航空铆钉的动态力学性能测试

Dynamic Mechanical Test of Aeronautic Rivets

在飞机鸟撞的课题研究中,数值模拟占据着日益重要的地位,而数值模拟的精度在很大程度上依赖于铆钉力学参数的准确性,但是目前航空铆钉的动态力学性能参数还很匮乏。本文测定了航空铝合金铆钉在不同加载速度下的剪切和拉伸力学性能。设计了基于分离式Hopkinson拉杆系统的铆钉动态性能测试装置,并利用此装置对7种不同型号的航空铆钉进行了动态剪切和拉伸试验,得到了每种型号铆钉的动态力学性能。利用电子万能试验机对7种铆钉进行了两种应变率下的准静态剪切和拉伸试验,并且和动态试验结果进行对比。讨论了加载速度、加载形式、铆钉直径以及铆钉形式对铆钉力学性能的影响,并利用扫描电子显微镜(SEM)观察了铆钉剪切破坏以及拉伸破坏的断口形貌,分析了其破坏形式。本文的研究结果对于航空铝合金铆钉在工程中的应用、尤其是在抗冲击领域的应用具有指导意义。

Numerical simulation is playing an important role in the research of bird strikes,the accuracy of which depends to a large extent on the dynamic mechanical properties of rivets.Despite the importance of the dynamic mechanical properties of rivets,only limited amounts of published data are available on this issue.In this paper the shear and tension mechanical properties of aluminum alloy rivets under different loading velocities are determined.To explore the dynamic shear and tension mechanical properties of rivets,shear and uniaxial tension tests are carried out by using the split Hopkinson tension bar technique.An experimental setup for testing dynamic properties of rivets is designed based on the split Hopkinson tension bar system,and dynamic shear and tension tests of seven different types of aeronautic rivets are carried out using this system.Quasi-static shear and tension tests under two strain rates are carried out by using a universal electronic testing machine,and then the results are compared with those of the dynamic tests.Further discussions reveal the effect of loading velocity,loading modes,rivet radius and rivet modes on the mechanical properties of rivets.To analyze the failure modes,a detailed observation of fracture surfaces is performed using a scanning electron microscope （SEM）.The results of this study can provide some guidance for the application of aerospace aluminum alloy rivets in engineering,especially with respect to impact.