复合材料蜂窝夹层结构T型接头拉伸性能研究

通过试验测量了复合材料蜂窝夹层结构T型整体接头的拉伸性能,得到其拉伸强度与破坏模式。建立了接头结构有限元模型,利用分类损伤判据、失效准则与刚度退化准则对结构的损伤情况进行模拟,研究了接头的拉伸破坏行为。有限元分析结果与试验结果吻合良好。研究结果表明,结构的薄弱点位于腹板内靠近蒙皮的位置。蜂窝在此处发生面外拉伸破坏,从而导致结构的最终破坏。腹板上的拉伸载荷主要通过过渡区填料传递给蒙皮,腹板与蒙皮间的搭接段对载荷传递的贡献较小。参数研究表明,对于复合材料蜂窝夹层结构T型接头,搭接段长度对结构的强度几乎没有影响,而增大蒙皮蜂窝的高度或采用低模量蜂窝可以提高结构强度。

STUDY ON COMPOSITE HONEYCOMB SANDWICH STRUCTURE FORMED T-JOINTS UNDER TENSILE LOAD

The tensile behavior of T-joints consisting of integral composite honeycomb sandwich structure is studied by experiment. The strength and failure modes of such elements are both obtained. An FEM model of the joint is then established. The classified damage criterion, failure criterion, and stiffness degradation rules are applied in order to simulate the damage and the tensile properties of the joint. The result of the FEM model shows good correlation with those from experiments. Results have shown that the weak point of the structure is on the end of web panel near to the skin panel. Out-of-plane fracture of the honeycomb in this area leads to the final failure of the structure. Tensile load on the web panel is transmitted to the skin panel mainly through the transition area, while the lapping zone between the web panel and the skin panel contributes less to the transmission. Parameter studies show that the length of the lapping zone has marginal effects on the strength of the structure, while thickening the skin`s honeycomb or employing honeycombs with a lower modulus can increase the strength.