Modeling of Stress-State-Dependent Damage and Failure of Ductile Metals

2015 ◽  
Vol 784 ◽  
pp. 35-42 ◽  
Author(s):  
Michael Brünig ◽  
Daniel Brenner ◽  
Steffen Gerke
Keyword(s):  
Stress State ◽  
Evolution Equations ◽  
Damage Model ◽  
Continuum Damage ◽  
Ductile Metals ◽  
Damage And Failure ◽  
State Dependent ◽  
Wide Range ◽  
Stress States ◽  
Failure Conditions

The paper discusses an anisotropic continuum damage model. It takes into account the effect of stress state on damage and failure conditions as well as on evolution equations of damage strains. To validate the proposed framework experiments with biaxially loaded specimens and corresponding numerical simulations are performed covering a wide range of stress states. In addition, scanning electron microscope images of the fracture surfaces show different fracture modes corresponding to stress states revealed by numerical analyses.

scholarly journals Numerical analysis of stress-state-dependent damage and failure behavior of ductile steel based on biaxial experiments

2020 ◽  
Author(s):  
Michael Brünig ◽  
Marco Schmidt ◽  
Steffen Gerke
Keyword(s):  
Stress State ◽  
Numerical Analysis ◽  
Numerical Model ◽  
Evolution Equations ◽  
Image Correlation ◽  
Failure Behavior ◽  
Damage And Failure ◽  
State Dependent ◽  
Ductile Steel ◽  
Biaxial Experiments

Abstract The paper deals with a numerical model to investigate the influence of stress state on damage and failure in the ductile steel X5CrNi18-10. The numerical analysis is based on an anisotropic continuum damage model taking into account yield and damage criteria as well as evolution equations for plastic and damage strain rate tensors. Results of numerical simulations of biaxial experiments with the X0- and the H-specimen presented. In the experiments, formation of strain fields are monitored by digital image correlation which can be compared with numerically predicted ones to validate the numerical model. Based on the numerical analysis the strain and stress quantities in selected parts of the specimens are predicted. Analysis of damage strain variables enables prediction of fracture lines observed in the tests. Stress measures are used to explain different stress-state-dependent damage and failure mechanisms on the micro-level visualized on fracture surfaces by scanning electron microscopy.

scholarly journals A fracture criterion for ductile metals based on critical damage parameters

2020 ◽  
Author(s):  
Michael Brünig ◽  
Marco Schmidt ◽  
Steffen Gerke
Keyword(s):  
Stress State ◽  
Fracture Criterion ◽  
Evolution Equations ◽  
Damage Model ◽  
Strain Tensor ◽  
Ductile Metals ◽  
Fracture Modes ◽  
Damage And Fracture ◽  
Damage Condition ◽  
Critical Damage

Abstract The paper deals with the effect of different stress-state-dependent damage mechanisms on the onset of fracture in ductile metals. A continuum damage model is discussed using a strain tensor as an appropriate damage variable. It takes into account the influence of stress state on the damage condition and on the evolution equations of damage strains. A fracture condition based on critical damage parameters is developed analyzing results of a series of new experiments with different biaxially loaded specimens. After the tests, fracture modes are visualized by scanning electron microscopy. Numerical simulations of the biaxial experiments elucidate the stress states in critical regions of the specimens which are used to explain formation of different damage and fracture modes on the micro-level. Analysis of numerically predicted damage strains for different loading cases leads to a generalized fracture criterion.

scholarly journals A New 3D Empirical Plastic and Damage Model for Simulating the Failure of Concrete Structure

2019 ◽  
Vol 13 (1) ◽  
Author(s):  
Yan-tao Jiao ◽  
Bo Wang ◽  
Zhen-zhong Shen
Keyword(s):  
Damage Mechanics ◽  
Evolution Equations ◽  
Influence Factor ◽  
Yield Criterion ◽  
Kinematic Hardening ◽  
Damage Model ◽  
Nonlinear Behavior ◽  
Complex Stress State ◽  
Flow Rule ◽  
Wide Range

Abstract A new plastic–damage constitutive model based on the combination of damage mechanics and classical plastic theory was developed to simulate the failure of concrete. In order to explain different material behaviors of concrete under tensile and compressive loadings, the plastic yield criterion, the different kinematic hardening rule for tension and compressive and the isotropic flow rule were established in the effective stress space. Meanwhile, two different empirical damage evolution equations were adopted: one for compression and the other for tension. A multi-axial damage influence factor was also introduced to fully describe the anisotropic damage of concrete. Finally, the model response was compared with a wide range of experiment results. The results showed that the model could well describe the nonlinear behavior of concrete in a complex stress state.

An incremental stress state dependent damage model for ductile failure prediction

2016 ◽  
Vol 200 (1-2) ◽  
pp. 127-150 ◽  
Author(s):  
F. X. C. Andrade ◽  
M. Feucht ◽  
A. Haufe ◽  
F. Neukamm
Keyword(s):  
Stress State ◽  
Damage Model ◽  
Ductile Failure ◽  
Failure Prediction ◽  
State Dependent

Cohesive Model in Prediction of Multi-Axial Fatigue

2010 ◽  
Author(s):  
Deepak K. Jha ◽  
Anuradha Banerjee
Keyword(s):  
Stress State ◽  
Cohesive Zone Model ◽  
State Dependence ◽  
Life Assessment ◽  
Zone Model ◽  
State Dependent ◽  
Response To Stress ◽  
Frame Work ◽  
Stress States ◽  
Irreversible Nature

A fatigue failure model for life assessment of a structure that incorporates the stress-state dependence and irreversible nature of fatigue damage is presented. In the frame work of cohesive zone model, a stress state dependent traction separation law for plane strain is taken to represent an undamaged ferritic steel. The evolution of damage has two additional fatigue parameters: a stress and a length parameter. Initially a parametric study is done to show that the model is able to reproduce a typical uniaxial fatigue response to stress based cyclic load, that of a stress-life curve and reduction in life due to positive mean stress. The effect of the cohesive fatigue parameters on the characteristics of the stress-life curve is then established. The model is further applied for a range of sinusoidally varying in-phase stress states which are characterised by a fixed bi-axiality ratio. The initiation and growth of damage is shown to be more rapid for higher bi-axiality. Except for stress amplitudes in which the lower bi-axiality case has conditions close to monotonic failure, the effect of bi-axiality is shown to be detrimental to the life expectancy of the material as observed in available experimental literature.

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