The water absorption in isotropic material follows Fick' s Law.However,the moisture absorption experimental result of composite laminate indicates that composite laminate deviates from Fick' s Law.In order to study the nonFickian behavior of composite,a strain-assisted diffusion equation was established which may describe the moisture absorption behavior of composite more accurately.Taking the full coupling of moisture concentration and hygrothermal strain into consideration,supposing that the strain can also diffuse in composite,and introducing strain diffusion parameter and strain coupling item in moisture diffusion equation,the transient stress state in composite during diffusion process was calculated.The result demonstrates that strain-assisted result is in agreement with the experimental result and there is positive interaction between moisture contents and hygrothermal strain,which would affect the result of moisture concentration and strain.The transient temperature and moisture-induced stresses distribute in laminate nonuniformly,which is a significant factor in composite structure design.%为了研究复合材料吸湿过程中的Non-Fickian行为,建立基于应变的湿扩散方程,可以更准确地描述复合材料吸湿量随时间的变化关系.基于应变的湿扩散方程中考虑湿浓度与湿热应变间的相互耦合作用,假设应变也具有“扩散”行为,引入应变扩散系数与应变耦合项,并根据经典层压板理论计算层压板吸湿过程中产生的瞬时内应力状态.分析结果表明,基于应变的湿扩散方程所得到的吸湿量随时间变化的曲线与试验结果符合较好,层压板的湿浓度与湿热应变的相互耦合作用会影响吸湿量及湿热内应力的计算,在分析中不可忽略.受热和吸湿过程中产生的瞬态应力非均匀分布于层压板内,在复合材料结构设计时必须予以考虑.
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