effects on the dynamic response of composite beam frame structures of various factors, such as the shear connection boundary conditions and the mass distribution between the two components of the composite beam, are still not clear and deserve more investigation. The object of this paper is to provide deeper insight into the natural vibration properties and nonlinear seismic response behavior of composite beam frame structures and how they are influenced by various modeling assumptions. For this purpose, a materially nonlinear-only finite-element formulation is used for static and dynamic response analyses of steel–concrete frame structures using composite beam elements with deformable shear connection. Realistic uniaxial cyclic constitutive laws are adopted for the steel and concrete materials of the beams and columns and for the shear connection. The resulting finite-element model for a benchmark problem is validated using experimental test results from the literature review
The effects of boundary conditions and lamination arrangements
(i.e. stacking sequence and orientation of a lamina) were found to be important
factors in determining a suitable exact, analytical or semi – analytical method
for analyzing buckling loads on laminated plates. It was also found that: as the
derivative order of shear deformation increases, the accuracy of stresses, strains,
buckling loads … etc. increases and it doesn't need shear correction factors.
Design, Analysis and weight optimization of Crane Hook: A Reviewijsrd.com
Crane hook are highly liable component and are always subjected to failure due to accumulation of large amount of stress which can eventually lead to its failure .In this present work, to study the different design parameter & stress pattern of crane hook in its loaded condition for different cross section, the design and drafting of crane hook will be prepared by using ANSYS 14.5. By finite element analysis, the stress which is to be formed in various cross section are compared with design calculation .The stress concentration factors are used in strength and durability evaluation of structure and machine element. In this work and also we observe the parameter that affects the weight reduction.
NONLINEAR FINITE ELEMENT ANALYSIS FOR REINFORCED CONCRETE SLABS UNDER PUNCHIN...IAEME Publication
This paper presents an implementation of a three-dimensional nonlinear finite element model for evaluating the behavior of reinforced concrete slabs under centric load. The concrete was idealized by using eight-nodded solid elements. While flexural reinforcement and the shear were modeled as line elements, a perfected bond between solid elements and line elements was assumed. The nonlinear behavior of concrete in compression is simulated by an elasto-plastic work-hardening model, and in tension a suitable post-cracking model based on tension stiffening and shear retention models are employed. The steel was simulated using an elastic-full plastic model. The validity of the theoretical formulations and the program used was verified through comparison with available experimental data, and the agreement has proven to be good. A parametric study has been also carried out to investigate the influence of the slab thickness on column-slab connection response
A Novel Method for Prevention of Bandwidth Distributed Denial of Service AttacksIJERD Editor
Distributed Denial of Service (DDoS) Attacks became a massive threat to the Internet. Traditional
Architecture of internet is vulnerable to the attacks like DDoS. Attacker primarily acquire his army of Zombies,
then that army will be instructed by the Attacker that when to start an attack and on whom the attack should be
done. In this paper, different techniques which are used to perform DDoS Attacks, Tools that were used to
perform Attacks and Countermeasures in order to detect the attackers and eliminate the Bandwidth Distributed
Denial of Service attacks (B-DDoS) are reviewed. DDoS Attacks were done by using various Flooding
techniques which are used in DDoS attack.
The main purpose of this paper is to design an architecture which can reduce the Bandwidth
Distributed Denial of service Attack and make the victim site or server available for the normal users by
eliminating the zombie machines. Our Primary focus of this paper is to dispute how normal machines are
turning into zombies (Bots), how attack is been initiated, DDoS attack procedure and how an organization can
save their server from being a DDoS victim. In order to present this we implemented a simulated environment
with Cisco switches, Routers, Firewall, some virtual machines and some Attack tools to display a real DDoS
attack. By using Time scheduling, Resource Limiting, System log, Access Control List and some Modular
policy Framework we stopped the attack and identified the Attacker (Bot) machines
Hearing loss is one of the most common human impairments. It is estimated that by year 2015 more
than 700 million people will suffer mild deafness. Most can be helped by hearing aid devices depending on the
severity of their hearing loss. This paper describes the implementation and characterization details of a dual
channel transmitter front end (TFE) for digital hearing aid (DHA) applications that use novel micro
electromechanical- systems (MEMS) audio transducers and ultra-low power-scalable analog-to-digital
converters (ADCs), which enable a very-low form factor, energy-efficient implementation for next-generation
DHA. The contribution of the design is the implementation of the dual channel MEMS microphones and powerscalable
ADC system.
Influence of tensile behaviour of slab on the structural Behaviour of shear c...IJERD Editor
-A composite beam is composed of a steel beam and a slab connected by means of shear connectors
like studs installed on the top flange of the steel beam to form a structure behaving monolithically. This study
analyzes the effects of the tensile behavior of the slab on the structural behavior of the shear connection like slip
stiffness and maximum shear force in composite beams subjected to hogging moment. The results show that the
shear studs located in the crack-concentration zones due to large hogging moments sustain significantly smaller
shear force and slip stiffness than the other zones. Moreover, the reduction of the slip stiffness in the shear
connection appears also to be closely related to the change in the tensile strain of rebar according to the increase
of the load. Further experimental and analytical studies shall be conducted considering variables such as the
reinforcement ratio and the arrangement of shear connectors to achieve efficient design of the shear connection
in composite beams subjected to hogging moment.
