RTM成型非对称复合材料T型接头的拉伸失效机制  

Tensile failure mechanism of RTM-made asymmetric composite T-joint

作　　者：王帅 陈梦熊 李伟东 罗楚养 潘利剑 WANG Shuai;CHEN Mengxiong;LI Weidong;LUO Chuyang;PAN Lijian(Collaborative Innovation Center for Civil Aviation Composites,Donghua University,Shanghai 201620,China;Key Laboratory of Advanced Composites,Beijing Institute of Aeronautical Materials,AVIC Composites CO.,LTD.,Beijing 100095,China)

机构地区：[1]东华大学民用航空复合材料协同创新中心,上海201620 [2]中航复合材料有限责任公司北京航空材料研究院,先进复合材料重点实验室,北京100095

出　　处：《复合材料学报》2023年第1期613-624,共12页Acta Materiae Compositae Sinica

基　　金：航空科学基金(20180112008);青年人才托举工程(2016QNRC001);上海市科技创新行动计划项目(19DZ1100300)。

摘　　要：采用树脂传递模塑(RTM)工艺制备了结构对称和非对称两种复合材料T型接头试样,并对其进行了静态拉伸力学试验,对比分析了两种结构的拉伸破坏模式、结构刚度及破坏载荷。同时基于T接头内聚力模型(CZM),研究了两种不同结构T型接头的拉伸破坏过程及失效机制,并对比分析了不同偏转角下T接头的层间应力。结果表明:不同结构T型接头的拉伸破坏模式不同,偏转角的存在使结构非对称T型接头夹角大侧圆弧受力明显高于小侧圆弧,导致接头首先在大侧夹角圆弧与三角区界面定向萌生初始裂纹,随后裂纹主要沿大侧腹板翻边与蒙皮的界面扩展,进而导致接头最终破坏,最终失效载荷较对称T型接头提高了15.3%,且结构刚度更大。有限元结果表明T型接头三角区的初始失效主要由层间正应力及剪应力引起,有限元分析的失效模式与试验一致,结构对称及非对称T型接头最终失效载荷与试验值均吻合较好;且随着偏转角的增加,腹板圆弧处层间应力逐渐减小,初始失效载荷将随之增大;初始破坏位置将转移至大侧夹角圆弧末端。The tensile tests of structural symmetric and asymmetric composite T-joints prepared by resin transfer moulding(RTM)process were carried out,respectively.The failure process,structure stiffness and failure load of these composite T-joints were compared and analyzed.At the same time,the cohesive zone models(CZM)of composite T-joints were established and the failure process and failure mechanism of these two type T-joints were studied.The interlaminar stress of T-joints with different deflection angles were also compared.The test results show that the failure mode of structural asymmetric T-joint is different from that of symmetric T-joint.The existence of deflection angle causes higher stress at the large angle curved web than that of the small angle curved web,as a result,the initial crack of asymmetric T-joints orientationally occurs at the interface of triangular zone/curved web with large deflection angle.And then the crack directly propagates to the interface of large deflection angle flange/skin with 15.3%higher peak failure load than that of symmetric T-joints.The small bending deformation of the skin of asymmetric T-joint leads to the larger overall stiffness of the structure.The debonding of flange and skin is the prominent reason to the final failure of T-joint.The finite element analysis results show that the simulated peak failure loads of symmetric and asymmetric T-joints are within deviation.The simulated failure mode is in good agreement with the experiment.As the deflection angle increases,the interlaminar stress at the curved web of asymmetric T-joint decreases gradually,which indicates that the initial failure load of asymmetric T-joint may increase correspondingly.The position of initial crack will be shifted to the end of curved web at the same time.

关 键 词：复合材料 T型接头 失效机制 有限元分析 树脂传递模塑 

分 类 号：TB332[一般工业技术—材料科学与工程] V214.8[航空宇航科学与技术—航空宇航推进理论与工程]