It was conducted on Sunday ,7/9/2025, in Dr. Ihsan Yahya hall the discussion of the PhD Dissertation of the student Mohammed Abdulaal Kadhim, which is tagged:
” Enhancement of Crossed-Axes Helical Gear Drive Performance Using Modified Teeth Profiles”.
The discussion committee consisted of names listed below:
1- Prof. Dr. Fathi Abdul Sahib Alshamma (Chairman)
2- Prof. Dr. Majid Habeeb Faidh-Allah (Member)
3- Prof. Dr. Basim Ajeel Abass (Member)
4- Asst. Prof. Dr. Ibtehal Abbas Sadiq (Member)
5- Asst. Prof. Dr. Hamza A. Al-Tameemi (Member)
6- Prof. Dr. Mohammad Q. Abdullah (Supervisor)
This study investigated crossed helical gears with modified tooth profiles (hybrid symmetric and hybrid asymmetric) to improve contact stress, bending stress, heat generation, vibration, and noise. Numerical simulations using Finite Element Analysis (ANSYS 22 R1) and experimental tests on Aluminum 7075-T6 gears were conducted to evaluate the performance of standard and modified gear teeth under various operating conditions. Custom gear tooth profiles were generated using QuickBasic integrated with SolidWorks 2023.
Key Findings:
- Hybrid asymmetric teeth significantly reduce temperature (−25%) and thermal stress (−30%) and improve vibration stability at high speeds.
- Hybrid symmetric teeth are most effective at medium speeds, enhancing vibration stability by up to ~70% (x-direction) and ~62% (y-direction).
- Modified tooth flanks increase contact area, improving load distribution and reducing noise.
- Overall, hybrid asymmetric teeth outperform symmetric and standard gears in thermal, mechanical, and dynamic performance.
Recommendations:
- Use hybrid asymmetric tooth profiles for high-speed applications to optimize strength, thermal performance, and dynamic stability.
- Employ hybrid symmetric profiles for medium-speed applications where vibration reduction is critical.
- Apply Aluminum 7075-T6 for gear fabrication to enhance thermal and mechanical performance.
- Integrate numerical simulations with experimental testing to validate gear designs.
- Adopt modified tooth flanks (concave-convex) and custom profiles to maximize contact area and reduce noise and vibration.
committee, the researcher received a rating of (Excellent).
