Minimize Compliance for Linear Static Sensitivity-Based Optimization

The sensitivity-based bead optimization offers a large range of responses for static analysis. But note that the controller-based bead algorithm is often superior and amore effective in pure minimization of compliance designs. Of course, if you need more control of displacements of certain nodes within your model, you are better of using the sensitivity-based algorithm.

  1. To minimize the compliance of a shell structure the command structure is similar to the controller-based algorithm. Define a compliance design response and reference it in the objective function. 

    
DRESP
  ID_NAME    = dresp_compliance
  DEF_TYPE   = SYSTEM
  EL_GROUP   = ALL_ELEMENTS
  TYPE       = STRAIN_ENERGY
  GROUP_OPER = SUM
  LC_SET     = Static,1,All
END_

OBJ_FUNC
 ID_NAME =  min_compliance
 DRESP   = dresp_compliance
 TARGET  = MIN
END_

    A design response with the name "dresp_compliance" is defined for the first static load case.
  2. To define the design response, use GROUP_OPER = SUM over ALL_ELEMENTS which is also the correct definition because compliance must be equal to the outer work (force x displacement).
  3. Minimize the compliance design response in the object function with TARGET=MIN.

    Note: No constraint is required, but remember to add a DVCON_BEAD which constrains the nodes in positive and negative normal direction.