Experimental investigation of the crush performance of prepreg platelet molding compound tubes

Abstract

This work presents an experimental study characterizing the crush performance of hollow cylindrical tubes made with prepreg platelet molding compound (PPMC). PPMC is a composite material system that uses platelets from chopped and slit unidirectional prepreg as the basis for a molding compound. This material system has a higher fiber volume fraction and better mechanical properties than traditional short fiber systems and can be molded into complex geometries unlike continuous fiber systems. As such, this material system shows promise for use with complex structural members in vehicles. The failure morphology and specific energy absorption of the material are evaluated with different thickness-to-diameter geometries and test speeds. In addition, this work investigates how PPMC components compare to traditional continuous fiber components and finds that PPMC performs as well as continuous fiber layups with similar effective laminate stiffnesses.

A novel post-processing method for progressive failure analysis of brittle composite compression

“…The tubes were manufactured with a bladder molding process that reached a pressure of 690 kPa (100 psi) and a temperature of 180° C . 45,46 These conditions were held for 20 min before the tube was removed from the mold and allowed to cool.…”

“…Previous work has shown that the placement of axial and hoop layers relative to the external surface of the tube affects the energy absorption. 7,45 Comparing two tubes with the same percentage of axial fibers, the sample with the hoop layers on the exterior surface will consistently absorb more energy than the sample with the hoop layers on the internal surface of the tube. With this in mind, for each percentage of axial fibers, two layups could be employed: a stable layup (hoop fibers on the external surface) and an unstable layup (axial fibers on the external surface).…”

Direct Fiber Simulation of a Compression Molded Ribbed Structure Made of a Sheet Molding Compound with Randomly Oriented Carbon/Epoxy Prepreg Strands—A Comparison of Predicted Fiber Orientations with Computed Tomography Analyses

“…This material class is also called prepreg platelet molding compound (PPMC) [4,[16][17][18][19][20][21][22][23][24][25][26][27] or tow-based discontinuous composite (TBDC) [28][29][30][31][32][33]. The material system is characterized by a high fiber volume fraction with good impregnation, comparable to continuous fiber layups, and therefore higher mechanical properties are reachable than with traditional SMCs [18]. High performance CF-SMCs, such as the epoxy-based material used in this study (see Section 2.1), are further characterized by a high delamination resistance, near quasiisotropic in-plane stiffness, high out-of-plane strength and stiffness, and low notch sensitivity [13].…”