ANSYS Contact Modelling with ANSYS Mechanical Training Course

Contact Modelling with ANSYS Mechanical

Course Description

The interactions between components of an assembly are part of today’s simulation tasks. Contact in ANSYS Mechanical is a powerful tool and also the most common nonlinearity in structural mechanics simulations. The variety of possible settings of a contact region makes the topic of contact modelling often appear complex. However, using the Mechanical interface simplifies this process. In specifying the description of a contact region, the following questions are addressed in a logical manner: Have the correct surfaces been selected? What type of contact exists? How is the global stiffness behaviour of the design affected by the contact? Which contact algorithm is best for each contact region? How accurate is the calculated contact pressure? How much contact penetration is acceptable?

Who should attend?

Anyone who has or is studying for an engineering degree and needs to simulate the effect of nonlinear contact in their analyses.

Goal

To acquire comprehensive knowledge on how to simulate the interaction between components of an assembly through use of contact technology. To perform these simulations efficiently and robustly. To critically assess the results of the simulation, in order to ensure an accurate and dependable outcome.

Day 1:

Definition of contact areas and solver settings

Introduction to Contact Calculation

  • Performing a contact calculation (schematic)
  • Performing a contact calculation (in ANSYS Mechanical)
  • Discussion of concepts in contact calculation

Generation of connection groups and contact areas

  • Properties of the connection groups
  • Automatic grouping and searching (tolerance value)
  • Contacts between surface bodies
  • Consideration of the thickness of the surface bodies

Principles of nonlinear structural mechanics

  • Analysis Settings
  • Input and Output files
  • Newton – Raphson method and equilibrium theorems
  • Intermediate steps and automatic time step control
  • Force control vs. displacement control

Contact vs. Target

  • Contact behavior
  • Symmetric vs. Asymmetric contact

Day 2:

Contacts and their properties

Elements for contact calculation

Element types

Contact types

Real constants and key options

Modification of properties using command objects

Remote points and pilot nodes

Evaluation of Results

  • Results: averaged vs. unaveraged
  • Evaluation of results using the contact tool
    • Contact status
    • Penetration
    • Pressure
  • Connection between contact pressure, penetration and contact stiffness
  • Evaluation of results in symmetric vs. asymmetric contact areas
  • Evaluation of contact forces
    • Different extraction methods
  • Customized results
  • Tracking variables
  • Influence of meshing

Trimming the contact surface

  • Trim Tolerance
  • Use of HPC calculations

Contact type

  • Contact types and their properties
  • Linear and non-linear contact types
  • Influence of the initial condition and the pinball region

Detection methods

  • Contact at Gauss point
  • Contact at the node
  • Projection-based method

Pinball region

  • Settings
  • Preferences
  • Definition of the contact depth
  • Display the pinball region in the contact tool
  • Recommendations

Day 3:

Contact algorithms and convergence considerations

Contact algorithms (theoretical considerations)

  • Pure-penalty method
  • Lagrange method
  • Augmented Lagrange method

Contact stiffness

  • Convergence vs. Penetration
  • Determination of contact stiffness
  • Influence of element size
  • Settings
  • Update methods

Penetration

  • Penetration tolerance
  • Contact stiffness factor
  • Update contact stiffness

Convergence considerations

  • Rigid body movements
    • Reasons and possible ways of avoiding
  • Contact manager
    • Adjustment of the initial contact condition
    • Dealing with initial distances or initial penetrations
  • More convergence-enhancing measures
    • Numerical stabilization by weak springs
    • Contact damping

Bonded contact

  • MPC contact
    • Connecting components with MPC equations
    • Joining shells
    • Connecting bodies with different degrees of freedom
    • MPC background information
    • To avoid or deal with overconstraints
    • Remote points

Key terms:

Assemblies, nonlinear structural mechanics, contact stiffness, convergence, contact pressure

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