Analysis of Material Nonlinear Problems Using Pseudo-Elastic Finite Element Method

2000 ◽  
Vol 122 (4) ◽  
pp. 457-461 ◽  
Author(s):  
V. Desikan ◽  
Raju Sethuraman

A method based on linear elastic finite element analysis is presented for stress field determination of elasto-plastic problems. Hencky’s total deformation theory is used to define effective material parameters, which are treated as spatial field variables and considered to be functions of final state of equilibrium stress and material properties. These effective material parameters are obtained in an iterative manner using strain-controlled projection method, arc-length method, and Neuber rule applied on experimental uniaxial tension test curve. Three problems of von Mises material are considered to illustrate the application of the proposed method: a thick-walled cylinder subjected to internal pressure characterized by general work-hardening behavior, a V-notch specimen subjected to remote tensile load having elastic-perfectly plastic behavior, and a rotating disk with material having elastic linear work-hardening behavior. Obtained results for all the cases are compared with standard nonlinear finite element results and are found to be in good agreement. [S0094-9930(00)00104-9]

2008 ◽  
Vol 36 (1) ◽  
pp. 63-79 ◽  
Author(s):  
L. Nasdala ◽  
Y. Wei ◽  
H. Rothert ◽  
M. Kaliske

Abstract It is a challenging task in the design of automobile tires to predict lifetime and performance on the basis of numerical simulations. Several factors have to be taken into account to correctly estimate the aging behavior. This paper focuses on oxygen reaction processes which, apart from mechanical and thermal aspects, effect the tire durability. The material parameters needed to describe the temperature-dependent oxygen diffusion and reaction processes are derived by means of the time–temperature–superposition principle from modulus profiling tests. These experiments are designed to examine the diffusion-limited oxidation (DLO) effect which occurs when accelerated aging tests are performed. For the cord-reinforced rubber composites, homogenization techniques are adopted to obtain effective material parameters (diffusivities and reaction constants). The selection and arrangement of rubber components influence the temperature distribution and the oxygen penetration depth which impact tire durability. The goal of this paper is to establish a finite element analysis based criterion to predict lifetime with respect to oxidative aging. The finite element analysis is carried out in three stages. First the heat generation rate distribution is calculated using a viscoelastic material model. Then the temperature distribution can be determined. In the third step we evaluate the oxygen distribution or rather the oxygen consumption rate, which is a measure for the tire lifetime. Thus, the aging behavior of different kinds of tires can be compared. Numerical examples show how diffusivities, reaction coefficients, and temperature influence the durability of different tire parts. It is found that due to the DLO effect, some interior parts may age slower even if the temperature is increased.


Author(s):  
Md Anwar Ali Anshari ◽  
Murshid Imam ◽  
Mohd Zaheer Khan Yusufzai ◽  
Viswanath Chinthapenta ◽  
Rajnish Mishra

Author(s):  
A. Ajdari ◽  
P. K. Canavan ◽  
H. Nayeb-Hashemi ◽  
G. Warner

Three-dimensional structure of trabecular bone can be modeled by 2D or 3D Voronoi structure. The effect of missing cell walls on the mechanical properties of 2D honeycombs is a first step towards understanding the effect of local bone resorption due to osteoporosis. In patients with osteoporosis, bone mass is lost first by thinning and then by resorption of the trabeculae [1]. Furthermore, creep response is important to analyze in cellular solids when the temperature is high relative to the melting temperature. For trabecular bone, as body temperature (38 °C) is close to the denaturation temperature of collagen (52 °C), trabecular bone creeps [1]. Over the half of the osteoporotic vertebral fractures that occur in the elderly, are the result of the creep and fatigue loading associated with the activities of daily living [2]. The objective of this work is to understand the effect of missing walls and filled cells on elastic-plastic behavior of both regular hexagonal and non-periodic Voronoi structures using finite element analysis. The results show that the missing walls have a significant effect on overall elastic properties of the cellular structure. For both regular hexagonal and Voronoi materials, the yield strength of the structure decreased by more than 60% by introducing 10% missing walls. In contrast, the results indicate that filled cells have much less effect on the mechanical properties of both regular hexagonal and Voronoi materials.


2021 ◽  
Vol 2 (2) ◽  
pp. 93-97
Author(s):  
Satriawan Dini Hariyanto ◽  
Wikan Kurniawan

Stress analysis of the bender components in the design of the begel fabricator machine was carried out using FEA (Finite Element Analysis) with three variations of the constituent material parameters, namely 6061 aluminum, mild steel, and cast iron with a modulus of elasticity of 68.9 GPa, 220 GPa, 120.5 GPa, respectively. The test is carried out by a loading parameter 2520 MPa and fixed constraint. The maximum von misses stress and displacement obtained for each material parameter components using aluminum, mild steel, and cast iron are 17.78 MPa; 0.00765, 17.49 MPa; 0.00229, 17.62 MPa; 0.00427 respectively.


Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 397
Author(s):  
Bin Zhou ◽  
Weiwei Zhang ◽  
Zhongmei Gao ◽  
Guoqiang Luo

As a representative type of superalloy, Inconel 718 is widely employed in aerospace, marine and nuclear industries. The significant work hardening behavior of Inconel 718 can improve the service performance of components; nevertheless, it cause extreme difficulty in machining. This paper aims to investigate the influence of chamfered edge parameters on work hardening in orthogonal cutting of Inconel 718 based on a novel hybrid method, which integrates Coupled Eulerian-Lagrangian (CEL) method and grain-size-based functions considering the influence of grain size on microhardness. Orthogonal cutting experiments and nanoindentation tests are conducted to validate the effectiveness of the proposed method. The predicted results are highly consistent with the experimental results. The depth of work hardening layer increases with increasing chamfer angle and chamfer width, also with increasing feed rate (the uncut chip thickness). However, the maximum microhardness on the machined surface does not exhibit a significant difference. The proposed method can provide theoretical guidance for the optimization of cutting parameters and improvement of the work hardening.


2008 ◽  
Vol 130 (4) ◽  
Author(s):  
Vishnu Verma ◽  
A. K. Ghosh ◽  
G. Behera ◽  
Kamal Sharma ◽  
R. K. Singh

The miniature disk bending test is used to evaluate the mechanical behavior of irradiated materials and their properties (e.g., yield stress and strain hardening exponent) to determine mainly ductility loss in steel due to irradiation from the load-deflection behavior of the disk specimen. In the miniature disk bending machine the specimen is firmly held between the two horizontal jaws of punch, and an indentor with a spherical ball travels vertically. Analytical solutions for large amplitude plastic deformation become rather unwieldy. Hence, a finite element analysis has been carried out. The finite element model considers contact between the indentor and test specimen, friction between various pairs of surfaces, and elastic plastic behavior. This paper presents the load versus deflection results of a parametric study where the values of various parameters defining the material properties have been varied by ±10% around the base values. Some well-known analytical solutions to this problem have also been considered. It is seen that the deflection obtained by analytical elastic bending theory is significantly lower than that obtained by the elastoplastic finite element solution at relatively small values of load. The finite element solution has been compared with one experimental result and values are in reasonably good agreement. With these results it will be possible to determine the material properties from the experimentally obtained values of load and deflection.


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