12 December 2019

Magnetostrictive composite inspection for structural health monitoring commended at Tech Briefs Design the Future design Contest

An idea developed by University staff has placed in the top five of the Aerospace and Defense category in the 'Create the Future' Design Contest and in the top 100 design ideas from over 1,000 entries, receiving an honourable mention.

Fabricated composite samples with attached actuator layer
Fabricated composite samples with attached actuator layer; a thin epoxy-ferrite actuator was attached to the composite to be used for sensing purposes.

The contest is organised by Tech Briefs, publishers of NASA Tech Briefs, to help stimulate and reward engineering. (NASA is required by charter to report new commercially significant technologies)

Composites are complicated materials by nature - different materials are combined in a pre-defined way, each with their own role in imparting properties to the overall product, to give a material superior properties to its individual components. Damaged composites are even more complicated: the damage may be superficial, catastrophic, or somewhere in-between. The detection of damage to composite materials is often challenging, as it can be hidden by the outer layers. While there are a number of techniques for non-destructively testing composites, these are not without their drawbacks:

  • They are time-consuming and tedious
  • They are prone to mistakes and human error
  • There is a high cost for automated visual systems
  • It is inaccurate if the damage is not visible on the surface/subsurface, making visual inspection inadequate
  • It is challenging for mid-flight or in-line inspection.
Comparison of magentostrictive ferrite-epoxy actuators for damage-impacted samples through magnetostrictive characterisation (left) and ultrasound characterisation (right). Red crosses mark impact location.
Comparison of magentostrictive ferrite-epoxy actuators for damage-impacted samples through magnetostrictive characterisation (left) and ultrasound characterisation (right). Red crosses mark impact location.

Researchers from the Department of Materials Science and Engineering at the University of Sheffield recently presented a design idea, to address these drawbacks using magnetostrictive technology.

The idea, developed by Dr Zhaoyuan Leong, Professor Nicola Morley, and Dr Pratik Desai (Perlemax Ltd.), utilised actuator/sensor pairs for damage detection by embedding dispersions of inexpensive magnetostrictive microparticles within a suitably thin flexible matrix. On to this, a sparse-array sensor grid is attached, from which damage position can be determined. This approach can be used to monitor critical components in aircraft to obtain near-instantaneous updates, even for off-line detection.

Prototype determining damage positioning from a 3-sensor array
Prototype determining damage positioning from a 3-sensor array

Top in the Russell Group

We are the top-ranked Russell Group university for Graduate Prospects in Materials Science and Engineering. (The Times Good University Guide 2020)

Flagship institutes

The University’s four flagship institutes bring together our key strengths to tackle global issues, turning interdisciplinary and translational research into real-world solutions.