Defining a Thickness Control for the Plate Model

To control the thickness of a model, either define a minimum member size control or a maximum member size control. The specified thickness must be at least twice the average element edge length. Undesirable conditions might appear for smaller values.

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In Other Guides
About Member Size Control
  1. For a minimum member size control, define a Design Variable Constraint (DVCON_TOPO) as follows: 
    DVCON_TOPO
  ID_NAME    = DVCON_MIN
  EL_GROUP   = ALL_ELEMENTS
  CHECK_TYPE = MIN_MEMBER
  THICKNESS  = 6.0
END_
  2. For a maximum member size control, define a Design Variable Constraint (DVCON_TOPO) as follows: 
    DVCON_TOPO
  ID_NAME    = DVCON_MAX
  EL_GROUP   = ALL_ELEMENTS
  CHECK_TYPE = MAX_MEMBER
  THICKNESS  = 6.0
  !DISTANCE   = 6.0          !Use this value for METHOD = LOCAL_VOLUME
  !METHOD     = LOCAL_VOLUME !Different MAX_MEMBER algorithm, default METHOD = FILTER
END_
  3. For plane symmetry, define a Design Variable Constraint (DVCON_TOPO) as follows: 
    CS_DEF
  ID_NAME    = CS_1
  CS_TYPE    = RECTANGULAR
  DEF_TYPE   = LOCAL
  CS_REF     = cs_0
  ORIGIN_123 = 50.0, 100.0, 0.0
END_

LINK_TOPO
  ID_NAME = PLANE_SYMMETRY
  TYPE    = PLANE_SYM, AXIS_1
  CS      = CS_1
END_

DVCON_TOPO
  ID_NAME    = DVCON_PLANE_SYMMETRY
  EL_GROUP   = ALL_ELEMENTS
  CHECK_TYPE = LINK_TOPO
  CHECK_LINK = PLANE_SYMMETRY
END_
  4. To activate the control, reference the Design Variable Constraint in the OPTIMIZE command: 
    OPTIMIZE
  ID_NAME    = MAXIMIZE_STIFFNESS
  DV         = DV_DESIGN_ELEM
  OBJ_FUNC   = USER_OBJ_FUNC
  !insert this line for minimum member size constraint
  DVCON      = DVCON_MIN
  !insert this line for maximum member size constraint
  DVCON      = DVCON_MAX
  DVCON      = DVCON_PLANE_SYMMETRY
  CONSTRAINT = VOLUME_CONSTRAINT
END_

Depending on the control, you can see different results:

Using the LOCAL_VOLUME setting for the MAX_MEMBER restriction, a different algorithm is used resulting in another optimization result: