Structural Health Monitoring of Timber Using Electromechanical Impedance (EMI) Technique

Fang Han,Guangtao Lu,Jinwei Jiang,Chengfeng Wang,Quanjing Zhang

doi:10.1155/2020/1906289

Abstract

Nowadays, the electromechanical impedance method has been widely used in the field of structural healthy monitoring, especially for the concrete and steel materials. However, the electromechanical impedance studies on damage detection for timber are limited due to the anisotropic and ununiform biomaterial properties. As a low-cost and environment-friendly building material, timber has been widely used in the construction. Thus, it is beneficial to develop electromechanical impedance technique for structural healthy monitoring of timber so as to ensure the stability and safety of the entire timber structures. In this paper, two damage factors, i.e., the damage location factor and the damage size factor of timber specimens are investigated by using the electromechanical impedance method. The method is implemented by using a patch of Lead Zirconate Titanate transducer both as an actuator to generate stress waves and a sensor to detect stress waves after propagating across the timber specimens. Then, the damage index-root mean square deviation is employed to evaluate the damage severity of the timber specimens. The results indicate that the damage index changes consistently with the change of damage location and size factors, and the proposed method using electromechanical impedance technique can efficiently estimate the damage and its severity.

Highlights

Timber, as a renewable, ubiquitous, and environmentfriendly material, is one of the popular construction materials in the long human history [1]
Structural health monitoring (SHM) and damage detection techniques have advanced rapidly, various methods have been developed for timber structures, such as visual inspection, drill resistance, radiography, ultrasonics, vibration analysis, and stress waves [3]
In order to evaluate the severity of damage more quantitatively and accurately, the conventional damage index, root-mean-square deviation (RMSD) expressed as equation (2), is calculated to analyze the changes of impedance signatures

Summary

Introduction

As a renewable, ubiquitous, and environmentfriendly material, is one of the popular construction materials in the long human history [1]. Erefore, the damage of timber, whether it is congenital or acquired, if not detected at the early stage, can inevitably weaken the bearing capacity and shorten the service life span of the entire timber structures. Us, the damage detection of timber structures has received increasing attention. A consensus is made that the monitoring of timber damage is essential to ensure the safety and reliability of the entire timber structures [2]. Structural health monitoring (SHM) and damage detection techniques have advanced rapidly, various methods have been developed for timber structures, such as visual inspection, drill resistance, radiography, ultrasonics, vibration analysis, and stress waves [3]. Erefore, the methods which are convenient, real time, and easy to implement are more welcomed in timber damage monitoring fields Generally speaking, complex equipment and algorithms are always needed for these methods. erefore, the methods which are convenient, real time, and easy to implement are more welcomed in timber damage monitoring fields

Methods

Results

Conclusion