Optimization Methodology for Continuous Heterogeneous Structures: A Preliminary Design of an Engine Mounting Bracket

A numerical methodology is presented which is based on Topology Optimization (TO) approach for designing continuous heterogeneous structures. This method is then exploited to reduce weight and to increase stiffness in mechanical components. Useful guidelines for the evaluation of equivalent material properties of metallic cellular structures are discussed, and they are applied for the optimization process of an engine mounting bracket under realistic loading and boundary conditions. The outcome of TO, which is related to the material density distribution into the design space, is critically reviewed for the definition of bulk, lattice and void regions within the component.

Influence of Boundary Conditions on the Simulation of a Diamond-Type Lattice Structure: A Preliminary Study

Emergent additive manufacturing processes allow the use of metallic porous structures in various industrial applications. Because these structures comprise a large number of ordered unit cells, their design using conventional modeling approaches, such as finite elements, becomes a real challenge. A homogenization technique, in which the lattice structure is simulated as a fully dense volume having equivalent material properties, can then be employed. To determine these equivalent material properties, numerical simulations can be performed on a single unit cell of the lattice structure. However, a critical aspect to consider is the boundary conditions applied to the external faces of the unit cell. In the literature, different types of boundary conditions are used, but a comparative study is definitely lacking. In this publication, a diamond-type unit cell is studied in compression by applying different boundary conditions. If the porous structure’s boundaries are free to deform, then the periodic boundary condition is found to be the most representative, but constraint equations must be introduced in the model. If, instead, the porous structure is inserted in a rigid enclosure, it is then better to use frictionless boundary conditions. These preliminary results remain to be validated for other types of unit cells loaded beyond the yield limit of the material.