夹芯复合材料T型连接结构悬臂弯曲强度特性分析

针对夹芯复合材料T型连接结构,建立了有限元模型,模拟其在悬臂弯曲位移载荷下损伤产生、扩展及失效的过程,进行了悬臂弯曲试验验证模拟结果,进行了结构优化分析。试验结果表明:初始损伤产生时的位移为30 mm~32 mm,对应载荷为7.5 k N~7.7 k N,损伤产生后结构刚度降低,随着位移增加,承载力持续上升,失效强度较初始损伤强度提高了41%~55%;计算结果与试验结果相吻合,且表明初始损伤为复合材料压缩失效,产生于隔板下面板与增强区连接处,随着位移载荷的增加,损伤面积增大最终导致整体结构失效;优化结果表明,提高隔板下面板和芯材厚度,可降低隔板下面板的最大应力和失效因子,缩小上下面板的失效因子差,充分发挥结构性能。

RESEARCH OF LATERAL BENDING STRENGTH OF SANDWICH COMPOSITE MATERIALS T-JOINT

The numerical model of sandwich composite materials T-Joint is built by ANSYS.And,the damage formation,extension,failing process and optimization design of the T-Joint under bend displacement are investigated by numerical simulation.The Cantilever bending performance was tested to verify the simulation results.The test results show that the initial damage displacement is 30～32 mm,and the relative load is 7.5 kN ～ 7.6 kN.The bearing capacity of T-Joint is increased and stiffness is reduced.The failure strength is increased by 41％～ 55％ compared with initial damage strength.The results of experiment is consistent with the numerical simulation,indicating that the clapboard is the weak position of the structure.The initial damage is extrusion damage of composite material and appears to the connections between clapboard and enhancing area.With the increasing of bend displacement,the damage area is increased,leading to the failure of the whole T-Joint.By finite element optimization analysis,the improvement of the down-skin and core thickness of clapboard could lead to reduce the maximum stress and failure factor of down-skin of clapboard,and narrow failure factor difference of two clapboard skins,and give full play to the performance of overall structure.