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Ding Y.,Shandong Provincial Key Laboratory of Preparation and Measurement of Building MaterialsUniversity of JinanJinan 250022 China | Jia Y.,Key Laboratory for Liquid Solid Structural Evolution and Processing of Materials Ministry of Education Shandong UniversityJinan250061 China
Polymer Composites | Year: 2014

The mold filling time and resin flow front shape are of fundamental importance during resin transfer molding (RTM) processes, because the former influences productivity and the latter affects composites quality. In this article, considering both edge effect and curing reaction characteristics of the resin flow process, the sensitivity analysis method is introduced to investigate the sensitive degree of mold filling time and resin flow front shape to the key material and processing parameters. The function employed to describe the resin flow front shape is defined, and the mathematical relationships of the key physical parameters, such as fluid pressure sensitivity, flow velocity sensitivity, mold filling time sensitivity, and resin flow front shape sensitivity, are established simultaneously. In addition, then the resin infiltration process is simulated by means of a semi-implicit iterative calculation method and the finite volume method. The simulated results are in agreement with the analytical ones. The results show that under constant injection velocity conditions, both the change in the resin temperature and the alteration of the inlet velocity hardly affect the resin flow front shape, whereas the influence of edge permeability on the resin flow front shape is the greatest. This study is helpful for designing and optimizing RTM processes. © 2014 Society of Plastics Engineers. Source


Sun X.,Key Laboratory for Liquid Solid Structural Evolution and Processing of Materials Ministry of Education Shandong UniversityJinan250061 China | Liu G.,National Key Laboratory of Advanced CompositesBeijing Institute of Aeronautical Materials | Yi X.,National Key Laboratory of Advanced CompositesBeijing Institute of Aeronautical Materials | Su H.,Key Laboratory for Liquid Solid Structural Evolution and Processing of Materials Ministry of Education Shandong UniversityJinan250061 China | Jia Y.,Key Laboratory for Liquid Solid Structural Evolution and Processing of Materials Ministry of Education Shandong UniversityJinan250061 China
Polymer Composites | Year: 2015

The intralaminar and interlaminar damages of U3160/3266 laminated composites toughened by polyamide nonwoven fabric (PNF) under low velocity impact are investigated through a numerical model which considers both the three-dimensional continuum damage mechanics (CDM) and the bilinear cohesive zone model (CZM). The analysis of the intralaminar damage is implemented by the ABAQUS/Explicit finite element code coupled with a user-defined subroutine VUMAT where the longitudinal failure, transverse matrix cracking, and nonlinear shear of the material are taken into account. Then the effects of the thickness and strength of PNF/3266 interlayer on the damage of composites are numerically analyzed. The results reveal that damage morphology can be simulated qualitatively compared to the experimental counterparts. With the decreasing interlayer thickness or the increasing interlayer strength, the damage area is effectively reduced. This work provides an effective model to predict the low velocity impact damage of composites, and is helpful for the optimization of interlayer toughened composites. © 2015 Society of Plastics Engineers. Source

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