INCOMPLETE MODAL MEASUREMENTS-BASED DAMAGE IDENTIFICATION FOR TRUSS BRIDGE STRUCTURE

Some factors, e.g., incomplete measurements and measurement noise, are main difficulties confronted in damage identification method for application. On the basis of the work carried out by earlier researchers, the complete mode shapes are formulated using both the measured mode shapes on partial measurement points and the remaining unmeasured ones of the finite element model. Then, a damage identification method applicable to the structural systems composed of beam or bar using incomplete modal measurements is presented. The localization and quantification of the structural damage can be determined simultaneously due to the scalar damage model adopted. The numerical simulation of a planar truss is carried out with the Levenberg-Marquardt nonlinear least squares algorithm, in which the effects of the measured number of degrees of freedom (DOFs), the number of modes and measurement noise on the structural damage identification are investigated in detail. Experiments indicate that the method presented shows good performance even in the case of incomplete measurements and limited noise.