Learning Forum

[SJ123]

1. How to decide which body must be made contact and target while defining a contact in Ansys?

2. What are symmetric and asymmetric contacts?

3. What is the small sliding assumption in Ansys?

 

 

[peteroznewman]

1.  Read this.

2. Symmetric means putting two sets of contact elements on the two surfaces and each side has both Target and Contact elements.  Asymmetric means putting just one set of contact elements on the two surfaces and you specify which side gets which type of element.

3. Frictional and frictionless contact works over large sliding distances, but that requires extra computation that increases the solution time. If you know that the two surfaces cannot slide very far due to the constraints on the model, then you can tell the solver that by invoking the small sliding assumption. The solver will not do the extra computation to check for changes in position between the two sides and the solution will take less time.

[SJ123]

 4. Bonded and no separation contacts are linear contacts while frictional and frictionless contacts are non-linear contacts. What is meant by linearity and non-linearity of contacts?

[peteroznewman]

A model with a linear contact can be solved in a single matrix inversion operation (if the materials are linear).

A model with frictional contact requires the matrix inversion operation to be iterated until the convergence tolerance is met.

Modal Analysis, Harmonic Response Analysis and Eigenvalue Buckling are linear methods and so require linear models.