An Approximate Method for Calculating Elastic-Plastic Stress and Strain on Notched Specimens.

Maxim Lutovinov,Jan Papuga,Michal Bartošák,Jiří Kuželka,Milan Růžička,Radim Halama

doi:10.3390/ma15041432

Maxim Lutovinov, Jan Papuga + Show 4 more

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https://doi.org/10.3390/ma15041432

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Abstract

The paper deals with an approximate method for calculating elastic–plastic stresses and strains on the surface of notched samples. The method is based on the Abdel–Karim–Ohno cyclic plasticity model. The plane stress condition is considered within the evaluation. The output of the approximation on several multiaxial axial–torsion load paths is compared to our own experimental results. Experiments were carried out on samples of two notch types manufactured from the 2124-T851 aluminum alloy. Strain distribution in the notch area was measured by digital image correlation. The comparison between computational solution and measured response shows that the new method allows for obtaining reasonably good approximation, even for relatively complicated multiaxial load cases.

Highlights

Most initially isotropic engineering materials exhibit elastic–plastic behavior
The combination allows for analysts to estimate elastic–plastic notch tip stresses and strains without performing elastic–plastic FE analysis because only elastic stress history and material data are needed as input
The prediction of ratcheting is not precise; it is possible to adjust the amount of ratcheting for different materials by changing the ratcheting parameter μ

Summary

Introduction

Most initially isotropic engineering materials exhibit elastic–plastic behavior. the finite-element calculation of plasticity is time-consuming and requires more input data. Engineers dealing with fatigue life estimation, often use approaches that consider only elastic behavior to assess the durability of structures. Such a simplification is possible in the domain of high-cycle fatigue, but it is unacceptable if the low-cycle regime is evaluated, where the scale of plasticity is much more substantial. The methods do not take cyclic hardening or cyclic softening into account, and they do not describe the movement of the yield surface. This group of methods is not suitable for cyclic loading. The investigation of these methods can be found in [6]

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