基于多尺度数值模型的复合材料各向异性热膨胀系数预测

Prediction of anisotropic coefficient of thermal expansion for laminated composite using multiscale numerical models

  • 摘要: 依据复合材料内部纤维在基体内的排布规律及层合板铺层特性,基于多尺度方法,建立单层板和层合板代表性体积单元(RVE)模型,施加相应的边界条件,预测单层板的热膨胀系数和工程常数,进而预测复合材料层合板各向异性的等效热膨胀系数。通过与实验数据对比发现,基于正六边形单层板RVE模型预测的热膨胀系数,相比理论预测值,整体更接近实验值,其中预测的单向T300/5208碳纤维增强环氧树脂基复合材料、P75/934碳纤维增强环氧树脂基复合材料和C6000/Pi碳纤维增强环氧树脂基复合材料的横向热膨胀系数与实验结果的误差分别只有3%、1%和2%;采用单层板RVE预测的单向ECR/Derakane 510C玻璃纤维增强乙烯基酯树脂基复合材料的工程常数与实验值最大相差7.5%;层合板RVE模型预测的正交AS4/8552碳纤维增强环氧树脂基复合材料厚度方向的热膨胀系数与实验结果误差可以忽略,只有0.08%。最后以大型复合结构常用的正交铺层结构为研究对象,基于给出的单层板和层合板RVE模型预测了不同铺层复合材料烟道层合板的等效热膨胀系数,环向铺层比例对厚度方向的热膨胀系数影响较小。

     

    Abstract: Representative volume element (RVE) in lamina and laminate levels were build based on the arrays of fiber into resin and stacking sequences in laminated composites. In combination with the specified boundary conditions in RVE models, coefficient of thermal expansions (CTEs) and engineering constants for lamina were predicted, followed by an evaluation of anisotropic CTEs for laminate using multiscale method. The results show that numerically predicted CTEs match well with experimental data as compared to theoretically calculated value as a whole, especially for the numerically predicated CTEs of unidirectional T300/5208, P75/934 and C6000/Pi carbon fiber reinforced epoxy resin matrix composites with a difference of 3%, 1% and 2%, respectively. And the predicted engineering constants using RVE model for unidirectional ECR/Derakane 510C glass fiber reinforced vinyl ester resin matrix composites were also in good agreement with experimentally measured results, with a maximum difference of 7.5%. Meanwhile, the difference between experimental results and forecasted CTEs in through-thickness direction for cross-ply AS4/8552 carbon fiber reinforced resin matrix composites using RVE model of laminated composites is nearly negligible with a difference of 0.08%. Finally, the equivalent CTEs of laminated composite with different stacking sequences were estimated using RVE models of lamina and laminate levels for cross-ply composite structures in large large-scale structures, and the results reveal that CTEs in through-thickness direction are weakly related to the ratio of stacking sequences in hoop direction.

     

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