Robert L. Piziali, Ph.D., P.E.

Dr. Piziali's expertise is in the area of engineering mechanics and design with a speciality in biomechanics. His biomechanical experience includes injury biomechanics applied to a wide variety of environments. He has testified extensively on occupant kinematics and injury biomechanics in automotive collisions, including rollovers and frontal, side, and rear impacts. This testimony has evaluated the performance of vehicle structures, restraints, glazing, and helmets. Dr. Piziali's experience in transportation-related accidents has also included bicycles, motorcycles, ATV's, UTV's, jet skis, and airplanes. His railroad experience includes train accidents, ride vibrations, and workplace injuries. His analysis of human movements and injuries has included cases involving industrial accidents, construction accidents, farming accidents, elevator accidents, falls, and sports accidents involving exercise equipment, snow and water sports, track, and diving. His consulting involves full scale testing and computer modeling using MADYMO. In the area of medical products, Dr. Piziali has experience with orthopedic devices, breast implants, and IUD's.

Prior to joining Exponent, Dr. Piziali was a tenured full professor at Stanford University. He taught engineering mechanics, design, and biomechanics at the undergraduate and graduate levels. His research focused on the biomechanics of injury with emphasis on the lower extremity and spine. He also conducted research on the development of medical equipment and received patents on three devices. He has been President and Vice President of Engineering for Technical Advisors and Phase 2 Automation. Dr. Piziali previously worked for Failure Analysis Associates (now Exponent) and was a Corporate Vice President. Prior to rejoining Exponent, Dr. Piziali was President of Piziali and Associates.

Merala R, Piziali RL. Water ski binding release loads: Test method and results. Skiing Trauma and Safety, Tenth Volume, ASTM STP 1266, Mote CD Jr, Johnson RL, Hauser W, Schaff PS (eds), American Society for Testing and Materials, pp. 361–379, Philadelphia, PA, 1996.

Ebi KL, Piziali RL, Rosenberg M, Wachob HF. Evidence against tailstrings increasing the rate of pelvic inflammatory disease among IUD users. Contraception 1996 Jan; 53(1):25–32.

Piziali RL, Paver JG, Khatua TP, Whitestone J, Kaleps I, Taylor C. The prediction of Hybrid III manikin head-neck kinematics and dynamics. SAE 1990 Transactions, Journal of Passenger Cars 1990; 99(6):669–676.

Piziali RL, Phillips ES, Khatua TP, Kost G. Vision and visibility in vehicular accident reconstruction. SAE 1990 Transactions, Journal of Passenger Cars 1990; 99(6):547–561.

Stawitcke FA, Ream AK, Piziali RL. Pressure control to accommodate patient breathing efforts during volume ventilation. Journal of Clinical Monitoring 1987 Apr; 3(2).

Kim KS, Piziali RL. Harmonic wave propagation in materials with periodic beam-structure. Journal of Sound and Vibration 1986; 107(1):59–70.

Mahanian S, Piziali RL. Finite element evaluation of the AIA shear specimen for bone. Journal of Biomechanics 1988; 21(5):347–356.

Kim KS, Piziali RL. Continuum models of materials with beam-microstructure. International Journal of Solids and Structures 1985; 23(11):1563–1578.

Piziali RL, Nagel DA, Koogle T, Whalen R. Knee and tibia strength in snow skiing. Proceedings, Ski Trauma and Skiing Safety IV, International Society for Skiing Safety, Italy, 1981, Munich: TUEV-Edition, 1982.

Nagel DA, Koogle TA, Piziali RL, Perkash I. Stability of the upper lumbar spine following progressive disruptions and the application of individual internal and external fixation devices. Journal of Bone and Joint Surgery 1981 Jan; 62–70.

Swenson LW, Schurman DJ, Piziali RL. Finite element temperature analysis of a total hip replacement and measurement of PMMA curing temperatures. Journal of Biomedical Materials Research 1981; 15:83–96.

Hight TK, Piziali RL, Nagel DA. Natural frequency analysis of a human tibia. Journal of Biomechanics 1980; 13(2):139–148.

Rastegar J, Piziali RL, Nagel DA, Schurman DJ. The contribution of the cruciate ligaments to the load-displacement characteristics of the human knee joint. Journal of Biomechanical Engineering 1980 Nov; 102:277–283.

