Professor David Hills

The Silver Medal is a national award in recognition of an exceptionally meritorious contribution to the science and technology of tribology.

David’s PhD was undertaken at what was then Trent Polytechnic, and although his thesis was entitled ‘Some effects for subsurface stress on wear’, it was clear from the content that his main interests were in the mechanics of contacts. He was awarded the Bronze Tribology medal in 1979, and was honoured on that occasion to meet both Jack Archard who received the silver medal that same year, and Peter Jost.  In 1983 he went to University of Michigan at Ann Arbor, and learned a lot of advanced techniques of analysis from Jim Barber, forming a friendship and research collaboration which has endured ever since.

In 1984, instead of returning to Trent, David was elected to a fellowship at Lincoln College Oxford together with a University appointment in Engineering Science, where he has been ever since.  Building on what was then the recent work of John O’Connor he has studied fretting fatigue both experimentally and theoretically ever since. The experimental work, both fundamental and with particular application to gas turbine blades, has sought to separate out the basic physical elements of the process – that is that slip both ameliorates the state of stress and at the same time causes damage (it expends energy), and this has led him to study the phenomenon of ‘partial slip’ – where part of the contact slips and other parts slip, with ever more rigour, and often in collaboration with Jim Barber.

Friendships and collaborations with several European Institutions have followed, and the contributions of many research students -some of whom have gone on to do greater things – has made the process enjoyable as well as extremely constructive.

Of course no job is ever finished, and David continues to expand the understanding of wider classes of contact than are often represented in contact text books (that doesn’t apply to Jim Barber’s), and current efforts are aimed at removing the restrictions of half-plane theory from studies of convex contacts, the difficulties of complex loading histories having been recently conquered.  There is always something interesting, and useful, yet to discover.

He is therefore a worthy winner of the 2023 Tribology Silver Medal.