关键词: 碳纤维复合材料, 激光烧蚀, 多场耦合, 多尺度模型

Abstract:

A multi-physics coupling and multi-scale model is established to describe laser damage process of carbon fiber composites. The multi-physics coupling model includes three aspects： Thermal， mechanical and chemical model； the multi-scale model involves the micro-scale of fiber， resin and their chemical reaction products， the meso-scale of fiber yarn， matrix and interface layer， and the macro-scale of laminates. A multi-physics alternating coupling analysis process is established， and finite element method and numerical integration method are combined to solve the governing equations of the model. Taking the laser ablation experiment of a woven composite laminate with 5 plies as an example， the model predictions demonstrate good agreement with the experimental results for both the damage morphology of the laminate and the temperature rise history at the center of the back surface， validating the effectiveness of the model. Simulations of ablation effects in different gaseous environments indicate that higher oxygen concentrations in the ablation environment lead to more intense oxidation reactions of the carbon fibers and pyrolytic carbon residue， resulting in more significant damage to the composite material. Thus， to fully exploit the excellent high-temperature mechanical properties of carbon fibers， suppressing oxidation represents a viable approach for enhancing the laser damage resistance of carbon fiber composites. This model and solution method can effectively predict the material damage threshold under various laser irradiation parameters， facilitating in-depth research on the laser damage mechanisms of composite materials. It thereby provides a new theoretical analysis methodology for the laser-resistant protection design of aerospace structures.

Key words: carbon fiber composites, laser ablation, multi-physics coupling, multi-scale model