Reduced-Order Models for Acoustic Response Prediction of a Curved Panel

Abstract

Predicting the response of stiffened shell structures subjected to extreme acoustic loading and aerodynamic heating is a challenging computational task. The acoustic loading induces nonlinear, stochastic vibratory response. The aerodynamic heating results in significant quasi-static thermal stresses which can significantly alter the dynamic response. Curvature effects in stiffened skin structures exposed to these loadings can further complicate numerical analysis. Reduced-order nonlinear models have been shown to be accurate and computationally efficient in simulating the time response of simple beams and plates with acoustic and thermal loading. The next step in the development and verification of reducedorder methods for acoustic response prediction of real structures is their application to curved panels. This paper presents the results of a numerical study of reduced-order models using and modes applied to a curved panel with static thermal and acoustic loading. The cold modes approach uses normal modes of the structure at ambient temperature while the hot modes approach uses modes from the thermally loaded state. In general, results from both approaches agree closely with full-order finite element simulations of a curved panel example problem. However, both approaches suffered from stability problems at very high sound pressure levels. While the cold modes models are more desirable for analysis at multiple temperatures, more modes are generally required to achieve results equivalent to a hot modes model.