基于三胞模型的2.5D编织复合材料力学性能研究

Investigation of Mechanical Properties of 2.5D Braided Composites Based on Triple-cell Model

为了准确预测2.5D编织复合材料的纵向力学性能,本工作以2.5D等厚度和变厚度编织复合材料为研究对象,基于细观结构表征结果,建立了一种考虑表面挤压效应和纱线错位滑移影响的2.5D等厚度和变厚度编织复合材料的全胞和三胞模型;并在所建立的全胞和三胞几何模型的基础上,基于逐渐损伤法开展了2.5D等厚度和变厚度编织复合材料的数值模拟分析,对不同结构的纵向刚度和强度进行了预测,模拟了不同结构的损伤扩展过程和损伤行为,并与实验结果进行对比验证。结果表明:考虑表面挤压效应和纱线错位滑移影响的全胞和三胞模型能更准确地预测2.5D编织复合材料的力学性能;三胞模型的数值模拟结果能更准确地反映2.5D编织复合材料的损伤扩展过程,更全面地表征2.5D编织复合材料的损伤行为。

In order to accurately predict the longitudinal mechanical properties of 2.5D braided composites,this work takes 2.5D equal thickness and va-riable thickness braided composites as the research object.Based on the microstructure characterization results,whole cell and triple-cell models of 2.5D equal thickness and variable thickness braided composites considering the effects of surface extrusion and yarn dislocation and slip is established.Based on the established whole cell and triple-cell geometric models,the numerical simulation analysis of 2.5D braided composites with equal thickness and variable thickness is carried out based on the progressive damage method,the longitudinal stiffness and strength of different structures are predicted,the damage propagation process and damage behavior of different structures are simulated,which is compared with the experimental results.The results show that the whole cell and triple-cell model considering the effects of surface extrusion and yarn dislocation slip can more accurately predict the mechanical properties of 2.5D braided composites;the numerical simulation results of the triple-cell model can more accurately reflect the damage propagation process of 2.5D braided composites and more comprehensively characterize the da-mage behavior of 2.5D braided composites.