Full EHD-SIMPACK-Tower Analysis of a Flexible Conrod Jochen Lang, IST GmbH, Aachen 19.05.2011 Agenda 1. SIMPACK-TOWER EHD-Inerface - Overall Concep - Elasohydrodynamic - Mixed Lubricaion Regime 3. TOWER Model Levels - Impedance-Chars - Online-FEM or (E)HD - Elasohydrodynamik (EHD) 4. Applicaion Example: Flexible Conrod 5. Conclusion 1
SIMPACK Wih TOWER-EHD-Inerface EHD-Inerface 2
Applicaion Area For SIMPACK Wih TOWER-EHD-Inerface Acousics Srengh Calculaion EHD-Inerface Bearing Design 3
Workflow Of Coupled SIMPACK-TOWER EHD-Simulaion Newon s Newonschen Equaion of Bewegungsgleichung Moion M u &&+ Du & + Ku = F u & &, u &, u SIMPACK Coupling User- Subrouine Algorihm RBD Boundary Condiions Srukur Srucure --Kineik Kineics --Kinemaik Kinemaics Local hydrodynamische hydrodynamische / Global Bearing --Elasiziä Elasiciy Reakionen Reakionen Reacion Ouer äußereforces Lasen + Posiions, Lage, Lage, Geschwindigkeien Geschwindigkeien Velociies BC RBD Clearance Lagerspiel Viscosiy Ölviskosiä Bearing Lagergeomerie Geomery 1. Impedance (E)HD 2. Online-FEM Impedance 3. EHD - Kennfeld =(,)εϑ So =(,)εϑ So 1 1 0.5 0.5 0 0-0.5-0.5-1 L / D -1 = 0.5 L / D = 0.5-1 -1-0.5-0.5 0 0 0.5 0.5 ϑ ϑ TOWER ε ε 1 1 Bearing Forces Minimal Gap Maximum Pressure 4
Theory Micro Hydrodynamics Hydrodynamic Pressure Buildup Reynolds DE 1 r ϕ h η p ϕ z s p h W 6Wσ Φ = 6 h + + 12 z z z 3 3 p p Φ + Φ 2 1 1 h η Microhydrodynamics Rough Surfaces Druck Umfang Höhe u 2 p 1 p2 u 1 Φ P Druckflußfakor q h 3 Φ S Scherflußfakor S q Φ = rauh u σ Φ P = rauh qgla h h / σ h / σ Rigid Body Conac Normal Force F = F + F Fricion Hyd F = f F + µ r Hyd cfc c p c Spread of Greenwood/Tripp Conac Model IST Conac Pressure 3D Surface Conac Pressure Gap h 5
Model Levels Hydrodynamics Reynolds Equalion ρ ρ x 12η x z 12η z 2 x 3 3 h p h p 1 + = (u 1 + u 2 ) ρ h + ρ h ( ) ( ) Mehods Impedanzce Mehod Global Elasiciy Local Elas. 1. Impedance Char Mehod - Inerpolaion in dimensionless char - Cylindrical bearing geomery - Consan gap in axial direcion (no iling) - No surface roughness conac 2. Online FEM Mehod - Soluion of Reynolds Equaion in every ime sep - Arbirary bearing geomery (Grooves, Oil supply) - Variable gap in axial direcion (Tiling) - Wih surface roughness conac 3. EHD Mehod - Feaures as Online FEM Mehod - In addiion local bearing deformaion - Wih surface roughness conac Online FEM Mehod EHD Mehod x y z Model Complexiy Calculaion Speed 6
Workflow For Impedance Mehode Newon s Newonschen Equaion of Bewegungsgleichung Moion M u &&+ Du & + Ku = F u & &, u &, u RBD Boundary Condiions Srukur Srucure --Kineik Kineics --Kinemaik Kinemaics --Elasiziä Elasiciy Ouer äußere Forces Lasen SIMPACK + Posiions, Lage, Lage, Geschwindigkeien Geschwindigkeien Velociies Coupling User- Subrouine Algorihm hydrodynamische hydrodynamische Global Bearing Reakionen Reakionen Reacion RBD Lagerspiel Moion Ölviskosiä of coupling Lagergeomerie nodes of shell and shaf (E)HD Impedance Impedance - Chars Kennfeld =(,)εϑ So =(,)εϑ So 1 0.5 1 0 0.5-0.5 0-1 -0.5 L / D = 0.5-1 -1-1 -0.5 L / D = 0.5-0.5 0 0 0.5 ϑ TOWER 0.5 Bearing Forces (Minimal Gap) (Maximal Pressure) 1 ε ϑ 1 ε Available For Journal Bearings 7
Hydrodynamic coupling: Impedance 1. Posiion Coupling Shaf One coupling node in he cener No consideraion of bending and iling Shell Four coupling nodes on he shell Leas square fi of a rigid cylinder Exz. F res 2. Force Coupling Coupling Nodes Shaf Resuling Coupling node forces from he chars Shell Opimal force disribuion Precise resuling forces No pull forces from he fluid film 8
