Biaxial and Triaxial Failure Strengths of 6061-T6 Aluminum and AS4/3501-6 Carbon/Epoxy Laminates Obtained by Testing Thickness-Tapered Cruciform Specimens

Abstract

Using a thickness-tapered cruciform specimen, uniaxial and biaxial tests were performed on 6061-T6 aluminum as well as biaxial and triaxial tests on an AS4/3501-6 carbon/epoxy cross-ply laminate. Designed in conjunction with a new triaxial test facility, the performance of the cruciform specimen was analyzed using an anisotropic, linear-elastic, finite element analysis. The results of this analysis, as well as the experimental data generated for both the aluminum and AS4/3501-6 carbon/epoxy material systems, are presented. An undesirable failure mode was observed in several biaxial tension tests, and the triaxial tension tests were not performed successfully. This study represents the initial effort using this specimen design and test facility, and several recommendations to improve the performance of the thickness-tapered cruciform specimen in future studies are presented. The potential of the triaxial testing facility and the thickness-tapered cruciform specimen has been demonstrated.