Gold prospecting using Remote Sensing ‘A case study of Sudan’IJERD Editor
Gold has been extracted from northeast Africa for more than 5000 years, and this may be the first
place where the metal was extracted. The Arabian-Nubian Shield (ANS) is an exposure of Precambrian
crystalline rocks on the flanks of the Red Sea. The crystalline rocks are mostly Neoproterozoic in age. ANS
includes the nations of Israel, Jordan. Egypt, Saudi Arabia, Sudan, Eritrea, Ethiopia, Yemen, and Somalia.
Arabian Nubian Shield Consists of juvenile continental crest that formed between 900 550 Ma, when intra
oceanic arc welded together along ophiolite decorated arc. Primary Au mineralization probably developed in
association with the growth of intra oceanic arc and evolution of back arc. Multiple episodes of deformation
have obscured the primary metallogenic setting, but at least some of the deposits preserve evidence that they
originate as sea floor massive sulphide deposits.
The Red Sea Hills Region is a vast span of rugged, harsh and inhospitable sector of the Earth with
inimical moon-like terrain, nevertheless since ancient times it is famed to be an abode of gold and was a major
source of wealth for the Pharaohs of ancient Egypt. The Pharaohs old workings have been periodically
rediscovered through time. Recent endeavours by the Geological Research Authority of Sudan led to the
discovery of a score of occurrences with gold and massive sulphide mineralizations. In the nineties of the
previous century the Geological Research Authority of Sudan (GRAS) in cooperation with BRGM utilized
satellite data of Landsat TM using spectral ratio technique to map possible mineralized zones in the Red Sea
Hills of Sudan. The outcome of the study mapped a gossan type gold mineralization. Band ratio technique was
applied to Arbaat area and a signature of alteration zone was detected. The alteration zones are commonly
associated with mineralization. The alteration zones are commonly associated with mineralization. A filed check
confirmed the existence of stock work of gold bearing quartz in the alteration zone. Another type of gold
mineralization that was discovered using remote sensing is the gold associated with metachert in the Atmur
Desert.
Reducing Corrosion Rate by Welding DesignIJERD Editor
The paper addresses the importance of welding design to prevent corrosion at steel. Welding is
used to join pipe, profiles at bridges, spindle, and a lot more part of engineering construction. The
problems happened associated with welding are common issues in these fields, especially corrosion.
Corrosion can be reduced with many methods, they are painting, controlling humidity, and also good
welding design. In the research, it can be found that reducing residual stress on the welding can be
solved in corrosion rate reduction problem.
Preheating on 500oC and 600oC give better condition to reduce corosion rate than condition after
preheating 400oC. For all welding groove type, material with 500oC and 600oC preheating after 14 days
corrosion test is 0,5%-0,69% lost. Material with 400oC preheating after 14 days corrosion test is 0,57%-0,76%
lost.
Welding groove also influence corrosion rate. X and V type welding groove give better condition to reduce
corrosion rate than use 1/2V and 1/2 X welding groove. After 14 days corrosion test, the samples with
X welding groove type is 0,5%-0,57% lost. The samples with V welding groove after 14 days corrosion test is
0,51%-0,59% lost. The samples with 1/2V and 1/2X welding groove after 14 days corrosion test is 0,58%-
0,71% lost.
Router 1X3 – RTL Design and VerificationIJERD Editor
Routing is the process of moving a packet of data from source to destination and enables messages
to pass from one computer to another and eventually reach the target machine. A router is a networking device
that forwards data packets between computer networks. It is connected to two or more data lines from different
networks (as opposed to a network switch, which connects data lines from one single network). This paper,
mainly emphasizes upon the study of router device, it‟s top level architecture, and how various sub-modules of
router i.e. Register, FIFO, FSM and Synchronizer are synthesized, and simulated and finally connected to its top
module.
Active Power Exchange in Distributed Power-Flow Controller (DPFC) At Third Ha...IJERD Editor
This paper presents a component within the flexible ac-transmission system (FACTS) family, called
distributed power-flow controller (DPFC). The DPFC is derived from the unified power-flow controller (UPFC)
with an eliminated common dc link. The DPFC has the same control capabilities as the UPFC, which comprise
the adjustment of the line impedance, the transmission angle, and the bus voltage. The active power exchange
between the shunt and series converters, which is through the common dc link in the UPFC, is now through the
transmission lines at the third-harmonic frequency. DPFC multiple small-size single-phase converters which
reduces the cost of equipment, no voltage isolation between phases, increases redundancy and there by
reliability increases. The principle and analysis of the DPFC are presented in this paper and the corresponding
simulation results that are carried out on a scaled prototype are also shown.
