Failure of Carbon Fibers at a Crease in a Fiber-Reinforced Silicone Sheet

Thin sheets of unidirectional carbon fibers embedded in a silicone matrix can be folded to very high curvatures, as elastic microbuckles with a half-wavelength on the order of 1 mm decrease the maximum strain in the fibers near the compression surface. This paper shows that probabilistic failure models derived from tension tests on individual fibers can be used to predict accurately the value of the outer surface curvature of the sheet at which a small percentage of fibers break when a crease is formed in the sheet. The most accurate results are obtained by using a strain-based Weibull distribution of the failure probability in tension.