Issue 48

T. Febra et alii, Frattura ed Integrità Strutturale, 48 (2019) 242-248; DOI: 10.3221/IGF-ESIS.48.25 242 Focused on the “Portuguese contributions for Structural Integrity” Response of fabric insert injection overmolding pp based composites subjected to single and muti-impact T. Febra, J.A.M. Ferreira, J. D. Costa, J. da Silva CEMMPRE, University of Coimbra, Department of Mechanical Engineering, Portugal tiago_Febra@geco-moldes.pt, http://orcid.org/0000-0002-9372-5072 martins.ferreira@dem.uc.pt , http://orcid.org/0000-0002-0295-1841 jose.domingos@dem.uc.pt , http://orcid.org/0000-0002-8274-3734 joel.jesus@uc.pt , http://orcid.org/0000-0002-7133-2331 C. Capela Instituto Politécnico de Leiria, ESTG, Department of Mechanical Engineering, Portugal ccapela@ipleiria.pt, http://orcid.org/0000-0003-3334-4945 A BSTRACT . This paper presents the results of a current study on the development and impact response of composite plates manufactured by injection overmolding on the two sides of a single reinforcement fibre mat. The injection polymer is a talc-filled polypropylene, nowadays used for structural purposes. Three configurations with different insert fibre mats were used: Kevlar, biaxial and multiaxial glass fibre mats. The parameters studied were the fibre mat type and the impact energy. For single impact tests, it was concluded that the highest impact energy required to achieve impactor perforation is obtained with Kevlar insert, while the highest percentage of energy recovered is achieved with biaxial glass fibre netting. Kevlar insert also allows for the maximum impact stiffness. For the multi-impact tests, the recovered energy and the dynamic stiffness show the same tendencies of the single impact tests. On low energy impacts, the effect of the insert fibre and of the previous impact are quite reduced, while for impact energies above 6J, previous impacts reduce significantly the recovered energy and the impact energy for which the perforation was achieved. K EYWORDS . Composites; Impact response; Injection overmolding. Citation: T. Febra, J.A.M. Ferreira, J. D. Costa, J. da Silva, C. Capela, Response of fabric insert injection overmolding pp based composites subjected to single and muti- impact, Frattura ed Integrità Strutturale, 48 (2019) 242-248. Received: 14.09.2018 Accepted: 09.01.2019 Published: 01.04.2019 Copyright: © 2019 This is an open access article under the terms of the CC-BY 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. I NTRODUCTION his paper is concerned with the manufacture and performance of a single piece final product made from a fibre mat insert with polymer injected overmolding in both sides. Polymers and fibre mats have very different mechanical properties but should remain safely bonded throughout their useful life. T