Materials Selection of 3D Printed Polyamide-Based Composites at Different Strain Rates: A Case Study of Automobile Front Bumpers

The selection of 3D printed composite materials considering multiple criteria has become a challenging issue for designers/engineers and can be regarded as a typical decision-making problem. Especially for diverse engi-neering applications, the different strain rates encountered need to be addressed in the decision-making process. In this study, a systematic hierarchical evaluation model of 3D printed polyamide-based composites with 27 indicators is established considering economic, environmental, social and mechanical aspects. The mechanical responses at four strain rates (8 x 10-4 s-1, 8 x 10-3 s-1, 1700 s- 1 and 3510 s- 1) are incorporated into the model. A hybrid decision-making approach combining the fuzzy DEMATEL (Decision Making Trial and Evalu-ation Laboratory)-Entropy and fuzzy TODIM (Tomada de Decisa similar to o Interativa Multicrite ' rio)-VIKOR (VlseKriter-ijumska Optimizacija I Kompromisno Resenje) methods is proposed to solve the composite material selection problem. An automobile front bumper, as an empirical application, is investigated to demonstrate the proposed model and decision-making approach. The results show that PACF-C, that is the short carbon fibre reinforced polyamide printed with a concentric strategy, is the optimal alternative. This study provides an effective approach for solving the material selection problem of 3D printed composites.