Application Research On Stochastic Loads Identification For Missile Vibration Test

In the present aviation field, it becomes more and more important to take the vibration test ofmissile in order to predict the actual environment in the air. Even though the Military Criterion isadopted for the dynamic tests of missile in mainland of China, the dynamic environment predictiontest of the missile should be taken constantly for the corresponding updating experiment condition,which is caused by the development of the structure design of missile based on the increasingrequirement of missile’s characteristics. In this paper, the study focuses on stochastic loadsidentification for missile during the vibration test, by using the measured data.Firstly, the theory of stochastic loading identification is illustrated, and several commonalgorithms are given to avoid the ill-condition matrix, program for stochastic loads identification iswritten subsequently. Simulation cases are given to identify the stochastic loads based on continuousbeams, which validate the correctness of the program. The influence of environment noise, thenumber and location of sensors, the precision of measured data, the damping ratio and the error ofsystem parameters are analyzed in detail and then some methods are given to improve theidentification precision according to the analyzed result above. Secondly, simulation on vibration testof the captive flight of the missile is analyzed, including the reasonable equivalence andsimplification of the finite element model of the missile both in entirety and local, and the design andanalysis of clamp for the vibration test. For the missile, the power spectrum of response is calculatedfirst according to the Military Criterion. Then it is used to identify the stochastic loads along withobtaining the best number and locations of sensors. At last, the stochastic loads are identified usingthe power spectrum of measured response, through which the power spectrum density of impactioncased by vibration generator is also acquired. The differences between the identified impaction andthe one supported by Military Criterion are analyzed, which could be a reference for MilitaryCriterion.This research is supported by the National Natural Science Foundation of China through GrantNo.11172131.This research is supported by State Key Laboratory of Mechanics and Control of MechanicalStructures.