Katmanlı üretilen tpms kafes yapılarının dinamik karakterizasyonu ve optimizasyonu

Additive manufacturing (AM) has opened new avenues for the manufacturing of structures to achieve challenging engineering tasks. Triply periodic minimal surface (TPMS) lattices, a unique example of such structures, exhibits many attractive properties, such as high stiffness-to-weight ratio and impact characteristics. This study aimed to focus on the dynamic characterization and optimization of additively manufactured TPMS lattice structures. In parallel with this purpose, five main research topics are examined in this thesis dissertation. First, the frequency response predictions of a finite element-based model of the gyroid sandwich structure were first validated against the modal testing in terms of its natural frequencies and mode shapes. Subsequently, the effects of the plate and gyroid wall thickness on the dynamic characteristics of the structure were investigated by varying these across their expected limit ranges as part of a parametric study using the validated finite element model. Thereafter, modal characterization of additively manufactured TPMS structures is studied using five different modeling methods for a beam, which is composed of primitive, diamond, IWP, and gyroid unit cells. These methods include (1) shell modeling, (2) solid modeling, (3) homogenization, (4) super-element modeling, and (5) voxelization. The modal characterization is performed by using modal analysis, and the aforementioned models are compared in terms of their computational efficiency and accuracy. As a follow up study, a new design methodology using an integrated TO process is proposed for the development of FGL structures. For that purpose, a material penalization formula derived by the application of homogenization is integrated into the TO process. As a result, relative densities of the TO are mapped directly and radial basis functions (RBFs) are then used to create the geometry of the FGLs efficiently. The proposed methodology is demonstrated on a case study, where a cantilever beam with a desired bandgap characteristic is designed. Moreover, a novel Free-size Optimization based Graded Lattice Generation (FOGLG) method, that generates the functionally graded lattice structures using free-size optimization, is proposed. In addition, the reconstruction method suitable for the construction of 3D FGL structures using AM is presented. Finally, a hybrid optimization framework is presented to jointly use different surface-based lattices into a design domain to improve the mechanical performance of the lattice structures. It was concluded that newly proposed simulation and optimization techniques play a crucial role in improving the dynamic characteristics of additively manufactured lattice structures and the ever-challenging design requirements can be satisfied using the modelling guidelines proposed in this thesis.