Seering W, Piziali RL, Nagel DA, Schurman DJ. The function of the primary ligaments of the knee in anterior-posterior and medial-lateral motions. Journal of Biomechanics 1980; 13(9):777–784.

Piziali RL, Seering W, Nagel DA, Schurman DJ. The function of the primary ligaments of the knee in varus-valgus and axial rotations. Journal of Biomechanics 1980; 13(9):785–794.

Piziali RL, Hight TK, Nagel DA. Geometric properties of human leg bones. Journal of Biomechanics 1980; 13(10):881–886.

Hight TK, Piziali RL, Nagel DA. A dynamic non-linear large displacement model of a human leg. Journal of Biomechanical Engineering 1979 Aug; 101:176–184.

Hight TK, Piziali RL, Nagel DA. A dynamic nonlinear finite element model of a human leg. Journal of Biomechanical Engineering 1979 Aug; 101.

Rastegar J, Piziali RL, Nagel DA, Schurman DJ. Effects of fixed axes of rotation on the varus-valgus and torsional load-displacement characteristics of the in vitro human knee. Journal of Biomechanical Engineering 1979 May; 101:134–140.

Whitcher C, Zimmerman DC, Piziali RL. Control of occupational exposure to N2O in the oral surgery office. Journal of Oral Surgery 1978.

Whitcher CE, Zimmerman DC, Tonn EM, Piziali RL. Control of occupational exposure to nitrous oxide in the dental operatory. Journal of American Dental Association 1977 Oct; 95:763–776.

Piziali RL, Rastegar JC, Nagel DA. Measurement of the nonlinear coupled stiffness characteristics of the human knee. Journal Biomechanics 1977; 10:45–51.

Koogle TA, Piziali RF, Nagel DA, Perkash I. A motion transducer for use in the intact in vitro human lumbar spine. Journal of Biomechanical Engineering 1977 Aug; 160–165.

Piziali RL, Whitcher C, Sher R, Moffat RJ. Distribution of waste anesthetic gases in the operating room air. Anesthesiology 1976 Nov; 45(5):487–494.

Mancini LJ, Piziali RL. Optimal design of helical springs by geometrical programming. Engineering Optimization 1976; 2:73–81.

Piziali RL, Hight TK, Nagel DA. An extended structural analysis of long bones—Application to the human tibia. Journal Biomechanics 1976; 9:695–701.

Piziali RL, Nagel DA. Modeling of the human leg in ski injuries: Putting it all together. Clinical Orthopaedics in North America 1976 Jan.

Dekker D, Piziali RL, Dong E, Jr. A system for ultrasonically imaging the human heart in three dimensions. Computers and Biomedical Research 1974 Dec.

Dekker D, Piziali RL, Dong E, Jr. Effect of boundary conditions on the ultrasonic-beam characteristics of circular disks. Journal of Acoustical Society of America 1974 Jul; 87–93.

Articles in Proceedings

Raphael E, Piziali RL, Le H, Hinger J, Cooper E, Croteau J. Physical evidence associated with seatbelt entanglement during a collision. SAE 2007 Transactions Journal of Passenger Cars – Electronic and Electrical Systems No. 2007-01-1501, 2007.

Piziali RL, Fox JC, Girvan DS, Raphael EH, Ridenour J. A review and analysis of the performance of laminated side glazing in rollover accidents. Society of Automotive Engineers International Congress and Exposition, Paper No. 2007-01-1166, Detroit, MI, April 16–19, 2007.

Piziali RL, Hopper RH, Girvan D, Merala R. Injury causation in rollover accidents and the biofidelity of Hybrid III data in rollover tests. Society of Automotive Engineers International Congress and Exposition, Paper No. 980362, Detroit, MI, February 23–26, 1998.

Piziali RL, Khatua TP, Cheng LY, Girvan DS, Fijan RS. Use of computer simulations in support of litigation. 5th International MADYMO Users' Meeting, Fort Lauderdale, FL, November 3–4, 1994.

Piziali RL, Ayres TJ, Paver JG, Fowler G, McCarthy RL. Investigation of the net safety impact of an occupant protection system from all-terrain vehicles. Society of Automotive Engineers International Congress and Exposition, Paper No. 930208, Detroit, MI, March 1–5, 1993.

