Three-dimensional crack detection method for structures using simulated strain gages and the body force method

A method for estimating the stress field of an observed domain by considering the surface of a 3-dimensional object as a pseudo-3-dimensional object has been proposed in a previous report by the present authors. In this method, some strain gages and the body force method are used. In this paper, the method is applied to crack detection in notched structures. A characteristic stress field attributable to the crack can be expected in the observed domain. Crack detection is then tried by showing the characteristic stress field. Detection of an ideal crack, which is a through crack or a quarter-circular crack on the hidden side, is studied using the finite-element method (FEM). Moreover, the stress fields are estimated using the present method from the FEM's stress values instead of actual stress values. In both a through crack and a quarter-circular hidden crack, the characteristic stress field can be shown; the characteristic stress field means that two stress concentrations exist along the notch. Finally, the application limits of the present method are shown.