The failure mechanism and failure protection of 3A21 aluminum alloy under random vibration and shock loading

Abstract

To reveal the failure mechanism under random vibration and shock loading, the typical spacecraft electronic equipment of 3A21 aluminum alloy was tested in 16.1g of RMS acceleration by using electric shaker and 1600g of pyroshock magnitude by using pendulum shock equipment. And the fracture specimens were analyzed by scanning electron microscopy (SEM). The results show that 3A21 aluminum alloy exhibits brittle fracture followed by fatigue fracture under random vibration and brittle fracture directly under shock loading. To study the failure protection under random vibration and shock loading of 3A21 aluminum alloy, the good agreement has been achieved in the dynamic response between the numerical simulation and tests, which verifies the method of response spectrum analysis (RSA) under random vibration and time history waveform synthesis (WAVSYN) under shock loading. The maximum relative error was 14.3%. Then the equipment was optimally designed based on the numerical simulation, and the feasibility of the optimization method was verified by dynamic loading tests.