Experimental investigation of pull-through force of wing-type fastening inserts co-cured in long fiber prepreg sheet (LFPS)

In order to overcome the shortcomings of conventional fibrous composites, such as the limitations in the mass production of continuous fiber-reinforced composites and the inferior mechanical properties of short fiber-reinforced composites, long fiber prepreg sheets (LFPSs) are introduced in this paper. The LFPS is designed to form complex structures by thermoforming; however, highly complex shapes require mechanical fastening, after the composite parts are thermoformed. For this purpose, wing-type metal inserts embedded in the LFPS during thermoforming are investigated, and the most appropriate insert configuration is suggested. The specimens are subjected to a pull-through test, in accordance with insert parameters, such as the width and length of the insert wings, and the condition that ensures the highest pull-through force is determined. To check for wing deformation after thermoforming, the projected area and bending angle are measured through X-ray observation, and correlated with the pull-through force.