Research On Determination Method Of Test Magnitude And Optimization Design Of Fixture Based On Data Induction Standard Spectrum

Environmental vibration test is an important means to test the working environment endurance of spacecraft products.In the environmental vibration test,it is the guarantee of the reliability of the environmental vibration test results to restore the vibration state of the product as realistically as possible.This paper takes a certain type of aircraft as the research object,and deeply studies the environmental vibration test technology from two aspects:vibration data summarization,test conditions formulation,and fixture optimization design.Firstly,in order to determine the test magnitude of the vibration environment,a Gaussian distribution test was performed on the environmental vibration signal of the aircraft during operation.The kernel density induction method is used to summarize the measured environmental vibration data satisfying the non-Gaussian distribution,and the comparison with the traditional bootstrap data induction method is used to verify the correctness of the kernel density induction method for the induction of non-Gaussian signals.Secondly,in order to solve the magnitude deviation problem caused by vibration excitation transmitted to the aircraft cabin by the fixture in the test process,this paper established the objective function of minimum root mean square deviation between response spectrum and reference spectrum under multi-point weighted control,and optimized the fixture size by GA-SQP algorithm.The simulation results show that the weighted root mean square value of the optimized fixture is closer to the root mean square value of the reference spectrum,and the optimization method is feasible.Finally,the processing fixture was developed,and the frequency sweep test and random vibration test were carried out to verify the fixture’s natural frequency and the transmission stability of the fixture to the reference spectrum.The frequency sweep test and random vibration test of fixture and cabin assembly were carried out to verify the natural frequency of the assembly and the vibration stability of the assembly under control spectrum.