Dr. Jamal Ahmad
Associate Professor, Mechanical Engineering Department
Ruwais Building, Room 3118
Office: +971 (0)2 607 5338
Dr. Ahmad received a Ph.D. in mechanical engineering from NC State University in 1993. His research focuses in the areas of machining polymer composites, friction stir welding and energy efficiency. He has worked for the past twenty five years with government, academic and industry organizations on applied research (experimental and analytical) in secondary manufacturing of composites, composites machining and tooling, composites applications in the petroleum industry and metal machining by both traditional and nontraditional techniques. His work in the area of traditional machining of fiber-reinforced polymer composites is internationally recognized. Before his current appointment, he was a post-doctoral associate and a research assistant professor at the Department of Mechanical and Aerospace Engineering at NC State University (1993-1998) and a faculty member at Wichita State University (1998-2005).
Advisor to the following students & staff
- Razi Ul Haq
- Ph.D. Mechanical Engineering, North Carolina State University, US (1988-1993)
- M.S. Mechanical Engineering, North Carolina State University, US (1986-1988)
- B.S. Mechanical Engineering, Birzeit University, Palestine (1981-1986)
- MEEN 325 Mechanics of Solids
- MEEN 370 Introduction to Manufacturing Processes
- MEEN 387 Machine Element Design
- MEEN 420 Materials Strength and Fracture
- MEEN 421 Mechanics of Deformable Solids
- MEEN 606 Advanced Mechanics of Solids and Materials
- MEEN 633 Advanced Manufacturing Processes
- MEEN 701 Fracture Mechanics and Fatigue
- MEEN 781 Materials Selection in Mechanical Design
- Machining of polymer composites
- Friction stir welding of metals, polymers and hybrid structures
- Thermal aspects in manufacturing
Recent Research Projects
- “Advanced Welding Technique for Light-Weight Hybrid Structures” (Sponsor: Borouge (in-kind support), Principal/Co-Investigator: Jamal Ahmad, Fahad Almaskari, Firas Jarrar, Suleyman Devici):
The demand for fuel-efficient transportation created the need for lightweight hybrid structures. This often requires the joining of similar and dissimilar materials to obtain complex structures for load bearing and aesthetics. Traditionally, joining is achieved by mechanical fastening and adhesive bonding. However, these methods have limitations, such as the requirement to drill holes and the associated stress concentration. Friction stir welding (FSW) is a new solid-state joining method that proved to be very effective in welding aluminum alloys. This project aims to investigate the joining mechanisms of polymers and metals to polymers by friction stir welding and friction lap welding. Experimental and numerical methods will be used to investigate the material flow and microstructure/crystallinity evolution in the stir zone and the joining mechanisms between metals and polymers. The welding of polymers, such as HDPE, PP and PA66 to aluminum alloys will be conducted to achieve lightweight hybrid structures.
Temperature distribution on a transverse cross section of HDPE during friction stir welding.
- “Cutter Optimization for Composite Parts.” (Sponsor: STRATA Manufacturing, 2015-2016). Principal/Co-Investigator: Jamal Ahmad, Fahad Almaskari, Farrukh Hafeez.
Machining of composite parts is a critical step in the manufacturing cycle of good quality components. Conventional operations such as trimming, drilling, counterboring and countersinking are most common operations used to prepare parts for assembly after full curing. Machining these parts at high rates and with minimum damage is the objective of this activity. It is well known that conventional machining processes impart some undesirable defects on the machined parts. These include thermal damage, delamination, matrix cracking and fiber pullout. If these damages are not controlled and minimized, they may compromise the mechanical performance on the machined parts. In this project we investigate new technologies for machining composites and composite/metal stacks. These new technologies include: new cutter geometries and cutter materials and ultrasonic assisted drilling.
Thermographic images of the cutting zone when edge trimming CFRP at 4000 rpm and 800 mm/min.
