Use of Lattice Structures in Topological Optimization – Case Study: PLT-2 TIR Mission Space Telescope Frame

In the engineering sector, for some years now, it has been common to look for the best shape of a structure in terms of high mechanical performance. To do this, it is used what is commonly called optimization, that is a process through which a certain analysis software implements certain parameters set by the user and calculates, with regard to these constraints, the optimal shape of the structure considered, reorganizing the distribution of the material. Aim of this thesis is to apply the optimization criteria to the mechanical frame of a space telescope. The initial geometry of PLATiNO Space Telescope, used for a preliminary feasibility study, has been used as case study with the objective to identify an optimized design solution in term of minimum mass and maximum stiffness (i.e.: maximize resonant frequencies). The design process can summarized in the following steps: •??Analyse the original design to identify its structural performances (stress levels under the design static load and resonant frequencies); these performances have been used as baseline to assess the behaviour of the optimized design; •??Identify a working volume, the design space, that is the volume that the optimization tool can use to calculate the optimized geometry; verify the performance of the obtained solution and implement changes to reach the solution as much as possible. These changes consist in the introduction of manufacturing constraints to take into account the production process too; •??Fill the identified geometry with different type of lattice; optimization software identifies the best lattice solution, through the insertion of constraints and shape controls; •??Design the external ply to fully connect the lattice structure with the non-design space; structural performances of the optimized solution have been analysed and compared with the baseline to identify improvements; •??Find a way to transfer the optimized two-dimensional lattice geometry to a three-dimensional CAD or STL to manage additive manufacturing process. The design activities have been carried out by the use of software tools from Altair HyperWorks 2020 suite: •??HyperMesh, a high-fidelity finite element modeling tool (a so called pre-post tool); •??Optistruct, an optimization-enabled structural FEM solver; •??HyperView, a comprehensive CAE Post-processing and Engineering Data Visualization and from Altair Inspire 2020, that allows geometry creation and modification, as well as simplified FEM analysis. All the activities relevant to this thesis, have been carried out in collaboration with personnel from Electronic Division of Leonardo S.p.A. and with the support of Altair staff.