Anticipating steel failure

Sensor technology that can be used to estimate the life of steel-welded structures and give advance warning of failure has been developed at Cambridge-based TWI.

It is claimed that the device, called CrackFirst, could help engineers to avoid unplanned downtime on a range of structures such as bridges, vehicle chassis, cranes and oil rigs.

TWI project manager John Davenport explained that the system consists of a steel shim or ‘coupon’ that can be placed on a structure’s critical joint for the duration of its lifetime.

As the joint degrades over time, so does the shim, and by interrogating thin-film circuitry that is mounted on the shim, maintenance engineers can get an accurate picture of the structure’s overall state. By comparing this data to initial design predictions of the structure’s service life, engineers can tell precisely how much life remains.

‘If you’re running a large container vessel or have a huge piece of highway mining equipment in a remote part of the world and you can use sensors to demonstrate that there’s premature damage occurring somewhere in your structure, you can plan to repair it at your convenience — and planned downtime is far less financially damaging.’

Depending on the application, the device could be interrogated using a plug-in box, or by wireless technology for hard-to-reach joints.

Caterpillar, one of the project partners in the development of CrackFirst, is said to be very interested using the gauge on its plant. So far, a number of prototype gauges have been built and tested in both laboratory and service trials.

Davenport declined to reveal the identity of test partners, but confirmed that the project has generated high levels of interest in the off-highway and mining and marine sectors. He said he expects the device to make its commercial debut as a specialist product within the next 12 months.

Davenport can be contacted at john.davenport@twi.co.uk.