On the Mutual Interactions of Monotonic and Cyclic Loading and their Effect on the Strength of Aluminium Alloys

Zbigniew L Kowalewski,Tadeusz Szymczak

doi:10.4028/www.scientific.net/amm.24-25.213

Abstract

The paper investigates the interaction of monotonic cyclic loading and their effect on the yield strength of aluminium alloy. Two different loading combinations were considered, i.e. torsion-reverse-torsion superimposed on monotonic tension and monotonic torsion combined with tension-compression cycles. All strain controlled tests were carried out at room temperature using thin-walled tubular specimens. The maximum value of the total cyclic strain amplitude was less than 1%. The influence of amplitude, frequency and shape of cyclic loading signal on the proportional limit and conventional yield point was investigated. The experimental results presented in the paper may be useful to designers of structures that utilize manufacturing processes such as drawing, extrusion, forging of selected semi-finished elements or researchers working on the development of new constitutive equations.

Highlights

In many branches of industry the loading of engineering components is complex and can have an significant influence on the mechanical properties of engineering materials
Since the mechanical parameters of materials can be modified by complex loading many research groups are looking at complex loading in an effort to optimize some of the manufacturing processes [1], [2], [3], [4], [6] in order to reduce costs and prolong the lifetimes of engineering components
The results exhibit a significant lowering of the following mechanical parameters: magnitude of hardening, proportional limit and conventional yield point

Summary

Introduction

In many branches of industry the loading of engineering components is complex and can have an significant influence on the mechanical properties of engineering materials. It can be concluded that knowledge of loading history has at least a twofold role It is important for adequate choice of materials of structural elements, and it allows the design of forming processes to guarantee optimal mechanical parameters for particular applications. Many mechanical laboratories are involved in such research programmes, which would be able to provide new knowledge related to the influence of complex loading on the selected material parameters of importance in industry. The total cyclic strain amplitude was less than 1%, since for that magnitude it can. After the main loading programme a yield surface concept was applied to check if the effects observed during cyclic loading have a permanent character

Experimental results

A Plastic Strain

Remarks and conclusions