Statistical aspects of the mechanical behaviour a paste adhesive

We present experimental results describing the mechanical behaviour of an epoxy-based structural paste adhesive with aluminium powder filler under proportional loading. The main aim of the present study is to relate the dispersion on joint strength (variability) to void and particle sizes and distributions, also taking into account effects of the curing cycle. Tensile tests with dogbone specimens were done at different strain rates. The statistical nature of results is related to the heterogeneous material microstructure, containing voids as well as mineral particles for reinforcement. A Weibull-type statistical analysis is suggested for use when the stress distribution is heterogeneous. Mechanical dynamical analyses were done with evaluation of polymerisation steps. Multiple dynamical testing was done with temperature scanning on samples having undergone various cure cycles.