Mitigation of Voltage Sag/Swell with Fuzzy Control Reduced Rating DVRIJERD Editor
Power quality has been an issue that is becoming increasingly pivotal in industrial electricity
consumers point of view in recent times. Modern industries employ Sensitive power electronic equipments,
control devices and non-linear loads as part of automated processes to increase energy efficiency and
productivity. Voltage disturbances are the most common power quality problem due to this the use of a large
numbers of sophisticated and sensitive electronic equipment in industrial systems is increased. This paper
discusses the design and simulation of dynamic voltage restorer for improvement of power quality and
reduce the harmonics distortion of sensitive loads. Power quality problem is occurring at non-standard
voltage, current and frequency. Electronic devices are very sensitive loads. In power system voltage sag,
swell, flicker and harmonics are some of the problem to the sensitive load. The compensation capability
of a DVR depends primarily on the maximum voltage injection ability and the amount of stored
energy available within the restorer. This device is connected in series with the distribution feeder at
medium voltage. A fuzzy logic control is used to produce the gate pulses for control circuit of DVR and the
circuit is simulated by using MATLAB/SIMULINK software.
Study on the Fused Deposition Modelling In Additive ManufacturingIJERD Editor
Additive manufacturing process, also popularly known as 3-D printing, is a process where a product
is created in a succession of layers. It is based on a novel materials incremental manufacturing philosophy.
Unlike conventional manufacturing processes where material is removed from a given work price to derive the
final shape of a product, 3-D printing develops the product from scratch thus obviating the necessity to cut away
materials. This prevents wastage of raw materials. Commonly used raw materials for the process are ABS
plastic, PLA and nylon. Recently the use of gold, bronze and wood has also been implemented. The complexity
factor of this process is 0% as in any object of any shape and size can be manufactured.
Spyware triggering system by particular string valueIJERD Editor
This computer programme can be used for good and bad purpose in hacking or in any general
purpose. We can say it is next step for hacking techniques such as keylogger and spyware. Once in this system if
user or hacker store particular string as a input after that software continually compare typing activity of user
with that stored string and if it is match then launch spyware programme.
A Blind Steganalysis on JPEG Gray Level Image Based on Statistical Features a...IJERD Editor
This paper presents a blind steganalysis technique to effectively attack the JPEG steganographic
schemes i.e. Jsteg, F5, Outguess and DWT Based. The proposed method exploits the correlations between
block-DCTcoefficients from intra-block and inter-block relation and the statistical moments of characteristic
functions of the test image is selected as features. The features are extracted from the BDCT JPEG 2-array.
Support Vector Machine with cross-validation is implemented for the classification.The proposed scheme gives
improved outcome in attacking.
Secure Image Transmission for Cloud Storage System Using Hybrid SchemeIJERD Editor
- Data over the cloud is transferred or transmitted between servers and users. Privacy of that
data is very important as it belongs to personal information. If data get hacked by the hacker, can be
used to defame a person’s social data. Sometimes delay are held during data transmission. i.e. Mobile
communication, bandwidth is low. Hence compression algorithms are proposed for fast and efficient
transmission, encryption is used for security purposes and blurring is used by providing additional
layers of security. These algorithms are hybridized for having a robust and efficient security and
transmission over cloud storage system.
Application of Buckley-Leverett Equation in Modeling the Radius of Invasion i...IJERD Editor
A thorough review of existing literature indicates that the Buckley-Leverett equation only analyzes
waterflood practices directly without any adjustments on real reservoir scenarios. By doing so, quite a number
of errors are introduced into these analyses. Also, for most waterflood scenarios, a radial investigation is more
appropriate than a simplified linear system. This study investigates the adoption of the Buckley-Leverett
equation to estimate the radius invasion of the displacing fluid during waterflooding. The model is also adopted
for a Microbial flood and a comparative analysis is conducted for both waterflooding and microbial flooding.
Results shown from the analysis doesn’t only records a success in determining the radial distance of the leading
edge of water during the flooding process, but also gives a clearer understanding of the applicability of
microbes to enhance oil production through in-situ production of bio-products like bio surfactans, biogenic
gases, bio acids etc.
Gesture Gaming on the World Wide Web Using an Ordinary Web CameraIJERD Editor
- Gesture gaming is a method by which users having a laptop/pc/x-box play games using natural or
bodily gestures. This paper presents a way of playing free flash games on the internet using an ordinary webcam
with the help of open source technologies. Emphasis in human activity recognition is given on the pose
estimation and the consistency in the pose of the player. These are estimated with the help of an ordinary web
camera having different resolutions from VGA to 20mps. Our work involved giving a 10 second documentary to
the user on how to play a particular game using gestures and what are the various kinds of gestures that can be
performed in front of the system. The initial inputs of the RGB values for the gesture component is obtained by
instructing the user to place his component in a red box in about 10 seconds after the short documentary before
the game is finished. Later the system opens the concerned game on the internet on popular flash game sites like
miniclip, games arcade, GameStop etc and loads the game clicking at various places and brings the state to a
place where the user is to perform only gestures to start playing the game. At any point of time the user can call
off the game by hitting the esc key and the program will release all of the controls and return to the desktop. It
was noted that the results obtained using an ordinary webcam matched that of the Kinect and the users could
relive the gaming experience of the free flash games on the net. Therefore effective in game advertising could
also be achieved thus resulting in a disruptive growth to the advertising firms.
