Experimental and Numerical Investigation of Prepreg-RTM Co-Curing Molding Composite Bolted T-Joint under Bending Load

Abstract

A set of polymer composite bolted T-joints with a novel configuration consisting of an internal skeleton and external skin was fabricated using a prepreg-RTM co-curing molding process. Experiments were conducted to study their mechanical properties under a bending load. A finite element model with a polymer resin area between the skin and skeleton was established and verified by the experimental results. Then, the damage propagation process and failure mechanism of the joint and the influence of three factors related to the layer characteristics of the skin and skeleton were investigated by the validated models. The results show that the bending stiffness and the yield limit load of the novel composite T-joint are 0.81 times and 1.65 times that of the 2A12 aluminum T-joint, respectively, while at only 55.4% of its weight. The damage of the joint is initiated within the resin area and leads to the degradation of the joint’s bending performance. The preferred stacking sequence of the skeleton is [0/+45/90/−45]ns when primarily subjected to bending loads. The decrease in the bending performance is within 5% of the inclining angle of the skeleton, less than 12 degrees. The more 90° layers in the skin, the better the bending performance of the joints, while the more 0° layers, the poorer the bending performance.

Multi-optimization for thermal deformation of gravitational wave telescope based on CFRP characteristics

“…Previous studies on CFRP layup optimization and application have primarily focused on lightweight design 8 , 9 and optimization of mechanical properties 10 – 13 . These studies typically limited the orientation of the laminae to conventional angles, such as ± 45°, 0°, and 90°, which are known to enhance mechanical design efficiency and achieve superior mechanical properties in longitudinal, transverse, and shear directions 14 – 17 . Nevertheless, given that the main challenge for the TQ telescope at this stage is thermal deformation of the structure, with lesser emphasis on mechanical properties, unconventional angle layups become a viable option.…”