The College of Engineering at the University of Baghdad held the public defense of the PhD dissertation submitted by Hussam Hussein Ali Majid Al-Mousawi, a PhD candidate in the Department of Mechanical Engineering. The dissertation was entitled:

“Experimental and Numerical Analysis of a Pylon for Below-Knee Amputation.”

The defense was held on Tuesday, June 2, 2026, in the Department of Mechanical Engineering, as part of the requirements for the PhD degree in Mechanical Engineering, Applied Mechanics specialization.

The defense committee consisted of:

• Prof. Dr. Mohammed Qasim Abdullah – University of Baghdad, College of Engineering — Chair.
• Prof. Dr. Fadhil Abbas Abdullah – Al-Mustansiriyah University, College of Engineering — Member.
• Prof. Dr. Mohsen Abdullah Al-Shammari – University of Baghdad, College of Engineering — Member.
• Prof. Dr. Abdullah Dhayi Asi – University of Baghdad, College of Engineering — Member.
• Assist. Prof. Dr. Ali Ibrahim Hassan – University of Baghdad, College of Engineering — Member.
• Prof. Dr. Majeed Habib Faydallah – University of Baghdad, College of Engineering — Supervisor.

The dissertation focused on the design, fabrication, and analysis of a pylon for a prosthetic limb intended for below-knee amputees, with the aim of improving patient comfort, reducing shocks resulting from torsional movements during walking, and minimizing the weight and cost of the prosthetic limb.

For the fabrication of the pylon, the researcher used two types of materials: Al-6061 aluminum alloy and composite materials consisting of fiberglass, layers of perlon, and silica sand powder, with polyester used as a binding material. A specialized torsional shock-absorbing device was also designed and fabricated using polyurethane rubber to enable the pylon to more naturally simulate body movement and provide greater stability during walking.

The study comprised three main aspects:

• Theoretical aspect: A mathematical model of the pylon was developed, and the forces, moments, and stresses acting on it were determined and analyzed both with and without the torsional shock-absorbing device.
• Experimental aspect: Specimens made from composite materials and aluminum alloy were fabricated and subjected to density, tensile, compressive, impact, torsional, and fatigue tests. The torsional shock absorber was also fabricated and experimentally tested.
• Numerical aspect: ANSYS Workbench 2023 was used to analyze equivalent stresses, total deformation, fatigue life, and factor of safety for the cases under investigation.

Four prosthetic pylon configurations were evaluated, including an aluminum pylon and a composite-material pylon, each tested with and without the torsional shock-absorbing device. The configurations were subsequently tested experimentally on a patient with a right lower-limb amputation.

The results showed that the composite-material pylon equipped with the torsional shock-absorbing device was the best overall option. It achieved the smallest difference in step length between the two feet, at 1 cm, and the smallest difference in step time, at 0.02 seconds, in addition to achieving a 2% difference during the pre-swing phase. The numerical results also demonstrated the effectiveness of the composite materials in terms of stresses, deformations, and factor of safety compared with the aluminum alloy.

The study recommended the use of composite materials in the fabrication of prosthetic pylons and the incorporation of torsional shock-absorbing devices to improve patient stability and reduce the loads acting on the joints and muscles. It also emphasized the importance of combining experimental testing with numerical analysis to develop more efficient and safer prosthetic designs.

Following an extensive scientific discussion and the student’s defense of his dissertation, the committee approved the dissertation and awarded the researcher a grade of Very Good.