Hardware Analysis of Resonant Frequency Converter Using Isolated Circuits And...IJERD Editor
-LLC resonant frequency converter is basically a combo of series as well as parallel resonant ckt. For
LCC resonant converter it is associated with a disadvantage that, though it has two resonant frequencies, the
lower resonant frequency is in ZCS region[5]. For this application, we are not able to design the converter
working at this resonant frequency. LLC resonant converter existed for a very long time but because of
unknown characteristic of this converter it was used as a series resonant converter with basically a passive
(resistive) load. . Here, it was designed to operate in switching frequency higher than resonant frequency of the
series resonant tank of Lr and Cr converter acts very similar to Series Resonant Converter. The benefit of LLC
resonant converter is narrow switching frequency range with light load[6] . Basically, the control ckt plays a
very imp. role and hence 555 Timer used here provides a perfect square wave as the control ckt provides no
slew rate which makes the square wave really strong and impenetrable. The dead band circuit provides the
exclusive dead band in micro seconds so as to avoid the simultaneous firing of two pairs of IGBT’s where one
pair switches off and the other on for a slightest period of time. Hence, the isolator ckt here is associated with
each and every ckt used because it acts as a driver and an isolation to each of the IGBT is provided with one
exclusive transformer supply[3]. The IGBT’s are fired using the appropriate signal using the previous boards
and hence at last a high frequency rectifier ckt with a filtering capacitor is used to get an exact dc
waveform .The basic goal of this particular analysis is to observe the wave forms and characteristics of
converters with differently positioned passive elements in the form of tank circuits.
Simulated Analysis of Resonant Frequency Converter Using Different Tank Circu...IJERD Editor
LLC resonant frequency converter is basically a combo of series as well as parallel resonant ckt. For
LCC resonant converter it is associated with a disadvantage that, though it has two resonant frequencies, the
lower resonant frequency is in ZCS region [5]. For this application, we are not able to design the converter
working at this resonant frequency. LLC resonant converter existed for a very long time but because of
unknown characteristic of this converter it was used as a series resonant converter with basically a passive
(resistive) load. . Here, it was designed to operate in switching frequency higher than resonant frequency of the
series resonant tank of Lr and Cr converter acts very similar to Series Resonant Converter. The benefit of LLC
resonant converter is narrow switching frequency range with light load[6] . Basically, the control ckt plays a
very imp. role and hence 555 Timer used here provides a perfect square wave as the control ckt provides no
slew rate which makes the square wave really strong and impenetrable. The dead band circuit provides the
exclusive dead band in micro seconds so as to avoid the simultaneous firing of two pairs of IGBT’s where one
pair switches off and the other on for a slightest period of time. Hence, the isolator ckt here is associated with
each and every ckt used because it acts as a driver and an isolation to each of the IGBT is provided with one
exclusive transformer supply[3]. The IGBT’s are fired using the appropriate signal using the previous boards
and hence at last a high frequency rectifier ckt with a filtering capacitor is used to get an exact dc
waveform .The basic goal of this particular analysis is to observe the wave forms and characteristics of
converters with differently positioned passive elements in the form of tank circuits. The supported simulation
is done through PSIM 6.0 software tool
Amateurs Radio operator, also known as HAM communicates with other HAMs through Radio
waves. Wireless communication in which Moon is used as natural satellite is called Moon-bounce or EME
(Earth -Moon-Earth) technique. Long distance communication (DXing) using Very High Frequency (VHF)
operated amateur HAM radio was difficult. Even with the modest setup having good transceiver, power
amplifier and high gain antenna with high directivity, VHF DXing is possible. Generally 2X11 YAGI antenna
along with rotor to set horizontal and vertical angle is used. Moon tracking software gives exact location,
visibility of Moon at both the stations and other vital data to acquire real time position of moon.
“MS-Extractor: An Innovative Approach to Extract Microsatellites on „Y‟ Chrom...IJERD Editor
Simple Sequence Repeats (SSR), also known as Microsatellites, have been extensively used as
molecular markers due to their abundance and high degree of polymorphism. The nucleotide sequences of
polymorphic forms of the same gene should be 99.9% identical. So, Microsatellites extraction from the Gene is
crucial. However, Microsatellites repeat count is compared, if they differ largely, he has some disorder. The Y
chromosome likely contains 50 to 60 genes that provide instructions for making proteins. Because only males
have the Y chromosome, the genes on this chromosome tend to be involved in male sex determination and
development. Several Microsatellite Extractors exist and they fail to extract microsatellites on large data sets of
giga bytes and tera bytes in size. The proposed tool “MS-Extractor: An Innovative Approach to extract
Microsatellites on „Y‟ Chromosome” can extract both Perfect as well as Imperfect Microsatellites from large
data sets of human genome „Y‟. The proposed system uses string matching with sliding window approach to
locate Microsatellites and extracts them.
