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ANSYS Conference & 26th CADFEM Users´ Meeting
CAE analysis of a conrod for motorbike application
R. Testi ([email protected])Piaggio & C. SpA – Italy (www.piaggio.com)
ANSYS Conference & 26th CADFEM Users´ Meeting
Presentation outline
• Company profile• Object of the study• Analysis methodology• Results• Synopsis
ANSYS Conference & 26th CADFEM Users´ Meeting
Company profile – Piaggio Group
Business areas
2-wheelers
Light Transport Vehicles
Light Transport Vehicles
Engines
Spare parts and accessoriesSpare parts
and accessories
ANSYS Conference & 26th CADFEM Users´ Meeting
Company profile – Piaggio Group
Brands managed
ANSYS Conference & 26th CADFEM Users´ Meeting
Company profile – Piaggio Group
A few figures
• one of the world’s top four manufacturers of two-wheel motor vehicles
• consolidated leadership position on the European 2-wheeler market
• approximately 7,000 employees• facilities: Pontedera (Pisa-Italy); Scorzè (Venice-Italy); Mandello del Lario (Lecco-Italy); Barcelona (Spain); Baramati (India)
• R&D centres: Italy, Spain, China and India• vehicle sold in 2007: 708,500• net sales in 2007: 1,692 million Euro
ANSYS Conference & 26th CADFEM Users´ Meeting
Presentation outline
• Company profile• Object of the study• Analysis methodology• Results• Synopsis
ANSYS Conference & 26th CADFEM Users´ Meeting
Object of the study
Aprilia ShiverAprilia ShiverNew 1200 cctwin engine
New 1200 cctwin engine
ConrodConrod
Prediction of fatigue performance
Prediction of fatigue performance
Max power ���� 103 kWMax torque ���� 120 Nm
ANSYS Conference & 26th CADFEM Users´ Meeting
Presentation outline
• Company profile• Object of the study• Analysis methodology• Results• Synopsis
ANSYS Conference & 26th CADFEM Users´ Meeting
Analysis methodology
CAD software
Geometry ANSYS/Workbench
Dynamic Load/stress transfer functions
MBS software
Durability softwareLoad time-histories
Safety factor
Static stresses
Inertia propertie
s
ANSYS Conference & 26th CADFEM Users´ Meeting
ANSYS/Workbench analyses
NonlinearNonlinear LinearLinear
ANSYS/Workbench
Dynamic Load/stress transfer functions
Static stresses
ANSYS Conference & 26th CADFEM Users´ Meeting
ANSYS/Workbench nonlinear static analysis
Frictional contacts with interferenceFrictional contacts with interference Bolt pretensionsBolt pretensions
ANSYS Conference & 26th CADFEM Users´ Meeting
ANSYS/Workbench analyses
NonlinearNonlinear LinearLinear
ANSYS/Workbench
Dynamic Load/stress transfer functions
Static stresses
ANSYS Conference & 26th CADFEM Users´ Meeting
ANSYS/Workbench linear static analysis (1/2)
Unit loads at conrod’s interfacesUnit loads at conrod’s interfaces
Cylindrical jointsCylindrical joints
Unit magnitude bearing loadsUnit magnitude bearing loads
ANSYS Conference & 26th CADFEM Users´ Meeting
ANSYS/Workbench linear static analysis (2/2)
Stepped Static Structural analysis
RST file’s structure
Loadstep Content
1 Bearing load #1
2 Bearing load #2
… …
Ready to be coupled with load time-histories
One load per step
Inertia relief on
ANSYS Conference & 26th CADFEM Users´ Meeting
Analysis methodology
CAD software
Geometry ANSYS/Workbench
Dynamic Load/stress transfer functions
MBS software
Durability softwareLoad time-histories
• Stress tensor • Safety factor
Static stresses
Inertia propertie
s
ANSYS Conference & 26th CADFEM Users´ Meeting
ANSYS/Workbench analyses
NonlinearNonlinear LinearLinear
Requirement for durability analysisRequirement for durability analysis
Same node/element numberingSame node/element numbering
ANSYS/Workbench
Dynamic Load/stress transfer functions
Static stresses
ANSYS Conference & 26th CADFEM Users´ Meeting
ANSYS/Workbench analyses – dummies to keep same numbering
Workbench
NonlinearNonlinear
LinearLinear
Dummies to keep the
PRETS179s
Dummies to keep the
PRETS179s
Dummies to keep the SURF154s
Dummies to keep the SURF154s
ANSYS Conference & 26th CADFEM Users´ Meeting
Analysis methodology
CAD software
Geometry ANSYS/Workbench
Dynamic Load/stress transfer functions
MBS software
Durability softwareLoad time-histories
• Stress tensor • Safety factor
Static stresses
Inertia propertie
s
ANSYS Conference & 26th CADFEM Users´ Meeting
MBS analysis (1/2)
Bench test conditions Testrig rotary inertia
Gearbox
Gas forces
ANSYS Conference & 26th CADFEM Users´ Meeting
MBS analysis (2/2)
Gas forces
— Conrod #1 --Conrod #2
Longitudinal forces on conrod #2
— Big eye --Small eye
Combined with load/stress TF by
durability SW
Combined with load/stress TF by
durability SW
ANSYS Conference & 26th CADFEM Users´ Meeting
Analysis methodology
CAD software
Geometry ANSYS/Workbench
Dynamic Load/stress transfer functions
MBS software
Durability softwareLoad time-histories
• Stress tensor • Safety factor
Static stresses
Inertia propertie
s
ANSYS Conference & 26th CADFEM Users´ Meeting
MBS
Durability analysis (1/2)
Workbench
Load/stress transfer functions
Load time-history
X = Stress tensor time-history
Dummy unit time-histories for static loads
ANSYS Conference & 26th CADFEM Users´ Meeting
Durability analysis (2/2)Model structure
FEM results
MBS results
Linear combinations
Solver parameters
ANSYS Conference & 26th CADFEM Users´ Meeting
Presentation outline
• Company profile• Object of the study• Analysis methodology• Results• Synopsis
ANSYS Conference & 26th CADFEM Users´ Meeting
Results (1/3)Safety factor vs. endurance limit
Minimum allowable value according to Piaggio standards
1.25
SOUND CONROD DESIGN
ANSYS Conference & 26th CADFEM Users´ Meeting
Results (2/3)
Most damaging load
Omitting given load channel
ANSYS Conference & 26th CADFEM Users´ Meeting
Results (3/3)
Most severe condition
TDC – start of power stroke
ANSYS Conference & 26th CADFEM Users´ Meeting
Presentation outline
• Company profile• Object of the study• Analysis methodology• Results• Synopsis
ANSYS Conference & 26th CADFEM Users´ Meeting
Synopsis
New engineNew engine
CAE assessment of
critical components (crankshaft, crankcase, conrod, ...)
CAE assessment of
critical components (crankshaft, crankcase, conrod, ...)
Combined use of different
tools
Combined use of different
tools
Central role of ANSYS/Workbench
Central role of ANSYS/Workbench
Load/stress TF computation
Load/stress TF computation
� Both linear and nonlinear models� Inertia relief� Compatiblity with other SW by
dummy outline branches
� Both linear and nonlinear models� Inertia relief� Compatiblity with other SW by
dummy outline branches
Design soundness proved by ensuing durability analysisDesign soundness proved by ensuing durability analysis
Thank you for your patience!