Jian Song

The influence of fiber volume content on the mechanical properties of two-dimensional (2D) plain carbon-fiber woven composites is a crucial concern that necessitates immediate attention for large-scale applications in wind turbine blades. In this study, various mechanical tests were conducted on 2D plain carbon-fiber woven composites with different fiber volume contents, and the influences of fiber volume content on the mechanical properties and failure mode of the composite material were analyzed. Using carbon fiber as reinforcement and epoxy resin as a matrix, three types of plates with fiber volume contents of 47%, 50% and 53% were fabricated by using autoclave technology. The tensile, compression and interlaminar shear tests of the two-dimensional woven composites were carried out using MTS series testing machines. The influences of fiber volume content on tensile strength and modulus, compressive strength and modulus, interlaminar shear strength and shear strain energy were investigated. Additionally, the progressive damage development of these two-dimensional woven composites under different stress states was studied using scanning electron microscopy (SEM). The results indicate that the tensile strength and compressive strength increase almost linearly with the increase in fiber volume content, while the interlaminar shear strength increases slowly at low fiber volume content and rapidly at high fiber volume content. The tensile modulus of elasticity slightly increases as the fiber volume content increases, whereas the compressive modulus remains stable at low fiber volume content but gradually decreases at high fiber volume content. With the increase in fiber volume content, the shear strain energy of the specimen increases significantly.

High temperature mechanical properties of 3D woven composites play a significant role in applying composites in high-performance aero-engines. This paper first investigates the warp and weft direction thermo-mechanical behaviors of high-temperature resistant resin matrix 2.5D shallow straight-link-shaped woven composites (2.5DSWCs) at 20, 180 and 240 °C based on experimental and numerical methods. Experimental results showed that the warp and weft direction moduli and strengths of 2.5DSWCs were much higher than those of 2.5D shallow curve-link-shaped woven composites at the same temperature. The warp and weft stress–strain curves totally remained linear up to a sudden fiber-dominated brittle fracture, despite at 240 °C. According to the experimental results, a thermo-mechanical prediction model taking the effects of interface and temperature into account was developed to predict the mechanical properties and damage propagation behaviors of 2.5DSWCs. The prediction errors of moduli and strengths at different temperatures were within 20%. The damage initiation and extension processed as a function of strain are predicted. The predicted results indicate that the proposed model can provide a suitable reference to the numerical study of the thermo-mechanical issues in this category textile composites at room and elevated temperatures.