scholarly journals A novel nonlinear constitutive model for rock: Numerical assessment and benchmarking

2020 ◽  
Vol 3 ◽  
pp. 100012
Author(s):  
R. Bustamante ◽  
S. Montero ◽  
A. Ortiz-Bernardin
Keyword(s):  
Constitutive Model ◽  
Nonlinear Constitutive Model ◽  
Numerical Assessment

scholarly journals A nonlinear strain-rate dependent constitutive model for uncured rubber materials under large deformation

2020 ◽  
Vol 37 ◽  
pp. 118-125
Author(s):  
Weihua Zhou ◽  
Changqing Fang ◽  
Huifeng Tan ◽  
Huiyu Sun
Keyword(s):  
Constitutive Model ◽  
Large Deformation ◽  
Mechanical Response ◽  
Uniaxial Tensile ◽  
Hysteresis Phenomenon ◽  
Mechanical Behaviors ◽  
Nonlinear Constitutive Model ◽  
Rate Dependent ◽  
Parallel Networks ◽  
Non Gaussian

Abstract Uncured rubber possesses remarkable hyperelastic and viscoelastic properties while it undergoes large deformation; therefore, it has wide application prospects and attracts great research interests from academia and industry. In this paper, a nonlinear constitutive model with two parallel networks is developed to describe the mechanical response of uncured rubber. The constitutive model is incorporated with the Eying model to describe the hysteresis phenomenon and viscous flow criterion, and the hyperelastic properties under large deformation are captured by a non-Gaussian chain molecular network model. Based on the model, the mechanical behaviors of hyperelasticity, viscoelasticity and hysteresis under different strain rates are investigated. Furthermore, the constitutive model is employed to estimate uniaxial tensile, cyclic loading–unloading and multistep tensile relaxation mechanical behaviors of uncured rubber, and the prediction results show good agreement with the test data. The nonlinear mechanical constitutive model provides an efficient method for predicting the mechanical response of uncured rubber materials.

A new nonlinear constitutive model of CSG

2021 ◽  
pp. 1-8
Author(s):  
Xinjun Feng ◽  
Fangfang Zhang ◽  
Lixia Guo ◽  
Ling Zhong
Keyword(s):  
Constitutive Model ◽  
Nonlinear Constitutive Model

scholarly journals Uniform Nonlinear Constitutive Model and Parameters for Clay in Different Consolidation Conditions Based on Regression Method

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Tao Cheng ◽  
Keqin Yan ◽  
Huazhi Zhang ◽  
Xianfeng Luo ◽  
Shengfang Li
Keyword(s):  
Constitutive Model ◽  
Initial Conditions ◽  
Constitutive Relations ◽  
Test Sample ◽  
Maximum Relative Error ◽  
Compression Tests ◽  
Stress Strain ◽  
Strain Behavior ◽  
Nonlinear Constitutive Model ◽  
Isotropic Consolidation

The nonlinear constitutive relations of clay are investigated considering different initial conditions. Highly compressible clay is selected as the test sample. Two groups of tri-axial compression tests are performed, respectively, afterK0consolidation and isotropic consolidation. On the basis of the framework ofE~vmodel, a uniform nonlinear constitutive model is proposed by fitting the test data. With the average slope of the unloading-reloading curve selected as the unloading modulus, the unloading function is constructed as the loading-unloading criterion. Moreover, a comparison between the experimental stress-strain curves and the results predicted by the constitutive model is made. It is shown that the prediction is reasonable, which can reflect the stress-strain behavior of the soil under theK0consolidation and isotropic consolidation conditions. The maximum relative error of the two series of curves is not remarkable, less than 6%.

Electrically Nonlinear Fracture Analysis of Piezoelectric Materials Based on CED (Crack Energy Density)

2007 ◽  
Vol 353-358 ◽  
pp. 1513-1516
Author(s):  
Rong Feng Liu ◽  
Byeung Gun Nam ◽  
Katsuhiko Watanabe
Keyword(s):  
Energy Density ◽  
Constitutive Model ◽  
Piezoelectric Materials ◽  
Compact Tension ◽  
Fracture Analysis ◽  
Compact Tension Specimen ◽  
Fracture Parameter ◽  
Tension Specimen ◽  
Nonlinear Constitutive Model ◽  
Nonlinear Fracture

An electrical nonlinear constitutive model for piezoelectric material is studied in this paper. Electric yielding criterion and yielding effect on CED are investigated. Using the mechanical part of CED as a fracture parameter, it is shown that the predicted fracture loads through FEA for compact tension specimen is in accordance with corresponding experimental results.

scholarly journals Energy-based constitutive modelling of local material properties of canine aortas

2016 ◽  
Vol 3 (9) ◽  
pp. 160365 ◽  
Author(s):  
Kaveh Laksari ◽  
Danial Shahmirzadi ◽  
Camilo J. Acosta ◽  
Elisa Konofagou
Keyword(s):  
Constitutive Model ◽  
Mechanical Behaviour ◽  
Computational Models ◽  
Constitutive Models ◽  
Constitutive Modelling ◽  
Axial Position ◽  
Aortic Tissue ◽  
Nonlinear Constitutive Model ◽  
Local Material Properties

This study aims at determining the in vitro anisotropic mechanical behaviour of canine aortic tissue. We specifically focused on spatial variations of these properties along the axis of the vessel. We performed uniaxial stretch tests on canine aortic samples in both circumferential and longitudinal directions, as well as histological examinations to derive the tissue's fibre orientations. We subsequently characterized a constitutive model that incorporates both phenomenological and structural elements to account for macroscopic and microstructural behaviour of the tissue. We showed the two fibre families were oriented at similar angles with respect to the aorta's axis. We also found significant changes in mechanical behaviour of the tissue as a function of axial position from proximal to distal direction: the fibres become more aligned with the aortic axis from 46° to 30°. Also, the linear shear modulus of media decreased as we moved distally along the aortic axis from 139 to 64 kPa. These changes derived from the parameters in the nonlinear constitutive model agreed well with the changes in tissue structure. In addition, we showed that isotropic contribution, carried by elastic lamellae, to the total stress induced in the tissue decreases at higher stretch ratios, whereas anisotropic stress, carried by collagen fibres, increases. The constitutive models can be readily used to design computational models of tissue deformation during physiological loading cycles. The findings of this study extend the understanding of local mechanical properties that could lead to region-specific diagnostics and treatment of arterial diseases.

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