A swift technique for damage detection of determinate truss structures

In this study, a novel two-stage approach for damage detection of determinate truss structures is proposed. The method lies in the group of vibration-based methods but it just needs the first natural frequency and mode shape vector of these structures for identifying the location and severity of damage. In the first stage, the modal residual force vector for different modes of a structure is introduced and the one associated with the first mode is applied to the structure as an external nodal force vector. Then, the residual local nodal force vector can be computed for all elements of the structure. Next, the elements with non-zero residual internal force are considered as damaged elements. In the second stage, the damage severity of each damaged element is determined using a new relation which can be categorized as a force–displacement relation. To show the efficiency and simplicity of the proposed method, three truss structures including a 13-bar planar truss, a 29-bar planar truss, and a 77-bar planar truss under different damage scenarios are studied; the results of which indicate that the method is innovatively capable of suitably detecting, for determinate truss structures, not only damaged members but also their individual damage severity by carrying solely one analysis.

     

A swift technique for damage detection of determinate truss structures (2)

This paper introduces a novel and robust probable statistical approach for the applied damage detection of determinate truss structures. This technique involves two steps; the first is called most probable damaged element identification step and the second is called probable damage severity prediction step. In the first step, a new index based on modal residual forces plays a major role to independently identify damage-suspected elements for each considered mode. Then among them, the elements, the most probable to damage, are extracted. In the second step, the probable damage severity for each most probable damaged element is individually predicted using a novel statistical approach. Finally, to justify the validity and robustness of the technique, three commonly used bridge trusses including a 29-bar Pratt truss, a 29-bar Warren truss, and finally, a 37-bar K truss under different damage scenarios are thoroughly studied while their modal parameters are corrupted by noise. The obtained results indicate that the method is innovatively capable of swiftly predicting, for determinate truss structures, not only damaged elements but also their damage severities by carrying out solely few structural analyses.