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DR. RORY R. DAVIS, P.E.
CONVERGENCE ENGINEERING CORP.
1638 Finch Drive
Gardnerville, NV 89410
B.S., Mechanical Engineering, University of California, Davis, 1979
B.S. Senior Project: Design of Aluminum Bicycle Frames
M.S., Mechanical Engineering, University of California, Davis, 1980
M.S. Thesis: Measurement of Foot-Pedal Loads During Bicycling
Ph.D., Mechanical Engineering, University of California, Davis, 1989
Ph.D. Dissertation: Practical Nonlinear Simulation of Rotating Machinery Dynamics With Application to Turbine Blade Rubbing
12/90-present: Chief Engineer and Chief Executive Officer
Employer: Convergence Engineering Corp.
Gardnerville , NV
Duties: Technical leader for the company in mechanical engineering. Specific coverage in the areas of engineering applied mechanics, thermal/stress and design analysis, structural dynamics, and advanced probabilistic, optimization and statistical methods. Major tasks include
1) metallic and composite hardware thermal, stress, dynamic, and fatigue analysis
2) composite material testing, including sample design and test planning
3) mechanical design, concept development, prototype hardware testing and development
4) vibration qualification test design and execution
5) complex dynamic system analysis, including rotordynamics and nonlinear multi-energy domain systems
6) multi-disciplinary system analysis and optimization
7) expert witness consulting to attorneys and insurance companies.
Breadth of projects are described elsewhere on the web site
04/05-present: Chief Engineer and Managing Member
Employer: SquidTech LLC
Gardnerville , NV
Duties: Technical leader for the company in mechanical engineering, particularly test planning and management, engineering of fixtures and test systems, and complex data processing.
Breadth of projects are described elsewhere on the web site
7/84-11/90 : Engineering Specialist
Employer: System Analysis Department
Aerojet Propulsion Division
Duties: Technical leader for the company in the areas of structural dynamics and advanced probabilistic and statistical methods. Led the building of most of the company's analytical capability in rotordynamics over the last five years (see Ph.D. dissertation on page 1). Planned and performed original research under company IR&D in the areas of rolling element bearings, fluid film bearings, and rotordynamic nonlinear coupled system analysis methods. Also acted as subgroup manager including task allocation, review, and project planning of structural dynamics efforts.
Performed a NASA technology contract entitled Modeling of Rolling Element Bearing Mechanics, which was a result of the IR&D work. Included detailed nonlinear static and dynamic analysis of rolling element bearings with flexible races and housing interface gaps.
Applied probabilistic analysis knowledge to the Advanced Launch System project in areas of sensitivity, variability, and thrust/mixture ratio trimming of candidate engine power systems. Applications of experiment design, regression, and variance propagation methods were involved. Developed new approaches to the probabilistic description of trimming operations.
Other previous significant work includes:
1) Participated as a dynamics expert on Titan 34D failure analysis teams and have provided continuing support to the Titan program in areas of design loads definition, vibration analysis, and start transient structural system response. Failure analysis included comprehensive structural start transient response prediction, and support of POGO analysis. Involved in reviews at Aerospace Corp., Sheldon Rubin in charge.
2) Performed extensive structural random and transient dynamic response analysis of High Endoatmospheric Interceptor (HEDI) components and systems. Also have led the overall dynamic analysis effort for this project intermittently.
3) Provided ongoing leadership within the company in methods development and planning to address customer needs and increase productivity.
4) Led the development and implementation of a comprehensive dynamic system analysis computer code, RODYNE. Initially developed to perform complex time and frequency domain rotordynamic analysis in an interactive environment, it has also been useful for engine power system and other analyses. It is now a foundation computer program for the system analysis group, and was recognized by the company via an innovation award (see below).
5) Performed as lead dynamicist on the Space Shuttle Engine Study. Work included turbine blade and disk vibration analysis, rotordynamic analysis including structural coupling of engine mounting, and detailed ball bearing analysis.
6) Performed testing and troubleshooting of the TRANSTAR turbopump which had a rotor stability problem. Recommended design changes to solve the problem. Have also performed troubleshooting on high capacity firefighting pumps (Aerosafe) and bearing testers.
7) Provided dynamics support on various proposals to NASA, including the SSME Alternate Turbopump Development Program, Influence of Rubbing on Rotordynamics, Blade Tip Rubbing Stress Prediction, and others.
8) Performed extensive modeling and stress analysis of Titan pump housings for uprate applications.
9/82 - 7/84 : Mechanical Engineering Consultant
Duties: Private part time business performing engineering consulting for varied clients. Jobs included farm equipment failure troubleshooting (strain gage testing and finite element analysis), dump truck failure analysis, vibrating equipment stress testing, library research and on-site investigations for liability cases, and beer can design refinement using finite element methods. Other references available upon request.
