Thesis Defense - Barış Vatansever (MSME)

Barış Vatansever – M.Sc. in Mechanical Engineering

Assoc. Prof. Polat Şendur – Advisor

Dr. Aydın Özcan – Co-advisor

Date: 28.11.2024

Time: 11.00

Location: AB4 428 Seminar Room

“Development of Novel Metaporous Structure at Low-Mid Frequency for Airborne Compressor Noise of an Electrical Vehicle”

Assoc. Prof. Polat Şendur, Özyeğin University

Assist. Prof. Ramazan Ünal, Özyeğin University

Prof. Çetin Yılmaz, Boğaziçi University

Abstract:

Metamaterials have gained increasing attention as a way of absorbing noise to achieve improved acoustic performance on vehicles, and thanks to their novel functionalities compared to traditional designs, these structures are employed by many automotive companies as noise-reduction solutions for engineering applications. One of the key challenges for automotive original equipment manufacturers (OEMs) in the noise, vibration, and harshness (NVH) development process is absorption performance in the frequency range of 400 Hz to 800 Hz. Although sound engineers use porous polyurethane in these frequency ranges, the absorption performance of these designs is limited to meeting increasing customer expectations. Managing airborne noise in vehicles is particularly challenging in the low frequency spectrum, where Helmholtz resonators are widely used. The main purpose of this study is to develop a meta-porous sound barrier by incorporating a Helmholtz resonator, effective in the low to mid-frequency range of the spectrum. For this purpose, a frequency domain simulation was carried out to obtain the absorption coefficient, analyze frequency-dependent effects, and identify critical frequencies in vehicle acoustics. Furthermore, local resonance effects to prevent acoustic waves were investigated and design parameters of meta-structure were analyzed using a multi-physics-based simulation model. These results were validated experimentally using an acoustic impedance tube. The methodology is demonstrated in a battery electric vehicle (BEV) to improve airborne compressor noise during engine idling. The optimum design parameters were determined using the Taguchi design method. Finally, the performance of developed meta-porous material was validated through vehicle-level tests, with results showing an improvement of 3 dB(A).

Bio:

Barış Vatansever obtained his Bachelor of Science in Mechanical Engineering from Uludağ University in 2019, with a focus on acoustics, vibration, computational fluid dynamics (CFD), and the finite element method (FEM). His undergraduate graduation project involved the design and optimization of a multi-element cross-sectional airplane wing for transonic speeds, carried out in collaboration with Turkish Aerospace Industries.

After graduation, he pursued a Master’s degree in Mechanical Engineering at Özyeğin University under the supervision of Assoc. Prof. Polat Sendur. During his MSc program, he contributed to various research projects at the ÖzÜ Vibration and Acoustics Laboratory and the Acoustic Semi-Anechoic Room at TOFAŞ. Alongside his academic endeavors, he worked as an NVH (Noise, Vibration, and Harshness) Test Specialist, tackling insulation and global NVH challenges through a collaborative partnership between Özyeğin University and TOFAŞ. His research interests lie in acoustic material characterization, vehicle NVH diagnostics, vibration and acoustics, sound-package systems, CAE, and the design and optimization of metamaterials.