Composite structural components are often subjected to service loads that cause cracks in off-axis layers, without compromising the load bearing capability of the structure. In marine or humid environments fluid ingress in the material can be accelerated by the presence of such cracks, leading to further strength degradation.

Several studies have been dealing with the effect of cracks on fluid diffusion in composites, sometimes with contradictory results. In this work the difference between cracks on the external and internal plies of the laminate has been addressed both experimentally and analytically, showing that the first ones have a strong influence on diffusivity, while the second have a negligible effect.

复合结构构件通常承受服务载荷，该载荷会在离轴层中引起裂缝，而不会损害结构的承载能力。在海洋或潮湿的环境中，此类裂纹的存在会加速材料中的流体进入，从而导致强度进一步降低。

已有几项研究研究了裂纹对复合材料中流体扩散的影响，有时得出的结果相互矛盾。在这项工作中，通过实验和分析方法都解决了层压板内外层裂缝之间的差异，表明第一个对扩散率有很大影响，而第二个影响可忽略不计。