9/82 - 7/84 : Visiting Lecturer and Researcher
Employer: Mechanical Engineering Department
University of California
Duties: Course preparation, instruction, and student consultation in upper division mechanical engineering subjects. Courses taught included introductory and intermediate dynamics, introductory and intermediate mechanical design, and probabilistic design. Also developed new computer-aided design teaching methods for intermediate mechanical design courses.
7/80 - 9/82 : Project Manager, Consulting Services
Employer: Structural Dynamics Research Corporation
San Diego, CA
Duties: Solved difficult mechanical design and vibration problems on a consulting basis for various industrial clients. Sophisticated computer analysis methods were commonly used. Responsibilities included all items for the satisfaction of clients, including:
1) Sales calls and initial customer contacts
2) Research, financial planning, and preparation of contract proposals
3) Data collection on site, often including modal and vibration tests of existing mechanical equipment.
4) Comprehensive analysis of mechanical systems under study using static and dynamic techniques, most often via finite element methods with computers.
5) Interpretation of test and analysis data and determination of proper courses of action for the client.
6) Ongoing financial tracking and control.
7) Preparation of complete engineering reports.
Some of the subjects of study were seismic qualification of hardware, heavy truck ride studies, electron beam etching machine vibration control, train hopper car stress analysis, beer can holder design analysis, electronic equipment vibration isolation, and CNC machine tool frame design to minimize vibration.
pre-1980 : Engineering Intern and others
Employer: IBM, Weyerhauser, University of California
Duties: Various summer internships, teaching assistant, research assistant, and reader jobs. Highlights include:
1) work in UC Davis agricultural engineering dept. building forest engineering research equipment (welding, mechanic, mechanical designer)
2) Weyerhauser work on a new tree nursery cultivation implement which led to an invention report. Implement was conceived, designed, built, and tested in 3 months.
-Extensive mechanical design and analysis experience, including function, failure, and durability.
-Extensive experience in the analysis of rolling element bearing mechanics.
-Extensive knowledge in structural dynamics, including rotating machinery dynamics as a subset.
-Extensive knowledge in modal synthesis and other reduction techniques with application to real dynamic systems.
-Extensive experience in the use of finite element methods and computer programs. Experienced in porting finite element data into other codes for different analyses. Particular experience in the use of ANSYS, with some experience with NASTRAN and others.
-Extensive knowledge of probabilistic, optimization, and statistical methods and their application to engineering problems, including experiment design, regression, response surface methodology, hypothesis testing, probabilistic design methods, and advanced signal processing.
-Training in general system dynamics, including classical and modern control.
-Engineering-oriented computer coding experience, mostly with FORTRAN. Also experience with assembly language, APL, and BASIC, VISUAL BASIC, GAUSS, EXCEL, MATHCAD.
-Experience with PC computers and associated commercial software (word processors, spreadsheets, and specialty engineering analysis codes).
-Instrumentation, testing, and machinery diagnosis experience using strain gages, accelerometers, proximity probes and modern filtering and analog/digital data acquisition equipment.
-Hands on experience with design and fabrication of analog electronics.
-Welding and general mechanical proficiency. Experienced in prototype fabrication and testing.
Honors and Awards:
-R.B. Young Technical Innovation Award, Aerojet TechSystems Company, 1987,"RODYNE: Simple and Efficient Linear/Nonlinear Integrated Dynamic Analysis"
-Earl C. Anthony Fellowship, University of California, Davis, 1983-84
-Distinguished Scholar Research Award, University of California, Davis, 1979-80
-Graduate Division Fellowship, University of California, Davis, 1979-80
-B.S. Degree with highest honors and Mechanical Engineering Departmental Citation, University of California, Davis, 1979
-William Stout Award, University of California, Davis, 1977
-Cal Aggie Alumni Association Award, University of California, Davis, 1977
Affiliations and Licenses:
-American Society of Mechanical Engineers (ASME)
- Society of Automotive Engineers (SAE)
- American Society for Metals (ASM)
-Tau Beta Pi Engineering Honor Society
-Phi Kappa Phi Honor Society
-Registered Professional Engineer in California, Mechanical, No. 22810
-Registered Professional Engineer in Nevada, Mechanical, No. 11336
co-inventor,"Pedalling Efficiency Indicator", U.S. Patent No. 4,463,433, July 1984.
co-inventor,"Force-Resisting Devices and Methods for Structures", U.S. Patent No. 7,043,879, May 2006.
co-inventor,”Force-Resisting Devices and Methods for Structures”, U.S. Patent No. 7,458,187, December 2008.
1. Brinkley,A.L., and Davis,R.R., “Response Surface Modeling of a Closed-Cycle Split-Expander Liquid Rocket Engine” 6th JANNAF Modeling and Simulation Subcommittee Meeting, Orlando, FL, December, 2008.
