Block Format Keyword Describes the Lagrange Multiplier interface TYPE7. multi usage impact interface between a main surface and a list of secondary nodes.


All limitations encountered with interfaces TYPE3 and TYPE5 are solved with this interface:
  • A node can be at the same time a secondary and a main node.
  • Each secondary node can impact each main segment; except if it is connected to this segment.
  • A node can impact on more than one segment.
  • A node can impact on the two sides, on the edges and on the corners of each segments.
  • Fast search algorithm without limitations. Time step is not reduced.
The main limitations are:
  • Friction models are not yet implemented
  • It is not compatible with any standard kinematic conditions
  • It is not compatible with SPMD parallel version


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grnd_IDs surf_IDm                
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Field Contents SI Unit Example
inter_ID Interface identifier

(Integer, maximum 10 digits)

inter_title Interface title

(Character, maximum 100 characters)

grnd_IDs Secondary nodes group identifier


surf_IDm Main surface identifier


Gapmin Minimum gap for impact activation


Bumult Sorting factor - used to speed up the sorting algorithm.

Default set to 0.20 (Real)



  1. The defined nodes must have non-zero mass.
  2. The Gapmin may be smaller than non-Lagrange interface type 7. It is used in order to determine if a secondary node is in contact or not.
  3. The default value for Bumult is automatically increased to 0.30 for models which have more than 1.5 million nodes and to 0.40 for models with more than 2.5 million of nodes.