Influence of joint line remnant on crack paths under static and fatigue loadings in friction stir welded Al-Mg-Sc alloy

The influence of the joint line remnant (JLR) on tensile and fatigue fracture behaviour has been investigated in a friction stir welded Al-Mg-Sc alloy. JLR is one of the microstructural features formed in friction stir welds depending on welding conditions and alloy systems. It is attributed to initial oxide layer on butting surfaces to be welded. In this study, two different tool travel speeds were used. JLR was formed in both welds but its spatial distribution was different depending on the tool travel speeds. Under the tensile test, the weld with the higher heat input fractured partially along JLR, since strong microstructural inhomogeneity existed in the vicinity of JLR in this weld and JLR had weak bonding. Resultantly, the mechanical properties of this weld were deteriorated compared with the other weld. Fatigue crack initiation was not affected by the existence of JLR in all welds. But the crack propagated preferentially along JLR in the weld of the higher heat input, when it initiated on the retreating side. Consequently, such crack propagation behaviour along JLR could bring about shorter fatigue lives in larger components in which crack growth phase is dominant

Influence of joint line remnant on crack paths under static and fatigue loadings in friction stir welded Al-Mg-Sc alloy

The influence of the joint line remnant (JLR) on tensile and fatigue fracture behaviour has been investigated in a friction stir welded Al-Mg-Sc alloy. JLR is one of the microstructural features formed in friction stir welds depending on welding conditions and alloy systems. It is attributed to initial oxide layer on butting surfaces to be welded. In this study, two different tool travel speeds were used. JLR was formed in both welds but its spatial distribution was different depending on the tool travel speeds. Under the tensile test, the weld with the higher heat input fractured partially along JLR, since strong microstructural inhomogeneity existed in the vicinity of JLR in this weld and JLR had weak bonding. Resultantly, the mechanical properties of this weld were deteriorated compared with the other weld. Fatigue crack initiation was not affected by the existence of JLR in all welds. But the crack propagated preferentially along JLR in the weld of the higher heat input, when it initiated on the retreating side. Consequently, such crack propagation behaviour along JLR could bring about shorter fatigue lives in larger components in which crack growth phase is dominant

Data depth for simple orthogonal regression with application to crack orientation

Orthogonal regression through the origin, Tangential data depth, Simplicial data depth, Statistical tests, Crack orientation,

Individual differences in empathy are associated with apathy-motivation

Empathy - the capacity to understand and resonate with the experiences of other people - is considered an essential aspect of social cognition. However, although empathy is often thought to be automatic, recent theories have argued that there is a key role for motivation in modulating empathic experiences. Here we administered self-report measures of empathy and apathy-motivation to a large sample of healthy people (n = 378) to test whether people who are more empathic are also more motivated. We then sought to replicate our findings in an independent sample (n = 198) that also completed a behavioural task to measure state affective empathy and emotion recognition. Cognitive empathy was associated with higher levels of motivation generally across behavioural, social and emotional domains. In contrast, affective empathy was associated with lower levels of behavioural motivation, but higher levels of emotional motivation. Factor analyses showed that empathy and apathy are distinct constructs, but that affective empathy and emotional motivation are underpinned by the same latent factor. These results have potentially important clinical applications for disorders associated with reduced empathy and motivation as well as the understanding of these processes in healthy people