Preliminary Study on the Deformation of Yuxi Basin under Gravity Action by Nonlinear Finite Element Simulation

2012 ◽  
Vol 170-173 ◽  
pp. 1097-1106
Author(s):  
Tie Fei Li ◽  
Xue Liang Chen ◽  
Meng Tan Gao
Keyword(s):  
Constitutive Model ◽  
Great Influence ◽  
Constitutive Models ◽  
Secondary Development ◽  
Modified Model ◽  
Nonlinear Constitutive Model ◽  
Element Simulation ◽  
Calculation Results ◽  
Nonlinear Elastic ◽  
Nonlinear Finite Element Simulation

Abstract. A secondary development of the ADINA software for Duncan-Chang E-B nonlinear elastic constitutive model was conducted in this paper, and the veracity of calculation results was verified. To contrast linear constitutive model and Duncan-Chang nonlinear constitutive model, the deformation of YuXi basin profile model under gravity action was calculated by both of the constitutive models. The results show that the subsidence in the linear results is about 12% larger than the nonlinear results, and the nonlinear model has advantages in parameter choosing. Meanwhile, a modified model of YuXi basin which depends on the latest data from our recent work in YuXi area was built to compare with the original model, the calculation results show that the changes in the basin basement structure and basin depth have great influence on the distribution and maximums of the deformation results, when the changes in the internal structure and sequence influence relatively little.

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.

scholarly journals A Thermodynamic Constitutive Model for Saturated Sand

Entropy ◽  
2019 ◽  
Vol 21 (2) ◽  
pp. 136
Author(s):  
Shize Xiao ◽  
Xiaohui Cheng ◽  
Zhou Yang
Keyword(s):  
Constitutive Model ◽  
Soil Mechanics ◽  
Constitutive Models ◽  
Yield Function ◽  
Flow Rule ◽  
Saturated Sand ◽  
Coupling Energy ◽  
Dissipative Mechanism ◽  
Nonlinear Elastic ◽  
Undrained Shear

This paper establishes a non-equilibrium thermodynamic constitutive model that can predict the undrained shear behavior of saturated sand. Starting from the basic laws of thermodynamics, the model does not require the classical concepts in elasto-plastic models, such as the yield function, the flow rule, and the hardening rule. It is also different from the existing thermodynamic constitutive models in soil mechanics literatures. The model does not use a complex nonlinear elastic potential as usually and introduces a coupling energy dissipative mechanism between the viscosity and elasticity relaxation, which is essential in granular materials. Then this model was used to simulate the undrained shear test of Toyoura sand. The model can predict the critical state, dilatancy-contraction and hardening-softening characteristics of sand during undrained triaxial shearing.

scholarly journals Anisotropic Nonlinear Elastic Model of Concrete and Secondary Development in ABAQUS

2016 ◽  
Vol 10 (1) ◽  
pp. 615-624 ◽  
Author(s):  
Wei Sun ◽  
Yansheng Huang
Keyword(s):  
Constitutive Model ◽  
Simulation Model ◽  
Constitutive Relation ◽  
Secondary Development ◽  
Elastic Model ◽  
Convergence Problem ◽  
Plastic Damage ◽  
User Material Subroutine ◽  
Nonlinear Elastic ◽  
Abaqus Software

In order to solve the convergence problem of concrete constitutive in the softening phase, an anisotropic nonlinear elastic constitutive model (ANECM) was proposed, which was developed based on the uniaxial concrete constitutive relation in the Chinese code for design of concrete structures (GB 50010-2010). The user material subroutine (UMAT) based on ANECM is developed in ABAQUS software. The above UMAT is applied to analyze a simulation model in ABAQUS software. The result shows that compared to the default plastic-damage concrete constitutive in ABAQUS, ANECM is an effective and appropriate model to simulate the performance of concrete and it has improved the convergence problem.

Nonlinear Constitutive Model Research on Concrete (Uni-Axial or Multi-Axial)

2011 ◽  
Vol 261-263 ◽  
pp. 238-241
Author(s):  
Jia Wei Yao ◽  
Shi Yong Sun ◽  
Hao Ran Chen
Keyword(s):  
Theoretical Model ◽  
Simple Model ◽  
Constitutive Model ◽  
Isotropic Material ◽  
Strain Energy ◽  
Strain Energy Function ◽  
Biaxial Stress ◽  
Nonlinear Constitutive Model ◽  
Model Research ◽  
Nonlinear Elastic

Combined with Jones-Nelson-Morgan model applied to ceramics and graphite successfully, the nonlinear constitutive model of concrete is obtained through large number of tests in this paper. The model takes concrete as nonlinear elastic isotropic material. By using strain energy function, it makes the nonlinear mechanics behavior of concrete as the function of strain energy. According to the mechanics behavior of concrete, a simple model is obtained by increasing stress to realize the model calculation program. The model can be extended to the constitutive model analysis of concrete under biaxial stress. The theoretical model conforms to testing results well.

