A study of tension test specimens of laminated hybrid composites. 1: Methods of approach

Abstract

This paper covers the statistical analysis, stress analysis, and failure characteristics of two types of tension specimens used for testing fiber/metal hybrid laminates. The specimen geometries considered are straight-sided and dogbone-type specimens. Statistical analysis of the results from both specimen types shows that the longitudinal mean tensile ultimate strength is significantly different at the 5% significance level, however, this difference becomes insignificant if the size effect is taken into account. However, the means of the tensile yield strength and tensile modulus are found to be independent of specimen type. Stress analysis of the dogbone-type specimen shows it to be subjected to high shear stresses and tensile stress concentrations which tend to degrade its mechanical performance. Results from both analytical and experimental studies suggest that it is better to use the straight-sided specimen on tension testing for fiber/metal hybrid laminates. Fracture topography of specimens is also investigated and interpreted.