scholarly journals An Image-Based Finite Element Approach for Simulating Viscoelastic Response of Asphalt Mixture

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Wenke Huang ◽  
Xiaoning Zhang ◽  
Yingmei Yin
Keyword(s):  
Finite Element ◽  
Constitutive Model ◽  
Asphalt Mixture ◽  
Viscoelastic Behavior ◽  
Ct Images ◽  
Asphalt Mastic ◽  
Numerical Predictions ◽  
Linear Viscoelastic Material ◽  
Digital Sample ◽  
Viscoelastic Constitutive Model

This paper presents an image-based micromechanical modeling approach to predict the viscoelastic behavior of asphalt mixture. An improved image analysis technique based on the OTSU thresholding operation was employed to reduce the beam hardening effect in X-ray CT images. We developed a voxel-based 3D digital reconstruction model of asphalt mixture with the CT images after being processed. In this 3D model, the aggregate phase and air void were considered as elastic materials while the asphalt mastic phase was considered as linear viscoelastic material. The viscoelastic constitutive model of asphalt mastic was implemented in a finite element code using the ABAQUS user material subroutine (UMAT). An experimental procedure for determining the parameters of the viscoelastic constitutive model at a given temperature was proposed. To examine the capability of the model and the accuracy of the parameter, comparisons between the numerical predictions and the observed laboratory results of bending and compression tests were conducted. Finally, the verified digital sample of asphalt mixture was used to predict the asphalt mixture viscoelastic behavior under dynamic loading and creep-recovery loading. Simulation results showed that the presented image-based digital sample may be appropriate for predicting the mechanical behavior of asphalt mixture when all the mechanical properties for different phases became available.

Significance of material constitutive model and forming parameters on the crashworthiness performance of capped cylindrical tubular structures

2019 ◽  
Vol 234 (2) ◽  
pp. 320-334
Author(s):  
Praveen Kumar A ◽  
Afdhal Akbar ◽  
Annisa Jusuf ◽  
Leonardo Gunawan
Keyword(s):  
Finite Element ◽  
Constitutive Model ◽  
Performance Indicators ◽  
Thickness Distribution ◽  
Material Constitutive Model ◽  
Numerical Predictions ◽  
Forming Parameters ◽  
Crushing Force ◽  
Cylindrical Tubes ◽  
Energy Absorbing

An accuracy of crushing performance indicators is critical to evaluate in finite element crushing simulations particularly for the press-formed capped tubular energy absorbing structures. It is essential to select the appropriate material constitutive model and to incorporate the forming parameters into the finite element crushing model as a vital input. Hence in the present article, the influence of various material constitutive models and forming (multi-stage deep drawing) parameters on the axial crashworthiness characteristics of thin-walled capped cylindrical tubes were investigated numerically. Both forming and crushing simulations were executed by nonlinear finite element LS-DYNA® code. The forming parameters such as thickness distribution, residual stress, and effective plastic strain were mapped to a finite element crushing model of the tube. The numerical predictions of the thickness distribution and final deformed profiles of the capped cylindrical tubes are correlated with the experiments. The results revealed that the forming parameters have a substantial effect on the crushing performance of the deep drawn capped cylindrical tubes. As a result of these analyses, the thickness and strain predictions strengthens the tube and significantly influenced the crushing performance indicators such as initial peak crushing force, mean crushing force, and the energy absorbing capacity.

Finite element simulation of ferromagnetic shape memory alloys using a revised constitutive model

2017 ◽  
Vol 28 (19) ◽  
pp. 2853-2871 ◽  
Author(s):  
Siavash Jafarzadeh ◽  
Mahmoud Kadkhodaei
Keyword(s):  
Finite Element ◽  
Shape Memory Alloy ◽  
Constitutive Model ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Model Parameters ◽  
Ferromagnetic Shape Memory Alloy ◽  
Ferromagnetic Shape Memory Alloys ◽  
Numerical Predictions ◽  
Ferromagnetic Shape Memory

In this article, a previously developed constitutive model for ferromagnetic shape memory alloys is phenomenologically enhanced using experimental observations. A modified phase diagram along with a method for calibration of the required model parameters is further presented. The model is implemented into a user material subroutine to equip commercial finite element software ABAQUS with the capability of simulating magneto-mechanical behaviors of ferromagnetic shape memory alloys. A combined convergence scheme is employed to solve the implicit equations. The proposed model together with the presented numerical solution is shown to be able to study shape memory effect and pseudoelasticity at different constant magnetic fields. The simulated magnetic loading/unloading cycles at different constant stresses are found to be well-fitted to the experimental findings. As a practical application of the ferromagnetic shape memory alloy coupled magneto-mechanical response, a spring actuator (a bias spring serially connected to one ferromagnetic shape memory alloy element) is investigated, and the numerical predictions are shown to be in a good agreement with available experimental results. As a novel case, geometrically graded NiMnGa elements are also introduced and are simulated with the use of this approach.

