Moisture diffusion model of composites considering fiber/matrix inter phase
-
摘要: 通过类比复合材料湿扩散与热传导的控制方程以及边界条件，以Halpin & Tsai模型为基础，发展了一个考虑了纤维/基体界面相的三相复合材料湿扩散模型，并研究了纤维界面随机损伤对湿扩散的影响。建立了纤维周期排布、随机排布、界面相损伤随机分布3种细观有限元模型。用上述模型分析了单向复合材料横向有效湿扩散系数（TEMDUC）随纤维和界面相体积分数、湿扩散性能以及界面相损伤率变化的规律，理论预测与有限元计算结果一致。研究发现：界面相或纤维相的扩散系数存在一个临界值，当扩散系数小于该临界值时，TEMDUC随纤维体积分数的增大而减小；反之，TEMDUC随纤维体积分数的增大而增大，此临界值的大小与纤维体积含量无关。研究还发现纤维界面损伤率相同的条件下，其分布的随机性对复合材料的有效湿扩散系数影响不大。Abstract: A three-phase moisture diffusion approach of composites was developed based upon the Halpin & Tsais model by analogizing the governing equations and boundary conditions of moisture diffusion and heat conduction. In this approach, the moisture diffusion effect of fiber/matrix inter-phase was taken into account. Three types of micro-scale FE models, i.e. hexagonally, randomly packed fibers and randomly distributed inter-phase damage, were built to valid the theoretical model. The predictions from theoretical approach and FE models are in good agreements under the conditions of various volume fractions, diffusivities of fiber and inter-phase as well as randomness of inter-phase damage. Critical inter-phase and fiber moisture diffusivities, independent on fiber volume fraction, are found in this study. When the inter-phase or fiber diffusivity is less than the critical value, the transverse effective moisture diffusivity of unidirectional composite(TEMDUC) will decrease with the increase of fiber volume fraction. On the contrary, the trend is opposite. Also, the fluctuation range of composites' effective moisture diffusivities is found narrow with the change of inter-phase damage distribution if the damage ratio has been given.
-
Keywords:
- composites /
- effective moisture diffusivity /
- damage of inter-phase /
- random /
- probability density
-
-
计量
- 文章访问数: 654
- HTML全文浏览量: 63
- PDF下载量: 523
下载:
