Mechanical Characterization of CFRP Woven Laminates between Room Temperature and 4K

In order to evaluate the mechanical properties of T800H/3633 CFRP woven laminates for cryogenic tankage in RLV, tensile and in-plane shear tests were performed at room temperature, liquid nitrogen temperature (77K) and liquid helium temperature (4K). The tensile tests were conducted in accordance with ASTM D 3039 and JIS K 7073. Tensile strength and modulus were evaluated for both the warp and fill directions. A problem was encountered with obtaining acceptable failure of the specimens. We could not achieve failure in the test section. This problem was avoided by using dogbone shaped specimens. A two-dimensional finite element analysis was also used to study the stress distributions within the specimens and to interpret the experimental measurements. The in-plane shear modulus and shear strength were measured by tensile tests on the ±45° specimens (ASTM D 3518 and JIS K 7079). The effects of temperature on the stress-strain responses in tension and in-plane shear are examined. Fracture topography of specimens is also investigated and interpreted.