scholarly journals Investigation on Microstructural Damage Properties of Asphalt Mixture Using Linear and Damage-Coupled Viscoelastic Model

2019 ◽  
Vol 9 (2) ◽  
pp. 303
Author(s):  
Wenke Huang ◽  
Zhibin Ren ◽  
Xiaoning Zhang ◽  
Jiangmiao Yu
Keyword(s):  
Stress Distribution ◽  
Viscoelastic Model ◽  
Asphalt Mixture ◽  
Viscoelastic Behavior ◽  
Von Mises Stress ◽  
Micromechanical Modeling ◽  
Fe Model ◽  
Asphalt Mastic ◽  
Simulation Results ◽  
Von Mises

This paper presents an image-based micromechanical modeling approach for simulating the damage-couple viscoelastic response of asphalt mixture. Details of the numerical damage-couple viscoelastic constitutive formulation implemented in a finite element code are presented and illustrated by using the ABAQUS user material subroutine (UMAT). Then, an experimental procedure based on the Linear Amplitude Sweep test for obtaining the viscoelastic and damage parameters at a given temperature was conducted. An improved morphological multi-scale algorithm was employed to segment the adhesive coarse aggregate images. We developed a pixel-based digital reconstruction model of asphalt mixture with the X-ray CT image after being processed. Finally, the image-based FE model incorporated with damage-coupled viscoelastic asphalt mastic phase and elastic aggregates was used for the compressive test simulations successfully in this study. Simulation results showed that the damaged simulation results have a larger stress distribution compared with the undamaged simulation due to the irregularity of the coarse aggregates. The von Mises stress distribution is smaller as the loading time increases due to the viscoelastic behavior of asphalt mastic. It can also provide insight on the damaged mechanisms and the possible location in asphalt mixture where microscopic cracking would most likely occur.

A study on warpage behavior of EMC in post-mold cure stage using Moldex3D

2016 ◽  
Vol 2016 (DPC) ◽  
pp. 000826-000850 ◽  
Author(s):  
Hsu Chih-Chung ◽  
Srikar Vallury ◽  
Srikar Vallury ◽  
Kai Lin ◽  
Anthony Yang
Keyword(s):  
Three Dimensional ◽  
Viscoelastic Behavior ◽  
Product Yield ◽  
Maxwell Model ◽  
Factors Affecting ◽  
Numerical Predictions ◽  
Linear Viscoelastic Material ◽  
Cure Time ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

Warpage and residual stress are the two most important factors affecting product yield rate and reliability in IC encapsulation process. This study presents the prediction of warpage in post-mold cure stage using a three-dimensional finite element approach coupled with linear viscoelastic material property. Furthermore, cure-induced volumetric shrinkage and thermal expansion mismatch are considered. The shrinkage of the EMC is described by Pressure-Volume-Temperature-Cure (PVTC) model, and Generalized Maxwell model; WLF relation is adopted to describe the viscoelastic behavior of EMC. In order to obtain accurate numerical results, Cure-Time-Temperature superposition is considered. For verifying the numerical predictions of three dimensional simulations, the calculated results are compared with the available experimental data from literature.

Influence of degradation of structure on the behaviour of a full-scale embankment

2012 ◽  
Vol 49 (3) ◽  
pp. 344-356 ◽  
Author(s):  
S. Panayides ◽  
M. Rouainia ◽  
D. Muir Wood
Keyword(s):  
Finite Element ◽  
Constitutive Model ◽  
Pore Water ◽  
Model Comparison ◽  
Field Measurements ◽  
Full Scale ◽  
Numerical Predictions ◽  
Pore Water Pressures ◽  
Finite Element Procedure ◽  
Degradation Of Structure

The advanced constitutive model KHSM for structured clays, which incorporates the effects of loss of structure within an elastoplastic framework, has been implemented in a finite element procedure and used to investigate the failure height and pore-water pressures of embankment A constructed at Saint Alban, Quebec. For the purpose of model comparison, simulations were also performed using the standard bubble model (KHM) without destructuration. The numerical predictions of pore-water pressures and settlements are also compared with field measurements. The results clearly demonstrate the importance of including the effects of loss of structure in the analysis.

