Maximizing the Stiffness of the Rib Plastic Part Example

This example shows the usage of the rib pattern restriction using a plastic injection part.

See Also
About Checking the Quality of the Optimization Result
  1. Define input data and Design Variables: 
    FEM_INPUT
  ID_NAME  = INPUT_FILE
  FILE     = topo_ribs_plastic.inp
END_

DV_TOPO
  ID_NAME  = globalDesignArea
  EL_GROUP = globalDesignRegion
END_
  2. Define additional groups for nondesign elements: 
    GROUP_DEF
  ID_NAME = designAreaNonFrozen
  TYPE    = ELEM
  FORMAT  = LIST_SUBTRACT_GROUP
  LIST_BEGIN
globalDesignRegion, globalFrozenRegion
END_
  3. To use the compliance in the objective, define a Design Response (DRESP) as follows: 
    DRESP
  ID_NAME         = TASK_STIFFNESS
  DEF_TYPE        = SYSTEM
  TYPE            = ENERGY_STIFF_MEASURE
  EL_GROUP        = ALL_ELEMENTS
  GROUP_OPER      = SUM
END_
  4. Define the Objective Function (OBJ_FUNC) as follows: 
    OBJ_FUNC
  ID_NAME         = MY_OBJECTIVE
  DRESP           = TASK_STIFFNESS
  TARGET          = MIN
END_
  5. To define the mass constraints, do the following:
    1. Define the corresponding design response: 
      DRESP
  ID_NAME         = TASK_MASS
  DEF_TYPE        = SYSTEM
  TYPE            = WEIGHT
  EL_GROUP        = globalDesignRegion
  GROUP_OPER      = SUM
END_
    2. Define the constraints (CONSTRAINT): 
      CONSTRAINT
  ID_NAME         = TASK_MASS_CONSTRAINT
  DRESP           = TASK_MASS
  MAGNITUDE       = REL
  LE_VALUE        = 0.4
END_
  6. Define the rib pattern and frozen DVCONs: 
    DVCON_TOPO
  ID_NAME         = PreservedRegion1
  CHECK_TYPE      = FROZEN
  EL_GROUP        = globalFrozenRegion
END_

DVCON_TOPO
  ID_NAME         = RibControl1
  CHECK_TYPE      = RIB_DESIGN
  EL_GROUP        = designAreaNonFrozen
  CHECK_GROUP     = designAreaNonFrozen
  RIB_THICKNESS   = 0.015
  RIB_DISTANCE    = 0.025
  RIB_DIRECTION   = 0.000419, -0.000034, -0.000907
  RIB_CS          = CS_0
END_
  7. Reference the Objective Function, Design Variables and Constraint as well as DVCON in the OPTIMIZE command: 
    OPTIMIZE
  ID_NAME         = Objective
  STRATEGY        = TOPO_SENSITIVITY
  DV              = globalDesignArea
  OBJ_FUNC        = MY_OBJECTIVE
  CONSTRAINT      = TASK_MASS_CONSTRAINT
  DVCON           = PreservedRegion1
  DVCON           = RibControl1
END_

The optimization result looks as follows:

Using a standard casting restriction instead of the rib feature, more materials are accumulated in few areas resulting in a bulkier structure: