Study on failure of single-bolt double-lap composite joints based on test and numerical emulation

基于试验及数值仿真的复合材料单钉双剪连接件失效研究

¹ State Key Laboratory of Mechanics and Control of Mechanical Structures, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China
² Chengdu Aircraft Design and Research Institute, Aviation Industry Corporation of China, Ltd., Chengdu 610091, China

Received: 25 August 2022

Abstract

In order to study the mechanical properties of ZT7G/LT-03A carbon fiber reinforced composite bolted joints, the single-bolt double-lap joints tests were carried out with 3 kinds of ply and 3 kinds of width, and the effects of the different ply ratios, width to diameter ratios on the failure load and failure mode were analyzed. Then, the failure process of the specimens was simulated by using the progressive damage and failure analysis method. The failure mode and failure load of the model are consistent with that of the specimen, which verified the accuracy of the model. On this basis, the stress and damage status of each ply during initial load shedding were studied, and the influence of the ply ratios and width to diameter ratios on the performance of laminates was further studied. The results show that when the width to diameter ratio of laminates increases, the failure mode changes from tensile failure to bearing failure, and to change the ply ratios does not affect the failure mode in a certain range.

摘要

为研究ZT7G/LT-03A碳纤维环氧树脂复合材料单钉双剪连接件的力学性能, 对3种铺层与3种宽度的层合板开展了复合材料单钉双剪试验, 分析了不同铺层比例、宽径比对失效载荷与失效模式的影响。采用渐进损伤失效分析方法对试件的失效过程进行了有限元模拟, 模型与试件的失效模式以及失效载荷吻合良好, 验证了模型的准确性。在此基础上, 研究了初次掉载时层合板各个铺层的应力分布与损伤状况, 并进一步探究了整个加载历程中不同铺层比例与宽径比对连接件性能的影响。结果表明, 当层合板的宽径比增加时, 失效模式由拉伸失效转变为挤压失效, 而在一定范围内改变铺层比例时, 失效模式基本不受影响。