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

2022 ◽  
Keyword(s):  
Ductile Metals ◽  
Damage And Failure ◽  
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.

Biaxial experiments on characterization of stress-state-dependent damage in ductile metals

2019 ◽  
Vol 14 (1) ◽  
pp. 87-93
Author(s):  
Michael Brünig ◽  
Moritz Zistl ◽  
Steffen Gerke
Keyword(s):  
Stress State ◽  
Ductile Metals ◽  
State Dependent ◽  
Biaxial Experiments

scholarly journals Microstructure Based Failure Criterion For Ductile Materials

2018 ◽  
Vol 183 ◽  
pp. 03005
Author(s):  
Saryu Fensin ◽  
George Gray ◽  
Neil Bourne ◽  
Robert Hixson
Keyword(s):  
Failure Process ◽  
Spall Strength ◽  
Peak Stress ◽  
Material Microstructure ◽  
Shock State ◽  
Ductile Metals ◽  
Damage Area ◽  
Ductile Materials ◽  
Damage And Failure ◽  
Photon Doppler Velocimetry

For ductile metals, the process of dynamic fracture occurs through nucleation, growth and coalescence of voids. The stress required to nucleate these voids is inferred from the velocimetry data (using the acoustic approach) and termed as the spall strength. This is a key parameter that is used to evaluate a material’s susceptibility to damage and failure. However, it is also well recognized that the dynamic parameters used to generate the shock state such as pulse duration, tensile strain-rate and peak stress coupled with material microstructure itself affect the material response in a complex manner. Yet, it is impossible to capture all this information by assessing only the spall strength measured from simple one-dimensional Photon Doppler Velocimetry measurements. Although, there exist widely used corrections proposed by Kanel et. al. that allow for the inclusion of some of these complexities into the measured spall strength but still does not take the microstructure into account. In this work, we propose another scheme for normalization of spall strength with a damage area to capture the complexities included in the damage and failure process especially pertaining to microstructure. We will also demonstrate the application of this scheme by applying to examples of materials such as Copper, Copper-24 wt%Ag, Copper-15 wt% Nb and additively manufactured 316L SS.

scholarly journals Modelling stress‐state dependent nonlocal damage and failure of ductile metals

PAMM ◽  
2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Marvin Nahrmann ◽  
Anton Matzenmiller
Keyword(s):  
Stress State ◽  
Nonlocal Damage ◽  
Ductile Metals ◽  
Damage And Failure ◽  
State Dependent
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