Aircraft Structure’s Response Prediction Analysis and Experimental Study in High-strength Broadband Noise Environments

Since dynamic environment of the hypersonic aircraft has a wide frequency domain, it is difficult to predict the vibration response with finite element methods. A certain type of high-speed aircraft's vibro-acoustic dynamics model is established based on statistical energy analysis (SEA) theory. By using theory analytical method and the empirical formula to determine the input parameters of each subsystem, setting the actual noise test conditions as the input incentives of the SEA model, the aircraft cabin's noise pressure level and the vibration acceleration response of the subsystems are predicted, and compared to the test results. The results show that the acceleration power spectral density (PSD) of subsystem has a good consistency with the results of test in the middle and high frequency and the error of sound pressure level in cabin throughout the spectrum is less than 3 dB, so the dynamic model and calculation method is reliable and it solves the limitation of calculating the response of vibro-acoustic problems in middle and high frequency using the finite element and boundary element methods. The main source of the sound field in the cabin is found out by transfer path analysis. A method of the control and optimization design of noise based on the variable of loss factor is put forward, using the genetic algorithm to solve the optimization of the nonlinear constraint, and provides an effective means for study on aircraft structures and the complex dynamic environments and the optimization design of aircraft noise reduction.