This paper investigates the effect of moisture content upon the degradation behaviour of composite materials. A coupled phase field framework considering moisture diffusion, hygroscopic expansion, and fracture behaviour is developed. This multi-physics framework is used to explore the damage evolution of composite materials, spanning the micro-, meso- and macro-scales. The micro-scale unit-cell model shows how the mismatch between the hygroscopic expansion of fibre and matrix leads to interface debonding. From the meso-scale ply-level model, we learn that the distribution of fibres has a minor influence on the material properties, while increasing moisture content facilitates interface debonding. The macro-scale laminate-level model shows that moisture induces a higher degree of damage on the longitudinal ply relative to the transverse ply. This work opens a new avenue to understand and predict environmentally-assisted degradation in composite materials.

翻译：本文研究了水分含量对复合材料退化行为的影响。提出了一种耦合相场框架，综合考虑了水分扩散、湿膨胀和断裂行为。该多物理场框架用于探索复合材料在微观、细观和宏观尺度上的损伤演化。微观尺度单胞模型揭示了纤维与基体之间湿膨胀不匹配导致界面脱粘的机制。通过细观尺度层板级模型发现，纤维分布对材料性能的影响较小，而水分含量的增加会促进界面脱粘。宏观尺度层合板模型表明，水分对纵向铺层造成的损伤程度高于横向铺层。本研究为理解和预测复合材料的环境辅助降解开辟了新途径。