Contact

The fully automated contact analysis in LS-DYNA is easy to use, robust and validated.  It uses constraint and penalty methods to satisfy contact conditions


AVI 61a 2.25MB		 Segment based automatic contact is now available for parallel processing in Version 970 of MPP LS-DYNA.  The basis of this contact algorithm was developed in the mid 80's by Professor Belytschko and his co-workers as the "Pinball Contact Algorithm".  Segment based contact has some advantages over the "Standard" node to segment contact as can be seen from the example below.


AVI 61B 2.03MB

 In this example of segment based automatic contact one brick element defines each block.  The ball impacts the stack of bricks which are acted on by a large gravitational force.   In the initial configuration, the nodes defining the blocks are not in contact with the contact segments. 
Constraint and penalty techniques have worked extremely well over the past 20 years in numerous applications such as full-car crashworthiness studies, system/component analysis and occupant safety analyses.  Coupled thermo-mechanical contact can also be handled.  Over 25 different contact options are available.  These options primarily treat contact of deformable to deformable bodies, single surface contact in deformable bodies and deformable or rigid to rigid body contact.  Multiple definitions of contact surfaces are possible, for example:
  • Single Surface Contact
  • Contact with Rigid Walls
  • Edge-Edge Contact
  • Beam-Beam Contact
  • Eroding Contact
  • Contact with CAD Surfaces
  • Tied Surfaces
  • 2D Contact
  • Shell Edges Tied to Shell Surfaces
  • Resultant Force Contact
  • Fluid-Structure Interfaces
  • Pinball Contact

A special option exists for treating contact between a rigid surface (usually defined as an analytical surface) and a deformable structure.  One example of an application is in metal forming, where the punch and die surface geometries can be input as IGES- or VDA-surfaces which are assumed to be rigid.  Another example is in occupant modeling, where the rigid-body occupant dummy (made up of geometric surfaces) contacts deformable structures such as airbags and instrument panels.

Friction Models:

  • Static and Dynamic Coulomb
  • Viscous Friction
  • Pressure Dependent Friction
  • User-Defined Friction Models

Contact input is made easier by allowing contact to be defined by part identifiers, by boxes or by simply including the entire model in the contact definition