Importance of Measurements in Smart GridIJERD Editor
- The need to get reliable supply, independence from fossil fuels, and capability to provide clean
energy at a fixed and lower cost, the existing power grid structure is transforming into Smart Grid. The
development of a smart energy distribution grid is a current goal of many nations. A Smart Grid should have
new capabilities such as self-healing, high reliability, energy management, and real-time pricing. This new era
of smart future grid will lead to major changes in existing technologies at generation, transmission and
distribution levels. The incorporation of renewable energy resources and distribution generators in the existing
grid will increase the complexity, optimization problems and instability of the system. This will lead to a
paradigm shift in the instrumentation and control requirements for Smart Grids for high quality, stable and
reliable electricity supply of power. The monitoring of the grid system state and stability relies on the
availability of reliable measurement of data. In this paper the measurement areas that highlight new
measurement challenges, development of the Smart Meters and the critical parameters of electric energy to be
monitored for improving the reliability of power systems has been discussed.
Study of Macro level Properties of SCC using GGBS and Lime stone powderIJERD Editor
One of the major environmental concerns is the disposal of the waste materials and utilization of
industrial by products. Lime stone quarries will produce millions of tons waste dust powder every year. Having
considerable high degree of fineness in comparision to cement this material may be utilized as a partial
replacement to cement. For this purpose an experiment is conducted to investigate the possibility of using lime
stone powder in the production of SCC with combined use GGBS and how it affects the fresh and mechanical
properties of SCC. First SCC is made by replacing cement with GGBS in percentages like 10, 20, 30, 40, 50 and
by taking the optimum mix with GGBS lime stone powder is blended to mix in percentages like 5, 10, 15, 20 as
a partial replacement to cement. Test results shows that the SCC mix with combination of 30% GGBS and 15%
limestone powder gives maximum compressive strength and fresh properties are also in the limits prescribed by
the EFNARC.
Accelerate your Kubernetes clusters with Varnish CachingThijs Feryn
A presentation about the usage and availability of Varnish on Kubernetes. This talk explores the capabilities of Varnish caching and shows how to use the Varnish Helm chart to deploy it to Kubernetes.
This presentation was delivered at K8SUG Singapore. See https://feryn.eu/presentations/accelerate-your-kubernetes-clusters-with-varnish-caching-k8sug-singapore-28-2024 for more details.
Securing your Kubernetes cluster_ a step-by-step guide to success !KatiaHIMEUR1
Today, after several years of existence, an extremely active community and an ultra-dynamic ecosystem, Kubernetes has established itself as the de facto standard in container orchestration. Thanks to a wide range of managed services, it has never been so easy to set up a ready-to-use Kubernetes cluster.
However, this ease of use means that the subject of security in Kubernetes is often left for later, or even neglected. This exposes companies to significant risks.
In this talk, I'll show you step-by-step how to secure your Kubernetes cluster for greater peace of mind and reliability.
Connector Corner: Automate dynamic content and events by pushing a buttonDianaGray10
Here is something new! In our next Connector Corner webinar, we will demonstrate how you can use a single workflow to:
Create a campaign using Mailchimp with merge tags/fields
Send an interactive Slack channel message (using buttons)
Have the message received by managers and peers along with a test email for review
But there’s more:
In a second workflow supporting the same use case, you’ll see:
Your campaign sent to target colleagues for approval
If the “Approve” button is clicked, a Jira/Zendesk ticket is created for the marketing design team
But—if the “Reject” button is pushed, colleagues will be alerted via Slack message
Join us to learn more about this new, human-in-the-loop capability, brought to you by Integration Service connectors.
And...
Speakers:
Akshay Agnihotri, Product Manager
Charlie Greenberg, Host
DevOps and Testing slides at DASA ConnectKari Kakkonen
My and Rik Marselis slides at 30.5.2024 DASA Connect conference. We discuss about what is testing, then what is agile testing and finally what is Testing in DevOps. Finally we had lovely workshop with the participants trying to find out different ways to think about quality and testing in different parts of the DevOps infinity loop.
LF Energy Webinar: Electrical Grid Modelling and Simulation Through PowSyBl -...DanBrown980551
Do you want to learn how to model and simulate an electrical network from scratch in under an hour?
Then welcome to this PowSyBl workshop, hosted by Rte, the French Transmission System Operator (TSO)!
During the webinar, you will discover the PowSyBl ecosystem as well as handle and study an electrical network through an interactive Python notebook.
PowSyBl is an open source project hosted by LF Energy, which offers a comprehensive set of features for electrical grid modelling and simulation. Among other advanced features, PowSyBl provides:
- A fully editable and extendable library for grid component modelling;
- Visualization tools to display your network;
- Grid simulation tools, such as power flows, security analyses (with or without remedial actions) and sensitivity analyses;
The framework is mostly written in Java, with a Python binding so that Python developers can access PowSyBl functionalities as well.
What you will learn during the webinar:
- For beginners: discover PowSyBl's functionalities through a quick general presentation and the notebook, without needing any expert coding skills;
- For advanced developers: master the skills to efficiently apply PowSyBl functionalities to your real-world scenarios.
JMeter webinar - integration with InfluxDB and GrafanaRTTS
Watch this recorded webinar about real-time monitoring of application performance. See how to integrate Apache JMeter, the open-source leader in performance testing, with InfluxDB, the open-source time-series database, and Grafana, the open-source analytics and visualization application.
