It was conducted on Monday, 1/9/2025, in the Dr. Munther Al-Droubi Hall in the mechanical Engineering Department. the discussion of the master’s thesis of the student Ali Sadeq Jaafar, which is tagged:
” Influence of varying aircraft wing ribs number on structural strength and dynamic response under certain flight conditions “.
The discussion committee consisted of names listed below:
1- Prof. Dr. Mohammad Qaim Abdullah (Chairman)
2- Asst. Prof. Dr. Anmar Hamid Ali (Member)
3 Asst. Prof. Dr. Tariq Mohammad Hammza (Member)
4- Asst. Prof. Dr. Nassear Rasheid Hmoad (Supervisor)
This thesis investigates the enhancement of structural strength and reduction of vibrational behavior in unmanned aerial vehicle (UAV) wings through rib design optimization. The study examines the effects of four critical parameters angle of attack, airflow velocity, air density, and the number of internal ribs on both the aerodynamic characteristics (lift and drag) and the structural dynamic response (stress, strain, and natural frequencies). A comprehensive methodology was employed, combining theoretical derivations, numerical simulations using ANSYS (CFD, static structural, and modal analyses), and experimental validation through modal and frequency response tests.
Key Results:
- Increasing the number of ribs reduced stress and strain by about 30% and increased the sixth natural frequency by more than 120%, with diminishing benefits beyond 13 ribs.
- Higher airflow velocity (9 → 17 m/s) amplified stress by 85% and strain by 93%.
- Higher air density (0.365 → 1.225 kg/m³) increased stress by 85% and strain by 60%.
- Angle of attack showed nonlinear behavior: maximum stress (~35%) occurred at 10°, then decreased at 15°.
- Close agreement between numerical and experimental results (≈ 7.5% difference) validated the simulation models.
Recommendations:
- Adopt optimized rib configurations with no more than 13 ribs for the best balance between weight and stiffness.
- Consider the effects of airflow velocity and air density in operating conditions to avoid excessive dynamic loads.
- Use an optimal angle of attack below 10° to minimize stresses.
- Apply the integrated methodology (theoretical + numerical + experimental) to develop stiffer, more efficient UAV wings, especially under resource-limited manufacturing contexts.
After the scientific discussion by the members of the discussion committee, the researcher received a rating of (Very good).
