Guided waves for stress identification

The measurement of stress in structural componentswould be of great value in engineering. Here, a numerical model is set up to expound experimental tests on a prestressed plate in the light of acoustoelasticity and in view of the formulation of an inverse problem, in which response is measured and stress is identified. The theory of acoustoelasticity is used to describe wave propagation in a prestressed guided wave, accounting for selected sources of nonlinearities. In particular, finite strains are used, and energy is written as a third-order function of the strains. The experiments are performed on a rectangular plate held by a machine, inducing prestress in the plate and applying in-plane impulsive loadings by an instrumented hammer. The time histories of both loading and dynamic response are recorded and the variation of the relevant dynamic response quantities are investigated. The aim of the experimental tests is to observe the transmission of waves in the plate, relating the prestress to the variation of the propagation speed of waves. © 2013 Taylor & Francis Group, London, UK.