Effects of Joint Congruency on the Response of a Tension-Compression Nonlinear Constitutive Model for Cartilage

2008 ◽  
Author(s):  
Benjamin J. Ellis ◽  
Gerard A. Ateshian ◽  
Andrew E. Anderson ◽  
Clare Canal ◽  
Steve A. Maas ◽  
...  
Keyword(s):  
Constitutive Model ◽  
Solid Phase ◽  
Constitutive Models ◽  
Incompressible Material ◽  
Material Behavior ◽  
Nonlinear Material ◽  
Similar Response ◽  
Joint Congruency ◽  
Nonlinear Constitutive Model ◽  
Rate Dependent

Articular cartilage exhibits inhomogeneous, rate-dependent and tension-compression (TC) nonlinear material properties. It is a biphasic material (solid and fluid phases) and its solid phase is stiffer in tension than compression [1]. Despite this complex material behavior, elastic, incompressible material models can be used to predict the short-time loading response of cartilage [2]. To our knowledge, the use of an anisotropic incompressible material to represent cartilage in a finite element (FE) joint model has not been investigated and thus the importance of the TC nonlinearity in the analysis of 3D articular contact models is limited [3]. We have been investigating a TC nonlinear incompressible constitutive model to represent hip cartilage. The objective of this study was to assess the influence of TC nonlinearity on FE predictions of stress and strain as a function of congruency between two spherical cartilage layers. It was hypothesized that the TC nonlinear and neo-Hookean constitutive models would yield a similar response when the cartilage layers were nearly congruent, but as the congruency of the cartilage layers decreased the predicted response from the two materials would be different.

Analysis on Parameters in Duncan-Chang Constitutive Model

2011 ◽  
Vol 368-373 ◽  
pp. 2900-2903
Author(s):  
Bo Zhang
Keyword(s):  
Constitutive Model ◽  
Geotechnical Engineering ◽  
Constitutive Models ◽  
Reference Value ◽  
Main Property ◽  
Ansys Software ◽  
Engineering Problems ◽  
Solution Methods ◽  
Calculation Results ◽  
Chang Model

Duncan—Chang constitutive model is widely used for it reflecting the main property—nonlinearity of soil. In the paper, the geotechnical Duncan—Chang constitutive model is introduced into ANSYS software by using the User Programmable Features (UPFS) of ANSYS. The calculation results with eight parameters variation in Duncan—Chang model are analyzed, which has much wider reference value for geotechnical engineering problems. The relative solution methods provide important reference for other constitutive models to be introduced into and analyzed in ANSYS program.

scholarly journals A Simplified Analysis Method for the Deformation Response of an Existing Tunnel to Ground Surcharge Based on the Pasternak Model

2021 ◽  
Vol 11 (7) ◽  
pp. 3255
Author(s):  
Zheng Wei ◽  
Yusheng Jiang
Keyword(s):  
Longitudinal Displacement ◽  
Maximum Displacement ◽  
Deformation Response ◽  
Reaction Coefficient ◽  
Element Simulation ◽  
Tunnel Model ◽  
Calculation Results ◽  
Pasternak Model ◽  
Boussinesq Solution ◽  
Euler Bernoulli Beam

Surface surcharge changes the existing equilibrium stress field of the stratum and adversely affects the existing tunnel. This paper presents a simplified analytical solution for calculating the longitudinal displacement of existing tunnels that are subjected to adjacent surcharge loading. Based on the Boussinesq solution, the distribution of the additional load matrix caused by the surface surcharge on the existing tunnel was obtained. A Euler–Bernoulli beam with a Pasternak foundation was used as a simplified model for tunnel stress analysis. Using the corrected reaction coefficient of the foundation bed, the differential equation of tunnel deformation was established, and the solution matrix of the longitudinal displacement of the tunnel was obtained by using the finite difference method. The reliability and applicability of the proposed method were verified by comparing the results with finite element simulation results, field test data, and the calculation results of three simplified elastic analysis methods with different foundation bed coefficients. On this basis, the parameters of the load–tunnel model were analyzed, and the effects of the buried depth, the size of the load, the relative positions of the load and the tunnel, and the relative stiffness of the tunnel soil on the maximum displacement of the existing tunnel were calculated. An empirical formula is proposed for calculating the maximum longitudinal displacement of the existing tunnel subjected to surface surcharge. The findings of this research can provide a basis for the theoretical verification of the deformation response of an existing tunnel subjected to adjacent surface surcharge.

scholarly journals Calibration of Finn Model and UBCSAND Model for Simplified Liquefaction Analysis Procedures

2021 ◽  
Vol 11 (11) ◽  
pp. 5283
Author(s):  
Jui-Ching Chou ◽  
Hsueh-Tusng Yang ◽  
Der-Guey Lin
Keyword(s):  
Numerical Simulation ◽  
Constitutive Model ◽  
Structural Damage ◽  
Simulation Analysis ◽  
Constitutive Models ◽  
Soil Liquefaction ◽  
Analysis Procedure ◽  
Liquefaction Resistance ◽  
Simplified Procedure ◽  
Liquefaction Analysis

Soil-liquefaction-related hazards can damage structures or lead to an extensive loss of life and property. Therefore, the stability and safety of structures against soil liquefaction are essential for evaluation in earthquake design. In practice, the simplified liquefaction analysis procedure associated with numerical simulation analysis is the most used approach for evaluating the behavior of structures or the effectiveness of mitigation plans. First, the occurrence of soil liquefaction is evaluated using the simplified procedure. If soil liquefaction occurs, the resulting structural damage or the following mitigation plan is evaluated using the numerical simulation analysis. Rational and comparable evaluation results between the simplified liquefaction analysis procedure and the numerical simulation analysis are achieved by ensuring that the liquefaction constitutive model used in the numerical simulation has a consistent liquefaction resistance with the simplified liquefaction analysis procedure. In this study, two frequently used liquefaction constitutive models (Finn model and UBCSAND model) were calibrated by fitting the liquefaction triggering curves of most used simplified liquefaction analysis procedures (NCEER, HBF, JRA96, and T-Y procedures) in Taiwan via FLAC program. In addition, the responses of two calibrated models were compared and discussed to provide guidelines for selecting an appropriate liquefaction constitutive model in future projects.

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.

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