Energy-based ductile failure predictions in cracked friction-stir welded joints

Abstract

This research aims to study the fracture behaviour in dissimilar aluminum alloys adjoined by friction stir welding (FSW). In this way, experimental data dealing with this topic was taken from the recent literature. In those experimental results, two metal sheets made of Al 7075-T6 and Al 6061-T6 were adjoined together by FSW in the form of well-known specimen, namely the cracked semi-circular bend (CSCB) and then they are tested under mixed mode I/II loading condition. Due to the fact that substantial plastic behavior exist in the welded material and consequently significant plastic deformations were observed around the crack tip, failure prediction of the mentioned specimens needs failure prediction models in the basis of the elastic-plastic fracture mechanics which can be realized as sophisticated operations inquiring long time. In this way, the Equivalent Material Concept (EMC) is utilized in this research and then coupled with two eligible energy-based criteria, namely the averaged strain energy density (ASED) and J-integral criteria. Thus, the critical failure load of the welded samples is predicted. Comparison between the empirical data and theoretical predictions from energybased evaluations showed that this model has enough capability in estimating the critical failure load of the CSCB samples.

Failure Analysis of a Base Support Plate of a Semolina Purifier Machines Subjected to Fatigue Loading

“…The immediate objective is to find the root causes of the failure in order to obtain the compensation for the induced damage even if the really important is to prevent similar failures in new components [3]. Literature review revealed that fatigue and Failure analysis of various machines and machine parts such as anti-return valve of a high pressure machine [13], yarn twisting machine [14], diesel engine injector [15], excavator buckets [16], welded steel plates for conveyor belts [17], aluminum alloy elastic coupling [18], friction-stir welded joints [19,24], bridge conveyor [20], cutting blades [21] and gear and transmission shafts [22,23]. The subject of fatigue damage development and design according to fatigue damage is a subject that has been studied extensively in the literature.…”

Analysis of tensile-shear strength of single and multi-friction stir spot welding joints under fixed welding process conditions

“…17–21 Although recent studies on fracture analysis of FSW joints provided capability of predicting the load caring capacity of cracked specimens using maximum tangential stress (MTS) along with equivalent material concept (EMC) and the mean stress (MS) criteria. 22,23 The failure of FSSW is limited to considering uncracked specimens.…”