Piziali RL, Khatua TP, Merala R. The application of biomechanics to the analysis of automotive and skiing accident injuries. Proceedings, the 4th International Conference on Structural Failure, Product Liability and Technical Insurance, Vienna, Austria, July 6–9, 1992.

Cheng L, Rifai S, Khatua T, Piziali RL. Finite element analysis of diffuse axonal injury. Vehicle Crashworthiness and Occupant Protection in Frontal Collisions, Society of Automotive Engineers, pp. 141–154, February 1990.

McCarthy RL, Kost G, Piziali RL, Khatua T, Werner S, Phillips E. Technical aspects of complex accident reconstruction. 1989 Practicing Law Symposium, October 1989.

Piziali RL, Khatua TP. Emergency management technology: Technology for predicting the past-emergency reconstruction. 1989 Society of Computer Science Western Multiconference, San Diego, CA, January 5, 1989.

Piziali RL, Cheng LY, Khatua TP. ATB simulation of Hybrid III dummy in sled tests. Society of Automotive Engineers International Congress and Exposition, Paper No. 880646, Detroit, MI, February 29–March 4, 1988.

Piziali RL. Cervical spine injuries in sports. Winter Annual Meeting, American Society of Mechanical Engineers, Rekow ED, Thacker JG, Erdman AG (eds), Boston, MA, December 1987.

Schurman DJ, Swenson LW Jr, Piziali RL. Bone cement with and without antibiotics: A study of mechanical properties. The Hip, Proceedings, 67th Open Scientific Meeting of the Hip Society, 1978.

Kienholz DA, Piziali RL. Analysis of torsional vibration in a high bandwidth angular position servo. Proceedings, American Society of Mechanical Engineers, December 1976.

Piziali RL, Mote CD, Jr, Nagel DA, Hight TK, Rastegar JC. The biomechanics of lower limb response and injury. Proceedings, the 2nd International Forum on Skiing and Safety II, Davos, Switzerland, September 1976.

Mote CD, Jr, Hull ML, Piziali RL, Nagel DA. Experimental measurements of forces and moments during downhill skiing. Proceedings, the 2nd International Forum on Skiing and Safety II, Davos, Switzerland, September 1976.

Kienholz D, Piziali RL. A finite element analysis of torsion in axisymmetric solids. ASME Paper No. 76-WA/Aut-9, 1976.

Nagel DA, Perkash I, Piziali RL, Hayes WC. Mechanics of dorsal lumbar spine injury: A preliminary report. Proceedings, 19th Conference of the American Association for Automotive Medicine, 1975.

Piziali RL. The dynamic torsional response of the human leg relative to skiing injuries. ASME, Proceedings, the Mechanics and Sport Symposium, pp. 305–315, November 1973.

Proceedings, Abstracts, and Presentations

Hovey CB, Kaplan ML, Piziali RL. Model for occupants ejected from vehicles with roll and yaw. American Society of Biomechanics, Stanford, CA, August 22–25, 2007. Also found in SAE 2008 World Congress Transactions –Journal of Passenger Cars: Mechanical Systems.

Piziali RL. Occupant motion in rollover crashes. Passenger Car Rollover TOPTEC: Cause & Prevention, San Diego, CA, January 1999.

Piziali RL, Girvan D, Hopper RH. Errors in using MADYMO and other computer models. Emerging Issues in Motor Vehicle Product Liability Litigation, American Bar Association, Phoenix, AZ, May 20–21, 1997.

Piziali RL, Merala R, Hopper RH. The biomechanics of head and neck injuries in skiing. 12th Symposium on Ski Trauma and Safety, Whistler, British Columbia, CAN, May 4–10, 1997.

Piziali RL, Merala R, Hopper RH, Girvan D. The effects of helmets and padding on head injuries and falls from lifts. Association of Ski Defense Attorneys Winter Conference, Taos, NM, March 1–4, 1997.

Piziali RL, Fowler GF, Merala R, Grewal DS, McCarthy RL. Evaluation of a proposed ATV design modification. International Congress and Exposition, Detroit, MI, February28–March 3, 1994.

Piziali RL, Paver JG, Merala R, Ayres TJ, Fowler G, McCarthy RL. Evaluation of an occupant protection system for all-terrain vehicles. ASME Presentation, Anaheim, CA, November 8–13, 1992.

