Verification of Puck's criterion for CFRP laminates under multiaxial loads at ambient and cryogenic temperatures

Objective of the present study is the verification of Puck's failure criterion for multiaxial mechanical loading situations in the ambient and cryogenic thermal regimes. The assessment is based on the material data and the failure envelope determined in a previous study on uniaxially loaded single-ply specimens study. Here, the pre-existing experimental data base is complemented by experiments on specimens made from angle ply laminates featuring holes, tapered sections and combinations thereof. The specimens were tested at ambient temperature and in a liquid Helium environment at 4.2 K. For determination of the local stress states in the individual plies at the stress concentrations induced by the holes and tapered sections, the experiments were simulated numerically by the finite element method. It is found that Puck's criterion in most cases provides conservative results. Unresolved additional safety margins may develop if a structural failure in an inter-fiber mode requires development of larger delaminations of adjacent plies to form a through crack.