An MSC.Nastran Primer for Rotordynamics Chuck Lawrence NASA Glenn Cleveland, Ohio
MSC.Nastran Rotordynamics Damage Resulting from Blade-Out
MSC.Nastran Rotordynamics Types of Analyses Engine performance critical speeds whirl forced response (unbalance, cabin noise) damping Static Analysis (external loads, maneuver loads) Transient blade off structural system response windmilling
MSC.Nastran Rotordynamics Typical Structural Model Engine Static Structure
MSC.Nastran Rotordynamics Background 1998 Meeting with engine and airframe manufacturers and MSC.Software All manufacturers performing similar types of analysis All manufacturers using similar, but self developed and maintained, software tools Common need to develop standardized analysis tools
MSC.Nastran Rotordynamics Participants Boeing Commercial Airplane Group Pratt & Whitney General Electric Aircraft Engines Rolls Royce Ohio Aerospace Institute MSC.Software NASA
MSC.Nastran Rotordynamics Process Form Working Group Define General Program Plan, Benefits and Advocacy Package Secure Funding Develop Boeing Document Bring MSC.Software Aboard Develop Software Requirements Document Develop Software Validate Software Phase II
MSC.Nastran Rotordynamics Unique Features General Finite Element Capabilities Component Substructuring Condensation of 3D Rotors Rotor Damping Non-Constant Rotor Speed Complex Mass Unbalance Fan-Case Interactions Multi-Spool Rotors Maneuver Loads Parametric Excitations
Primer Table on Contents I. Single Spool Rotor 1. Geometry 2. Gravity Loads 3. Maneuver Loads 4. Transient Unbalance Response 5. Synchronous Vibration (Critical Speeds) 6. Asynchronous Vibration (Whirl Analysis) 7. Comparison of Damping Models II. Dual Spool Rotor 1. Geometry 2. Synchronous Vibration (Critical Speeds) 3. Asynchronous Vibration (Whirl Analysis) 4. Transient Unbalance Response III. Squeeze Film Damper IV. Three Dimensional Model Reduction
Single Spool Rotor With Rotor and Support Damping Disk Unbalance Load 101 102 103 (104) (105) Rigid Shaft Rotation Vector Support Damper Support Springs Rotor Damper Z Y X
1 $ 2 $ ROTOR DYNAMICS SAMPLE PROBLEM 3 $ SINGLE ROTOR, UNBALANCE LOAD 4 $ 5 6 ID SAMPLE ROTOR 7 SOL 129 8 DIAG 5, 8, 56 9 CEND 11 10 RGYRO= 111 12 TSTEP= 100 13 SET 500 = 102 14 DISPLACEMENT(PUNCH) = 500 15 16 BEGIN BULK 17 18 UNBALNC, 111, 100.0, 102, 0., 1., 0., 19, 1.0, 0.0, 0.0, 0.0,, NONE 20 TSTEPNL, 100, 40000, 1.E-3, 20 21 22 $ 23 $ ROTOR 1 24 $ Single Spool Rotor Transient Analysis 26 ROTORG 10 101 THRU 103 27 RSPINT, 10, 101, 102,, RPM, 100 28 TABLED1, 100 29, 0.0, 800., 100.0, 800., ENDT 30 31 GRID, 101,, 0., 0., 0. 32 GRID, 102,, 1., 0., 0.,, 14 33 GRID, 103,, 2., 0., 0. 34 GRID, 104,, 0., 0., 0. 35 GRID, 105,, 2., 0., 0. 36 37 RBE2, 1001, 102, 123456, 101, 103 38 RBE2, 1002, 101, 123456, 104 39 RBE2, 1003, 103, 123456, 105 40 41 CONM2, 1004, 102,, 50., 42, 5.0,, 15.0,,, 15.0 43 44 CELAS1, 1005, 1000, 104, 2 45 CELAS1, 1006, 1000, 104, 3 46 CELAS1, 1007, 1000, 105, 2 47 CELAS1, 1008, 1000, 105, 3 48 PELAS, 1000, 1.0E+5, 0.0 49 50 ENDDATA
Single Spool Rotor Transient Response
Single Spool Rotor - Critical Speeds 1 $ 2 $ ROTOR DYNAMICS SAMPLE PROBLEM 3 $ SINGLE ROTOR, CRITICAL SPEEDS 4 $ 5 6 ID SAMPLE ROTOR 7 SOL 107 8 DIAG 5, 8, 56 9 CEND 10 11 RGYRO= 111 12 DISP = ALL 13 CMETHOD = 100 14 15 BEGIN BULK 16 17 EIGC, 100, CLAN, 18, 0., 0.,,,,, 10 19 RGYRO, 111, SYNC, 10, RPM, 0., 2500. 20 21 $ 22 $ ROTOR 1 23 $ 24 25 ROTORG 10 101 THRU 103 26 RSPINR, 10, 101, 102,, RPM, 9999. 27 28 GRID, 101,, 0., 0., 0. 29 GRID, 102,, 1., 0., 0.,, 14 30 GRID, 103,, 2., 0., 0. 31 GRID, 104,, 0., 0., 0. 32 GRID, 105,, 2., 0., 0. 33 34 RBE2, 1001, 102, 123456, 101, 103 35 RBE2, 1002, 101, 123456, 104 36 RBE2, 1003, 103, 123456, 105 37 38 CONM2, 1004, 102,, 50., 39, 5.0,, 15.0,,, 15.0 40 41 CELAS1, 1005, 1000, 104, 2 42 CELAS1, 1006, 1000, 104, 3 43 CELAS1, 1007, 1000, 105, 2 44 CELAS1, 1008, 1000, 105, 3 45 PELAS, 1000, 1.0E+5, 0.0 46 47 ENDDATA
Single Spool Rotor Campbell Diagram and Critical Speeds 2/rev 1/rev Mode 4 Third Critical First Critical Second Critical Mode 3 Mode 1,2
Dual Spool Rotor Asynchronous Vibration 1 $ 2 $ ROTOR DYNAMICS SAMPLE PROBLEM 3 $ Dual Spool Rotor, Asynchronous Vibration 4 $ 5 6 ID SAMPLE ROTOR 7 SOL 107 8 DIAG 5, 8, 56 9 CEND 10 11 RGYRO = 300 12 DISP = ALL 13 CMETHOD = 100 14 15 BEGIN BULK 16 17 RGYRO, 300, ASYNC, 20, FREQ, 0., 100., 40. 18 19 EIGC,100,CLAN, 20, 0., 0.,,,,, 14 21 22 $ 23 $ ROTOR 1 24 $ 25 26 ROTORG 10 101 THRU 104 27 RSPINR, 10, 101, 102,, FREQ, 20., 25., 35., 28, 50. 29... 52 $ 53 $ ROTOR 2 54 $ 55 56 ROTORG 20 201 THRU 203 57 RSPINR, 20, 201, 202,, FREQ, 10., 20., 30., 58, 40. 59... 81 ENDDATA
Dual Spool Rotor Relative Rotor Speeds
Dual Spool Rotor Campbell Diagram and Critical Speeds 1/rev 6th Critical Mode 6 5th Critical Mode 5 1 st & 2nd Critical 3 rd & 4 th Critical Mode 3,4 Mode 1,2
Dual Spool Rotor Transient Response
Squeeze Film Damper
MSC.Nastran Rotordynamics Summary Unified front and team effort enabled rotordynamics to be implemented into MSC.Nastran Rotordynamics primer is available for distribution MSC.Software did an outstanding job of satisfying customer s needs