复合材料π接头拉伸力学性能的试验和计算研究

采用试验和数值模拟的方法对整体化复合材料π接头在拉伸载荷作用下的力学特性进行研究。在Instron 8803电液伺服材料试验机上进行了π接头试验件的拉伸试验，记录试验过程中损伤产生及破坏过程，记录初始失效载荷和最终失效载荷。试验结果表明，填料是π接头破坏的关键部位，需要进行深入研究。提出了复合材料π接头力学性能数值模拟的基本假设和方法，基于通用有限元商用软件，建立π接头三维力学分析模型，获得π接头各部位应力分布情况；基于基本假设，对最大应力失效准则进行修正，并给出π接头各部位损伤载荷的预测值。计算预测π接头的初始损伤部位与试验吻合，初始失效载荷计算值与5个试件试验数据均值相比误差为0.53%，表明了数值分析方法的可行性。

Experimental and numerical research on mechanics performance of compositeπjoint under tensile loading

The mechanical behaviour of compositeπjoints under out-of-plane tensile load was investigated by the experimental and numerical simulation method. The tests were operated on the Instron 8803. During the experiments，the onset of the damage initiation，the failure process and their corresponding load were tested. The experimental results show that the fillers on the joint connection represent a potential zone of weakness and it is essential that their mechanical behaviour is well characterized. To simulate the mechanical behaviour of the weakness，basic assumptions and simulated method were presented. Based on the general FEM sof tware，the stress distribution of each composite lamina and filler was investigated with a 3D FE model and the estimated damage load was obtained by the modified maximum stress criteria. The filler as a critical component of the joint is pointed numerically，which is consistent with the experimental phenomena. At the same time，the predicted load of the onset of the damage has good agreement with the mean value of experimental data. These agreements verify the feasibility of the numerical analysis.