Nonlinear Reduced-Order Analysis with Time-Varying Spatial Loading Distributions

• Published in: Journal of aircraft 2009-07, Vol.46 (4), p.1395-1402
• Main Authors: Przekop, Adam, Rizzi, Stephen A
• Format: Article
• Language: English
• Subjects: Acoustics; Aircraft; Exact sciences and technology; Fundamental areas of phenomenology (including applications); Load; Measurement and testing methods; Oscillators; Physics; Solid mechanics; Structural and continuum mechanics; Vibration, mechanical wave, dynamic stability (aeroelasticity, vibration control...)
• ISSN: 0021-8669; 1533-3868
• DOI: 10.2514/1.39790

Oscillating shocks acting in combination with high-intensity acoustic loadings present a challenge to the design of resilient hypersonic-flight vehicle structures. This paper addresses some features of this loading condition and certain aspects of a nonlinear reduced-order analysis with emphasis on system identification, leading to the formation of a robust modal basis. The nonlinear dynamic response of a composite structure subject to the simultaneous action of locally strong oscillating pressure gradients and high-intensity acoustic loadings is considered. The reduced-order analysis used in this work has been previously demonstrated to be both computationally efficient and accurate for time-invariant spatial loading distributions, provided that an appropriate modal basis is used. The challenge of the present study is to identify a suitable basis for loadings with time-varying spatial distributions. Using a proper orthogonal decomposition and modal expansion, it is shown that such a basis can be developed. The basis is made more robust by incrementally expanding it to account for changes in the location, frequency, and span of the oscillating pressure gradient. [PUBLICATION ABSTRACT]