Design optimisation of 3D woven T-joint reinforcements

To facilitate the design of 3D woven composite T-joint preforms, the effects of fibre architecture variations on mechanical performance under tensile pull-off loading were studied, based on the FE modelling framework proposed in a previous study. In search of the optimum fibre architecture, the study was restricted to only vary the path of weft yarns at the junction of the T-joints, as this maintains quasi-constant fibre volume fraction for the composites and does not require any modification on the weaving machine producing the preforms from that used for the two types of T-joint specimens tested previously. A comprehensive search for the optimum preform design for the T-joint composite would require a tremendous amount of computational resources when evaluating the mechanical performance of the individuals, even using a highly efficient optimisation algorithm. Inspired by the weave patterns of the two types of T-joint specimen, the problem was simplified by grouping the weft yarn arrangements into three basic design variables. Quantified by the proportions of design variables at the junction of the 3D woven T-joints, new weave pattern variations were designed and analysed. Finally, a design optimisation philosophy for 3D woven T-joint reinforcements under tensile pull-off loading is given.