Hydrodynamic coupling: Impedance Applicaion: Bearing load deerminaion for saically indeerminae sysems Bearing 3 Bearing 1 Bearing 4 F 1 F 2 F 3 F 4 F 5 Bearing 2 Bearing 5 9
Hydrodynamic coupling: Impedance Applicaion: Surface Velociy, Acousics 10
Workflow for Online-FEM Mehod Newon s Newonschen Equaion of Bewegungsgleichung Moion M u &&+ Du & + Ku = F u & &, u &, u SIMPACK + FEM mesh of bearing Posiions, Lage, Lage, Geschwindigkeien Geschwindigkeien Velociies Soluion of Reynolds-DGL Global Deformaion C TOWER Moion of coupling nodes of shell and shaf RBD Boundary Condiions Srukur Srucure --Kineik Kineics --Kinemaik Kinemaics --Elasiziä Elasiciy Ouer äußere Forces Lasen Coupling User- Subrouine Algorihm hydrodynamische hydrodynamische Global Bearing Reakionen Reakionen Reacion H0 ^ Pmax Bearing Forces (Minimal Gap) (Maximal Pressure) Available For Journal Bearings and Cylindrical Slider 11
Hydrodynamic Coupling: Online-FEM 1. Posiion Coupling Shaf Several coupling nodes in he cenerline Consideraion of bending and iling Shell Four coupling nodes on he shell Leas square fi of a rigid cylinder sarrer Zylinder h F res 2. Force Coupling Shaf Local Forces on Coupling node forces from pressure disribuion Shell Opimal force disribuion (Singular Value Decomposiion) Precise resuling forces Approximaion of Pressure Disribuion p Coupling Nodes 12
Workflow for EHD-Mehod Newon s Newonschen Equaion of Bewegungsgleichung Moion M u &&+ Du & + Ku = F u & &, u &, u SIMPACK + FEM mesh of bearing Posiions, Lage, Lage, Geschwindigkeien Geschwindigkeien Velociies TOWER Moion of coupling nodes of shaf and local deformaion of shell Soluion of Reynolds-DGL Local Deformaion RBD Boundary Condiions Srukur Srucure --Kineik Kineics --Kinemaik Kinemaics --Elasiziä Elasiciy Ouer äußere Forces Lasen Coupling User- Subrouine Algorihm hydrodynamische Local hydrodynamische / Global Bearing Reakionen Reakionen Reacion Pressure Disribuion (Gap Disribuion) Available For Journal Bearings and Cylindrical Slider 13
Hydrodynamic Coupling: EHD 1. Posiion Coupling (Gap Funcion) Shaf Several coupling nodes in he cenerline Consideraion of bending and iling h Shell Posiion and velociy of all bore nodes Deformaion and global moion 2. Force Coupling Shaf Local Forces on Coupling node forces from pressure disribuion Shell Local pressure forces on all bore nodes Precise resuling forces Precise pressure disribuion 14
Applicaion Example: EHD Conrod Bearing SIMPACK MBS-Sysem TOWER Elasohydrodynamic Pressure Disribuion Deformed bearing geomery considered during online EHD calculaion 15
Applicaion Example: EHD Conrod Bearing SIMPACK MBS-Sysem TOWER Elasohydrodynamic Pressure Disribuion Comparison of rigid and elasic conrod bearing 16
Applicaion Example: EHD Conrod Bearing Tribological Parameers: Minimal Gap, Maximum Pressure, Fricion Power Loss 17
Applicaion Example: EHD Conrod Bearing Tribological Parameers: Gap Disribuion, Roughness Conac, Mixed Lubricaion Regime 18
Applicaion Example: EHD Conrod Bearing Gap Disribuion Over All Pressure Disribuion Conac Pressure Disribuion Applicaion: Appraisal of Load Disribuion Power Loss Disribuion 19
Conclusion IST has long erm experience in EHD sofware developmen and bearing analysis Close cooperaion beween SIMPACK and IST in cusomer suppor The SIMPACK-TOWER EHD-Inerface provides hree model levels Impedance Mehod - Suiable for evaluaion of resuling bearing forces Online-FEM Mehod, (E)HD - Consideraion of load disribuion and oil supply in he bearing wih global srucural deformaions EHD - Suiable for bearing design analysis and opimizaion wih local shell deformaions 20
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