Abstract
The 2024-T351 aluminum alloy is extensively used for fabricating aircraft parts. This alloy shows a relatively low ductility at room temperature and is generally heat treated in various conditions to suit particular applications. The present study experimentally and numerically analyzes the damage mechanism of an Al2024-T351 plate (short transverse direction) subjected to multi-axial stress states. The purpose of this work is to predict the cyclic lifetime of the considered alloy, based on the local approach of damage evolution using continuum damage modeling (CDM). The experimental program involves different kinds of specimens and loading conditions. Monotonic and cyclic tests have been conducted in order to measure the mechanical response and also to perform micromechanical characterization of damage and fracture processes. The cyclic plasticity behavior has been characterized by means of smooth cylindrical specimens. For analyzing the evolution of plastic deformation and damage under multi-axial stress conditions, cyclic loading tests in the low cycle regime have been conducted on different round notched bars. The predictions of the CDM were compared to the experimentally observed mechanical response and to the micromechanical characterization of damage. Emphasis was placed on the prediction of the number of cycles to failure.
Highlights
In contrast to high cycle fatigue (HCF), low cycle fatigue (LCF) is generally characterized by failure in less than 104 cycles showing a pronounced plastic mechanical response
All specimens were cut from the same plate of Al2024-T351 in S-direction and they were mechanically treated with a turning machine
The results predicted by the continuum damage modeling (CDM) approach have shown very good agreement with experimental data
Summary
In contrast to high cycle fatigue (HCF), low cycle fatigue (LCF) is generally characterized by failure in less than 104 cycles showing a pronounced plastic mechanical response These loading conditions can occur in airplane structures during or after unpredictable mechanical impacts, e.g., hard landing, bad weather conditions, operational errors, failure of structural integrity, etc. Crack initiation as the result of LCF is a complex process that is influenced by many factors: stress (strain) history, rate of loading, environmental influence, temperature, hold times, etc. In addition to these extrinsic factors, numerous features of the micro-structure of the material undergoing cyclic loading affect crack initiation as well. It is reasonable to examine stress singularities showing material yielding which leads to crack initiation
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
