Measurement uncertainty evaluation of ultrasonic wall thickness measurement

Abstract

Ultrasonic thickness measurement (UTM) is regularly applied and important NDT (Non destructive) method in structure and component integrity assessment. This method provides wall thickness determination by measuring the transit time of ultrasonic pulses between two walls. This widely applicable ultrasonic technique provides quantitative information about specimen wall thickness and belongs to the area of metrology activities.In NDT laboratory accreditation process, the EA 4/15 guideline is required, which defines estimation of measurement uncertainty in those methods which quantitatively display the measurement result. However, in the area of ultrasonic measurement of the wall thickness, the result is displayed without the relevant estimation of measurement uncertainty, so there is no specified doubt in the obtained measurement result.This paper presents mathematical model for ultrasonic thickness measurement uncertainty estimation by using Monte Carlo simulation.