Abstract: This paper presents a numerical study which investigates the effect of high temperature on the dynamic response of a vibro-acoustic system excited by 165 dB acoustic pressure based on a hybrid finite element-statistical energy analysis (FE-SEA) in 1 800 Hz broadband frequency. The study takes into consideration the thermal stress and temperature-dependent material properties mainly through which the thermal environment influences the dynamic response. The coupled system is composed of an FE model of X-43A and an SEA model of its internal acoustic field. The energy response distribution at the top-surface in the space and frequency domain are obtained, which reveals that the thermal stress has only slight effect on the natural frequencies due to the unconstrained structure condition. The velocity response has a similar trend as that in room-temperature, with a small decrease of root mean square (RMS) and power spectral density (PSD) in most bands. Changes in material property reduce obviously the natural frequencies of the structure, and shift the response peaks to lower frequencies. For the central part of the structure, the material property exerts an increasing effect on the RMS value and energy at several bands, while for the forepart the material property has a decreasing effect on the RMS value.

Key words: vibro-acoustic response, hybrid FE-SEA, broadband, thermal stress, material property