2. Raymer,D.P, Doupe,C., Zweber,J., Fry,T., Munro,B., Davis,R., Crockett,D., Mallick,K., and Weatherly,H., “An Affordable Flight Demonstrator for Fully-Reusable Access to Space Technologies”, paper presented in Session 3C at the 54th JANNAF Joint Propulsion Meeting (JPM 2007), Denver, CO, May 14, 2007.
3. Cheng,G.C, Davis,R.R., Johnson,C.W., Muss,J.A., Greisen,D.A., and Cohn, R.K., “Development of GOX/Kerosene Swirl-Coaxial Injector Technology”, paper AIAA 2003-4751, presented at the 39th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit, Huntsville, AL, July 20, 2003.
4. Johnson,C.W., Palmer, S.M., and Davis,R.R., “Improvements to ROCETS (ROCket Engine Transient Simulation)”, presented at JANNAF Conference, JANNAF Interagency Propulsion Committee, 3rd Modeling and Simulation Subcommittee, Colorado Springs, CO, December 1-5, 2003 (limited distribution, Critical Technology).
5. Davis, R.R., "The Ball Piston Engine – A New Concept in High Efficiency Power Machines", SAE Paper #970066, presented at the SAE International Congress and Exposition, Detroit, Michigan, February 24, 1997.
6. Davis, R.R.,"Practical Nonlinear Simulation of Rotating Machinery Dynamics With Application to Turbine Blade Rubbing", Ph.D. Dissertation, University of California, Davis, 701 pg, May 1989.
7. Davis, R.R.,"Enhanced Rotor Modeling Tailored for Rub Dynamic Stability Analysis and Simulation", Rotordynamic Instability Problems in High Performance Turbomachinery 1988, Proceedings of a workshop held at Texas A&M University, College Station, Texas, pp. 431-444, May 16-18 1988.
8. Davis, R.R. and Vallance, C.S.,"Incorporating General Race and Housing Flexibility and Deadband in Rolling Element Bearing Analysis", Rotordynamic Instability Problems in High Performance Turbomachinery 1988, Proceedings of a workshop held at Texas A&M University, College Station, Texas, pp. 373-387,May 16-18 1988.
9. Davis, R.R.,"Enhanced Rotor Modeling Tailored for Dynamic Stability Analysis and Nonlinear Simulation", presented at the Second International Symposium on Transport Phenomena, Dynamics, and Design of Rotating Machinery, Honolulu, Hawaii, Proceedings Preprints, Vol. 2: Dynamics, pp. 182-193, April 3-6 1988.
10. Davis, R.R. and Vallance, C.S.,"Incorporating General Race and Housing Flexibility and Deadband in Rolling Element Bearing Analysis", presented at the Second International Symposium on Transport Phenomena, Dynamics, and Design of Rotating Machinery, Honolulu, Hawaii, Proceedings Preprints, Vol. 2: Dynamics, pp. 241-254, April 3-6 1988.
11. Davis, R.R. and Hull, M.L.,"Design of Aluminum Bicycle Frames", ASME J. of Mechanical Design, vol. 103, no. 4, pp. 901-907, October 1981.
12. Hull, M.L. and Davis, R.R.,"Measurement of Pedal Loading in Bicycling: I. Instrumentation", J. of Biomechanics, vol. 14, no. 12, pp. 843-856, 1981.
13. Davis, R.R. and Hull, M.L.,"Measurement of Pedal Loading in Bicycling: II. Analysis and Results", J. of Biomechanics, vol. 14, no. 12, pp. 857-872, 1981.
14. Davis, R.R. and Hull, M.L.,"Performance Analysis of Bicycle Pedalling", 1981 Biomechanics Symposium, ASME Publication AMD-Vol. 43, no. G00201, pp. 109-112, June 1981.
15. Hull, M.L. and Davis, R.R.,"Biomechanics of Overuse Injuries in Bicycling: Instrumentation", 1980 Advances in Bioengineering, ASME Publication no. G00176, pp. 129-132, November 1980.
16. Davis, R.R. and Hull, M.L.,"Pedalling Efficiency in Bicycling", 1980 Advances in Bioengineering, ASME Publication no. G00176, pp. 133-136, November 1980.
17. Hull, M.L. and Davis, R.R.,"A Six-Axis Bicycle Pedal Load Measurement System", presented at the ISA/80 International Conference and Exhibit, Houston, Texas, Instrument Society of America Publication no. C.I. 80-698, pp. 677-689, October 1980.
18. Davis, R.R.,"Measurement of Foot-Pedal Loads During Bicycling", M.S. Thesis, University of California, Davis, 49 pg, October 1980.
19. Davis, R.R. and Hull, M.L.,"Design of Aluminum Bicycle Frames", California Engineer, vol. 58, no. 4, pp. 10-15, Spring 1980.