Professor Olgierd (Olek) Cecil Zienkiewicz, DSc, CBE, FREng, FRS, died of cancer on 2 January 2009. Although born in the UK (in Caterham, Surrey, on 18 May 1921), he attended primary and secondary schools in Poland, where his father was a judge. The start of the Second World War interrupted his studies, and following the fall of France in 1940 his family returned to England, where he completed his BSc in 1943, and his PhD (on finite difference modelling) in 1945 at Imperial College, London. Following graduation, Zienkiewicz joined the consulting engineers Sir William Halcrow and Partners, working on dam design, before becoming an academic, first at Edinburgh and then at Northwestern University in the USA. In 1961 he joined Swansea University as Professor and Head of the Department of Civil Engineering, where he was to work for the rest of his life, retiring in 1988 to become Professor Emeritus. Over this period he held visiting positions in a number of other institutions, including the University of Texas at Austin and the University of Technology of Catalunya, Barcelona.
Zienkiewicz was one of the pioneers and giants in the research, development and application of the finite element method. His central achievement was in pioneering the finite element method's use outside the area of solid mechanics, including the field of geomechanics. His books on the subject remain standard reference texts, and at the time of his death he was working on a seventh edition. The first non-structural application of the finite element method was undertaken by Zienkiewicz et al. (1965) in the treatment of a groundwater flow problem. From that time the method become widely established and accepted in engineering design. The first industrial use of the technique was made by him for the stress analysis of the Clywedog dam at Llanidloes, Mid Wales, in 1963.
Having been the senior engineer in design and dam construction with Halcrow, he had a great interest in dams, and his first published paper in the ICE Proceedings was on ‘The stress distribution in gravity dams' (Zienkiewicz, 1947). His first publication in Géotechnique was on the ‘Stress analysis of rock as a no-tension material' (Zienkiewicz et al., 1968). He made a substantial contribution in the implementation of constitutive models such as classical elasto-plasticity and viscoplasticity within the finite element method, and the application of non-linear numerical procedures including the unification of various different classical material models into a single convenient model, still used in many finite element software packages. This remained one of the main themes of his research in geomechanics, cumulating in the generalised plasticity theory and various numerical procedures.
Being aware that pore water pressure plays an important role in porous elastic solids, he investigated the effect of pore pressure on stress distribution in porous elastic solids (Zienkiewicz & Park, 1958). In 1980 he published a comparison of the analytical and numerical solutions of the steady-state behaviour of consolidation, the so-called u–p and u–U formulation for dynamic saturated soil and pore fluid interaction under periodic loading (Zienkiewicz et al., 1980). This work eventually led to the development of various non-linear finite element procedures for the analysis of dynamic phenomena for saturated and partially saturated soil, including liquefaction and cyclic mobility. These were summarised in two papers in the Proceedings of the Royal Society in 1990 (Zienkiewicz et al., 1990a, 1990b). Such procedures had great success in the predictions at the VELACS project organised by the US National Science Foundation in 1993, establishing the fact that the use of effective stress is imperative in the analysis of such phenomena. They were comprehensively explained in his book on Computational Geomechanics (Zienkiewicz et al., 1999).
His life-long passion and interest in dams were also reflected in his analysis of the lower San Fernando dam failure under earthquake (Zienkiewicz & Xie, 1991). In the last decade, in geotechnical-related areas, he focused on element technology, algorithms and numerical procedures for problems related to incompressible behaviour due to undrained condition and localisation. He strived to make these numerical procedures better, faster, more efficient, and easier to use, for example by the introduction of error estimators and automatic adaptive refinement. He also tried to make such algorithms more general, more powerful and all-encompassing by unifying different procedures under a single framework, combining various classical elasto-plastic models along with static, consolidating, dynamic as well as static and dynamic undrained analysis of saturated porous media in a single numerical code (Zienkiewicz, 1985).
Over his research career he supervised more than 70 PhD students. Since his first paper in 1947, he published nearly 600 papers and wrote or edited more than 25 books.
He received many awards, honours and honorary degrees, including Commander of the Order of the British Empire (CBE), the Carl Friedrich Gauss Medal of the West German Academy of Science, the Nathan Newmark Medal of the American Society of Civil Engineers, the Newton-Gauss Medal of the International Association for Computational Mechanics, the Gold Medal of the Institution for Mathematics and its Applications, a Gold Medal from the Institution of Structural Engineers, and the Timoshenko Medal of the American Society of Mechanical Engineers. He was elected to the Royal Society and the Royal Academy of Engineering in 1979, and was a Foreign Member of the United States National Academy of Engineering, the Polish Academy of Science, the Italian National Academy of Sciences, and the Chinese National Academy of Sciences.
To his colleagues and research students Professor Zienkiewicz will always be fondly remembered with deep reverence as a genius, and a creative and innovative thinker with great insight and engineering sense. He had Einstein's quote that ‘Imagination is more important than knowledge' displayed prominently in his office. He was a determined and hugely experienced explorer in the vast ocean of research, discovering new frontiers. He was bold and courageous in taking risks, but he was also well aware of the pitfalls of new techniques, as could be seen with various cartoons displayed in his office, including one of a Stone Age inventor of triangular wheels, stating that they were an improvement on square wheels as they had one less bump per revolution.
Professor Zienkiewicz was buried on a small hill overlooking Swansea Bay and the Bristol Channel, where he spent many days pursuing his life-long passion of sailing, near to the town of Mumbles, and facing the house where he had spent most of his life. He is survived by his widow Helen, two sons, one daughter and four grandchildren.
Selected papers in geomechanics and related areas:
