Dr. Bo Persson awarded Tribology Gold Medal 2022
Bo Persson, who was born in Sweden, studied Physics at Chalmers University in Göteborg, getting a PhD on the dynamical processes at surfaces. There followed postdoctoral work at the Kernforschungsanlage (later known as Forschungszentrum) Jülich, and IBM Yorktown Heights before returning to Jülich, where he has spent the rest of his career. Bo has collaborated with innumerable theoretical and experimental groups worldwide, and has had research visits at such institutions as Brookhaven National Labs, Toyama University, Oak Ridge National Lab, ICTP Trieste, and ITP Santa Barbara.
Bo Persson wrote a seminal book on tribology, Sliding Friction, which appeared in the late ‘90s. Sliding Friction treats the topic comprehensively from the standpoint of physics. In this sense, it can be thought of as an update to F.P. Bowden and D. Tabor’s classic The Friction and Lubrication of Solids. This work showed how far our understanding of tribology fundamentals had evolved since Bowden and Tabor, thanks to the extraordinary experimental and computational developments that had taken place in the intervening decades. Bo was in an excellent position to write such a useful book, in that his background was in surface physics, rather than tribology. In other words, he had spent his PhD and the following decade dealing with fundamental issues that are relevant to tribological phenomena, before he embarked on the topics in tribology for which he is now world renowned. In fact, he was already very well regarded, and honored, in the surface physics field, especially in the areas of STM and surface vibrational relaxation, before he was seriously interested in tribology. He was the winner of the prestigious Walter Schottky Award of the German Physical Society in 1996.
As Bo himself puts it, in 2000, he had an insight in approximately one second, which was to occupy him for the next 20 years: his multiscale contact mechanics theory, known by most of the tribology world simply as “Persson Theory”. Persson Theory tackles what is possibly the central and challenging problem in tribology, namely the way in which the random surface roughness of real surfaces influences the way in which they contact each other. This is central to understanding friction in dry and lubricated contacts, whether stationary or sliding. In other words, it is a crucial issue in both tribology and adhesion. Persson very recently won the highly coveted Adhesion Society Award of Excellence.
Persson Theory involves considering surfaces at different levels of magnification, and determining how quantities, such as contact area or the probability distribution of stress, change with this magnification. In other words, after dealing with the problem on a coarse scale, the theory goes on to consider the effect of introducing small-scale random undulations. Crucially, the theory shows the importance of including longrange elastic coupling between asperity contacts. Persson Theory has found applications in such practically important areas as:
• Contact mechanics for elastic/viscoelastic and elastoplastic systems
• Contact mechanics of layered materials
• Adhesion, including capillary adhesion
• Thermal and electric contact resistance
• Rubber friction
• Leak-rate of seals
• Fluid squeeze-out between rough elastic surfaces
• Elastohydrodynamics at low sliding velocities
• Contact phenomena on human skin
• Contact phenomena on cellulose fibers
Dr. Persson has had extraordinary impact on the field of tribology on all levels, ranging from the highly fundamental (origin of friction, asperity contacts) to the highly applied and industrial (tires on the road, the efficiency of bearing seals, skin-contact of medical devices). His Sliding Friction book has played a major role in the education of a generation of those involved in tribological science. He continues to publish heavily (ca. 500 publications to date), expanding our understanding of contact throughout all facets of our diverse field.