Principal Vibration Engineer II

Years of Experience: 38

Education & Licenses:

  • Doctor of Philosophy, Mechanical Engineering, 1985, Virginia Polytechnic Institute, Blacksburg, VA
  • Master of Science, Mechanical Engineering, 1977, Virginia Polytechnic Institute, Blacksburg, VA
  • Bachelor of Science, Mechanical Engineering, 1976, Virginia Polytechnic Institute, Blacksburg, VA

Areas of Specialization:

  • Vibration and other diagnostic testing – emergency on-site response, coordinated with plant technical, involving vibration, pressure pulsation, strain, torsional dynamics, and more
  • Data acquisition (DAQ) testing – multi-channel, continuous, real-time high-speed DAQ monitoring to capture rapid transients and identify system natural frequencies and response levels; see publication [3]
  • Vibration Experimental Modal Analysis (EMA) and Operating Deflection Shape (ODS) testing
  • Experimental stress analysis – using strain gauges
  • Pressure pulsation analysis – computer simulation of steady-state pressure and flow pulsation in plunger pump and reciprocating compressor systems
  • Hydraulic Transients Analysis (HTA) – “waterhammer” testing and computer modeling
  • Piping fatigue failure risk assessment – screening based on measured vibration
  • Flow-induced vibration testing and modeling of dip tubes, agitator internals, spargers, etc.
  • Relief valve chatter analysis
  • Mechanical design


Much of Dr. Blanding’s career was devoted to reciprocating plunger compressors or “Hypers” in 2,000+ BARG service in low-density polyethylene or LDPE units.  Short life of packing is a major problem, which is described in detail in publication [2], along with engineering efforts Dr. Blanding conducted to diagnose and solve root cause problems.  He also developed a computer model for check valve dynamics, which enabled design modifications to improve valve life.  Dr. Blanding carried out pressure pulsation analyses to develop modifications to the high-pressure tubing that reduced severe pulsation and vibration to acceptable levels.  He also developed a methodology and acceptance criteria for screen for allowable vibration levels of high-pressure tubing.

High-pressure process systems in general make up a large portion of Dr. Blanding’s work.  This includes pressure pulsation methodology Dr. Blanding advanced in-house, some of which is described in publication [1].  He also developed and/or advanced in-house computer simulation capabilities in the areas of dynamic flow performance of PD pumps, reciprocating compressors and dynamics, and cyclic stress of their internal check valves.  He also wrote the in-house algorithms in DuPont for flow-induced vibration of spargers, dip tubes, and agitated reactor internals.

Dr. Blanding led numerous efforts using rotary tachometers to diagnose and solve problems involving torsional dynamics of gearboxes, extruder screws, natural gas engine crankshafts, and web transport systems.  In this last instance he traced the root cause to film drive chain wear and developed a chain repair design involving a disposable wear-part insert that reestablished the original chain pitch and negated the cost and time delay of new chains.  This design is still in use after more than 20 years.

Dr. Blanding currently serves on the Pump Advisory Committee for the Turbomachinery and Pump Symposium (TPS), sponsored by the Turbomachinery Laboratory at Texas A&M University.


  1. Blanding, J.M., Walters, T., “Pulsation Analysis in Positive Displacement Pump Systems Using Waterhammer, Modal, and Animation Software,” Turbomachinery and Pump Symposium, 2016.
  2. Miller, E.S., Blanding, J.M., “Strain Gage and Thermocouple Measurements of Hyper Compressor Packing Cups to Study Pressure Sealing Performance,” Proceedings of the ASME 2015 Pressure Vessel and Piping Conference PVP2015, 2015.
  3. Martinez, F., Philippin, M., Blanding, J.M., “Dynamic Monitoring for Early Failure Diagnosis and Modern Techniques for Design of Positive Displacement Pumping Systems,” Turbomachinery and Pump Symposium, 2010.
  4. Schlucker, E., Blanding, J.M., “Guidelines to Maximize Reliability and Minimize Risk in Plants Using High-Pressure Diaphragm Pumps,” Turbomachinery and Pump Symposium, 2009.