INVESTIGATIONS ON THE SUITABILITY OF CARB ON-FIBER-REINFORCED EPOXY FOR USING AT CRYOGENIC TEMPERATURES

The following investigations show the mechanical properties of some ca rbon fiber reinforced epoxies under quasistatic load. Both prepregs an d wet laminates are tested to get a suitable fiber/matrix-combination for using at cryogenic temperatures. Therefore the material research i s done at room temperature and at liquid nitrogen atmosphere. The char acteristics, which serve for the basis of valuation are ultimate stren gth, elongation at fracture and modulus of elasticity. At liquid nitro gen temperature ultimate tensile strength and elongation at fracture s how a decrease in comparison to room temperature, but Young's Modulus increases insignificantly with tensile loading. In the compression tes t all the characteristics grow larger. Furthermore the influence of th e testing temperature on the mechanical characteristics of prepregs an d wet laminates is pronounced differently. The experiments also show, that the dependence of the temperature on the mechanical properties ma y be influenced by the kind of the reinforcing fibers. This statement applies especially to the value of the obtainable interlaminar shear s trength.