Identification of tension distribution of thin plate using vibration characteristics (Applying to the under operating lines of thin aluminum plate)

Abstract

The flatness of the metal thin plate shape is required in the production lines. Though, the convenient method for measuring small buckles of the thin plate has not been established. The tension distribution corresponding to the strain distribution occurs adding the strip running tension to the buckled thin plate. We propose an identification method by using natural frequencies and vibration modes, which are related to tension distributions of the thin plate. In this paper, a new tension identification method in the thin plate using modal analysis method is investigated. We develop a simplified dynamic model of the thin plate, and tension distribution is modeled by springs. A simplified model spring constants are obtained by the least-squares method, which minimize the difference between a simplified model modal parameters and the measured values. We applied the modal analysis method based on subspace system identification theory to measured vibration characteristics of the thin aluminum plate under operating lines. As a result, it is shown that identified tension distributions are valid result to the straightening line.