Deformation and Strength of Carbon Laminates at Temperatures of 293 and 77 K

The regularities of deformation of a carbon laminate with symmetrical stacking of layers with respect to its median surface at temperatures of 293 and 77 K have been studied. From the results of tensile, compression, and three-point bend testing of specimens, the parameters of elasticity and strength for an "equivalent" orthotropic body have been determined on the basis of Bolotin's principle of energy smoothing. The influence of cooling of the material down to 77 K and subsequent thermal cycling on the mechanical behavior of carbon laminates has been studied. Analysis has been made of the reliability of determination of their elastic and strength parameters depending on the type of testing.