Temperature-dependent interlaminar shear strength of unidirectional continuous fiber-reinforced thermoplastic profiles

摘要

Fiber-reinforced thermoplastic composites offer a high potential for high-volume car body structures. A tailored use of thermoformed and subsequently injection overmolded unidirectional pultruded material in the so-called "skeleton design" is a promising approach towards economical lightweight design.The paper investigates the interlaminar shear strength of pultruded specimens for polyamide 6 and polypropylene as matrices at various temperature degrees. The specimens are made of different ratios of glass and carbon fibers. The results are compared to tape-laid specimens of the same materials to show the influence of the manufacturing technology. The performance is tested using a compression shear device at three testing temperatures -35 degrees C, +23 degrees C and + 85 degrees C covering the typical temperature range for automobile structures as well as in conditioned and dry state.The interlaminar shear strength decreases on average by 65% from 35 degrees C to +85 degrees C, whereas conditioning reduces interlaminar shear strength by 25% at -35 degrees C and + 23 degrees C with no influence at -35 degrees C.The results are analytically described in order to obtain a continuous description of the interlaminar shear strength within the analyzed temperature range.