Influence of Plying Strategies and Trigger Type on Crashworthiness Properties of Carbon Fiber Laminates Cured through Autoclave Processing

Abstract

A small-scale experimental test able to characterize the energy absorption of a material under compression was developed by innovatively introducing self-supporting sinusoidal shape specimens, thus avoiding the complex anti-buckling devices of classical flat specimen tests. Two carbon-fiber-reinforced polymer (CFRP) pre-preg types were tested: 12 plies of unidirectional tape or 8 plies of plain weave fabric for a laminate approximately 1.8 mm thick in both cases. Three stacking sequences were analysed, in order to identify the configuration able to maximize the specific energy absorption (SEA), i.e. the energy absorbed per unit mass of crushed structure is expressed in J/g, with the unidirectional specimen providing the best results. In order to have a controlled crush, the specimens were produced with different auto-triggering configurations. Indeed, the fibers’ continuity was interrupted in selected position and to different degrees in order to investigate the SEA of the weakened laminates. For unidirectional specimens, the SEA maximum value and behaviour over the stroke were unaffected by the trigger position. Therefore, the auto-triggering configuration was able to control the position of the initial failure of the specimen without any decrease in safety performance.