Creep behaviour of adhesive lap joints in thermoplastics composites

Environmental factors, most of which are of a non-mechanical nature, have an influence on the properties of materials. A typical case is the temperature, which associated with load affects the performance of any structure in service. To study the effect of temperature in polypropylene-glass fibre composite adhesive lap joints, tests within the temperature range from 20 to 50 °C were carried out, and the results were plotted in terms of the deformation and strain rate versus time. The failure surfaces were also observed by the scanning microscopy technique to obtain the failure mechanisms. Creep parameters were correlated using the Manson-Haferd parameter, the Findley et al. equation and the Little et al. equation, the best agreement being with experimental results obtained with the last model.