Dr Robert L. Spliker, Professor of Biomedical Engineering and Chair of the Biomedical Engineering Department, Rensselaer Polytechnic Institute (RPI), USA.
It is with much sadness that we mourn the loss of our great friend and colleague, Dr Robert L. Spilker, Professor of Biomedical Engineering at RPI. Bob died on 9 October 2012, following a 4-year battle with cancer.
Bob received his undergraduate degree in the Aeronautical Engineering Department, at University of Illinois (BS 1971) and his graduate training in the Department of Aeronautics and Astronautics at the Massachusetts Institute of Technology (Sc.D. 1974). He was a faculty member in the Department of Civil Engineering, Mechanics and Metallurgy at the University of Illinois at Chicago (1976–1984), and in 1984 joined the faculty of RPI in the Department of Mechanical Engineering, Aeronautical Engineering and Mechanics. Bob later assumed the chairmanship of the Biomedical Engineering Department at RPI from 1994 to 2004 and, while battling cancer, transitioned to emeritus status in October 2010.
Bob was a pioneer in the field of computational modelling of biological tissues, having developed a comprehensive suite of finite element programs for the biphasic theory formulated by his close colleagues, Drs Van C. Mow and W. Michael Lai. Together, this team of investigators made major advances in our understanding of the mechanics of hydrated soft tissues, such as articular cartilage, meniscus and intervertebral disc. Bob's finite element programs made it possible to investigate a number of competing hypotheses about the underlying mechanisms responsible for experimental observations of soft tissue responses to loading. Thanks to his code and analyses, it became possible to elucidate the influence of a wide range of factors on the characterisation of tissue properties from unconfined compression and indentation experiments. These findings were critical to the subsequent discovery that the mechanical response of cartilage to loading was highly dependent on the disparity between the tissue's tensile and compressive moduli, arising from the fibrillar nature of its extracellular matrix. In turn, this disparity was found to considerably augment cartilage interstitial fluid pressurisation in response to loading, thereby reducing friction between contacting articular surfaces.
At a time when commercial packages lagged behind, Bob's finite element codes incorporated all features essential for modelling hydrated biological soft tissues, including strain-dependent permeability, finite deformation and anisotropy. He was a pioneer in the formulation of contact algorithms for biphasic materials, a challenging topic that he continued to pursue until the end. Bob was intent on having his programs become available to a broad audience, initiating many collaborations over the years to disseminate these tools. His finite element code served as the fundamental curve-fitting tool for the broad set of studies by Kyriacos Athanasiou that comprehensively characterised the properties of articular cartilage from many diarthrodial joints in human and animal species. Bob's code was also the primary tool in the characterisation of growth plate cartilage nonlinear properties by Boaz Cohen, and the pioneering computational analyses of chondrocyte mechanics by Farshid Guilak.
Bob had a profound influence on a large number of students who pursued research under his mentorship and that of Mow and Lai. To name only a few, J.-K. Francis Suh was his first student to work on biphasic finite element modelling, helping to develop the widely disseminated FEMLIN and FEMNON codes. Peter Donzelli played a major role in the formulation of biphasic contact algorithms and transverse isotropy, while his contemporary, Edgar Almeida, examined alternative formulations for finite deformation analyses. Bill Dunbar, Kerem Ün, Taiseung Yang and Hongqiang Guo continued Bob's advances in modelling biphasic contact in 3D and under finite deformation. Bob's extended academic family includes Athanasiou, Guilak, Cohen, Lori Setton, Lou Soslowsky, Wenbo Zhu, Jeffrey Nickel, Laura Iwasaki, Luigi Gallo, Suzanne Maher and Gerard Ateshian, all of whom benefited immensely from his teachings on finite element modelling and went on to apply this knowledge to many other research areas. Beyond Bob's NY academic involvement, his professional touch was felt nationally and internationally, marked by presentations, planning, chairing conference and symposium including the International Symposium Series ‘Computer Methods in Biomechanics and Biomedical Engineering’.
As a result of his contribution to biomechanics, Bob became a member of various Editorial Boards of International Journals. In 1995 (launch year of this journal) he joined the newly formed editorial board of ‘Computer Methods in Biomechanics and Biomedical Engineering’ for which he has been a member, reviewer, author and much-appreciated supporter since that time. Indeed he made a significant contribution to the very first issue of the journal, which was in two parts, and this is respectfully referenced below:
Almeida ES, Spilker RL. 1997. Mixed and penalty finite element models for the nonlinear behavior of biphasic soft tissues in finite deformation. Part I. Alternate formulations. Comput Methods Biomech Biomed Eng. 1:25–46.
Almeida ES, Spilker RL. 1998. Mixed and penalty finite element models for the nonlinear behavior of biphasic soft tissues in finite deformation. Part II. Nonlinear examples. Comput Methods Biomech Biomed Eng. 1:151–170.
He was not just a supporter of the journal but was also present at many of the CMBBE symposia in which he was a member of the organising committee, invited speaker and often involved in the judging of symposium prizes. He and his wife Jan attended CMBBE2010 which was held in Valencia, Spain, and here he was, as usual, full of new ideas, suggestions and innovations. His commitment here in reviewing, publishing, chairing and acting on various committees is testament to his enthusiasm and motivation in developing biomechanics and biomedical engineering.
In addition to his research contributions, Bob was widely admired at Rensselaer as an outstanding educator and leader who helped transition the Biomedical Engineering Department from bioinstrumentation emphasis to biomechanics and biomaterials and eventually towards functional tissue engineering during his 10-year tenure as Chairman. Through NSF-sponsored ‘Project Links’ (Mark H. Holmes and Robert L. Spilker, co-Directors), he helped integrate mathematics in science and engineering curricula through browser-based modules of mathematical concepts and applications for use in the studio model of educational delivery, pioneered at Rensselaer. His finite element and introductory engineering courses attracted and motivated many students including all three of his children, their eventual spouses and numerous friends, many of whom reported that Bob was one of their favourite instructors.
Above all, Bob was a thorough gentleman who, without doubt, had the respect and admiration of the many students, researchers, engineers and academics who had the pleasure to have known and worked with him. His contributions and innovative thinking on biomechanics are well documented as is his influence on new initiatives which have impacted on many worldwide. He was an outstanding colleague, friend and personality and his presence will be greatly missed by all.
Notes
Some of the contents above have been taken from an Obituary prepared by Gerard Ateshian, Columbia University, New York and Deepak Vashishth, Rensselaer Polytechnic Institute, Troy.