Evaluation of tensile strength of woven carbon/epoxy composite laminates at cryogenic temperatures using the open hole specimens

We propose a combined numerical-experimental method for the evaluation of the tensile strength properties of woven carbon fiber reinforced polymer (CFRP) composite laminates at cryogenic temperatures using the open hole specimens. Cryogenic tensile tests were conducted on the open hole specimens of quasi-isotropic woven CFRP laminates, and the length of the hole edge damage zone corresponding to the specimen failure was determined by the microscopic examinations of failed specimens. A finite element based method was developed for estimating the cryogenic tensile strength of the unnotched woven laminates using the experimentally determined failure load and damage zone length. In the damage zone, the material was assumed to carry a uniform normal stress equal to the tensile strength. The results demonstrate that the present method is an efficient approach to measuring the tensile strength of high-strength advanced composites at cryogenic temperatures.