Structural Damage Identification Based On Residual Energy Sensitivity Analysis

Affected by various factors,civil engineering structures inevitably suffer different extent damage in the course of a long-term operation. As one of important contents in health monitoring,structural damage identification is a hot research topic in recent years. The dynamic characteristic sensitivity analysis of engineering structures plays an important role in many fields of structural engineering such as damage identification,dynamic design,structural optimization design,control theory and dynamic modification. Due to the sensitivity to damage,the energy-based indicators like strain energy and residual energy derived from basic modal parameters draw worldwide attention in recent years. This paper analyzes the sensitivity of the residual energy and the element residual energy,and their applications to structural damage identification. Some useful conclusions are made.The main contents are detailed as following:1.Review the development of damage identification. Research situation of the structural dynamic sensitivity analysis and damage identification are summarized and the shortcomings in damage identification are pointed out.2.Propose the damage identification method based on residual energy sensitivity,The corresponding damage identification equations are established. Damage location and severity can be simultaneously determinated by solving the equations.Numerical simulation studies show that the proposed method is effective.3.Propose the new indicator-element residual energy. Based on this,the first order and the second order sensitivity formula for linear system without damping are derived,and the sensitivity of element residual energy of the damage parameter is analyzed. Furthermore,the damage identification equations based on sensitivity analysis of element residual energy are also established. To solve the ill-conditioned problem of the equations,a new solution technique-augmented system method is introduced. The method can simultaneously identify the damage location and severity by only using the first order mode parameters. 4.The applicability of the residual energy sensitivity analysis-based damage identification method for different structures is studied by numerical simulation for a simply supported beam and a plane truss structure.The results indicate that the presented method is able to identify the location and severity of damaged element.5.The Monte-Carlo method is used to research anti-noise performance of the damage identification method based on element residual energy sensitivity analysis.Damage identification accuracy related with damage severity,noise level and structure type is also investigated.