Thermomechanical analysis of the onset of strain concentration zones in wet polyamide 6.6 subjected to cyclic loading

•Putting forward some experimental results on the local thermomechanical behavior of a wet PA6.6 matrix subjected to cyclic loading.•Using photomechanical techniques to assess the creep and cyclic strain rate fields, as well as the associated dissipation and coupling heat source fields.•Tracking the onset of strain concentration zones and noting their limited development.•Highlighting the co-existence of glassy, rubber and mixed thermal responses.

In the present paper, we put forward some experimental results on the local thermomechanical behavior of a wet PA6.6 matrix subjected to cyclic loading. We used photomechanical techniques to assess the creep and cyclic strain rate fields, as well as the associated dissipation and coupling heat source fields. This thermomechanical analysis enabled us, from the very beginning of the cyclic test, to track the onset of strain concentration zones and note their limited development. Moreover, this analysis helped us to highlight the co-existence of glassy, rubber and mixed thermal responses. This revealed that wet PA6.6 was a graded material whose property variations surely promoted the development of strain concentration zones.