Martin KF, Banister JA, Piziali RL. Engineering visualization of vehicle accidents: Data sources and methods of production. International Congress and Exposition, Detroit, MI, February25–March 1, 1991.

Piziali RL. Investigation of racquetball eye injury Re: Stephen Herskovitz v. Richcraft. Failure Analysis Associates Report No. FaAA-PA-R-86-09-12.

Piziali RL, Koogle TA, Swenson LW Jr, Kim KS, Nagel DA. On the flexibility of vertebrae. ASME Advances in Bioengineering, 1980.

Schurman DJ, Piziali RL, Swenson LW Jr, Rinsky L, Kajiyama G. Shortwave diathermy and fracture healing in rabbit fibula model—Preliminary report. Transactions of the 26th Annual Meeting of the Orthopaedic Research Society, Vol. 5, p. 160, Atlanta, GA, February1980.

Koogle TA, Swenson LW Jr, Piziali RL. A large displacement dynamic model of the lumbar spine with experimentally determined material properties. Transactions of the 26th Annual Meeting of the Orthopaedic Research Society, Vol. 5, p. 276, Atlanta, GA, February1980.

Swenson LW, Piziali RL, Schurman DJ. An electromechanical model for human articular cartilage. Transactions of the 26th Annual Meeting of the Orthopaedic Research Society, Vol. 5, p. 277, Atlanta, GA, February1980.

Eibeck PA, Swenson LW, Schurman DJ, Piziali RL. Finite element stress analysis of hinged tibial component total replacements. Transactions of the 25th Annual Meeting of the Orthopaedic Research Society, Vol. 4, San Francisco, CA, February 1979.

Seering WP, Nagel DA, Piziali RL, Schurman DJ. Measuring the principal and coupled loads transmitted by each of the ligaments of the knee. Transactions of the 25th Annual Meeting of the Orthopaedic Research Society, Vol. 4, San Francisco, CA, February 1979.

Seering WP, Piziali RL, Nagel DA, Schurman DJ. Load transmissions characteristics of knee ligaments during axial tibial rotations. 1979 Advances in Bioengineering, ASME Press, New York, NY, 1979.

Swenson LW Jr, Piziali RL, Schurman DJ. An electromechanical model for human cartilage. 1979 Advances in Bioengineering, ASME Press, New York, NY, 1979.

Koogle TA, Swenson LW, Piziali RL. Dynamic three dimensional modeling of the human lumbar spine. 1979 Advances in Bioengineering, ASME Presentation, New York, NY, 1979.

Nagel DA, Koogle TA, Piziali RL, Perkash I. Contribution of the posterior ligaments, annulus fibrosis, and facet joints to the stability of the dorsal-lumbar spine and evaluation of various external and internal means of restoring stability. Proceedings, the International Research Society for Orthopaedics and Traumatology, Tokyo, Japan, October 1978.

Schurman DJ, Swenson LW Jr, Piziali RL. Bone cement with and without antibiotics: A study of mechanical properties. The Hip, Proceedings, 6th Open Scientific Meeting of the Hip Society, 1978.

Seering WP, Piziali RL, Nagel DA, Schurman DJ. Measuring the primary and coupled loads transmitted by the various ligaments of the human knee. 1978 Advances in Bioengineering, ASME Press, New York, NY, 1978.

Nagel DA, Koogle TA, Perkash I, Piziali RL. External and internal stabilization of the disrupted lumbodorsal spine. Transactions of the 24th Annual Meeting of the Orthopaedic Research Society, Vol. 3, p. 18, Dallas, TX, February 21–23, 1978.

Swenson LW Jr, Schurman DJ, Piziali RL. A mattice theory for a continuum representation of cancellous bone. Transactions of the 24th Annual Meeting of the Orthopaedic Research Society, Vol. 3, p. 96, Dallas, TX, February 21–23, 1978.

Swenson LW Jr, Piziali RL, Schurman DJ. Fundamental mechanics of articular cartilage revisited. Transactions of the 24th Annual Meeting of the Orthopaedic Research Society, Vol. 3, p. 203, Dallas, TX, February 21–23, 1978.

