Implementation of Constitutive Model in FEA for Nonlinear Behavior of Plastics

2008 ◽  
pp. 83-83-15
Author(s):  
ID Skrypnyk ◽  
JL Spoormaker ◽  
W Smit
Keyword(s):  
Constitutive Model ◽  
Nonlinear Behavior

Nonlinear Finite Element Analysis of Super-Long Pile and Soil Interaction in Soft Soil

2011 ◽  
Vol 201-203 ◽  
pp. 1601-1605 ◽  
Author(s):  
Shang Ping Chen ◽  
Wen Juan Yao ◽  
Sheng Qing Zhu
Keyword(s):  
Finite Element ◽  
Constitutive Model ◽  
Soft Soil ◽  
Three Dimensional ◽  
Nonlinear Behavior ◽  
Element Model ◽  
Element Analysis ◽  
Friction Resistance ◽  
Tip Resistance ◽  
Side Friction

In this paper, a nonlinear three-dimensional finite element model for super-long pile and soil interaction is established. In this model, contact elements are applied to simulate the nonlinear behavior of interaction of super-long pile and soil. A nonlinear elastic constitutive model for concrete is employed to analyze stress-strain relation of pile shaft under the axial load and the Duncan-Chang’s nonlinear constitutive model is used to reflect nonlinear and inelastic properties of soil. The side friction resistance, axial force, pile-tip resistance, and developing trend of soil plastic deformation are obtained and compared with measured results from static load tests. It is demonstrated that a super-long pile has the properties of degradation of side friction resistance and asynchronous action between side and pile-tip resistance, which is different from piles with a short to medium length.

A Nonlinear Compressible Transversely-Isotropic Viscohyperelastic Constitutive Model of the Periodontal Ligament

2008 ◽  
Author(s):  
Alexei I. Zhurov ◽  
Sam L. Evans ◽  
Catherine A. Holt ◽  
John Middleton
Keyword(s):  
Constitutive Model ◽  
Periodontal Ligament ◽  
Nonlinear Behavior ◽  
Strain Energy Function ◽  
Transversely Isotropic ◽  
Material Parameters ◽  
Identification Technique ◽  
Optical Motion ◽  
Analysis System ◽  
Advanced Version

The periodontal ligament may be treated as a transversely-isotropic viscohyperelastic fibre-reinforced compressible material which is subject to large deformations and has an essentially nonlinear behavior. Within these assumptions, a continuum constitutive model of the PDL was proposed recently [48], which involves a number of material parameters that have to be identified from experimental data. An optical motion analysis system was developed [26] to collect data on the deformation of the PDL. In the present paper, an advanced version of the model is suggested, which is based on the assumption of the existence of an additive strain-energy function dependent on a number of principal invariants. The sensitivity analysis of the material parameters is performed and a parameter identification technique is suggested.

Numerical Prediction Method for Elasto-Viscoplastic Behavior of Glass Fiber Reinforced Polyurethane Foam Under Various Compressive Loads and Cryogenic Temperatures

2015 ◽  
Author(s):  
Chi-Seung Lee ◽  
Myung-Sung Kim ◽  
Kwang-Ho Choi ◽  
Myung-Hyun Kim ◽  
Jae-Myung Lee
Keyword(s):  
Constitutive Model ◽  
Strain Rate ◽  
Glass Fiber ◽  
Polyurethane Foam ◽  
Prediction Method ◽  
Nonlinear Behavior ◽  
Cryogenic Temperatures ◽  
Fiber Reinforced ◽  
Rate Dependent ◽  
Glass Fiber Reinforced

In the present study, the material characteristics of a glass fiber-reinforced polyurethane foam (RPUF) which is widely adopted to a liquefied natural gas (LNG) insulation system was investigated by a series of compressive tests under room and cryogenic temperatures. In addition, a temperature- and strain rate-dependent constitutive model was proposed to describe the material nonlinear behavior such as increase of yield stress and plateau according to temperature and strain rate variations. The elasto-viscoplastic model was transformed to an implicit form, and was implemented into the ABAQUS user-defined subroutine, namely, UMAT. Through a number of simulation using the developed subroutine, the various stress-strain relationships of RPUF were numerically predicted, and the material parameters associated with the constitutive model were identified. In order to validate the proposed method, the computational results were compared to a series of test of RPUF.

