Node-based or parameter free structural optimization is characterized through the definition of the optimization variables directly on the finite element model. This brings the advantage of a reduced modelling effort, because the simulation modell can also be used for the optimization. The designspace covers all shapes that can be represented by the chosen finite element model. In case of shape optimization, normal directions of the surface nodes are used as optimization variables. The tangential movement of the surface nodes does not affect the shape, but is considered to maintain a good quality of the mesh. Based on the same principle, also other parameters of the finite element model can be used as opimization variables, e.g. elemental thickness or element-wise fiber angles of reeinforced structures.