Seering WP, Hirshman P, Piziali RL, Nagel DA. A method for preserving the mechanical properties of ligaments during testing. Transactions of the 24th Annual Meeting of the Orthopaedic Research Society, Vol. 3, p. 237, Dallas, TX, February 21–23, 1978.

Rastegar JC, Piziali RL, Nagel DA. The contribution of the cruciate ligaments and condular interference to medial-lateral and anterior-posterior stiffness of the in vitro human knee joint. Transactions of the 24th Annual Meeting of the Orthopaedic Research Society, Vol. 3, p. 238, Dallas, TX, February 21–23, 1978.

Piziali RL, Rastegar JC, Nagel DA. The axis of varus-valgus rotation of the in vitro human knee joint. Transactions of the 24th Annual Meeting of the Orthopaedic Research Society, Vol. 3, p. 239, Dallas, TX, February 21–23, 1978.

Hight TK, Piziali RL, Nagel DA. Dynamic non-linear large displacement model of human leg. Transactions of the 24th Annual Meeting of the Orthopaedic Research Society, Vol. 3, p. 240, Dallas, TX, February 21–23, 1978.

Seering WP, Piziali RL, Nagel DA. The effect of strain rate on the mechanical properties of human ligaments. Transactions of the 24th Annual Meeting of the Orthopaedic Research Society, Vol. 3, p. 241, Dallas, TX, February 21–23, 1978.

Koogle TA, Piziali RL, Nagel DA, Perkash I. A motion transducer for use in the intact in vitro human lumbar spine. Proceedings, the 1977 Joint Applied Mechanical Fluids Engineering and Bioengineering Conference, Yale University, New Haven, CT, Jun 1977. (Printed in 1977 Biomechanics Symposium, Skalak R, Schultz AB (eds), ASME Press, New York, NY, pp. 103–105, 1977.

Rastegar JC, Piziali RL, Nagel DA. Torsional load-displacement characteristics of the in vitro human knee. Proceedings, the 30th Annual Conference on Engineering in Medicine and Biology, p. 235, November 5–9, 1977.

Hight TK, Piziali RL, Nagel DA. The effect of modeling techniques on natural frequencies of a human tibia. Transactions of the 23rd Annual Meeting of the Orthopaedic Research Society, Vol. 2, Las Vegas, NV, February 1–3, 1977.

Koogle TA, Piziali RL, Nagel DA, Perkash I. A six degree of freedom motion transducer for use in the intact in vitro human lumbar spine. Transactions of the 23rd Annual Meeting of the Orthopaedic Research Society, Las Vegas, NV, February 1977.

Koogle TA, Piziali RL, Nagel DA, Perkash I. A motion transducer for use in the intact in vitro human lumbar spine. Proceedings, the 97th Winter Annual Meeting of the ASME, New York, NY, December 1976.

Koogle TA, Piziali RL, Nagel DA, Perkash I. A motion transducer for use in the intact in vitro human lumbar spine. 1976 Advances in Bioengineering, ASME Press, New York, NY, 1976.

Piziali RL, Hight TK, Nagel DA. Dynamic structural analysis of the human tibia. Proceedings, the Orthopaedic Research Society, New Orleans, LA, January 1976.

Piziali RL, Schurman DJ, McDonald A. The effects of gentamicin on the material properties of PMMA. Proceedings, the Orthopaedic Research Society, New Orleans, LA, January 1976.

Rastegar JC, Piziali RL, Nagel DA. Varus-valgus stiffness of the in vitro human knee. ASME Winter Annual Meeting, Advances in Bioengineering, p. 5, 1976.

Rastegar JC, Piziali RL, Seering WP, Nagel DA. Coupled stiffness coefficients of the human knee. 28th Annual Conference on Engineering in Medicine and Biology, New Orleans, LA, September 1975.

Piziali RL, Hight TK, Nagel DA. Finite element analysis of stresses in the tibia arising from dynamic loading. 28th Annual Conference on Engineering in Medicine and Biology, New Orleans, LA, September 1975.

Piziali RL, Seering WP, Rastegar JC, Nagel DA. The function of passive knee structures in anterior-posterior tibial displacement. 28th Annual Conference on Engineering in Medicine and Biology, New Orleans, LA, September 1975.

