Structural Health Monitoring Using Smart Materials By Peak of Frequency Response

Structural Health Monitoring Using Smart Materials By Peak of Frequency Response

The objective of this project is damage detection in structures and equipment and diagnosing and locating the probable corrosion and hydrate formation points. These long distance subsurface structures are almost inaccessible and mostly experiencing harsh environments, thereby utilizing systems capable of real time and exact monitoring of defects and damage comes up a vital priority. The present work goes through consideration, design and analysis of structures equipped with smart sensors and actuators which in a broad frequency range, give a distributed, continues and real time report of the structures health. Using dynamic vibration and frequency response analysis for damage detection in different structures has been developing for years but exact locating and size diagnosing of the defects sill have a long way ahead. In this paper utilizing ABAQUS software a new approach to finding damages is introduced. The technique takes advantage of smart materials which consist of one piezoelectric patch to vibrate the specimen; a aluminum plate in present work; and two other piezo patches in different positions to transducer the frequency responses into voltages. in The mentioned 20 cm by 5 cm plate, there are 18 different holes assumed ranges from 0.0625 mm to 4 mm of diameter. They are dislocated horizontally, vertically and on a slant line with the slope of 72° that leads to the two transducer piezo patches. By analyzing the dislocation of each hole on each track which is divided into 10 positions, a certain procedure for firstly defect detection and next for diagnosing its location and size is achieved. These holes are representative of cracks, hole, pitting, corrosion, rupture and other similar defects which can be approximately generalized. The harmonic analysis is done in steady state mode and each hole in each position is analyzed in 4500 intervals through 0 to 1.2 GHz. the resulting voltages and accelerations of the point under the patch on the surface is recorded for each and every case so that an analytical trend can be extracted. Finally fingerprint diagrams that have a unique shape for each hole in certain position are achieved. This method is based on energy absorption by a hole that are acquired by piezoelectric patches in different frequencies and voltages. Next by counting peak points in certain frequency domain and certain variable amounts (voltage or acceleration) corresponding to each hole in every position, we can find the location of the hole.