-New equipment Non-contact vibration measurement Non-contact measurement of vibration at low cost is available to design engineers wi th the introduction by Ometron of VPI Sensor. This stand-alone is an advanced laser Doppler interferometer making up a single-point vibration measurement system.

The optical techniques employed to generate digital data of a structure under examination have previously only been available as a computer-generated full field image. As such, the system provided a degree of sophistication and performance well in excess of the needs of engineers requiring only basic vibration measurement data.

In its simplest form it is a non-contact laser Doppler sensor for mechanical vibration measurement incorporating in-bui l t scanning. It provides a level of performance that enables it to be directly linked to spectrum analysers so that data can be measured in the manner of a non-contact ing accelerometer.

In this stand-alone form the instrument is able to measure structures onto which it may be diff icult or inadvisable to attach transducers, and to obtain data over a wide range of excitation frequencies at measurement distances up to 200 m. Structures in hostile environments can therefore be remotely monitored. Addit ionally, the sensor has optional scanning facilities so that automatic measurement at a number of preselected points can be carried out.

The basic technology used has already been successfully employed by over 20 dependent centres wor ldwide to analyse the vibration of spacecraft and aeroengine components, in modal analysis and acoustic studies, for automobile bodies, panels, components, running engines and

Stand-alone non-contact sensor from Ometron board under vibration

gearboxes, telecommunication products and for detecting delamination in composites.

Ometron Ltd, Worsley Bridge Road, London SE26 5BX, UK

Aircraft wheel inspection system

The aircraft wheel inspection system announced by Staveley NDT Technologies is a direct

Aircraft wheel inspection equipment from Staveley

being used to examine a printed circuit

development of an original method introduced and approved by British Airways. Aircraft wheels are automatically scanned using eddy current techniques for the detection of cracks and flaws in wheel rim, tyre bead seat and barrel surfaces for defects as small as 1.0 mm in length and 0.5 mm in depth. The results obtained are recorded by pen recorder.

A single, custom-made eddy current probe works in conjunct ion wi th the eddy current instrument, the probe scanning the rotating surfaces of the wheel assembly in measured, pre-determined increments.

Capable of accepting a full range of wheel types and sizes, the wheel inspection rig is a self-contained, integrated system which can be moved to the most appropriate testing area at any time, the services required being suitable electricity and air supplies.

The unobstructed operating surface of the unit is positioned at a convenient working height to al low rapid loading and unloading.

Staveley ND T Technologies, Inspection Instruments Division, 18 Buckingham A venue, Slough, Berks SL 1 4QB, UK

60 NDT International February 1991