Structural damage detection of 3-D truss structure using nodal response analysis

Abstract

The health monitoring system is considered mandatory during the operating period of truss structures, which are periodically tested to investigate damage detection in the critical components of such structures. Wave propagation-based damage detection has just been implemented in health monitoring systems. This paper proposes four new, efficient, and robust methodologies for systematic structural damage detection of truss structures. The main key used in the proposed methods is the continuous detection of changes in the node position of an element, the velocity time series responses, or the frequency spectrum of the responses affected by probable damage. Maximum amplitude ratio (MAR), Coherency ratio (CR), Maximum amplitude ratio and summation ratio of PSD spectrum (MPSDR & SPSDR) are four approaches for damage detection in the structure, which are based on assigning a relative damage index (RDI) to each truss element and calculating the total damage intensity (TDI) for the entire considered span of the main structure. The proposed methods have been validated both experimentally and mathematically to determine they could be utilized as reliable methods of structural health monitoring. To validate the proposed methods, a laboratory was used to construct a three-dimensional truss structure with two spans. The results show that all methods are able to illustrate the presence of damage in one span of the structure by locating the damaged element that has a higher RDI value. Moreover, the SPSDR method is sensitive to the amount of damage, as the TDI parameter increases efficiently as the stiffness of the damaged element is reduced. The main feature of the proposed methods that distinguishes them from others is their ability to localize and identify the intensity of a 10 percent stiffness reduction in a well-organized element.