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Online Inspection

Introduction

In this section we outline several areas where we have already or are seeking partners to develop online inspection techniques using non-contact ultrasound. Non-contact ultrasound by its very nature lends itself to online inspection especially where product may be moving or hot. The technology is at a stage where in most an immediate commercial benefit can be demonstrated and the next step is to transfer this technology into industry. Some areas already have some existing degree of non-exclusive industrial collaboration.

If you have any interest in any of the areas outlined below then please contact us and we can discuss your needs and our capabilities further.


The Key Areas

Metal Billet Crack Detection in collaboration with Corus UK

Food and Drink - fill level & elastic behaviour of the product

Metal Plate and Tube Thickness Gauging - see thickness gauging in research section

Metal Plate / Sheet / Foil Grain Texture - - see anisotropy in research section

Adhesive Cure and Bond Inspection - see adhesive in research section



High Temperature online measurements of power plant components


This project, in collaboration with The Centre for Nondestructive Evaluation (CNDE) at Indian Institute of Technology Madras (IITM) and Bharat Heavy Electricals Limited (BHEL), will investigate and develop new next generation sensing and measurement technologies for online, in-process, high-temperature measurement of weld quality of steel tubes produced by BHEL. The ability to perform NDT on welds during manufacture will improve production efficiency and the manufacturing process, but more importantly will lead to the production of higher quality and safer plant. This project will establishing a new scientific approach to the inspection of pipe welds using ultrasonic guided waves over a "medium range" in a tomographic type approach, where the ultrasonic transducers are tens of centimetres away from the weld. Existing methods of inspecting similar welded components require the pipe to cool to a sufficient level in order to be examined. This means it is not possible to perform inspections during the welding process, and that a large production volume could be affected before defects are detected.

This project will utilise guided waves that, due to the practical constraints imposed by the pipe welding equipment, will propagate over distances less than a metre. Consequently, issues surrounding guided wave dispersion are not as prevalent as they are with long-range guided wave inspections. Over this medium distance range, the higher-order guided wave modes propagate at similar group velocities and hence form higher-order mode clusters of guided waves (HOMC-GW). The HOMC technique was first discovered and developed at the CNDE, and has many advantages over both bulk wave and long-range guided wave inspection, especially in terms of improved sensitivity and ability to handle complex shaped problems and high temperature conditions. Whilst ultrasonic inspection is often classified into either bulk wave examination or long-range guided wave techniques, this method exists an interim region where the wave propagation does not fit comfortably into either category.

In online inspections, the HOMC will propagate along a temperature gradient as it travels through the heat affected zone around the weld, in between the transducer positions. Consequently, modelling must be undertaken to in order to choose suitable guided wave modes and excitation frequencies, so that any temperature or geometric effects can be differentiated from defect signature signals.