Damage and failure mechanisms of ductile metals in biaxial experiments with non‐proportional loading paths

PAMM ◽  
2018 ◽  
Vol 18 (1) ◽  
Author(s):  
Moritz Zistl ◽  
Steffen Gerke ◽  
Michael Brünig
Keyword(s):  
Failure Mechanisms ◽  
Proportional Loading ◽  
Ductile Metals ◽  
Damage And Failure ◽  
Loading Paths ◽  
Biaxial Experiments

scholarly journals Analysis of Damage and Failure in Anisotropic Ductile Metals Based on Biaxial Experiments with the H-Specimen

2021 ◽  
Author(s):  
M. Brünig ◽  
S. Koirala ◽  
S. Gerke
Keyword(s):  
Stress State ◽  
Image Correlation ◽  
Experimental Program ◽  
Failure Behavior ◽  
Strain Fields ◽  
Ductile Metals ◽  
Damage And Failure ◽  
Loading Direction ◽  
Principal Axes ◽  
Biaxial Experiments

Abstract Background Dependence of strength and failure behavior of anisotropic ductile metals on loading direction and on stress state has been indicated by many experiments. To realistically predict safety and lifetime of structures these effects must be taken into account in material models and numerical analysis. Objective The influence of stress state and loading direction on damage and failure behavior of the anisotropic aluminum alloy EN AW-2017A is investigated. Methods New biaxial experiments and numerical simulations have been performed with the H-specimen under different load ratios. Digital image correlation shows evolution of strain fields and scanning electron microscopy is used to visualize failure modes on fracture surfaces. Corresponding numerical studies predict stress states to explain damage and fracture processes on the micro-scale. Results The stress state, the load ratio and the loading direction with respect to the principal axes of anisotropy affect the width and orientation of localized strain fields and the formation of damage mechanisms and fracture modes at the micro-level. Conclusions The enhanced experimental program with biaxial tests considering different loading directions and load ratios is suggested for characterization of anisotropic metals.

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.

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