Thesis Defense - Mirhan Özdemir (MSME)

Mirhan Özdemir – M.Sc. Mechanical Engineering

Asst. Prof. Polat Şendur – Advisor

Date: 05.08.2022

Time: : 14:00-15:00

Location: AB1 231

OPTIMIZATION OF TPMS LATTICE STRUCTURES VIA HYBRIDIZATION AND GRADING OF THE LATTICE MORPHOLOGIES

Thesis Committee:

Asst. Prof. Polat  Şendur, Özyeğin University

Assoc. Prof.  G. Güven Yapıcı, Özyeğin University

Assoc.  Prof.  Güllü Kızıltaş Şendur, Sabancı University

Abstract:

Owing to its excellent mechanical properties, triply periodic minimum surfaces (TPMS) lattice structures have recently gained more interest in engineering applications. The superior properties of these structures make it easier to achieve engineering design goals such as strength and weight. Thanks to recent developments in additive manufacturing, the fabrication of the lattices are easier compared to the traditional methods. Therefore, their usage in the designs is more popular in recent applications. However, technological advancements compel the designer to enhance the traditional TPMS design qualities. This thesis covers two approaches to enhance the design’s mechanical performance by infilling the design domain with the optimal lattice design parameters. Initially, homogenization-based topology (HMTO) and free-size optimization-based graded lattice generation (FOGLG) methods are studied to obtain optimum lattice thickness distribution. The optimization methods are conducted for the modal characterization of a sandwiched structure. In the second study, a new hybrid optimization framework in which genetic algorithm (GA) and homogenization-based topology optimization are used to enhance the mechanical performance of the design. The method initially selects suitable lattice mythologies via GA and then grades them by topology optimization. In addition, the graded multi-morphology design is reconstructed by a novel blending algorithm in the study.

The results of the studies clearly show that the proposed methods enable the designer to improve the mechanical performance of the designs. The proposed methods are also experimentally validated to assess their accuracy.

Bio: 

Mirhan Ozdemir graduated from Middle East Technical University in Mechanical Engineering in 2020. He mainly took courses related to dynamic analysis, vibration, acoustic, and finite element method (FEM) in the B.Sc program. His graduation project was related to the design and mathematical model of a vibration absorber for a cup holder. After graduation, he started the M.Sc Program in Mechanical Engineering at Özyeğin University under Dr. Polat Sendur. He did different studies by participating in studies in the Vibration and Acoustics Laboratory in order to pursue his research. He worked as a long-term intern in the field of additive manufacturing within the scope of the cooperation between Özyeğin University and GE Aviation TTC. His main research interests consist of modal characterization, dynamic analysis, vibration and acoustic, 3D printing, TPMS lattice structure, and optimization.