Experimental and Numerical Study of Damage Evolution in Knitted‐Fabric‐Reinforced Polymer Composites

ABSTRACT Knitted‐fabric‐reinforced shape memory polymer composites (SMPC) have good shape memory properties while their mechanical properties and damage evolution need to be in‐depth studied. In this work, the rib‐knitted fabric‐reinforced SMPCs (SMPC‐R) and weft‐yarn inserted rib‐knitted fabric‐reinforced SMPCs (SMPC‐W) were prepared. The effects of knitting densities and loop directions (0°/90°) on the tensile and flexural properties of SMPC‐R and SMPC‐W were investigated. The multi‐scale finite element models were established to analyze the damage evolution processes of loops, weft yarns, and the matrix of SMPCs. The experimental results show that the strengths of SMPCs in the 90° direction are significantly higher than that of SMPCs in the 0° direction, while the loop density has a relatively slight effect on the mechanical properties of SMPCs. The flexural strength of SMPC‐W‐D17‐90° with weft yarns is 1.2 times and 1.8 times that of SMPC‐W‐D17‐0° and SMEP, respectively. The addition of weft yarns to knitted‐fabric‐reinforced SMPCs can improve their strength and modulus. The finite element simulation results show reasonable agreement with the experimental stress–strain curves and support the analysis of the damage evolution processes of the SMPCs. The gained knowledge in this study is beneficial to the design of fabric‐reinforced SMPC.