Why is it necessary to use a damage model to simulate the mechanical behavior of concrete under drying and leaching?

2010 ◽  
Vol 14 (6-7) ◽  
pp. 923-935
Author(s):  
Thomas Rougelot ◽  
Cheng Peng ◽  
Nicolas Burlion ◽  
Dominique Bernard
Keyword(s):  
Mechanical Behavior ◽  
Damage Model

scholarly journals Extension of Flow Behaviour and Damage Models for Cast Iron Alloys with Strain Rate Effect

2020 ◽  
Author(s):  
Chuang Liu ◽  
Dongzhi Sun ◽  
Xianfeng Zhang ◽  
Florence Andrieux ◽  
Tobias Gerster
Keyword(s):  
Cast Iron ◽  
Constitutive Model ◽  
Strain Rate ◽  
Mechanical Behavior ◽  
Damage Model ◽  
Iron Alloys ◽  
Strain Rate Range ◽  
Strain Rates ◽  
Damage Models ◽  
Rate Dependent

Abstract Cast iron alloys with low production cost and quite good mechanical properties are widely used in the automotive industry. To study the mechanical behavior of a typical ductile cast iron (GJS-450) with nodular graphite, uni-axial quasi-static and dynamic tensile tests at strain rates of 10− 4, 1, 10, 100, and 250 s− 1 were carried out. In order to investigate the effects of stress state, specimens with various geometries were used in the experiments. Stress–strain curves and fracture strains of the GJS-450 alloy in the strain-rate range of 10− 4 to 250 s− 1 were obtained. A strain rate-dependent plastic flow law based on the Voce model is proposed to describe the mechanical behavior in the corresponding strain-rate range. The deformation behavior at various strain rates is observed and analyzed through simulations with the proposed strain rate-dependent constitutive model. The available damage model from Bai and Wierzbicki is extended to take the strain rate into account and calibrated based on the analysis of local fracture strains. The validity of the proposed constitutive model including the damage model was verified by the corresponding experimental results. The results show that the strain rate has obviously nonlinear effects on the yield stress and fracture strain of GJS-450 alloys. The predictions with the proposed constitutive model and damage models at various strain rates agree well with the experimental results, which illustrates that the rate-dependent flow rule and damage models can be used to describe the mechanical behavior of cast iron alloys at elevated strain rates.

Prediction of non-linear mechanical behavior of shear deformed twill woven composites based on a multi-scale progressive damage model

2019 ◽  
Vol 224 ◽  
pp. 111019
Author(s):  
Yeon-Taek Hwang ◽  
Kyung-Hee Choi ◽  
Jae-In Kim ◽  
Jaeyoung Lim ◽  
Byeunggun Nam ◽  
...  
Keyword(s):  
Mechanical Behavior ◽  
Damage Model ◽  
Woven Composites ◽  
Progressive Damage ◽  
Multi Scale ◽  
Non Linear ◽  
Progressive Damage Model

scholarly journals Numerical analysis of steel-fiber-reinforced concrete beams using damage mechanics

2016 ◽  
Vol 9 (2) ◽  
pp. 153-191
Author(s):  
W. M. Pereira Junior ◽  
D. L. Araújo ◽  
J. J. C. Pituba
Keyword(s):  
Reinforced Concrete ◽  
Mechanical Behavior ◽  
Damage Mechanics ◽  
Steel Fiber ◽  
Concrete Beams ◽  
Damage Model ◽  
Fiber Reinforced Concrete ◽  
Reinforced Concrete Beams ◽  
Fiber Reinforced ◽  
Steel Fiber Reinforced Concrete

ABSTRACT This work deals with numerical modeling of the mechanical behavior of steel-fiber-reinforced concrete beams using a constitutive model based on damage mechanics. Initially, the formulation of the damage model is presented. The concrete is assumed to be an initial elastic isotropic medium presenting anisotropy, permanent strains, and bimodularity induced by damage evolution. In order to take into account the contribution of the steel fiber to the mechanical behavior of the media, a homogenization procedure is employed. Finally, numerical analyses of steel-fiber-reinforced concrete beams submitted to bending loading are performed in order to show the good performance of the model and its potential.

Effects of cyclic wetting-drying on the mechanical behavior and improved damage model for sandstone

2020 ◽  
pp. 1-11
Author(s):  
Xuewei Liu ◽  
Quansheng Liu ◽  
Shibing Huang ◽  
Bin Liu ◽  
Jiang Liu
Keyword(s):  
Mechanical Behavior ◽  
Damage Model

scholarly journals A damage model of mechanical behavior of porous materials: Application to sandstone

2017 ◽  
Vol 27 (9) ◽  
pp. 1325-1351 ◽  
Author(s):  
MY Li ◽  
YJ Cao ◽  
WQ Shen ◽  
JF Shao
Keyword(s):  
Porous Medium ◽  
Mechanical Behavior ◽  
Porous Materials ◽  
Solid Phase ◽  
Damage Model ◽  
Multiscale Model ◽  
Elementary Volume ◽  
Elastoplastic Model ◽  
Porous Sandstone ◽  
Damage Process

