Design guide for composite-material flywheels: rotor dyamic considerations. Part I. System whirling and stability. Final report

Technical Report · Tue Sep 01 04:00:00 EDT 1981

DOI:https://doi.org/10.2172/5234632· OSTI ID:5234632

Bert, C W; Ramunujam, G

Information to designers of flywheels is provided which will enable them to predict many aspects of the dynamic behavior of their flywheel systems when spin-tested with a quill-shaft support and driven by an air turbine. Computer programs are presented for the following dynamic analysis to obtain the results indicated: free whirling for natural frequencies versus rotational speed and the associated mode shapes; rough-type stability analysis for determining the stability limits; and forced whirling analysis for estimating the response of major components of the system to flywheel mass eccentricity and initial tilt. For the first and third kinds of analyses, two different mathematical models of the generic system are investigated. One is a seven-degree-of-freedom lumped-parameter analysis, while the other is a combined distributed- and lumped-parameter analysis. When applied to an existing flywheel system, the two models yielded numerical values for the lowest first-order forward critical speed in very close agreement with each other and with experimental results obtained in spin tests. Therefore, for the second kind of analysis, only the lumped-parameter model is implemented. Qualitative discussions as to why forced retrograde whirling is not as severe as forward whirling are also presented. The analyses are applied to the multi-material ring type flywheel systems, a constant-thickness-diskring type, and a tapered-thickness-disk type. In addition, the effects of the following flywheel design parameters on system dynamics were investigated: flywheel mass; diametral and polar mass moments of inertia; location of mass center from the lower end of the quill shaft; quill shaft length; lower turbine-bearing support stiffness; equivalent viscous damping coefficient of the external damper; flywheel dead weight; and torque applied at the turbine.

• Research Organization: Lawrence Livermore National Lab., CA (USA); Oklahoma Univ., Norman (USA). School of Aerospace, Mechanical and Nuclear Engineering
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 5234632
• Report Number(s): UCRL-15420; ON: DE82011066
• Country of Publication: United States
• Language: English

Related Subjects

25 ENERGY STORAGE
250500* -- Energy Storage-- Flywheels
COMPOSITE MATERIALS
COMPUTER CALCULATIONS
COMPUTER CODES
DAMPING
DATA
DESIGN
DYNAMICS
EXPERIMENTAL DATA
FLYWHEELS
INFORMATION
MATERIALS
MATHEMATICAL MODELS
MECHANICAL ENERGY STORAGE EQUIPMENT
MECHANICAL VIBRATIONS
MECHANICS
NUMERICAL DATA
STABILITY
STRESS ANALYSIS
THEORETICAL DATA