Micro-mesoscopic prediction of void defect in 3D braided composites

Void defects will inevitably occur in 3D braided composites during Resin Transfer Molding (RTM) process, which may reduce mechanical properties of 3D braided composites. Therefore, this paper focuses on void generation in 3D braided composites and optimizes its manufacturing technology. First, the basic governing equations considering flow, temperature changing and resin curing process are derived to describe the conservation of momentum, energy and mass of resin during RTM process. Second, the whole RTM process for 3D braided preform cell is simulated by means of finite element method (FEM), which indicates the distribution of resin flow speed, pressure and void content. Third, influences of resin injection flow volume, outlet pressure, volatile content in resin and curing temperature on void distributions and contents in 3D braided composite cell are investigated. The results will provide theoretical basis for analyzing void generation and evaluating the quality of 3D braided composites made by RTM technology.