scholarly journals Damage Detection of Laminated Rubber Bearings Based on the Antiresonance Frequencies of Periodic Structure and Its Sensitivity Analysis

2022 ◽  
Vol 2022 ◽  
pp. 1-18
Author(s):  
Ying Zhang ◽  
Hongping Zhu ◽  
Shun Weng
Keyword(s):  
Sensitivity Analysis ◽  
Damage Detection ◽  
Characteristic Equation ◽  
Dynamic Stiffness ◽  
Steel Structure ◽  
Seismic Energy ◽  
Detection Scheme ◽  
Rubber Layer ◽  
Antiresonance Frequency ◽  
Rubber Bearings

An isolation bearing consumes most of the seismic energy of a structure and is vulnerable to destruction. The performance of isolation bearings is usually evaluated according to the global stiffness and energy dissipation capacity. However, the early minor damage in isolation bearings is difficult to identify. In this study, a damage detection scheme for the isolation bearing is proposed by focusing on the antiresonance of the quasiperiodic structure. Firstly, a laminated rubber bearing was simplified as a monocoupled periodic rubber-steel structure. The characteristic equation of the driving point antiresonance frequency of the periodic system was achieved via the dynamic stiffness method. Secondly, the sensitivity coefficient of the driving point antiresonance, which was obtained from the first-order derivative of the antiresonance frequency, with respect to the damage scaling parameter was derived using the antiresonance frequency characteristic equation. Thirdly, the optimised driving points of the antiresonance frequencies were selected by means of sensitivity analysis. Finally, from the measured changes in the antiresonance frequencies, the damage was identified by solving the sensitivity identification equation via a numerical optimisation method. The application of the proposed method to laminated rubber bearings under various damage cases demonstrates the feasibility of this method. This study has proven that changes in the shear modulus of each rubber layer can be identified accurately.

Shaking Table Tests of Full Scale Base-Isolated Structures

2002 ◽  
Author(s):  
C. S. Tsai ◽  
B. J. Chen ◽  
T. C. Chiang
Keyword(s):  
Structural Control ◽  
Control Strategies ◽  
Steel Structure ◽  
Seismic Energy ◽  
Full Scale ◽  
Shaking Table ◽  
Shaking Table Tests ◽  
Natural Period ◽  
Rubber Bearing ◽  
Rubber Bearings

Conventional earthquake resistant designs depend on strengthen and ductility of the structural components to resist induced forces and to dissipate seismic energy. However, this can produce permanent damage to the joints as well as the larger interstory displacements. In recently years, many studies on structural control strategies and devices have been developed and applied in U. S. A., Europe, Japan, and New Zealand. The rubber bearing belongs to one kind of the earthquake-proof ideas of structural control technologies. The installation of rubber bearings can lengthen the natural period of a building and simultaneously reduce the earthquake-induced energy trying to impart to the building. They can reduce the magnitude of the earthquake-induced forces and consequently reduce damage to the structures and its contents, and reduce danger to its occupants. This paper is aimed at studying the mechanical behavior of the stirrup rubber bearings (SRB) and evaluating the feasibility of the buildings equipped with the stirrup rubber bearings. Furthermore, uniaxial, biaxial, and triaxial shaking table tests are conducted to study the seismic response of a full-scale three-story isolated steel structure. Experimental results indicate that the stirrup rubber bearings possess higher damping ratios at higher strains, and that the stirrup rubber bearings provide good protection for structures. It has been proved through the full-scale tests on shaking table that the stirrup rubber bearing is a very promising tool to enhance the seismic resistibility of structures.

