Prediction of Braid Deformability During RTM Process

In composite materials, fibres orientation has a strong influence on the final part properties. This work concerns the manufacturing of a tube with braided reinforcement using a Resin Transfer Moulding (RTM) process. Specificities on piece do not allow using classical braiding machine for producing 3D preforms. Consequently, an innovative preforming procedure has been developed. The process analysis and experimental observations show that during the process, the reinforcement is mainly submitted to in plane shear and compaction between plies. To predict the feasibility of this preforming step, an analysis of the braid deformability, during the process, is conducted by experimental approach and development of a geometrical and analytical model. Starting from the characteristics of braid and process parameters and using an iterative calculation procedure, it enables to obtain the shear angle and the volume ratio of fibre in each place of the tube; yarns position and the homogeneity by deduction. Comparisons between the analytical model and experimental results are finally analysed to validate the model.