Recollections on Professor Peter Grootenhuis, Emeritus Professor in Vibrations in his 90th birthday year by Professor David Ewins

I first met Peter Grootenhuis in October 1962 in his office in 562 of the then very new Mechanical Engineering Building.  He was bent over his desk, poring over a long chart of vibration data that has been measured on the Metropolitan Line near the Barbican, and extracting information from the chart with a pair of dividers (and, presumably, a ruler).  At that time, he was heavily involved in a new project to install a mile or so of Metropolitan/Circle line track on a concrete bridge which was to be supported on the ground on rubber pads to isolate the new Barbican flats and concert halls from the trains which would be running immediately underneath.  This was what he did – he put things which either generated vibrations (like machines), or which needed to be insulated from vibrations (like buildings) on springs.  I had gone to see him because, as a 3^rd year undergraduate student, I was looking for a final year project and he had proposed a study of a box on springs which, allegedly, the new-fangled computers just available to us were understood to be capable of analysing all the 6 degrees of freedom in a single calculation!  And so it turned out to be the case that they could (do the calculations) and that gave me my first proper publication in IMechE.  Ironically, on almost exactly the same day as Peter celebrated his 90th birthday, I was emptying my own office of nearly 50 years’ papers and came across the folder of correspondence between him and the JMES for that very paper.  The associated experimental box on springs that Peter had constructed in 1964, for an MSc student who to this day still works for Bruel & Kjaer,  served as a lecture demonstration in ME until very recently.

Peter was a very practical vibration engineer, and relied heavily on measurements and observations on real hardware to give a strong physical insight before trying to work out a solution.  Indeed, one of his commercial ventures was as a Director of with Derritron, early manufacturers of electromagnetic shakers and the many VPxx shakers that can be found in service in vibration labs around the world carry his mark: the P in VP stands for ‘Peter’.  Throughout the 70s, the Vibrations Lab in 566, and the larger and heavier-duty custom-built lab in 123 (the Noise Lab)  were the home of much work on vibration isolation, led by Peter, partly for a longstanding association with the Admiralty (isolation of ship borne machinery) and partly for the various Civil Engineering projects that followed on from the Barbican days.   The applied, industrial, focus of much of Peter’s work led the formation in the early 1960s of the Society of Environmental Engineers – an organisation heavily involved with testing and which had its early meetings split between Mech Eng and the Bunch of Grapes in Brompton Road.  That Society still continues to this day…  

Today I find myself sitting at the desk, belonging to his grandfather-in law, that was Peter’s for most of his 60+ years at Imperial.  In its top drawer is a framed copy of his early patent on blade cooling (1949).  Few people know that he started out as a specialist in heat transfer (the subject of his own PhD was Theoretical and Experimental Studies in Transpiration Cooling).  However, Peter was one of the group assembled by Sir Owen Sunders to rebuild the Mechanical Engineering Department in the 1950s and 1960s and he was ‘invited’ to set up the Vibrations Lab because he was “good at maths”.  Behind these scenes, he had a major interest in the College Wine Cellar in the days when we had one, served as a church warden at Holy Trinity in Prince Consort Road and was known widely, and affectionately, across the College where he had spent his whole academic career.

Professor David Ewins, Dynamics Group