The Secondary Development of Nonlinear Viscoelastic Constitutive Model Based on ABAQUS

2011 ◽  
Vol 138-139 ◽  
pp. 466-470
Author(s):  
Long Yi ◽  
Yun Peng ◽  
Hou Quan Hong ◽  
Yu Liang Li
Keyword(s):  
Finite Element ◽  
Constitutive Model ◽  
Material Model ◽  
Secondary Development ◽  
Uniaxial Tensile ◽  
Finite Element Software ◽  
Material Constitutive Model ◽  
Nonlinear Viscoelastic ◽  
Linear Viscoelastic ◽  
Viscoelastic Constitutive Model

Based on the subroutine VUMAT, user-defined material model in the nonlinear finite element software ABAQUS/EXPLICIT, a nonlinear viscoelastic constitutive model is developed. The validify of the subroutine has been proven through the standard uniaxial tensile model. The shortage of finite element softwares which only have linear viscoelastic constitutive model is remedied. This paper presents the process of developing a material constitutive model and some useful technology. It can be referred for extending the material constitutive model in finite element softwares.

Numerical Simulation of Viscoelastic Behavior of Asphalt Mixture Using Fractional Constitutive Model

2021 ◽  
Vol 147 (5) ◽  
pp. 04021027
Author(s):  
Linhao Gu ◽  
Weiguang Zhang ◽  
Tao Ma ◽  
Xiaohua Qiu ◽  
Jian Xu
Keyword(s):  
Numerical Simulation ◽  
Constitutive Model ◽  
Asphalt Mixture ◽  
Viscoelastic Behavior

scholarly journals Size Effects of Finite Element Model for Three-Dimensional Microstructural Modeling of Asphalt Mixture

2019 ◽  
Vol 2019 ◽  
pp. 1-9
Author(s):  
Kuanghuai Wu ◽  
Qingzi Deng ◽  
Naiming Deng ◽  
Xu Cai ◽  
Wenke Huang
Keyword(s):  
Finite Element ◽  
Asphalt Mixture ◽  
Three Dimensional ◽  
Computational Time ◽  
Digital Models ◽  
Element Analysis ◽  
Stiffness Modulus ◽  
Voxel Size ◽  
Linear Viscoelastic Material ◽  
Creep Stiffness

Asphalt mixture is a particulate composite material consisting of aggregate, mastic, and air voids. The computed tomography (CT) image-based finite element approach is used as an effective method to simulate micromechanical response of asphalt mixture. For finite element analysis, the accuracy of the finite results is determined by the size of the finite element. In this paper, a voxel-based three-dimensional (3D) digital reconstruction model of asphalt mixture with the CT images after being processed was proposed. In this 3D model, the aggregate phase was considered as elastic materials while the asphalt mastic phase was considered as linear viscoelastic material. Four micromechanical digital models were generated, whose voxel sizes were 0.5 mm, 0.67 mm, 1.0 mm, and 2.0 mm, respectively. The four digital models were used to conduct uniaxial creep test for predicting creep stiffness modulus to investigate the effect of voxel size. Simulation results showed that the voxel sizes had a significant effect on creep stiffness modulus. For the creep simulation test, the most appropriate voxel size whose creep stiffness modulus changes within 2.5% is 1.0 mm with regard to time steps, computational time, aggregate, and mastic shape representations.

scholarly journals Characterizing the hyper-viscoelastic behavior of adhesive films

2021 ◽  
Vol 37 ◽  
pp. 446-453
Author(s):  
Hao-Hsun Hsu ◽  
Jia-Lin Tsai
Keyword(s):  
Experimental Data ◽  
Stress Relaxation ◽  
Constitutive Model ◽  
Viscoelastic Model ◽  
Viscoelastic Behavior ◽  
Tensile Tests ◽  
Single Step ◽  
Material Parameters ◽  
Reduced Gradient Method ◽  
Viscoelastic Constitutive Model

Abstract In this study, the hyper-viscoelastic behavior of adhesive films was characterized. A constitutive model was developed by combining the Mooney–Rivlin hyperelastic model and a viscoelastic model expressed in terms of the Prony series to describe the constitutive behavior of the adhesive films. The material parameters of the developed constitutive model were determined through single-step stress relaxation tests conducted for 30 min at four strain levels: 100%, 200%, 300% and 400%. Based on the reduced gradient method, the optimized material parameters were then evaluated by curve fitting the experimental data. To validate the proposed constitutive model, we performed the tensile tests at different strain rates from 5 × 10−4 to 5 × 10−1 s−1 and the multistep stress relaxation tests on the adhesive films. The model predictions and experimental data were in good agreement. Thus, the proposed hyper-viscoelastic constitutive model with parameters determined through single-step stress relaxation tests is effective in characterizing the mechanical behavior of adhesive films.

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