Experiments for damage location in a damped structure

In this paper, we describe the development of a laboratory truss testbed and the investigation of significant damping effects on the ability to locate damage. The testbed is a three-bay, vertically cantilevered truss which exhibits beam-like response for the first three modes (a pair of first bending modes in orthogonal directions and a torsional mode). Truss members were removed from the testbed to simulate various damage scenarios with reduced stiffness. In addition, up to four visco-elastic damping struts were placed in the truss testbed in various configurations to affect the damping of certain modes of the structure. A comprehensive test matrix of damping and damage effects was designed and completed to construct the data base for the damping and damage identification evaluations. The damage detection process used the differences between pre- and post-damage vibration characteristics, along with a structural model, to successfully locate and quantify the extent of structural damage in all cases. Damping matrix models were also identified and evaluated.