ansys mechanical advanced contact fasteners -...
TRANSCRIPT
© 2011 ANSYS, Inc. February 17, 20121
Customer Training MaterialCustomer Training MaterialCustomer Training Material
14. 0 Release
ANSYS MechanicalAdvanced Contact & Fasteners
Workshop 2CContact with Friction
© 2011 ANSYS, Inc. February 17, 20122
Customer Training MaterialCustomer Training MaterialCustomer Training MaterialWorkshop 2C: Contact with Friction Goal• Create contact pairs between three parts (piston, cylinder and seal).
• Run 2 load step analysis to simulate assembly of the three parts together.
• Post Process force along axis to assembly parts.
Model Description• 2D Axisymmetric• Piston is constrained from movement.• Cylinder is displaced to simulate assembly• Materials:– Steel for Piston and Cylinder– Elastomer for O‐Ring
• 1st load reconciles interference between piston and inside diameter of O‐ring
• 2nd load step slides cylinder onto piston‐O‐ring subassembly.
Piston
Cylinder
O-ring
© 2011 ANSYS, Inc. February 17, 20123
Customer Training MaterialCustomer Training MaterialCustomer Training Material… Workshop 2C: Contact with FrictionSteps to Follow:
Restore Archive… browse for file “W2c_friction.wbpz”
Save as • File name: “WS2c‐friction”• Save as type: Workbench Project Files (*.wbpj)
© 2011 ANSYS, Inc. February 17, 20124
Customer Training MaterialCustomer Training MaterialCustomer Training Material
The project Schematic should look like the picture to the right. • Highlight the Engineering Data Cell and open by clicking on the
Right Mouse Button (RMB)=>Edit to verify the predefined material properties – elastomer and Structural Steel
• Verify that the units are in Metric(Tonne,mm,…) system. If not, fix this by clicking on…
– Utility Menu=>Units=>Metric(Tonne, mm,…)
… Workshop 2C: Contact with Friction
© 2011 ANSYS, Inc. February 17, 20125
Customer Training MaterialCustomer Training MaterialCustomer Training Material
Return to the project schematic page
Double click (or RMB=>Edit…) on the Model Cell to open a Mechanical Session
… Workshop 2C: Contact with Friction
© 2011 ANSYS, Inc. February 17, 20126
Customer Training MaterialCustomer Training MaterialCustomer Training Material
Once inside the Mechanical application, verify the working unit system• “Unit > Metric (mm,kg,N,s,mV,mA)”
The piston‐cylinder assembly is already set up as a 2D axisymmetric model with the necessary boundary conditions and loads. It remains to define the contact pairs between the parts, set up the solution control analysis settings, run the solution and post process the results.
Expand each folder in the project tree to become familiar with the model and to confirm material assignments for each part, boundary conditions, loads and Analysis Settings.
… Workshop 2C: Contact with Friction
© 2011 ANSYS, Inc. February 17, 20127
Customer Training MaterialCustomer Training MaterialCustomer Training Material
Note: Auto contact detection did not create adequate contact relationships for this model. There is only one bonded contact pair created by default and it is insufficient for representing the assembly.
… Workshop 2C: Contact with Friction
© 2011 ANSYS, Inc. February 17, 20128
Customer Training MaterialCustomer Training MaterialCustomer Training Material… Workshop 2C: Contact with Friction
• Target definition should include the three surfaces on the piston side as shown. Contact should be on the o‐Ring side (2 edges)
• Change Type to Frictional– Friction Coefficient = 0.2
• Switch behavior to Asymmetric
• Normal Stiffness = 0.1 • Updated stiffness each iteration
• Pinball Radius = 2mm
• Redefine the O-ring To Piston contact region as follows:
target
© 2011 ANSYS, Inc. February 17, 20129
Customer Training MaterialCustomer Training MaterialCustomer Training Material
Target
• Insert an additional manual contact region between O‐ring and Cylinder wall by highlighting Contact branch and RMB>Insert>Manual Contact.
• Defined this new region with specifications below.Contact
… Workshop 2C: Contact with Friction
© 2011 ANSYS, Inc. February 17, 201210
Customer Training MaterialCustomer Training MaterialCustomer Training Material
Confirm the Analysis Settings • Large deflection is turned On• There are two load steps with different Auto Time Stepping specifications
… Workshop 2C: Contact with Friction
© 2011 ANSYS, Inc. February 17, 201211
Customer Training MaterialCustomer Training MaterialCustomer Training Material
Confirm the displacement load of 10mm is applied to the cylinder at load step 2.
… Workshop 2C: Contact with Friction
© 2011 ANSYS, Inc. February 17, 201212
Customer Training MaterialCustomer Training MaterialCustomer Training Material
Execute the solve. • After many iterations and a few bisections, the solution converges.
… Workshop 2C: Contact with Friction
© 2011 ANSYS, Inc. February 17, 201213
Customer Training MaterialCustomer Training MaterialCustomer Training Material
Review the Total Deformation results.• Change the contour bar to clarify the deformation of the O‐ring geometry• Animate the result
… Workshop 2C: Contact with Friction
© 2011 ANSYS, Inc. February 17, 201214
Customer Training MaterialCustomer Training MaterialCustomer Training Material
Highlight Solution Branch and RMB>Insert>Contact Tool• Insert and post process contact status, pressure, frictional stress and penetration
• After reviewing results, Re‐Save this Project for use later in Workshop 3B
… Workshop 2C: Contact with Friction