Thesis Defense - Ahmad Abbasi (MSME)

Ahmad Abbasi - M.Sc.

Asst.Prof. Polat Şendur – Advisor

Date: 31.12.2020

Time: 11:00

Location: This meeting will be held ONLINE. Please send an e-mail to gizem.bakir@ozyegin.edu.tr in order to participate in this defense.

Development of Novel Methodologies for Rotational Dynamics Applications

Thesis Committee:

Asst.Prof. Polat Şendur , Özyeğin University

Asst.Prof. Göktürk Poyrazoğlu, Özyeğin University

Asst.Prof. Birkan Tunç, Yeditepe University

Abstract:

     In this thesis, a novel methodology is proposed to determine the parameters of a rotating unbalance in a rotor-bearing system. For that purpose, the weighted sum of the squared difference between the analytical and predicted unbalance response due to rotational unbalance, is considered as the objective function. A hybrid algorithm integrating Salp Swarm algorithm (SSA) and Nelder–Mead algorithms (NM) is presented for detecting unbalance magnitude and phase as the unbalance parameters. Parameters of the aforementioned optimization algorithm are determined systematically using the Taguchi design of experiments method. The efficiency of the proposed method is compared with various optimization algorithms in the literature. To account for the variability and to mimic the actual experiment conditions, noise with different levels is added to the simulation results. The results show the superiority of the proposed hybrid algorithm (SSA-NM) in terms of the accuracy of the unbalance parameters and computational efficiency.

     In the last part of this thesis, the application of metaheuristic algorithm optimization on two engineering problems examined. The first one is related to the maximization of fatigue life of Tapered Roller Bearing (TRB). A boosted Harris Hawks algorithm is proposed to enhance the performance of TRB. In the second one, the performance and efficiency of Microchannel Heat Sink (MCHS) is improved by Harris Hawks optimization algorithm. In this problem, the entropy generation of MCHS is formulated as an objective function for the optimization problem and the Harris Hawks try to minimize the entropy generation, which is an undesirable factor for MCHS. Also, several fluids as coolant are considered for the MCHS that the ammonia has the best performance in comparison to the others.

Bio: 

     Ahmad Abbasi earned his B.Sc. degree in mechanical engineering. After graduation, he started his career in the mechanical department of Panel Sanat Company. He has been pursuing his M.Sc. degree in mechanical engineering at Ozyegin university since February 2019, under the supervision of Dr. Polat Şendur. He works on several topics including vibration in rotary machines, Tapared Roller Bearing design, and crack detection on mechanical systems in Dr. Polat Şendur’s vibration and acoustic laboratory. He is also interested in Micro-channel heat sink design and metaheuristic optimization algorithms and control theory.