A User Programmable MicroSlip Feature

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A User Programmable Micro-Slip Feature

• Ulf Sellgren and Ulf Olofsson
• Machine Elements
• Royal Institute of Technology (KTH)
• Stockholm, Sweden

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Applied research
Bearing wear and perfor- mance
Railway dynamics and wear
Grinding machine performance
Cam - follower wear
Robotics
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Micro-slip

• Fretting fatigue
• Geotechnical engineering
• Damping and stiffness of connections
• Control engineering

Frictional load (N)
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Theoretical background

• Increasing frictional load and decreasing
  frictional load

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Implemented friction model

• Global element coefficient of friction

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ANSYS 5.0 contact/target approach
Open architecture ANSYS UPF
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Logic for non-classical ??definition
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2D sliding example

• Body 1 - red brass, body 2 - steel

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Non-cyclic sliding with asperity model
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Cyclic sliding - asperity model versus elastic
Coulomb model
el. Coul.
asperity
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Conclusions

• 1) A non-classical friction law based on asperity
  deformation has been introduced into ANSYS.
• 2) The relative difference in energy dissipation
  between the the elastic Coulomb friction law and
  the non-classical friction law is greater than
  reported experimental scatter.
• 3) At local level significant differences in
  friction force distribution are detected between
  the two friction models. These local effects can
  have a major impact on the system (macro)
  behavior.