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 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 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 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

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 Contrasting the Role of Pores on the Stress State Dependent Fracture Behavior of Additively Manufactured Low and High Ductility Metals

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3657
Author(s):  
Alexander E. Wilson-Heid ◽  
Erik T. Furton ◽  
Allison M. Beese
Keyword(s):  
Stainless Steel ◽  
Stress State ◽  
Pore Size ◽  
Fracture Behavior ◽  
316L Stainless Steel ◽  
Equivalent Stress ◽  
Failure Behavior ◽  
High Ductility ◽  
State Dependent ◽  
Fracture Models

This study investigates the disparate impact of internal pores on the fracture behavior of two metal alloys fabricated via laser powder bed fusion (L-PBF) additive manufacturing (AM)—316L stainless steel and Ti-6Al-4V. Data from mechanical tests over a range of stress states for dense samples and those with intentionally introduced penny-shaped pores of various diameters were used to contrast the combined impact of pore size and stress state on the fracture behavior of these two materials. The fracture data were used to calibrate and compare multiple fracture models (Mohr-Coulomb, Hosford-Coulomb, and maximum stress criteria), with results compared in equivalent stress (versus stress triaxiality and Lode angle) space, as well as in their conversions to equivalent strain space. For L-PBF 316L, the strain-based fracture models captured the stress state dependent failure behavior up to the largest pore size studied (2400 µm diameter, 16% cross-sectional area of gauge region), while for L-PBF Ti-6Al-4V, the stress-based fracture models better captured the change in failure behavior with pore size up to the largest pore size studied. This difference can be attributed to the relatively high ductility of 316L stainless steel, for which all samples underwent significant plastic deformation prior to failure, contrasted with the relatively low ductility of Ti-6Al-4V, for which, with increasing pore size, the displacement to failure was dominated by elastic deformation.

Stress state characterization of ductile materials during scratch abrasion

Wear ◽  
2021 ◽  
pp. 203712
Author(s):  
Dhanraj Rajaraman ◽  
V. Keim ◽  
K. Pondicherry ◽  
A. Nonn ◽  
S. Hertelé ◽  
...  
Keyword(s):  
Stress State ◽  
Ductile Materials
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