Ultrasonic sensing system for detection of pipe surface deformation

Abstract

The utilisation of ultrasonic is widely applied for strain measurement. However, most of the measurements are performed using strain gages. The method used in this research made use of reflected signal using air as its working medium. The purpose of this experiment is to provide an alternative to the strain gage. Ultrasonic wave from transmitter transducer is transmitted to a point, and then reflected by the surface medium which experienced strain towards the ultrasonic receiver transducer. Aluminum probe cones attached to both ultrasonic transducers collimate the transmission and reception of the signals. The strain experienced by a PVC pipe is measured by the ultrasonic transducer. The difference in distance resulted in the difference of the ultrasonic wave as well as the electrical signal. When the strain started to deform, the length of deformation increased and the electric signal became weak due to the reduction of sound intensity. The received electric signal due to this change will undergo signal conditioning consisting of preamplifier, amplifier, band-pass filter and rectifier before being displayed onto the oscilloscope screen. There are two types of strain measured in this experiment: tensile and compression strain. The result is consistent throughout the experiment. An experiment using a strain gage and an experiment on the deflection measurement were also carried out to determine the value of strain due to deformation. From these two experiments, the relationship between strain formation created and sound intensity rate which relies on voltage change can thus be identified.