Experimental Study of a Multiple Bay Structure Isolated With Hybrid Bearings

2003 ◽  
Author(s):  
C. S. Tsai ◽  
Bo-Jen Chen ◽  
Tsu-Cheng Chiang ◽  
Guan-Hsing Lee
Keyword(s):  
Earthquake Engineering ◽  
Base Isolation ◽  
Steel Structure ◽  
Seismic Energy ◽  
Shaking Table ◽  
Element Formulation ◽  
Shaking Table Tests ◽  
Seismic Responses ◽  
Promising Tool ◽  
Rubber Bearings

In conventional earthquake resistance design approach (the ductility-design philosophy), the energy dissipation mechanism is based on plastic deformations at scattered locations in the structure. However, this can produce permanent damage to the joints as well as the larger interstory displacements. In recently years, the base isolation technology has been adopted as a feasible and attractive way in improving seismic resistance of structures. It can shift the natural periods of structures away from the rich periods contents of earthquake motions, but also provide considerable supplemental damping to dissipate seismic energy transmitted into structures during earthquakes. In this paper, uniaxial, biaxial, and triaxial shaking table tests are performed to study the seismic behavior of a 0.4-scale three-story isolated steel structure in the National Center for Research on Earthquake Engineering in Taiwan. Experimental results demonstrate that structures with hybrid rubber bearings can actually decrease the seismic responses of the superstructure. It has been proved through the shaking table tests that the rubber bearing is a very promising tool to enhance the seismic resistibility of structures. Moreover, it is illustrated that the proposed analytical model and finite element formulation in this paper can well predict the mechanical behavior of rubber bearings and seismic responses of the base-isolated structures.

scholarly journals Development of Laboratory-scale Lamb Wave-based Health Monitoring System for Laminated Composites

2021 ◽  
Vol 53 (4) ◽  
pp. 210407
Author(s):  
Leonardo Gunawan ◽  
Muhammad Hamzah Farrasamulya ◽  
Andi Kuswoyo ◽  
Tatacipta Dirgantara
Keyword(s):  
Damage Detection ◽  
Health Monitoring ◽  
Lamb Wave ◽  
Laminated Composite ◽  
Composite Plates ◽  
Laboratory Scale ◽  
Optimum Number ◽  
Detection Scheme ◽  
Damage Location ◽  
Location Detection

This paper presents the development process of a laboratory-scale Lamb wave-based structural health monitoring (SHM) system for laminated composite plates. Piezoelectric patches are used in pairs as actuator/sensor to evaluate the time of flight (TOF), i.e. the time difference between the transmitted/received signals of a damaged plate and those of a healthy plate. The damage detection scheme is enabled by means of evaluating the TOF from at least three actuator/receiver pairs. In this work, experiments were performed on two GFRP plates, one healthy and the other one with artificial delamination. Nine piezoelectric transducers were mounted on each plate and the detection of the delamination location was demonstrated, using 4 pairs and 20 pairs of actuators/sensors. The combinations of fewer and more actuators/sensor pairs both provided a damage location that was in good agreement with the artificial damage location. The developed SHM system using simple and affordable equipment is suitable for supporting fundamental studies on damage detection, such as the development of an algorithm for location detection using the optimum number of actuator/sensor pairs.

scholarly journals The method of direct finite perturbation of numerical models for studying of the dynamic, stiffness and strength properties for thin-walled elements of engineering constructions.

2014 ◽  
Vol 2014 (4) ◽  
pp. 114-124
Author(s):  
Юрий Костенко ◽  
Yuriy Kostenko ◽  
Анатолий Чепурной ◽  
Anatoliy Chepurnoy ◽  
Александр Литвиненко ◽  
...  
Keyword(s):  
Sensitivity Analysis ◽  
Finite Element ◽  
Natural Frequencies ◽  
Numerical Models ◽  
Dynamic Stiffness ◽  
Strength Properties ◽  
Test Problems ◽  
Finite Element Models ◽  
Direct Perturbation ◽  
Thin Walled

The methods of direct perturbation for finite element models of thin-walled engineering constructions for sensitivity analysis of their strength, stiffness and dynamic characteristics to the change in their thickness are proposed. The approach for prediction of distribution for natural frequencies migration as result of change in their thickness are presented. The applicability of the linearized models to determine displacements, stresses and natural frequencies slightly thinned design compared to the nominal (original) are shown. The examples of test problems are given.

