Damage Detection For Timber Beams Using Electromechanical Impedance (EMI) Technology

Wood as a strong earthquake resistance,good insulation,renewable environmental protection materials,is widely used in ancient buildings and modern buildings.However,due to the organic characteristics of wood,cracking,mildew,insect erosion,corrosion and other damages will inevitably occur in the use process,which will reduce the overall safety of wood structure,and then affect the safe service of wood structure.Therefore,it is very important to carry out health monitoring and damage identification on wood structure.In this paper,based on piezoelectric impedance technology,numerical simulation research and experimental verification are carried out for different damage position conditions and different damage degree conditions of wood beams,and BP neural network is established based on the experimental data to identify and quantify the damage position and damage degree parameters of wood beams,so as to provide reference for engineering practice.This paper firstly introduces the research status of piezoelectric impedance technology at home and abroad and the basic theory of piezoelectric impedance technology.Secondly,the finite element software ANSYS was used to conduct a numerical simulation study on the damage detection of wood beams with piezoelectric plates,analyze the changes of PZT impedance of damaged wood beams in different frequency bands,and evaluate the damage with RMSD damage index.Then,an experimental platform for wood beam damage identification was established.During the experiment,manual drilling and cutting were used to simulate the damage of holes and cracks in the wood beam.Finally,the changes of PZT impedance before and after the damage were compared and analyzed.Finally,the impedance curve data obtained from the experiment were extracted as input parameters,and BP neural network was established to detect the damage of wood beams.The results show that both finite element and experimental studies have verified the validity and feasibility of the piezoelectric impedance technology for wood beam damage identification,and it is reliable to use RMSD for damage assessment.