In this webinar, we will review the benefits of leveraging InfluxDB and Grafana when executing load tests and demonstrate how these tools are used to visualize performance metrics.
Length: 30 minutes
Session Overview
-------------------------------------------
During this webinar, we will cover the following topics while demonstrating the integrations of JMeter, InfluxDB and Grafana:
- What out-of-the-box solutions are available for real-time monitoring JMeter tests?
- What are the benefits of integrating InfluxDB and Grafana into the load testing stack?
- Which features are provided by Grafana?
- Demonstration of InfluxDB and Grafana using a practice web application
To view the webinar recording, go to:
https://www.rttsweb.com/jmeter-integration-webinar
Encryption in Microsoft 365 - ExpertsLive Netherlands 2024Albert Hoitingh
In this session I delve into the encryption technology used in Microsoft 365 and Microsoft Purview. Including the concepts of Customer Key and Double Key Encryption.
Kubernetes & AI - Beauty and the Beast !?! @KCD Istanbul 2024Tobias Schneck
As AI technology is pushing into IT I was wondering myself, as an “infrastructure container kubernetes guy”, how get this fancy AI technology get managed from an infrastructure operational view? Is it possible to apply our lovely cloud native principals as well? What benefit’s both technologies could bring to each other?
Let me take this questions and provide you a short journey through existing deployment models and use cases for AI software. On practical examples, we discuss what cloud/on-premise strategy we may need for applying it to our own infrastructure to get it to work from an enterprise perspective. I want to give an overview about infrastructure requirements and technologies, what could be beneficial or limiting your AI use cases in an enterprise environment. An interactive Demo will give you some insides, what approaches I got already working for real.
Knowledge engineering: from people to machines and back
International Journal of Engineering Research and Development
1. International Journal of Engineering Research and Development
e-ISSN: 2278-067X, p-ISSN: 2278-800X, www.ijerd.com
Volume 10, Issue 2 (February 2014), PP.79-83
79
Finite Element Buckling Analysis Of Stiffened Plates
Dr Alice Mathai1
, Shiney Varghese2
, T.V.Alice3
1
Associate Professor,Department of Civil Engineering,M A College of Engineering,Kothamangalam.
23
Professor,Department of Civil Engineering,M A College of Engineering,Kothamangalam .
Abstract:- Structures consisting of thin plates stiffened by a system of ribs have found wide application for
aircraft, ships, bridges, and buildings as well as in many other branches of contemporary structural engineering.
Buckling analysis can be used to find critical compressive loads at which a structure becomes elastically
unstable. In this paper, buckling analysis of stiffened plates was carried out using finite element software NISA.
The analytical investigations of stiffened plates are rarely found in literature; hence it is found apt to carryout
such investigations to provide design recommendations.
Keywords:- buckling , stiffener ,finite element, stiffness, nonlinear analysis.
I. INTRODUCTION
Stiffened plates are extensively used as structural components in naval and offshore industry. These
stiffened elements, representing a relatively small part of the total weight of the structures, substantially
influence their strength, stiffness and stability. The plates used in ship structure are of very thin dimension
subjected to very high compressive loading include the passenger crew, machines and other combinations of
dead load and live load. To increase the stability of the plates and to withstand the stress and deformations
developed it is not possible to increase the thickness of the plates.
Instead of increasing the thickness of plates and there by increasing the cost of materials, stiffeners are
provided. These stiffener elements presenting relatively small part of the weight of the structure substantially
influence the strength of the structure under different loading conditions. It is assumed that stiffener will have
the same displacement as that of plating. The stiffeners can be positioned any were within the plate element and
need not necessarily be placed on nodal lines as the stiffness matrix of a stiffened plate element is comprised of
the contributions of the plate element and that of the stiffener element. The stability of stiffened plate is
determined from the arrangement and the loading conditions on the plates. There are three types of stiffening
systems,
1) Transverse
2) Longitudinal
3) Combination of both longitudinal and transverse
II. REVIEW OF LITERATURE
Buckling analysis of these plate forms subjected to inplane loads is very relevant in the present
scenario. An attempt has been made here to realize the state of art in the analysis and design of stiffened plates.
Literature describing finite element analysis of stiffened plates are reviewed and presented below.
Jiang et al carried out finite element analysis for the bending and buckling of unstiffened, sandwich,
and hat stiffened orthotropic, rectangular plates. Systematic calculations were performed for deflection; stress
and critical buckling load of the plate using first order shell elements and first and second order three-
dimensional solid elements. The calculated results are compared with available analytical solution for
unstiffened plates. First order shell and second order three-dimensional solid elements are found to model
accurately bending and buckling of the plate structures. For thin unstiffened plates one layer of second order
three-dimensional solid elements through the thickness is found to give sufficient accuracy.
Masoka et al have developed a simple design equation for predicting the ultimate compressive strength
of unstiffened plate with misalignment, initial deflection and welding residual stresses is developed in this study.
