Document Type

Thesis

Degree

Master of Science

Department

Mechanical Engineering

Advisor's Name

Ibrahim Tansel

Advisor's Title

Committee chair

Advisor's Name

Igor Tsukanov

Advisor's Name

Sabri Tosunoglu

Keywords

Structural Health Monitoring, non-destructive evaluation, lamb waves, sweep sine wave, structural defects, piezoelectric elements, frequency response, damage detection

Date of Defense

11-10-2010

Abstract

Structural Health Monitoring (SHM) techniques are widely used in a number of Non – destructive Evaluation (NDE) applications. There is a need to develop effective techniques for SHM, so that the safety and integrity of the structures can be improved. Two most widely used SHM methods for plates and rods use either the spectrum of the impedances or monitor the propagation of lamb waves. Piezoelectric wafer – active sensors (PWAS) were used for excitation and sensing. In this study, surface response to excitation (SuRE) and Lamb wave propagation was monitored to estimate the integrity of the round objects including the pipes, tubes and cutting tools. SuRE obtained the frequency response by applying sweep sine wave to surface. The envelope of the received signal was used to detect the arrival of lamb waves to the sensor. Both approaches detect the structural defects of the pipes and tubes and the wear of the cutting tool.

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