New structural damage-identification method using modal updating and model reduction

Abstract

Early prediction of damages using vibration signal is essential in avoiding the failure in structures. Among different damage-detection approaches, the finite-element model updating and modal analysis-based methods are of most importance due to their applicability and feasibility. Owing to some restrictions in nodal measurements in experimental cases, finite-element model reduction is an indispensable part of fault-detection methods. Even though model reduction of dynamic systems leads to the less complicated models, an improved convergence rate and acceptable accuracy are highly required for a successful structural health monitoring of the real complex systems. In this paper, the aim is to design a damage-detection algorithm based on a new model updating method, which has a faster rate of convergence and higher accuracy. Then the proposed method is applied on a simulated damaged beam considering different noise levels to see how capable the method is in dealing with noise-corrupted data. Finally, the experimentally extracted data from a cracked beam in a real noisy condition are used to evaluate the efficiency of the proposed method in identifying the damages in a beam-like structure. It is concluded that the identification of the damages by the proposed method is encouraging and robust to the noise compared with the traditional method. Also, the proposed method converges faster and is more accurate in identifying damage than the traditional method.

Strain modal-based damage identification method and its application to crane girder without original model

“…Then by connecting every adjacent checkpoints with straight line, the strain modal shape can be derived, and the firstorder strain modal of the crane girder was picked up as shown Figure 5(c). According to different algorithm equations (10) and (11), the difference curve of the first-order strain modal of the crane girder was figured out as Figure 5(d). As seen from these figures,…”

“…According to equation (10), the equations of the two endpoints x 1 , x n can be represented as follow…”

“…Among them, methods based on the analysis of the mutation of the strain mode shape offer good chance to damage identification even without any reference of the undamaged structure. 10,11 Dong et al 12 put forward that methods based on displacement-type parameters harbor the possibility of giving a wrong result of damage identification. While Li 13 drew a conclusion that strain-type methods are more sensitive than displacement-type methods by analysis of vibration theory.…”

Efficiency of grey wolf optimization algorithm for damage detection of skeletal structures via expanded mode shapes

“…The reduced model was used for subsequent FEM updating and damage detection. Ettefagh et al (2015) developed a damage-detection algorithm based on FEM updating and model reduction using Guyan. The aforementioned study used an experimental beam under real environmental conditions to evaluate the efficiency of the proposed method.…”

Bearing assessment tool for longitudinal bridge performance

“…Model-based techniques have been traditionally applied in the field of civil engineering [12][13][14][15][16][17][18]. They employ computational models that incorporate the physics of the system, including geometry, material properties, and boundary conditions.…”