IDENTIFICATION OF EXTERNAL STRUCTURAL LOADS FROM MEASURED HARMONIC RESPONSES

• Published in: Journal of sound and vibration 1996-09, Vol.196 (1), p.59-74
• Main Author: Karlsson, S.E.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.1996.0467

In many practical situations, it is difficult to perform direct measurements or calculations of the external forces acting on an existing vibrating structure. Instead, the structural response may than be measured and the position and magnitude of the exciting forces be calculated from the measured response. Unfortunately, the results from this inverse process are often highly sensitive to noise in the measurements of the response and errors in the model of the structure. The present study is focussed on this sensitivity under the assumption of a linear relation between the unknown harmonic force amplitudes and the response at discrete measurement positions. A scalar measure of the sensitivity is suggested. Numerical examples that illustrate the sensitivity and its correlation to the proposed sensitivity measure are given. The present sensitivity measure can be calculated for different candidate experimental configurations prior to any actual measurements and hence assist in the experimental design.