Investigation of the incremental and deformation theories of plasticity on the elastoplastic postbuckling of plates

2020 ◽  
Vol 234 (7) ◽  
pp. 1017-1031
Author(s):  
HM Soltani ◽  
M Kharazi
Keyword(s):  
Finite Element ◽  
Boundary Conditions ◽  
Deformation Theory ◽  
Finite Element Code ◽  
Postbuckling Behavior ◽  
Incremental Theory ◽  
Aspect Ratios ◽  
Theory Of Plasticity ◽  
The Difference

This article investigates the elastoplastic response of buckling and postbuckling behavior of plates under uniaxial and biaxial end-shortening considering incremental theory and deformation theory of plasticity. According to elastoplastic buckling and postbuckling behavior of plates, the finite element code considering geometrically and material nonlinearities is developed based on incremental theory and deformation theory of plasticity. The results show that boundary conditions, loading ratios, and aspect ratios of a plate have a significant effect on the discrepancy between incremental theory and deformation theory. Moreover, differences in estimating the buckling point using incremental theory and deformation theory are less than 10%, while in a number of plates at the last loading steps, postbuckling paths determined by incremental theory and deformation theory are diverted from each other. Also the difference between these two theories in the postbuckling region is more noticeable by increasing the thickness of plates.

Forced Motions of Composite Conoidal Shell Roofs with Complicated Boundary Conditions

2010 ◽  
Vol 123-125 ◽  
pp. 89-92
Author(s):  
Kaustav Bakshi ◽  
Hari Sadhan Das ◽  
Dipankar Chakravorty
Keyword(s):  
Finite Element ◽  
Boundary Conditions ◽  
Forced Vibration ◽  
Vibration Characteristics ◽  
Finite Element Code ◽  
Isoparametric Finite Element

An eight noded isoparametric finite element code is applied to study static bending, free and forced vibration characteristics of composite conoidal shell roofs with complicated boundary conditions which are often encountered in the industry.

Plastic Deformation Theory Application in Finite Element Analysis

2012 ◽  
Vol 594-597 ◽  
pp. 2723-2726
Author(s):  
Wen Shan Lin
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Deformation Theory ◽  
Three Dimensional ◽  
Constitutive Laws ◽  
Constitutive Law ◽  
Element Analysis ◽  
Finite Element Program ◽  
Theory Of Plasticity ◽  
Element Program

In the present study, the constitutive law of the deformation theory of plasticity has been derived. And that develop the two-dimensional and three-dimensional finite element program. The results of finite element and analytic of plasticity are compared to verify the derived the constitutive law of the deformation theory and the FEM program. At plastic stage, the constitutive laws of the deformation theory can be expressed as the linear elastic constitutive laws. But, it must be modified by iteration of the secant modulus and the effective Poisson’s ratio. Make it easier to develop finite element program. Finite element solution and analytic solution of plasticity theory comparison show the answers are the same. It shows the derivation of the constitutive law of the deformation theory of plasticity and finite element analysis program is the accuracy.

scholarly journals Spatial thin-walled reinforced concrete structures taking into account physical nonlinearity in SCAD software. Rod finite element

2019 ◽  
Author(s):  
Sergiy Fialko ◽  
Viktor Karpilowskyi
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Plastic Flow ◽  
Deformation Theory ◽  
Numerical Solutions ◽  
Experimental Studies ◽  
Particle Method ◽  
Reinforced Concrete Beams ◽  
Principal Stresses ◽  
Theory Of Plasticity

This paper considers a spatial frame bar finite element for modeling reinforced concrete beams and columns. Both concrete and reinforcement are described by the equations of the deformation theory of plasticity and the theory of plastic flow. Degradation of concrete during cracking is modeled by the descending branch of the σ – ε diagram (the deformation theory of plasticity), as well as the compression of the yield surface and its displacement in the space of principal stresses (the plastic flow theory). The longitudinal reinforcement is considered discretely. It is assumed that there is no reinforcement slipping in concrete. The paper provides the results of the studies that reveal the causes of computational instability related to the presence of a descending branch of the σ – ε diagram for concrete, and proposes ways to overcome it. The reliability of the obtained results is confirmed by comparing them with the results of experimental studies performed by other researchers, as well as with the results of numerical solutions obtained by the particle method. This paper also provides an example of the nonlinear analysis of the fragment of a multi-storey building from the SCAD Soft collection of problems (www.scadsoft.com).

scholarly journals Effect of Torsional Element towards High-Speed Rotating Shaft’s Critical Speed at Different Boundary Conditions

