Academic Credentials
  • Ph.D., Mechanical Engineering, California Institute of Technology (Caltech), 2017
  • M.S., Mechanical Engineering, California Institute of Technology (Caltech), 2014
  • B.S., Mechanical Engineering, Milwaukee School of Engineering, 2008
Licenses & Certifications
  • Professional Engineer Mechanical, Arizona, #80157
  • Professional Engineer Mechanical, California, #39478
  • Professional Engineer Mechanical, Missouri, #2023036909
  • Professional Engineer Mechanical, Nevada, #031961
  • 40-Hour Hazardous Waste Operation and Emergency Response Certification (HAZWOPER)
  • Certified Forklift Operator (CFO)
  • IFPS Certified Fluid Power Electronic Controls Specialist, Certificate
  • IFPS Certified Fluid Power Hydraulic Specialist, Certificate
  • OSHA #511 Occupational Safety and Health Standards for General Industry
  • OSHA #7115 Lockout/Tagout
  • PADI Certified Open Water Scuba Diver
Professional Honors
  • NASA Aeronautics Fellowship, 2010
  • American Society of Mechanical Engineering, Foundation Gratitude Scholarship, 2009
Professional Affiliations
  • American Society of Mechanical Engineers
  • ANSI B11 – Safety of Machinery - Standards Development Committee
  • Association for Advancing Automation (A3) – member
  • • R15.06 Committee - Industrial Robots and Robot Systems – Safety Requirements
  • American Society for Quality (ASQ) - member
  • International Fluid Power Society (IFPS) - member
  • National Fluid Power Association (NFPA) – member
  • • US. TAG to ISO/TC 131/SC 9 – Installations and systems - member
  • • US. TAG to ISO/TC 131/SC 9/WG 1 – Hydraulic systems - member
  • ASTM International
  • • Committee F15 - Consumer Products - member
  • • Committee F42 - Additive Manufacturing Technologies - member

Dr. Zelhofer specializes in the development, evaluation, and failure analysis of industrial equipment and consumer products. He has provided consulting services on matters of industrial problem solving, product recalls, product defect litigation, workplace safety, OSHA and Cal/OSHA requirements, intellectual property disputes, and insurance issues. In addition to his technical evaluations, he frequently assembles and directs multidisciplinary teams.

Dr. Zelhofer's experience spans industrial sector advisor, litigation consultant, and academic lecturer. Specific categorical examples of his experience include:

  • Vehicles and equipment utilizing hydraulics including skid steers, line grinding vehicles, lawn mowers, forklifts, refuse hauling vehicles, tarping systems, and reach trucks.
  • Products utilizing hydraulics including hydraulic actuators, motor-driven hydraulic pumps, floor jacks, bottle jacks, and hand pumps.
  • Hydraulic associated components including control systems, hoses, couplings, valves, seals, and fluids.
  • Industrial equipment including automated equipment, forklifts, reach trucks, light towers, mowers, air compressors, generators, and conveyors.
  • Industrial equipment safety including guarding, lockout/tagout, interlocks, and risk assessment.
  • Material handling associated equipment including chains, liftings straps, winches, chain hoists, and conveyors.
  • Food preparation equipment including vats, food grinders, food choppers, food blenders, food warmers, and conveyors.
  • Woodworking equipment including power presses, planers, jointers, table saws, miter saws, bandsaws, circular saws, jig saws, scroll saws, sanders, and drill presses.
  • Metalworking equipment including mills, lathes, shears, bench grinders, angle grinders, die grinders, bandsaws, abrasive saws, arbor presses, brakes, and rivet guns. 
  • Offroad vehicles including three and four wheeled all-train vehicles (ATV).
  • Vehicle associated including jack stands, tailgates, winches, loading ramps, dock levelers, and gas fuel nozzles.
  • Micromobility vehicles including electric standing scooters, electric seated scooters, and electric bicycles.
  • Exercise equipment including strength training equipment, selectorized equipment, treadmills, leg presses, and stationary bikes.
  • Water supply and plumbing including press-fit fittings, compression fittings, push-to-connect fittings, threaded fittings, barbed fittings, toilet supply hoses, sink supply hoses, regulators, valves, float switches, filter housings, and pumps.
  • Consumer products including coffee makers, blenders, clothing irons, clothing steamers, ice makers, dishwashers, blowers, trimmers, battery operated and unpowered toys.

In the course of evaluation and failure analysis Dr. Zelhofer performs both non-destructive and destructive techniques of investigation. For non-destructive evaluation he frequently uses 3D scanning via LiDAR (light detection and ranging) and CT (computerized tomography), 2D X-ray, and dimensional measurement using a coordinate measuring machine (CMM). For destructive evaluation Dr. Zelhofer frequently employs his extensive woodworking and metalworking knowledge coupled with his expertise in machine design to dissect and/or test items of focus. He is frequently called upon to conduct destructive testing in high load applications.