- Prakash, R., Krishnaraj, V., Sheikh-Ahmad, J. High-speed edge trimming of carbon fiber-reinforced polymer composites using coated router tools. Journal of Composite Materials (2019)
- Jamal Sheikh-Ahmad, Yanli He, Lei Qin. Cutting force prediction in milling CFRPs with complex cutter geometries. Journal of Manufacturing Processes 45 (2019) 720–731
- Wei Xi, Ameen Elsinawi, Koushik Guha, Srinivasa Rao Karumuri, Jamal Shaikh‐Ahmad. A study of the effect of transient stresses on the fatigue life of RF MEMS switches. Int J Numer Model 32 (2019) e2570.
- J.Y. Sheikh-Ahmad, F. Almaskari, F. Hafeez, Fanyu Meng. Evaluation of Heat Partition in Machining CFRP using Inverse Method. Machining Science and Technology 23:4 (2019) 530-546.
- J. Y. Sheikh-Ahmad & F. Almaskari & F. Hafeez. Thermal aspects in machining CFRPs: effect of cutter type and cutting parameters. The International Journal of Advanced Manufacturing Technology 100 (2019) 2569–2582
- N Li, JY Sheikh-Ahmad, A El-Sinawi, V Krishnaraj. Multi-objective optimization of the trimming operation of CFRPs using sensor-fused neural networks and TOPSIS. Measurement 132 (2019) 252-262.
- JY Sheikh-Ahmad, DS Ali, S Deveci, F Almaskari, F Jarrar. Friction Stir Welding of High Density Polyethylene–Carbon Black Composite. Journal of Materials Processing Tech. 264 (2019) 402–413.
- G. Dai, F. Jarrar, F. Ozturk and J. Sheikh-Ahmad. On the Effect of the Complexity of the Constitutive Model in Simulating Superplastic Forming. Defect and Diffusion Forum 385 (2018) 379-384
- Z. Hou, J. Sheikh-Ahmad, F. Jarrar, and F. Ozturk. Residual stresses in dissimilar friction stir welding of AA2024 and AZ31: experimental and numerical study. Journal of Manufacturing Science and Engineering 140:5 (2018) 051015.
- Jiansha Dong, Fahrettin Ozturk, Firas Jarrar and Jamal Y. Sheikh-Ahmad. Numerical Post-buckling Analysis of Mechanically Lined CRA Pipes. Journal of Pressure Vessel Technology (2018) 140 (1) 014502.
- J.Y. Sheikh-Ahmad, Dima Ali, Fanyu Meng. Design and Implementation of a Force Dynamometer for Friction Stir Welding, Arabian Journal for Science and Engineering (2018) 43: 4649.
- K. Li, F. Jarrar, J. Sheikh-Ahmad and F. Ozturk. Using coupled Eulerian Lagrangian formulation for accurate modeling of the friction stir welding process. Procedia Engineering, (2017) 207:574–579.
- Z. Li, G. Dai, J. Shi, F. Jarrar, F. Ozturk, J. Sheikh-Ahmad. Using the particle swarm optimization method for the constitutive modeling of AZ31B. Material Science and Engineering Technology (2017) 48 (10) 993–997.
- Sheikh-Ahmad, J., Dhuttargaon, M. & Cheraghi, H. New Tool Life Criterion for Delamination Free Milling of CFRP. Int. J. Advanced Manufacturing Technology (2017) 92(5-8) 2131-2143
- V Krishnaraj, B Hari Krishna, Jamal Y Sheikh-Ahmad. An experimental study on end milling of titanium alloy (Ti-6Al-4V) under dry and minimum quantity lubrication conditions. Int. J. Machining and Machinability of Materials (2017) 19(4): 325-342
- Tianye Guo, Fahrettin Ozturk, Firas Jarrar and Jamal Y. Sheikh-Ahmad. Analysis of Contact Pressure of Mechanically Lined Corrosion Resistant Alloy Pipe by Hydraulic Expansion Process. J. Pressure Vessel Technol (2017) 139(2) 021212