Optimal Sensor Placement for Damage Detection in Complex Structures

2009 ◽  
Author(s):  
Sunilkumar Soni ◽  
Santanu Das ◽  
Aditi Chattopadhyay
Keyword(s):  
False Alarm ◽  
Damage Detection ◽  
False Alarm Rate ◽  
Structural Component ◽  
Detection Rate ◽  
Sensor Placement ◽  
False Alarms ◽  
Optimal Sensor Placement ◽  
Detection Scheme ◽  
Sensing Radius

An optimal sensor placement methodology is proposed based on detection theory framework to maximize the detection rate and minimize the false alarm rate. Minimizing the false alarm rate for a given detection rate plays an important role in improving the efficiency of a Structural Health Monitoring (SHM) system as it reduces the number of false alarms. The placement technique is such that the sensor features are as directly correlated and as sensitive to damage as possible. The technique accounts for a number of factors, like actuation frequency and strength, minimum damage size, damage detection scheme, material damping, signal to noise ratio (SNR) and sensing radius. These factors are not independent and affect each other. Optimal sensor placement is done in two steps. First, a sensing radius, which can capture any detectable change caused by a perturbation and above a certain threshold, is calculated. This threshold value is based on Neyman-Pearson detector that maximizes the detection rate for a fixed false alarm rate. To avoid sensor redundancy, a criterion to minimize sensing region overlaps of neighboring sensors is defined. Based on the sensing region and the minimum overlap concept, number of sensors needed on a structural component is calculated. In the second step, a damage distribution pattern, known as probability of failure distribute, is calculated for a structural component using finite element analysis. This failure distribution helps in selecting the most sensitive sensors, thereby removing those making remote contributions to the overall detection scheme.

Multi-Location Actuators and Piezoceramic Based 2-D Spiral Array for Structural Health Monitoring: Thin Isotropic Panels

2010 ◽  
Author(s):  
Byungseok Yoo ◽  
Darryll J. Pines ◽  
Ashish S. Purekar
Keyword(s):  
Damage Detection ◽  
Health Monitoring ◽  
Sensor Array ◽  
Array Signal Processing ◽  
Phased Array ◽  
Test Panel ◽  
Detection Scheme ◽  
Analysis Technique ◽  
Spiral Array ◽  
Multiple Actuators

In this paper, a new and robust 2-D phased array technique with multiple distributed actuators is studied for damage detection application based on Guided Lamb Wave (GLW) interrogation in a thin isotropic panel. A 2-D phased array technique using a single actuator located near the center of the 2-D phased array is unable to detect a linear crack oriented normal to the wavefront of the GLW excited from the actuator. To overcome this limitation, the 2-D phased array is coupled with multiple actuators in this study where the actuators are positioned at various locations on a test panel while the 2-D phased array is mounted at the center of the panel. A piezoceramic based 2-D phased array with a spiral configuration is used as a sensor array and the corresponding 2-D phased array signal processing is used to produce array responses and detect various damages. An innovative GLW propagation and reflection analysis technique is implemented to evaluate the damage locations in the panel. Experimental results demonstrate that the 2-D phased array damage detection technique using multiple distributed actuators can provide more robust damage detection scheme in thin isotropic panels than a technique with a single actuator element.

scholarly journals Structural Damage Identification Based on the Minimum System Realization and Sensitivity Analysis

2014 ◽  
Vol 2014 ◽  
pp. 1-12
Author(s):  
W. R. Li ◽  
Y. F. Du ◽  
S. Y. Tang ◽  
L. J. Zhao
Keyword(s):  
Sensitivity Analysis ◽  
Damage Detection ◽  
Structural Damage ◽  
Damage Identification ◽  
Structural Information ◽  
Structural Response ◽  
Frame Structure ◽  
Structural Damage Detection ◽  
System Realization ◽  
Minimum System

On the basis of the thought that the minimum system realization plays the role as a coagulator of structural information and contains abundant information on the structure, this paper proposes a new method, which combines minimum system realization and sensitivity analysis, for structural damage detection. The structural damage detection procedure consists of three steps: (1) identifying the minimum system realization matrixes A, B, and R using the structural response data; (2) defining the mode vector, which is based on minimum system realization matrix, by introducing the concept of the measurement; (3) identifying the location and severity of the damage step by step by continuously rotating the mode vector. The proposed method was verified through a five-floor frame model. As demonstrated by numerical simulation, the proposed method based on the combination of the minimum realization system and sensitivity analysis is effective for the damage detection of frame structure. This method not only can detect the damage and quantify the damage severity, but also is not sensitive to the noise.

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