Jackie D. Rehkopf, Ph.D.

Dr. Rehkopf has nearly 20 years of experience in the areas of mechanics of materials, structural mechanics and dynamics, experimental testing, and failure analyses. Dr. Rehkopf has significant expertise in high strain rate behavior of materials, having developed testing capabilities for high strain-rate tensile/compression testing at rates representative of automotive crash situations, and having evaluated a broad spectrum of materials for vehicle applications including AHSS, aluminum, magnesium, engineering plastics, and glass-fiber reinforced plastics. Dr. Rehkopf also has expertise in the areas of fatigue and creep, with emphasis on reinforced and non-reinforced polymers. Dr. Rehkopf has vast experience with component performance, particularly plastic fuel tanks and other fuel system components, bumpers, energy-absorbing foams, and plastic interior vehicle components. In concert with this, Dr. Rehkopf has authored material and engineering specifications, conducted root cause analyses on manufacturing and field failures, and supported finite element analyses with experimental data and selection of material behavior models.

Dr. Rehkopf investigates issues related to failure analysis and part performance. Investigations cover microscopy, analytical material characterization, and evaluation of material and component behavior both experimentally and analytically. Examples of past investigations include vehicle tires, nylon water tubing, HVAC valves, glass fiber reinforced nylon gaskets, and elastomeric fuel hose.

Prior to joining Exponent, Dr. Rehkopf worked for 12 years in materials R&D for an automotive OEM.

Conle FA, Rehkopf JD. Analysis of the results of strain controlled fatigue testing of reinforced polypropylene. SAE Paper 2009-01-0258, to be presented at SAE World Congress and Exhibition, Detroit, MI, April 2009.

Rehkopf JD, Conle FA. Strain-life fatigue approach applied to glass fibre reinforced polypropylene. SAMPE 2008 Fall Conference, Memphis, TN, September 8–11, 2008.

Baldwin JM, Bauer DR, Rehkopf JD, Guyer E, Ledwith P. Degradation of VMQ silicones in engine sealing applications. Presented at the 173rd Technical Meeting of the ACS Rubber Division, Dearborn, MI, April 2008.

Rehkopf JD. Nonstandard mechanical characterization of plastics for structural applications. Plastics Insights 2006; 5(4), Society of Manufacturing Engineers (www.sme.org/pcc).

Rehkopf JD. Use of relevant, non-standard mechanical characterization of fiber-reinforced thermoplastics for structural applications. Proceedings, SPE Automotive Composites Conference, September 2005.

Rehkopf JD, Conle FA. Fatigue properties of KabelSchlepp crane gantry track links. Ford Iinternal Web Report July 2004. http://fatigue.srl.ford.com/Consult/KabelSchlepp/ks.html.

Gonzalez L, Godlewski L, Rehkopf J, Lee L. Dynamic behavior of Class A metallic mold-in-color thermoplastic. Proceedings, SPE Automotive TPO Conference, 2004.

Rehkopf JD. Material behavior for modelling bumper impact. SAE Paper 2004-01-0010, Advances in Plastic Components, Processes, and Technologies SP-1850, 2004.

Krause AR, Rehkopf JD. Strain rate effects of AM60. Proceedings, International Symposium on Enabling Technologies for Light Metals and Composite Materials and Their End-Products, Light Metals 2002, MetSoc 41st Annual Conference of Metallurgists of CIM, p. 429–440, August 11–14, 2002.

Rehkopf JD, Barbat SD, Goldman NM, Cureton K. Environmentally responsive material to address human-system interaction in the automotive cockpit. Harris Gold SPIE Smart Materials and Structures Conference, Newport Beach CA, March 5–8, 2001.

Rehkopf JD. Coextruded blowmolded fuel tanks for new emissions requirements. SME Technical Paper IQ96-284, 1996.

Rehkopf JD, McNeice GM, Brodland GW. Fluid and matrix components of polyurethane foam behaviour under cyclic compression. Transactions of the ASME, Journal of Engineering Materials and Technology 1996; 118:58–62, January.