Piziali RL, Hight TK, Nagel DA. A detailed structural analysis of the human tibia. ASME Symposium on Biomechanics – Summer Applied Mechanics Conference at Rensselaer Polytechnic Institute, Troy, NY, June 1975.

Piziali RL, Mancini LJ. Optimal design of helical springs by geometric programming. Mathematical Optimization and Engineering Design Symposium sponsored by the Operations Research Society of America and the Institute of Management Sciences, with support from the Office of Naval Research, Chicago, IL, April–May 1975.

Piziali RL Nagel DA. Structural properties for a mathematical model of lower extremity dynamic response. The Orthopaedic Research Society Meeting, San Francisco, CA, February 1975.

Piziali RL, Sher R, Moffat RJ, Whitcher CE. Distribution of inhalation anesthetics in the operating room atmosphere. American Society of Anesthesiologists Annual Meeting, Washington, D.C., October 1974.

Dekker D, Dong E, Jr, Piziali RL. A system for ultrasonically producing time-varying cross sections of the human heart. Proceedings, the 26th Annual Conference on Engineering in Medicine and Biology, September–October 1973.

Dekker DL, Piziali RL, Dong E, Jr. An analysis of ultrasound characteristics related to computerized echo cardiology. Proceedings, the Annual Conference on Engineering in Medicine and Biology, 1972.

Piziali RL, Nagel DA. Dynamic model of the human leg applied to ski injuries. Proceedings, the Annual Conference on Engineering in Medicine and Biology, 1972.

Invited Seminars and Lectures

Piziali RL. Vehicle aggressivity. 1999 Emerging Issues in Motor Vehicle Product Liability Litigation, Phoenix, AZ, April 7–9, 1999.

Piziali RL. Design and product liability. Fall 1991. Stanford Design Division Graduate Course. Stanford Department of Aeronautics and Astronautics Course, Techniques of Failure Analysis, Biomechanics and Litigation, Spring 1992.

Piziali RL. Biomechanics and accident reconstruction. Stanford Applied Mechanics Seminar, Fall 1991.

Piziali RL. Accident reconstruction. Xerox, PARC Forum, January 1990.

Piziali RL. Crash reconstruction: Purpose and principles. Computer Programs for Occupant Kinematics, Association for the Advancements of Automotive Medicine, Orlando, FL, March 12–15, 1990.

Piziali RL. The Heisenberg Principle in biomechanics. Keynote speaker, 4th Annual Meeting of the American Society of Biomechanics, October 1980.

Piziali RL. The dynamic response of the human leg in snow skiing. Acoustical Society of America, Hawaii, November 1978.

Piziali RL. The biomechanics of snow skiing. Sierra Traumatalogical Society, January 1978.

Piziali RL. The dynamic response of the human leg in snow skiing. Northwestern University, May 1977.

Piziali RL. The biomechanics of lower limb response and injury. 2nd International Forum on Skiing and Safety II, Forum Davos, Davos, Switzerland, September 1976.

Piziali RL. The biomechanics of snow skiing. Sierra Traumatalogical Society, January 1975.

Piziali RL. The biomechanics of skiing injuries. American Association of Orthopaedic Surgeons Postgraduate Course on Skiing Injuries, Aspen, CO, February 1973.

Piziali RL. The dynamic characterization of snow skis. University of California, Berkeley, January 1971.

• President, Piziali and Associates, 1995–2011
• Failure Analysis Associates, Vice President, 1990–1994, Principal Engineer, 1987–1990,
  Managing Engineer, 1985–1987
• Vice President, Engineering, 2 Automation, 1983–1985
• Associate Director for Orthopaedic Biomechanics, Veterans Administration Medical Center, Rehabilitation Engineering Research and Development Center, 1979–1982
• Vice President, Technical Advisors, Inc., 1982–1983
• Professor, Stanford University, 1982–1984
• Associate Professor, Stanford University, 1976–1982
• Assistant Professor, Stanford University, 1970–1976
• IBM, San Jose, California, part-time Summer 1974 in conjunction with the Engineering Case Program of Stanford University

• American Society of Mechanical Engineers—ASME
• American Society for Testing Materials—ASTM
• Society of Automotive Engineers
• Tau Beta Pi
• Pi Tau Sigma
• Eta Kappa Nu
• Orthopaedic Research Society