3D topology optimization of a tall tower considering soil flexibility

Resumo

This paper investigates the effect of soil flexibility on the solution obtained by topology optimization
of a tall tower in continuous contact with the soil throughout its base. The tower is modeled with classical finite
elements, while the soil is modeled with boundary elements, which is more adequate to deal with unbounded soil
domains. Coupling between the tower and soil is established by imposing equilibrium and continuity conditions
at the soil–tower interface. The paper shows strategies for solving the different orders and types of elements at
that interface. The final equilibrium equation resulting from the coupling scheme contains the linear superposition
of the tower and soil stiffness matrices, and connects nodal forces and displacements as in classical finite element
assembly schemes. The Bi-Directional Evolutionary Structural Optimization method (BESO) is chosen to solve
the compliance minimization problem under prescribed volume constraints. The solutions for the tower resting
on the ground surface and for resting on rigid supports are compared, and the results show that both the optimal
topology of the tower and the compliance that is achievable are significantly affected by the flexibility of the soil.