Rehkopf JD, Brodland GW, McNeice GM. Experimentally separating fluid and matrix contributions to polymeric foam behaviour. Experimental Mechanics 1996; 36(1), March; Society for Experimental Mechanics, Inc., p. 1–6.

Hamdan MH, Rehkopf JD. Micropolar fluid flow through porous media. CSCE Engineering Symposium, Winnipeg, Manitoba, June 1–4, 1994.

Rehkopf JD, McNeice GM, Brodland GW, Kuczynski E, Kerman M. Dynamic behaviour of an automotive polyurethane foam under multiple compression cycles. Society of Automotive Engineers Annual Congress, Detroit, MI, February 28–March 4, 1994.

Rehkopf JD, McNeice GM, Rudin A. Standard semi-rigid PU foam specimens—Size effect on compression response. Journal of Cellular Plastics 1994; 30(1):34–43, January-February 1994.

Rehkopf JD, McNeice GM, Rudin A. Standard semi-rigid PU foam specimens—Size effect on compression response. Proceedings, ANTEC 1992, Society of Plastics Engineers, Vol. II, pp. 1925–1927, Detroit, MI, May 1992.

Rehkopf JD, McNeice GM, Rudin A. Dynamic compressive behaviour of a semi-rigid PU foam—Strain rate effects. Developments in Theoretical and Applied Mechanics Volume XVI, Proceedings, 16th Southeastern Conference on Theoretical and Applied Mechanics, Nashville, TN, pp. II.12.1–II.12.8, April 1992.

McLaren A, Magee F, Bullas R, Rehkopf J, Hedley A. The effect of IM rod stiffness on fracture healing. Proceedings, Canadian Orthopaedic Research Society 23rd Annual Meeting, Toronto, Ontario, p. 57, 1989.

McLaren A, Magee, F, Rehkopf J, Hedley A. The effect of intra-medullary rod stiffness on fracture healing—Mechanical aspects. Proceedings, Society For Biomaterials 15th Annual Meeting, Lake Buena Vista, FL, p. 212, 1989.

McLaren A, Rehkopf J, McNeice G. The effect of limb diameter, bone diameter and tourniquet width on stress distribution under tourniquets: finite element analysis. Proceedings, Canadian Orthopaedic Research Society, 22nd Annual Meeting, p. 118, Ottawa, Ontario, 1988.

Invited Presentations

Rehkopf J. High strain rate characterization of engineering materials. Invited Talk, SAE Fatigue Design and Evaluation Conference, October 2005.

Rehkopf J. Fatigue of glass reinforced thermoplastics. Invited Talk, SAE Fatigue Design and Evaluation Conference, October 2004.

• Technical Specialist, Materials Department, Ford Motor Co., Research & Advanced Engineering, 2003–2006
• Technical Specialist, Safety Department, Ford Motor Co., Research & Advanced Engineering, 1998–2003
• Materials Engineer, Ford Motor Co., Plastic Fuel Tank Department (contractee), 1994–1998
  

Managed the non-destructive evaluation of nylon gaskets in extensive class action lawsuits against an automotive OEM. Evaluation consisted of x-ray and CT to inspect for porosity, molding defects and glass-fiber distribution, 3-dimensional part analysis, and customized non-destructive compression testing to assess mechanical behaviour.

Devised and managed mechanical tests to evaluate the performance and failure mode of a fuel hose under different dynamic load conditions.

Conducted microscopy evaluation of throttle control cable covers to compare surface features of exemplar and evidence parts.

Developed testing protocol and evaluated impact performance of various material constructions for an automotive trunk pack.

Led efforts at an automotive OEM on high strain-rate characterization of materials (including PE, PP, TPO, painted and paint-alternative TPO, nylon, ABS, glass reinforced thermoplastics, cast aluminum, magnesium and advanced high strength steels) and implementation these high strain rate behaviors into CAE crash models.

Characterized the fatigue behavior of long glass fiber reinforced polypropylene candidate formulations for use in an automotive front-end module.

Developed the Materials Specification and the Engineering Specification for coextruded, blowmolded, plastic fuel tanks for an OEM.

• SAE (member)
• SPE (member) and SPE Automotive Division Board Member
• ASCE (member)