Dr. Harmon's areas of expertise include mechanical analysis, metallurgical analysis, materials development, and plastic processing. He also has experience in performing high-temperature mechanical characterization of metals and metallic glasses, and is familiar with foaming techniques and testing methods. He is also experienced in nondestructive ultrasonic pulse echo techniques. He has experience in alloy development, and is skilled in interpreting material phase changes in a variety of metal systems using thermodynamic techniques such as differential scanning calorimetry. He has utilized transmission and scanning electron microscopy to identify phases present in different alloy systems subjected to a variety of heat treatments. Dr. Harmon is also familiar with issues regarding in situ and engineered composite materials.
During his undergraduate studies, Dr. Harmon conducted research on surface modifications and interfacial shear strengths for epoxy/ceramic fiber composites. He focused on the development of a monolayer deposition process on a sapphire substrate to increase the interfacial bonding strength with the epoxy. He was also involved in characterizing the delamination properties of solar panel sections using a variety of testing methods.
Prior to joining Exponent, Dr. Harmon attended the California Institute of Technology where he conducted research on metallic glasses. Specifically, Dr. Harmon’s research focused on the high temperature characterization and description of the processing techniques applied to metallic glass. In addition to that research, he helped mechanically characterize high-temperature deformation of an experimental solid-state acid for use in fuel cells. He characterized the deformation of closed-cell metallic glass foams, and is familiar with the procedures by which foam may be produced.
Since joining Exponent, Dr. Harmon has worked on battery characterization and failure analysis for Li-polymer batteries. Dr. Harmon has dealt with accelerated testing methods and materials compatibility. Additionally, his experience has included work on electric motor failures, ignition propensity testing, heavy machinery design evaluation, and intellectual property rights.
Wiest A, Harmon J, Demetriou M, Conner RD, Johnson W. Injection molding metallic glass. Scripta Materialia 2008; 60(3):160.
Demetriou MD, Veazey C, Harmon J, Schramm J, Johnson W. Stochastic metallic-glass cellular structures exhibiting benchmark strength. Phys Rev Lett 2008; 101:145702.
Harmon J, Li H, Tang S, Mikolajczak C, Wu M. Pre-manufacture safety analysis: battery cell responses to simulated pack and system impact loading. Proceedings, 2nd IEEE International Interdisciplinary Conference on Portable Information Devices, August 17–20, 2008.
Mikolajczak C, Harmon J, Hayes T, Megerle M, White K, Horn Q, Wu M. Li-ion battery cell failure analysis: The significance of surviving features on copper current collectors in cells that have experienced thermal runaway. Proceedings, 25th International Battery Seminar & Exhibit for Primary & Secondary Batteries, Small Fuel Cells, and Other Technologies, March 17–20, 2008.
Harmon JS, Demetriou MD, Johnson WL, Samwer K. Anelastic to plastic transition in metallic glass-forming liquids. Physical Review Letters 2007; 99:135502.
Johnson WL, Demetriou MD, Harmon JS, Lind ML, Samwer K. Rheology and ultrasonic properties of metallic glass-forming liquids: A potential energy landscape perspective. Materials Research Society Bulletin, August 2007.
Harmon JS, Demetriou MD, Johnson WL. Rheology and ultrasonic properties of an Pt57.5Ni5.3Cu14.7P22.5 liquid. Applied Physics Letters 2007; 90(17), April 23.
Harmon JS, Demetriou MD, Johnson WL. Deformation of glass forming metallic liquids: Configurational changes and their relation to elastic softening. Applied Physics Letters 2007; 90:13, March 26.
Demetriou MD, Harmon JS, Tao M, Johnson WL. Cooperative shear model for the rheology of glass-forming metallic liquids. Physical Review Letters 2006; 97(6), August 11.
Battery Experience
Investigated battery failures for Li-polymer batteries found in various electronic devices. Identified probable causes of failure and prepared reports documenting findings.
Inspected and characterized battery assemblies for 18650 and soft pack Li-polymer batteries. Prepared reports detailing defects and other manufacturing issues.
Electric Motor Experience
Disassembled and analyzed electric motor failure in a team effort. Prepared reports for customer review detailing event.
Corrosion / Materials Compatibility Experience Organized and executed work including hydrostatic testing, dimensional analysis, and accelerated corrosion tests. Planned and performed accelerated testing of elastomer compatibility with various greases and cleaning solutions. Testing was done in regards to ongoing investigations of hydrant corrosion issues.
Prepared a hydrostatic testing fixture to test the seals of 18650 battery cells. Performed failure analysis for seals and suggested possible corrections.
Thermal Experience Performed testing for cigarette fabric ignition propensity.
Litigation / Intellectual Property Experience Evaluated and compared part designs for heavy haul trailers in an alleged patent infringement case. Prepared comparisons of parts in question.
Compiled and evaluated information sources regarding an aviation crash. Prepared internal documents reviewing probable causes of incident.
Design review of heavy machinery design using finite element analysis and established industry standards.