Research On Experimental Analysis Of Statistics Energy Parameters And Load Identificaion

Statistical Energy Analysis is widely used in the fields of aerospace and aviation for the solution of high-frequency dynamics problems of the complex structure. The key problem is to obtain the modal density, internal loss factor, coupling loss factor while using SEA to solve practical questions. Taking into account the theoretical analytical solution requiring a high specific structure, and large amount of calculation, experimental testing has become the main method of obtaining statistical energy analysis parameters. In this paper, the typical structure was used to carry out experimental analysis of modal density, internal loss factor, coupling loss. And the Statistical Energy Analysis method applied to high frequency load identification of structures was studied based on the SEA parameters. The main contents and conclusions are as follows:Power injection method was used to test inner loss factor of a rectangle aluminum alloy plate. The steady state test method was used to test inner loss factor and coupling loss factor of coupled plates. The internal loss factor by a single test plate fits well with the result by coupled test plates, confirming the applicability of the power injection method. Coupling loss factor was an order of magnitude smaller than inner loss factor, satisfying the assumptions of weak coupling while using the statistical energy analysis.The point admittance method was used to test modal density of a rectangle aluminum alloy plate. Impulse hammer excitations and swept-sine excitations were used respectively to get the result. The test result was modified by concerning the added mass of sensors. Experimental results show that different excitations have influence on the accuracy of test result; the influence of added mass on corrected result differs under different excitations in the same frequency. Based on the thin plate theory, modal density theoretical formula of orthotropic C/SiC composite plate was derived. Theoretical value fits well with the experimental test result after added mass correction in medium-high frequency band, confirming that theoretical analysis and experimental test take on high accuracy for the modal density identification of C/SiC composite plate.According to the completeness of loads location information and subsystem response set, the input power identification problems of structures are divided into three cases. Based on the two coupled subsystems, the experimental system of load identification and SEA analysis model were set up. The experimental results show that using statistical energy analysis for load identification of two coupled subsystems achieved a good result, confirming the Statistical Energy Analysis method applied to high frequency load identification of structures was effective and feasible for solving loading identification of complicated coupled structures in mid-high frequency.