Bulk Elements

The bulk element is intended as a sort of NASTRAN's CELAS card, that can be used to apply a stiffness term on an arbitrary degree of freedom. Extensions are planned to different kind of elements. The syntax of the bulk element is:

    <normal_arglist> ::= <bulk_type> , <bulk_arglist>

At present only the stiffness spring type is available.

Stiffness spring

    <bulk_type> ::= stiffness spring
    <bulk_arglist> ::= (node_dof) <dof> ,
                       (drive_caller) <stiffness_drive>

The equation related to the desired dof of the linked node is added a contribution based on the value of the desired degree of freedom (even the derivative can be used) multiplied times the stiffness.

Note: this family of elements has been partially superseded by the genel elements, which allow more generality.