Time domain responses of a prestressed beam and prestress identification

• Published in: Journal of sound and vibration Vol. 288; no. 4; pp. 1011 - 1025
• Main Authors: Law, S.S., Lu, Z.R.
• Format: Journal Article
• Language: English
• Published: London Elsevier Ltd 20-12-2005; Elsevier
• Subjects: Exact sciences and technology; Fundamental areas of phenomenology (including applications); Measurement and testing methods; Physics; Solid mechanics; Structural and continuum mechanics; Prestress; Displacement(deformation); Bernoulli Euler model; Orthogonal polynomial; Beam(mechanics); Polynomial function; Deformation measurement; Time domain method; Orthogonal function; Feasibility; System identification; Sinusoidal excitation; Regularization
• ISSN: 0022-460X; 1095-8568
• DOI: 10.1016/j.jsv.2005.01.045

The time-domain response of a prestressed Euler–Bernoulli beam under external excitation is studied based on modal superposition. The prestress force is then identified in the time domain by a system identification approach and Tikhonov regularization technique is used to provide bounds to the ill-conditioned results in the identified problem. Both measured displacements and strains are used. The noise effect is improved using the orthogonal polynomial function, and cases with either sinusoidal or impulsive excitations are illustrated to give very good results from the lower three measured modes and data obtained from three measurement points. Work in this paper demonstrates the feasibility of indirectly identifying the prestress force in a beam.