A non-linear finite element method is used to investigate the ultimate strength of the imperfect plate. The
method incorporates both geometric and material nonlinearity. Buckling and plasticity behavior of the plate
were expressed using the finite element system. The results from the finite element method and an analytical
method using large deflection theory together with rigid plastic theory were compared. Reduction factors of the
ultimate strength due to welding residual stresses and initial deflection were generated from the results of the
nonlinear finite element method. A new equation for ultimate strength of imperfect plates were developed using
these reduction factors. The accuracy of the proposed new equation was confirmed by comparing it with the
finite element results.
2. Finite Element Buckling Analysis Of Stiffened Plates
80
Rao et al have presented finite element large deflection behavior of stiffened platesusing the
isoparametric quadrilateral stiffened plate bending element. The evaluation of fundamental equation of the
stiffened plates is based on Mindlis’s hypothesis. The large deflection equation were based on von Karman’s
theory. The solution algorithm for the assembled non linear equilibrium equation is based on Newton Raphson
iteration technique. Numerical solutions are presented for rectangular plates and skew stiffened plates. Bergain
et al have carried out large deflection analysis of plates using the finite element method. Sadek et al have
developed A finite element model for the analysis of stiffened laminated plates.
III. FINITE ELEMENT ANALYSIS
The finite element method is an approximate technique by which an object is decomposed in to pieces
and treated as isolated, interacting sections. Finite element method provides a greater flexibility to model
complex geometries than finite difference and finite volume methods do. They also help in solving complex
elasticity, structural analysis problem. The advancement in computer technology enables as to solve even larger
system of equations, to formulate and assemble the discrete approximation, and to display the results quickly
and conveniently. Another important feature is the meshing that is discretization of a continuous domain in to a
set of sub-domains. When we use more number of elements, that is as the mesh size becomes coarser we
converge more to our accurate result. In this method we apply load in increments to each element. Each element
is checked for its stresses and deflections. So we are able to visualize the pattern of behavior for each element.
These all helped in finite element method in becoming a powerful tool.
IV. FINITE ELEMENT PROCEDURE
Following are the steps involved in finite element analysis for buckling analysis.
Idealisation:-
The process of converting the actual 3-D problem in to structure, which is simple and easy to handle, is
called idealization. Here the plate element with the stiffeners is analyzed.
Discretization:
The plate is cut in to many smaller elements called finite elements and these elements are connected at
fixed nodes. The degrees of freedom are chosen and the shape functions are selected.
Formulation of stiffness matrices:-
Bifurcation buckling pressure is determined from linear buckling analysis. Linear buckling analysis is
performed by constructing linear elastic stiffness matrix signifying the internal strain energy and geometric
stiffness matrix representing the work done by the prebuckling stresses on the buckling displacement of the
complete structure.
Element stiffness matrix [K]:-
The stiffness matrix of an element [K] calculated from the equation,
K = ∫v [B]T
[C] [B] dv
Where [B] is the strain-displacement matrix.
[C] is constitutive matrix.
Formulation of geometric stiffness matrix [Kg]:-
Geometric stiffness matrix can be derived from the expression [16] given below.
[Kg] = ∫v d[Bnl]T
{σ}dv
Where [Bnl] is the nonlinear strain-displacement matrix,
{σ} is the compressive stress matrix
Assembly of global stiffness matrices and application of boundary condition:-
The global stiffness matrix of the stiffened plate finite element model is obtained by computing the element
stiffness matrix of each shell element and assembling them by posting them in appropriate global locations
determined by node numbering and connectivity.
Linear buckling analysis
During buckling the total stiffness matrix becomes singular or the determinant of the total stiffness matrix
vanishes. The eigen value problem of instability is therefore formulated as
([Ko] +[KG]) {} = 0 .............................. (1.2)
([Ko]+ b [Kg]) {} = 0 .............................. (1.3)
The buckling pressure is evaluated for the condition
[Ko]+ b[Kg] = 0 ...............................(1.4)
where b is the nondimensional buckling pressure.
The solution procedure adopted for obtaining the linear buckling pressure is the determinant search
procedure. A value of is assumed and the determinant of the matrix is calculated. The process is repeated by
3. Finite Element Buckling Analysis Of Stiffened Plates
81
changing the value of until the determinant changes its sign. The value of for zero determinant is the
buckling pressure.
In the solution, eigen values will be the buckling pressure and eigen vectors will be the buckling
mode. Linear prebuckling analysis has the advantage of avoiding a full nonlinear analysis, which may be
expensive and time consuming.
V. FINITE ELEMENT MODELING
Stiffened plates are modeled as discrete stiffener model and super element model and are described
subsequently.
In the discrete stiffener model plate is modeled using 3D shell element (NKTP-20), which includes
membrane, bending and shear deformation effects. The element has 6 degrees of freedom per node. The
stiffeners are modeled as a 3D beam element (NKTP-12).
In the super element model plate as well as stiffener is modeled using 3D shell element (NKTP-20), which
includes membrane, bending and shear deformation effects. The element has 6 degrees of freedom per node.
Finite element modeling using DISPLAY III consists of two steps viz., geometric and finite element modeling.
