PARAMETER IDENTIFICATION FOR ALUMINUM HONEYCOMB SANDWICH PANELS BASED ON ORTHOTROPIC TIMOSHENKO BEAM THEORY

• Published in: Journal of sound and vibration 1997-11, Vol.208 (2), p.271-287
• Main Authors: Saito, T., Parbery, R.D., Okuno, S., Kawano, S.
• Format: Article
• Language: English
• Subjects: Exact sciences and technology; Fundamental areas of phenomenology (including applications); Measurement and testing methods; Measurement methods and techniques in continuum mechanics of solids; Physics; Solid mechanics; Structural and continuum mechanics
• ISSN: 0022-460X; 1095-8568
• DOI: 10.1006/jsvi.1997.1189

The present paper deals with parameter identification of aluminum honeycomb sandwich panels with the assumption that they can be treated as orthotropic continua. Elastic constants and modal damping ratios are considered as the identified parameters, and the basic equations of Timoshenko beam theory are employed in this paper. The numerical identification problem of minimizing the errors between the experimental and the analytical results leads to two optimization problems. We introduce, as objective functions, an error function calculated by the natural frequencies and another by the accelerances. Both non-linear optimization problems with constraints are solved by the downhill simplex method including a penalty function. The density is obtained experimentally and in the first optimization problem only the elastic constants are identified. For the second optimization problem, both elastic constants and modal damping ratios are identified simultaneously. The resulting parameters are applied to finite element analysis and the calculated time histories of accelerations are compared with the experimental results to examine the validity of these identified parameters.