Subsections

• Parts, Keyword Format Only

Element Topology

FEMGEN will generate a finite element mesh of nodes and geometric element types. These geometric element types are related to the DYNA3D element names via an element variant number. The element variant mappings for DYNA3D may be displayed by using the FEMGEN command 'UTILITY TABULATE FE DYNA', and these mappings are shown in table 2.1. In addition, the user can now set their own default DYNA3D element variants by defining them in a FEMGV resource file (see Chapter 1).

Element variants are assigned using the command 'MESHING TYPES part ELTYPE variantno'. The variant number is optional and the default is 1. It is also possible to specify an element variant by using its name directly, i.e. 'MESHING TYPES part SHELL'.

Eltype DYNA3D Element Variants

BE2 1 = B-S-BEAM 2 = H-L-BEAM 3 = TRUSS

TR3 1 = SHELL 2 = MEMBRANE

QU4 1 = SHELL 2 = MEMBRANE

PE6 1 = BRICK

HE8 1 = BRICK 2 = T-SHELL

P-EL 1 = P-MASS

 

The jacobian (or sense) of all elements is checked by the interface and corrected where necessary. The interface also re-numbers the elements according to the DYNA3D conventions. For models where one or more nodes lie outside the X-Y plane, the interface will not perform a jacobian check on TR3 or QU4 elements.

Element topology cards are generated for all elements in the model and grouped according to their generic type (Solid, Beam/Truss, Shell/Membrane, Thick Shell). The element topology section of the input file is preceded by the following cards:

*                                                                               
* SOLID ELEMENTS ...                                                            
*                                                                               
* BEAM ELEMENTS ...                                                             
*                                                                               
* SHELL AND MEMBRANE ELEMENTS ...                                               
*                                                                               
* THICK SHELL ELEMENTS ...                                                      
*

Point Masses and BE2 elements which have spring or damper type properties are output on mass cards and are preceded by the following comments:

*                                                                               
* SPRINGS, DAMPERS AND POINT MASSES ...                                                            
*

Parts, Keyword Format Only

DYNA3D input files written in the keyword format will contain parts definitions. All the elements having the same type and the same material and the same physical property will belong to the same part. However, if any contact definition uses beam elements, then a part will be created for each FEMGEN line containing beam elements. This is because the part number will be used in the contact definition.