The preprocessing phase consists of mesh generation, material definition, constraint definition load definition
and model displays. In the solution phase the element matrices, displacements and stress are calculated. In the
post processing phase stress contours and displacements are displayed.
VI. NISA-TOOL FOR ANALYSIS
Several software packages are now a days available for finite element analysis. NISA is a general
purpose finite element package for structural analysis. Different types of analysis like static, dynamic and
nonlinear analysis can be done by this package.
Fig. 1: Finite element model of stiffened plate (a/b=3, flat-bar stiffener)
Finite Element Details
a) Applied boundary conditions:
Along the short edge of the plate, we have
RY = 0, that is rotation about Y direction is restricted
Along the long edge of the plate, we have
UY = 0, that is deflection in the Y direction is restricted
RX = 0, that is we restrict rotation about X direction
Along the line of transverse girder, UX, UY, UZ is constrained
4. Finite Element Buckling Analysis Of Stiffened Plates
82
Fig. 2 Finite element model of stiffened plate (a/b=3, flat-bar stiffener)
with meshing and boundary conditions
b) Loads applied
Here we are going for only one load case that is inplane loading of compressive nature. Inplane load is
applied along the width of the plate and stiffener.
c) Load calculation
The load is applied as nodal load along the width of the plate as well as stiffener.
The total load on plate is calculated as,
In plates – yield stress x cross sectional area of plate
In stiffeners – yield stress x cross sectional area of stiffener
The load acting on each node is calculated as: total load/no of elements
As an example consider the following load calculation on a plate of size 2400 x 800 x 10 and stiffener of
dimensions 150 x 17
Total load on plate = 313.6 x (800 x 10)
Total load on stiffener = 313.6 x (150x17)
Fig. 3 Buckled shape for plate with flat bar as stiffener
5. Finite Element Buckling Analysis Of Stiffened Plates
83
VII. COMPARISON BETWEEN DISCRETE STIFFENER MODELING AND
RIGOROUS MODELING
There are two methods for modeling stiffened panels
1. Discrete stiffener modeling and
2. Rigorous modeling
Discrete stiffener modeling
In discrete stiffener modeling the stiffeners are discretised using 3D beam element and plate is
discretised using shell elements. Merging ensures the connection between the plate and stiffeners the nodes is
the interface between plate and stiffeners.
Rigorous modeling
In rigorous modeling the plate as well as the stiffener are discretised using shell elements. In NISA the
advantage of using rigorous modeling is that we can visualize the cross section of the stiffener and see the
deformation pattern for the web as well as flanges of the stiffener.
IV. RESULTS AND DISCUSSIONS
Table I shows the load factor obtained for flat bar stiffener using discrete stiffener modeling as well as
rigorous modeling.
Table I: Load Factor for Plate with Flat Bar Stiffener Using Discrete Stiffener and Rigorous Modeling
Type Load factor %
variationdiscrete stiffener rigorous modeling
F31015 0.4184 0.366 12.52
F31315 0.6165 0.5564 9.75
F31515 0.7835 0.7152 8.72
From the analysis results given in table I, it can be seen that the result obtained for discrete beam
analysis and rigorous analysis are close to each other. The percentage variations are 12.52% , 9.75%, 8.72%
respectively for plates having thickness 10,13,15 mm. The results obtained from rigorous analysis fall on the
safer side. Hence the rigorous stiffener modeling may be considered as more accurate. Since the % variation is
less and the and the memory space required for discrete analysis are minimal discrete stiffener analysis can be
effectively used for the analysis of complex structures. If the accuracy level required is much high rigorous
stiffener modeling may be adopted.
REFERENCES
[1]. Rajagopalan, K., Finite Element Buckling Analysis of Stiffened Cylindrical Shells. Oxford and IBH
Publishing Company, New Delhi, India, 1993.
[2]. Felippa, C.A., Lecture Notes in Nonlinear Finite Element Method, Center for Aerospace Structures,
Boulder, Colorado, 1999.
[3]. Cook, R.D, Malkus, D.S., Pleasha, M.E. Concepts and application of finite element analysis, 3/E, John
Wiley and sons, 2000.
[4]. S.Rajasekaran, Finite Element Analysis in engineering Design, Wheeler Publishing, 1993.
[5]. C.S Krishnamoorthy, Finite Element Analysis-Theory and Progarmming,Tata.Mc Graw-Hill
Publishing Company Ltd.1997
[6]. Crisfield, M.A., Incremental/Iterative Algorithm that Handles Snap through, Computers and Structures,
Vol. 13,pp 55-62, 1981.
[7]. Hughes, T.J.R., Hinton, E., Finite Element Method for Plate and Shell Structures, Vol. 1: Element
Technology; Vol. 2 Formulation and Algorithms, Pineridge, Swansea, 1986.
[8]. NISA manual, 2003.
[9]. Bryan,G.H., On the stability of a plane plate under thrust in its own plane, with application to buckling
of side of ship, London Mathematical Society Proceedings,22,54-67,1981
[10]. Troitsky, M. S., Stiffened plates bending, stability and vibrations, Elsevier publishing company-USA,
1976.