Both experimental and simulation approaches were employed to investigate the laser ablation mechanism and performances of Glass Fiber Reinforced Phenolic Composites (GFRP). During the ablation process, the difference in thermal conductivities of the glass fibers and the resin matrix as well as their discrepant physical and chemical reactions form a conical ablation morphology. The formation of a residual carbon layer effectively mitigates the ablation rate in the thickness direction. A higher power density results in a faster ablation rate, while a longer irradiation time leads to a larger ablation pit diameter. To account for the variation in thermal conductivity between the fiber and resin, a macro-mesoscale model was developed to differentiate the matrix from the fiber components. Finite element analysis revealed that laser irradiation leads to phenolic decomposition, glass fiber melting vaporization, and residual carbon skeleton evaporation. The dual-scale model exhibits precise prediction capabilities concerning the laser ablation process of GFRP, and its accuracy is confirmed through the comparison of simulation and experimental results for the GFRP laser ablation process. This model provides a feasible method for performance evaluation and lifetime prediction of GFRP subjected to continuous wave laser irradiation.

This study focuses on the thermo-mechanical properties of Carbon Fibre/Polyimide Composite (CFPC) attaching collars under transient heating. The CFPC attaching collars were fabricated by a high-temperature resin transfer moulding process, and their thermo-mechanical properties under the conditions of simultaneous transient heating and bending load were investigated. The results show that the attaching collar tends to fail at 118% of the limit load. The failure mode includes the fracture of the connecting screws, local extrusion damage of the hole edges, and slight ablation damage at the outer plies. And there is no observable residual deformation in the composite attaching collar. Furthermore, considering that the material properties vary with temperature, a progressive damage model based on the sequential thermo-mechanical coupling method was established to study the failure mechanism of the attaching collar. Finally, the damage factor of the CFPC was calculated to assess the safety status of the attaching collar. The results show that the primary damage modes of the composite attaching collar are intralaminar failure, which mainly occurs at the heat insulation layer and the hole edges, and these slightly affect the structural bearing capacity. A good correlation between the experiment and FEA is obtained. The test methods and analysis models proposed contribute to the safety assessment of composite structures under transient heating.