2019 ◽  
Vol 8 (4) ◽  
pp. 6787-6792
Keyword(s):  
Finite Element ◽  
Boundary Conditions ◽  
High Speed ◽  
Critical Speed ◽  
Element Model ◽  
Accurate Estimation ◽  
Fe Model ◽  
Rotating Shaft ◽  
Different Boundary Conditions ◽  
The Difference

Efficiency improvement that can be provided by the high-speed rotating equipment becomes a concern for designers nowadays. Since the high-speed rotating machinery was capable of rotating at very near to critical speed, the accurate estimation of critical speed needs to be considered. This paper investigated the effect of torsional element towards critical speed of high-speed rotating shaft system for pinned-pinned (P-P), clamped-free (C-F) and clamped-free (C-F) boundaries condition. The Nelson’s finite element model that considers the torsional effect was developed for formulating the finite element (FE) model. This FE model was used to derive Mathieu-Hill’s equation and then solved by applying the Bolotin’s theory. From the solution, the Campbell’s diagram of the high-speed shaft was plotted. It was found that torsional motion has significant effect on the critical speed for different boundary conditions. The difference between critical speed of 4DOF and 5DOF models can be as high as 6.91 %.

Thermo-mechanical induced vibration characteristics of shear deformable functionally graded ceramic—metal plates using finite element method

2010 ◽  
Vol 225 (1) ◽  
pp. 50-65 ◽  
Author(s):  
M Talha ◽  
B N Singh
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Temperature Field ◽  
Boundary Conditions ◽  
Vibration Characteristics ◽  
Functionally Graded ◽  
Thickness Direction ◽  
Aspect Ratios ◽  
Shear Deformable ◽  
Element Method

This paper deals with the thermomechanical-induced vibration characteristics of shear deformable functionally graded material (FGM) plates. Theoretical formulations are based on higher-order shear deformation theory with a significant improvement in the transverse displacement using finite-element method. The mechanical properties of the plate are assumed to be temperature-dependent and graded in the thickness direction according to a power-law distribution in terms of the volume fractions of the constituents. The temperature field is ascertained to be a uniform distribution over the plate surface and varied in the thickness direction only. The fundamental equations for FGM plates are derived using variational approach by considering traction-free boundary conditions on the top and bottom faces of the plate. A C0 continuous isoparametric Lagrangian finite-element with 13 degrees of freedom (DOF) per node have been used to accomplish the results. Convergence and comparison studies have been performed for square plates to demonstrate the efficiency of the present model. The numerical results are obtained for different thickness ratios, aspect ratios, volume fraction index, and temperature rise with different boundary conditions. The results reveal that the temperature field and the gradient in the material properties have significant effect on the vibration characteristics of the FGM plates.

scholarly journals NURBS-Based Isogeometric Analysis of Beams and Plates Using High Order Shear Deformation Theory

2013 ◽  
Vol 2013 ◽  
pp. 1-9
Author(s):  
Xinkang Li ◽  
Jifa Zhang ◽  
Yao Zheng
Keyword(s):  
Boundary Conditions ◽  
Shear Deformation ◽  
Isogeometric Analysis ◽  
Deformation Theory ◽  
Shear Deformation Theory ◽  
Basis Functions ◽  
B Splines ◽  
Aspect Ratios ◽  
Generalized Displacements ◽  
Thin Beams

Isogeometric analysis (IGA) based on nonuniform rational B-splines (NURBS) is developed for static analysis of beams and plates using the third-order shear deformation theory (TSDT). TSDT requires C1-continuity of generalized displacements; quadratic, cubic, and quartic NURBS basis functions are utilized to satisfy this requirement. Due to the noninterpolatory nature of NURBS basis functions, a penalty method is presented to enforce the essential boundary conditions. A series of numerical examples of thick and thin beams and plates with different boundary conditions are presented. Results are compared with analytical solutions and other numerical methods. First-order shear deformation theory (FSDT) is also employed and compared with TSDT in the stress analysis. The effects of aspect ratios and boundary conditions are discussed as well.

The Analysis on Effect of the Terrain to the Culverts Stress by the Finite Element Method

2012 ◽  
Vol 212-213 ◽  
pp. 643-646
Author(s):  
Qing Jiang ◽  
Huan Jun Lai ◽  
Zhi Zhong Su
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Boundary Conditions ◽  
The Finite Element Method ◽  
Filling Height ◽  
Homogeneous Complex ◽  
Non Linear ◽  
Complex Boundary ◽  
The Difference ◽  
Element Method

Highlight advantages of the finite element method is suitable for non-linear, non-homogeneous, complex boundary conditions. The paper adopts the finite element method to analysis culvert stress in Valley terrain. Gain that when the filling height H=40 meters, considering the valley topography calculated Ks=1.19, otherwise the Ks=1.435, the difference is about 17%. Therefore, the effects of the valley terrain to the high embankment culvert can not be ignored.

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