Bifurcation Analyses of Steel and Concrete with Rate-Dependent Properties Part Two: Bifurcation Analyses and Demonstration

2002 ◽  
Vol 4 (4) ◽  
pp. 225-232
Author(s):  
Luming Shen ◽  
Yuxing Liu ◽  
Zhen Chen
Keyword(s):  
Strain Rate ◽  
Bifurcation Analysis ◽  
Critical State ◽  
Damage Model ◽  
Tangent Stiffness ◽  
Rate Dependent ◽  
Elasto Plasticity ◽  
Failure Angle ◽  
Mohr’S Circle ◽  
The Continuum

Based on the continuum tangent stiffness tensors derived in part one for steel and concrete, bifurcation analyses of rate-dependent elasto-plasticity and elasto-damage are performed in (-(and (-(spaces of Mohr, respectively. Localization ellipse osculating Mohr's circle enables us to determine the critical state and failure angle. It is shown that strain rate has no effect on the failure angle, and that the parameters in rate-dependent damage model are restricted by the results of bifurcation analysis.

A study on the link between coupled plasticity and damage and decohesion for multiscale modelling

2001 ◽  
Vol 215 (3) ◽  
pp. 259-263 ◽  
Author(s):  
Z Chen ◽  
H E Fang
Keyword(s):  
Bifurcation Analysis ◽  
Failure Modes ◽  
Damage Model ◽  
Multiscale Modelling ◽  
Material Failure ◽  
Continuum Damage ◽  
Stiffness Tensor ◽  
Tangent Stiffness ◽  
The Continuum

To predict the transition from continuous to discontinuous failure modes, a bifurcation analysis is performed based on the continuum tangent stiffness tensor of a coupled plasticity and damage model. As a result, continuum damage and decohesion approaches can be combined for multiscale modelling of material failure.

scholarly journals A Strain Rate Dependent Progressive Damage Model for Carbon Fiber Woven Composites under Low Velocity Impact

2021 ◽  
Vol 2101 (1) ◽  
pp. 012073
Author(s):  
Xueyao Hu ◽  
Jiaojiao Tang ◽  
Wei Xiao ◽  
Kepeng Qu
Keyword(s):  
Strain Rate ◽  
Damage Model ◽  
Low Velocity Impact ◽  
Woven Composites ◽  
Progressive Damage ◽  
Low Velocity ◽  
Velocity Impact ◽  
Rate Dependent ◽  
Plane Direction ◽  
Progressive Damage Model

Abstract A progressive damage model was presented for carbon fiber woven composites under low velocity impact, considering the strain rate sensitivity of both mechanical properties and failure mechanisms. In this model, strain rate dependency of elastic modulus and nominal strength along in-plane direction are considered. Based on the Weibull distribution, stiffness progressive degradation is conducted by introducing strain rate dependent damage variables for distinct damage modes. With the model implemented in ABAQUS/Explicit via user-defined material subroutine (VUMAT), the mechanical behavior and possible damage modes of composites along in-plane direction can be determined. Furthermore, a bilinear traction separation model and a quadratic stress criterion are applied to predict the initiation and evolution of interlaminar delamination. Comparisons are made between the experimental results and numerical simulations. It is shown that the mechanical response and damage characteristics under low velocity impact, such as contact force history and delamination, are more consistent with the experimental results when taken the strain rate effect into consideration.

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.

Energy-based numerical modeling of the strain rate effect on fracture toughness of SA508 Gr. 1a

2017 ◽  
Vol 52 (3) ◽  
pp. 177-189 ◽  
Author(s):  
Hyun-Suk Nam ◽  
Yun-Jae Kim ◽  
Jin-Weon Kim ◽  
Jong-Sung Kim
Keyword(s):  
Fracture Toughness ◽  
Strain Rate ◽  
Damage Model ◽  
Type Model ◽  
Fracture Toughness Test ◽  
Ductile Tearing ◽  
Rate Dependent ◽  
Energy Concept ◽  
Axial Fracture ◽  
Dynamic Loading Conditions

This article presents an energy-based method to simulate ductile tearing under dynamic loading conditions. The strain rate–dependent material properties are characterized by the Johnson–Cook-type model. The damage model is defined based on the multi-axial fracture strain energy concept. The proposed damage model is applied to simulate the fracture toughness test of SA508 Gr. 1a under four different test speeds. Simulated results show a good overall agreement with the experimental results.

Bifurcation Analyses of Steel and Concrete with Rate-Dependent Properties Part One: Model Formulation and Verification

2002 ◽  
Vol 4 (4) ◽  
pp. 217-224
Author(s):  
Yuxing Liu ◽  
Luming Shen ◽  
Zhen Chen
Keyword(s):  
Damage Model ◽  
Three Dimensional ◽  
Plain Concrete ◽  
Environmental Engineering ◽  
Material Failure ◽  
Plasticity Model ◽  
Model Formulation ◽  
University Of Missouri ◽  
Rate Dependent ◽  
Elasto Plasticity

Department of Civil and Environmental Engineering, University of Missouri-Columbia, Columbia MO 65211–2200, U.S.A. The effects of strain rate on the mechanical properties of carbon steel and plain concrete are investigated through a rate-dependent elasto-plasticity model and rate-dependent elasto-damage model, respectively. Continuum tangent stiffness tensors are derived for both models so that bifurcation analyses can be performed to identify the onset of material failure. Three-dimensional constitutive model solvers are designed and the numerical results are compared with the experimental data to verify the proposed models.

scholarly journals ADI 1050-6 Mechanical Behavior at Different Strain Rates and Temperatures

2018 ◽  
Vol 925 ◽  
pp. 196-202 ◽  
Author(s):  
Andrew Ruggiero ◽  
Gianluca Iannitti ◽  
Stefano Masaggia ◽  
Federico Vettore
Keyword(s):  
Strain Rate ◽  
Damage Mechanics ◽  
Damage Model ◽  
Stress Triaxiality ◽  
Continuum Damage Mechanics ◽  
Tensile Tests ◽  
Yield Function ◽  
Strain Rates ◽  
The Continuum

An experimental characterization of the austempered ductile iron ISO 17804/JS/1050-6/S was performed carrying out tensile tests under different strain rates, temperatures and stress triaxiality levels. Then, composing a yield function surface, a hardening relation, and a damage criterion, a constitutive model was developed to describe the salient features of the observed macroscopic response. In particular, the Mohr-Coulomb yield function was selected to account for the pressure effect observed on the yield surface. A new hardening relation was proposed in order to account for both strain rate and temperature effects. The Bonora’s damage model, developed in the framework of the continuum damage mechanics, was adopted to capture the failure condition under different stress triaxiality levels. The damage model was appropriately modified to account for the effect of strain rate and temperature on the failure strain.

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