DVCON_SHAPE

Defines restrictions of the design variables in shape optimization.

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Restrictions (DVCON_SHAPE)

ID_NAME

= <name_of_dvcon_shape>

Name of the DVCON_SHAPE definition.

ND_GROUP

= <name_of_node_group>

Name of the node group which is valid for the restriction. The node group should be a subset of the nodes of the MESH_SMOOTH command.

CHECK_GROW

= <grow_value>

Maximum grow value (referring to the initial design).

(grow_value¯≥0)

CHECK_SHRINK

= <shrink_value>

Maximum shrink value (referring to the initial design).

(shrink_value¯≥0)

CHECK_MIN_MEM

= <radius>

Minimum member size: orthogonal to the surface material of minimum 2*radius thickness must remain.

CHECK_MAX_MEM

= <radius>

Maximum member size: orthogonal to the surface material of maximum 2*radius thickness must remain.

CHECK_SOLID

= <solid_name>

Name of the solid which is checked for penetration.

CHECK_ELGR

= <name_of_element_group>

Name of the element group which is checked for penetration.

CHECK_NDGR

=<member_size_check_node_group>

Name of surface node group for check of member size.

CHECK_BC

= YES

= NO

Accepts (YES) or ignores (NO) the nodal fixations read by the FE interface as constraints on the selected node group.

CHECK_DOF

= <cs_name>, <dof1>,<dof2>,<dof3>

(<dof*> = FIX, FREE)

The displacement in the corresponding coordinate direction in the referenced coordinate system is constrained (FIX) or allowed (FREE).

CHECK_SLIDE

= <link_shape_name>

Assign a slide surface defined with a LINK_SHAPE command.

CHECK_LINK

= <link_shape_name>

Assign a LINK_SHAPE definition.

FEASIBLE_START

= YES

= NO

premise feasible node group (YES) or accept infeasible node group (NO) in the start model.

TOLERANCE

= <tolerance_value>

Tolerance value for member size check (absolute positive real value).

AGGREGATION_PARAMETER

=<real>

This is only evaluated for the demold manufacturing in sensitivity based shape optimization. The parameter <p> should be > 1. Default value is 3.

AGGREGATION_NUM_CONSTRAINTS

=<integer>

This is only evaluated for the demold manufacturing in sensitivity based shape optimization. This parameter determines how many (optimization) constraints are created. Use -1 to disable constraint aggregation. This results in the creation of as many constraints as possible - namely one constraint for each face in the group specified by ND_GROUP. Use 1 (default) to activate constraint aggregation.

RESTRICT_ON_SURFACE

= YES

= NO

Restrict the nodes specified by ND_GROUP to move only tangential to their normal direction. This can be especially useful for variation areas - mesh smooth areas not part of the design area.

Remarks

  1. CHECK_SOLID (up to 6 operators with CHECK_SOLID are permitted) is the name of a solid already defined (SOLID). All nodes are checked for penetrating the solid (restricted solid) and against leaving the solid area (variational solid), respectively.
  2. CHECK_ELGR (up to 6 operators with CHECK_ELGR are permitted) is the name of an element group already defined. All nodes in the node group (ND_GROUP) are checked for penetrating the element group. Shell and element groups are admitted.
  3. CHECK_BC:
    • CHECK_BC=YES: The boundary conditions that are loaded with OPTIONS, READ_BC = ALL, are considered for the nodes of the node group.
    • CHECK_BC=NO: The BC entries are not considered.
  4. CHECK_DOF: Fixing the node coordinates named with FIX for the given coordinate system.
  5. CHECK_LINK: Identification name of a link condition (defined with LINK_SHAPE) which should be used for the node group.
  6. When several CHECK_* entries are specified in a DVCON_SHAPE definition, they are used in the following sequence: CHECK_GROW / CHECK_SHRINK, CHECK_MAX_MEM, CHECK_MIN_MEM, CHECK_SOLID, CHECK_ELGR, CHECK_BC, CHECK_DOF, CHECK_LINK. If there are conflicts in the sequence of the CHECK_* entries, the last entry overwrites the previous one. If there are no conflicts in the sequence of the CHECK_* entries, all the defined restrictions are considered.
  7. Apart from CHECK_SOLID and CHECK_ELGR entries (which can be used up to 6 times) only one entry of each other type is admitted in a DVCON_SHAPE definition. That means, e.g., that I cannot combine two CHECK_LINK entries in one DVCON_SHAPE definition but have to define two DVCON_SHAPE entries instead. On the other hand, one CHECK_LINK and CHECK_BC entry, for example, can be combined.

Examples

DVCON_SHAPE
 ID_NAME = my_dvcon_shape_01
 ND_GROUP = nd_side_a
 CHECK_DOF = csys1, FREE, FIX, FIX
 CHECK_GROW = 5.0
END_