Experiment and numerical simulation on compressive properties of 2.5D woven fabric composites

To investigate the damage and failure mechanisms of 2.5D woven fabric composites under compression, and verify the effectiveness of the finite element numerical simulation method with a two-scale, progressive damage model, quasi-static compression experiments were conducted on both warp and weft directional specimens to obtain the corresponding stress-strain curves. And the initial elastic modulus and ultimate strength of materials were measured. On this basis, the compressive stress-strain responses and the damage evolution behavior were simulated using the two-scale, progressive damage finite element numerical method. The results from both experiment and simulation show good agreements, and indicate that the main failure mode of 2.5D woven fabric composites in weft directional compression is the axial crush and fracture of weft yarns, from which relatively higher strength is obtained. Meanwhile, additional bending moment is added to the warp yarn under warp directional compression due to bending, which causes extrusion on surrounding matrix. Therefore, matrix fracture and delamination cracking between neighboring warp yarns easily occur before the axial fracture of warp yarns, which are not conducive to utilize the advantage of fibers in bearing load, and result in relatively lower strength.