In this work, a multiscale model based on the Fast Fourier Transform (FFT) technique is applied to describe the mechanical behavior of porous materials. The effects of the microstructures (such as pore shape, number, size, distribution and orientation) on the overall strength of the porous medium and its microstress distribution are fully studied. The elastoplastic model is further extended by including a damage process. The influences of microstructure on the damage evolution of the porous medium are discussed and illustrated numerically. Then the proposed multiscale damage model is applied to study the macroscopic behavior of porous sandstone. According to the microstructure of the studied material, a representative elementary volume with randomly distributed spherical pores is considered. The solid phase of the sandstone is assumed to obey the Drucker–Prager criterion. Taking advantage of the FFT-based method, the evolution of generated damage is clearly illustrated during the loading process at the microscopic level. Comparisons between numerical results and experimental data show the efficiency of the proposed numerical model.

scholarly journals Experimental and Numerical Study of Mechanical Behavior of Welded Steel Plate Joints

Metals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1293
Author(s):  
Hongwei Ma ◽  
Hao Zheng ◽  
Wei Zhang ◽  
Zhanzhan Tang ◽  
Eric M. Lui
Keyword(s):  
Mechanical Behavior ◽  
Failure Modes ◽  
Steel Plate ◽  
Numerical Study ◽  
Damage Model ◽  
Hysteretic Behavior ◽  
Cyclic Loads ◽  
Welded Steel ◽  
Damage Process ◽  
Monotonic Loads

This paper describes a study of welded steel plate joints using experimental and numerical methods. The objectives of this study are to observe the mechanical behavior of welded plate joints under monotonic and cyclic loads, identify their damage degradation processes, and provide useful test data for future damage analysis of beam-column connections in steel frame structures. Six specimens were designed, of which three were tested under monotonic loads, and the other three were tested under cyclic loads. The test setup consisted of three plates arranged in a cruciform and connected by two groove welds. The monotonic and cyclic loads were applied to the free end of the two outstanding plates, inducing a pulling force on the welded joint. Because the only element studied in the present work is the weld, the sizes of the three plates were kept constant. The responses of these welded plate joints are discussed in terms of their experimentally and numerically obtained mechanical parameters, hysteretic behavior, strain variations, stiffness degradation, damage process, and failure modes. The results show that the energy damage model outperforms the displacement damage model in terms of indicating the degree of damage. Furthermore, if designed according to code, all these welded plate joints perform satisfactorily.

A thermodynamics-based damage model for the non-linear mechanical behavior of SiC/SiC ceramic matrix composites in irradiation and thermal environments

2020 ◽  
Vol 29 (10) ◽  
pp. 1569-1599
Author(s):  
Mohammad Alabdullah ◽  
Nasr M Ghoniem
Keyword(s):  
Thermal Conductivity ◽  
Mechanical Behavior ◽  
Damage Mechanics ◽  
Damage Model ◽  
Ceramic Matrix Composites ◽  
Irradiation Damage ◽  
Continuum Damage ◽  
Wide Spread ◽  
Thermodynamic Framework ◽  
Non Linear

A damage model is developed and validated with experimental data for the non-linear mechanical behavior of SiC/SiC composite materials in nuclear applications. Cyclic thermal and mechanical loading associated with neutron irradiation effects of these composites leads to wide-spread and progressive micro-cracking that leads to loss of thermal conductivity and further enhancement of thermo-mechanical damage. A physics-based model of wide-spread micro-cracking is developed within the thermodynamic framework of continuum damage mechanics. Evolution equations for damage parameters that describe the growth of continuum damage are developed, where the material variables are obtained from experiments. The model novelty is in coupling mechanical, thermal, and irradiation damage through a consistent thermodynamic framework, including loss of thermal conductivity due to the evolution of mechanically induced micro-cracks. A number of thermo-mechanical experiments were conducted to confirm model assumptions. The model is shown to be validated with out-of-pile experiments, and then implemented using commercial finite element code COMSOL to the fuel cladding problem with normal and high radiation dose cases.

scholarly journals A Creep Damage Constitutive Model for a Rock Mass with Nonpersistent Joints under Uniaxial Compression

2019 ◽  
Vol 2019 ◽  
pp. 1-11
Author(s):  
Shuran Lv ◽  
Wanqing Wang ◽  
Hongyan Liu
Keyword(s):  
Rock Mass ◽  
Constitutive Model ◽  
Mechanical Behavior ◽  
Uniaxial Compression ◽  
Damage Model ◽  
Creep Damage ◽  
Model Parameters ◽  
Damage Constitutive Model ◽  
Set Up ◽  
Creep Damage Model

As part of the rock mass, both the mesoscopic and macroscopic flaws will affect the creep mechanical behavior of the rock mass with nonpersistent joints. This study focuses on this kind of rock mass and establishes a creep damage model to account for the effect of the joint on its creep mechanical behavior. First, on basis of analyzing the rock element creep mechanism and the typical creep deformation curve, a new creep damage constitutive model for the rock element is set up by introducing the damage theory and Kachanov damage evolution law into the classic creep constitutive model such as J body model. Second, the determination method of the proposed model parameters is studied in detail. Third, the calculation method of the macroscopic damage caused by the joint proposed by others is introduced which can consider the joint geometry, strength, and deformation parameters at the same time. Finally, the creep damage model for the rock mass with nonpersistent joints under uniaxial compression is proposed. The calculation examples indicate that it can present the effect of the joint on the rock mass creep mechanical behavior.

Sign in / Sign up

Export Citation Format

Share Document