A Second Generation of Numerical Implementation of Nonlinear Piezoelectric Models in Commercially Available Tools

2008 ◽  
Author(s):  
M. A. Siddiq Qidwai ◽  
V. G. DeGiorgi
Keyword(s):  
Finite Element ◽  
Constitutive Model ◽  
Domain Switching ◽  
Piezoelectric Materials ◽  
Nonlinear Behavior ◽  
Material Behavior ◽  
Device Performance ◽  
Performance Improvements ◽  
Rate Dependent ◽  
Theoretical Developments

Domain switching based nonlinear behavior is characteristic of relaxor-type piezoelectric material such as PMN-PT single crystals. These materials offer significant device performance improvements over traditional polycrystalline piezoelectric materials such as PZT-5A. The promise of increased performance of these materials has led to work in development of constitutive characterizations so that material behavior under load and material failure mechanisms can be understood and predicted. However, there is a gap between development of such theoretical developments and in workable manifestations available as part of commercial finite element codes for use in device design. In the current work, the authors extend previously documented implementation of a macro-mechanical constitutive model which addresses domain switching, into a commercially available finite element code. A rate dependent version of the constitutive model has been successfully realized and used to reproduce a variety of piezoelectric constitutive behaviors.

scholarly journals Temperature and strain rate effects of jammed granular systems: experiments and modelling

2021 ◽  
Vol 23 (4) ◽  
Author(s):  
Piotr Bartkowski ◽  
Grzegorz Suwała ◽  
Robert Zalewski
Keyword(s):  
Finite Element Analysis ◽  
Constitutive Model ◽  
Strain Rate ◽  
Nonlinear Behavior ◽  
Experimental Investigations ◽  
Granular Systems ◽  
Element Analysis ◽  
Strain Rate Effects ◽  
Mechanical Responses ◽  
Rate Effects

AbstractJammed granular systems, also known as vacuum packed particles (VPP), have begun to compete with the well commercialized group of smart structures already widely applied in various fields of industry, mainly in civil and mechanical engineering. However, the engineering applications of VPP are far ahead of the mathematical description of the complex mechanical mechanisms observed in these unconventional structures. As their wider commercialization is hindered by this gap, in the paper the authors consider experimental investigations of granular systems, mainly focusing on the mechanical responses that take place under various temperature and strain rate conditions. To capture the nonlinear behavior of jammed granular systems, a constitutive model constituting an extension of the Johnson–Cook model was developed and is presented. green The extended and modified constitutive model for VPP proposed in the paper could be implemented in the future into a commercial Finite Element Analysis code, making it possible to carry out fast and reliable numerical simulations.

scholarly journals Strategies for Analyzing Random Vibration of Jointed Structures

2013 ◽  
Author(s):  
Daniel J. Segalman ◽  
Michael J. Starr ◽  
Michael A. Guthrie
Keyword(s):  
Constitutive Model ◽  
Mathematical Models ◽  
Dynamic Analysis ◽  
Random Vibration ◽  
Nonlinear Behavior ◽  
System Response ◽  
Equivalent Linearization ◽  
Nonlinear Structures ◽  
Random Loads ◽  
Previous Approximation

Development of mathematical models for built-up structures, particularly those with many interfaces, is still primitive. This limitation is particularly evident when complex loads and load histories are considered, an example of which is random vibration. Two steps in simplifying this problem are explored here. First, the system response is approximated as that of the superposition of numerous decoupled modes, the coordinates of which evolve according to a constitutive model designed to capture the nonlinearity of the structure. Second, because among the categories of load for which dynamic analysis on nonlinear structures is particularly difficult is that of random loads and the resulting random vibration, and given the previous approximation, it is natural to apply the method of stochastic equivalent linearization to the governing equation of each mode. Both of these approximations are explored for the case where the nonlinear behavior of the interfaces is represented by a Masing-Prandtl-Ishlinskii-Iwan model employing a Palmov kernel.

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