People

Rolland Bejjani

Associate Professor

Office: Bassil 402
Extension: 2743
Email: roland.bejjani@lau.edu.lb

Office Hours:
TR 9:00-12:00

Research interests

Machining; tool design; tool wear; CVD PVD coatings; surface engineering; advanced micro manufacturing; machining simulation; 3D Printing; Material Characterization.

  • Unconventional manufacturing methods for metal composites as: machining as Laser Assisted Machining (LAM) using state of the art PCD tools.
  • Metal Cutting / Finite Element Method (FEM) Simulation for metal cutting: Determination of materials constitutive equations, dependent on strain, strain rate, temperature. Prediction of ASB and crack formation.
  • Characterization of surface integrity of manufactured aerospace and biomedical parts using: TEM, FIB, SAD, SEM, TEM, XRD, AUGER, White Light Interferometry, Confocal microscopes…
  • Quick stop and chip formation while cutting metal and MMC. Adiabatic Shear Band (ASB) and segmentation covering microstructural changes and dislocations in MMC as Titanium Metal Matrix Composites. Development of microstructure evolution model for Titanium composite ( TIMMC)
  • Monitor cutting tool wear and failure analysis and relation to material design and process defect possibilities in cemented carbides (Pressing, Sintering, surface preparation, grinding) and thin film coatings (CVD , PVD).
  • Monitoring and understanding the BUE formation when milling Stainless Steel under different conditions.
  • Development of metal cutting methods focused on the understanding of brittle fracture of tool edge.
  • Combining different manufacturing methods in Additive manufacturing and Subtractive manufacturing in relation to surface integrity and tool wear when machining 3D printed Titanium.
  • Modeling initial tool wear using as a deterministic cause of falter failure.
  • Study the tribology on textured CVD coated inserts wear evolution under different conditions.
  • Characterization of cutting tools coating quality & edge chipping under cyclic loads.  
  • Analysis of cohesion flaking, relation of stresses on tool/substrate adhesion.

Active Projects

  • Cryogenic Machining of difficult to cut alloys:  Using FEM simulation tools as ABAQUS and ANSYS to optimize the cutting process.
  • Ultrasonic Assisted Machining: Design of piezoelectric cutting device to optimize cutting hard and brittle materials.
  • High Pressure Tribometer: Design a tribometer for high pressure applications for identifying tribological behaviour at the cutting tools.
  • Initial wear of tools & coatings using SEM, EDS, TEM characterization: Collab.  Poly. Montréal.
  • Surface integrity and tool wear when machining 3D printed Titanium (Additive Manufacturing) with different methods (Ion Beam, Laser fusion): Collab. KTH Univ.

Selected publications

Peer reviewed, associated with an impact factor or other metrics:

  1. Bejjani, R.; Bamford, E.; Cedergren, S.; Archenti, A.; Rashid, A. Variations in the Surface Integrity of Ti-6Al-4V by Combinations of Additive and Subtractive Manufacturing Processes. ‘Materials’ Journal, 13, 1825 (2020).
  2. Bejjani, R, et.al;  Shift of wear balance acting on CVD textured coatings and relation to workpiece materials. Part J: Journal of Engineering Tribology (2020).
  3. Salame C., Bejjani R., Marimuthu P.; A better understanding of cryogenic machining using CFD and FEM simulation, Procedia CIRP, V81, pp 1071-1076 2019.
  4. Skordaris G, Bouzakis KD, Charalampous P, Kotsanis T, Bouzakis E, Bejjani R, Bias voltage effect on the mechanical properties, adhesion and milling performance of PVD films on cemented carbide inserts , WEAR ‘Journal’ (2018)
  5. Bouzakis KD; Kotsanis T; Charalampous P; Bouzakis E; Bejjani R “Bias voltage optimum adjustment considering coatings’ strength and adhesion requirements when cutting various steels”. CIRP Annals (2018)
  6. Kaplan B., Odelros S., Kritikos M., Bejjani R., Norgren S., Study of tool wear and chemical interaction during machining of Ti6Al4V, International Journal of Refractory Metals and Hard Materials (2017).
  7. Bejjani R, Collin M., “Three Dimensional topographic. studies on worn surfaces of coated  cemented carbide tools with different workpiece materials”,  CIRP Journal of Manufacturing Science and Technology,   2016, ISSN 1755-5817.
  8. Bejjani R, Balazinski M, Attia H, Plamondon P., L’Éspérance G., ”Chip formation and microstructure evolution in the adiabatic shear band when machining titanium metal matrix composites”, - Intl. Journal of Machine tools & Manuf- IJMACTOOL, (2016).
  9. Bejjani R, Collin M., Thersleff T., Odelros S.,  “Multi-scale study of initial tool wear on textured alumina coating, and the effect of inclusions in low alloyed steel”, Tribology International ‘Journal’ (2016).
  10. Bejjani R,: Eur. Patent: 15164846.6-1353 (Accepted, pat. pending): enhancement of performance for coated cutting tools with surface engineering 2016.
  11. Bejjani R, Shi B, Attia H, Balazinski M,” Simulation of segmented chip formation with laser assisted machining for TIMMC”, (under resubmission: Intl. jrl. Eng.).
  12. Bejjani R, Shi B, Attia H, Balazinski M,” Laser assisted turning of Titanium Metal Matrix Composite” , CIRP Annals, vol. 60, “1”,  pp.61-65, 2011.
  13. Bejjani R, Balazinski M, Shi B, Attia H, Kishawy H, “Machinability and Chip formation of Titanium Metal Matrix Composites”, Int. Journal of Advanced Manufacturing Systems, IJAMS,  vol. 13, “1” , 2011.
  14. Bejjani R, et.al;  “Segmentation and shear localization when turning TiMMC (Titanium Metal Matrix Composites)”, 26th Tech. conf., American Society of Composites, 2011.
  15. Ar. M, Ba. M, Ki. H, At. H, Bej. R, “ A Study on Phase Transformation and Particle Distribution During Machining TiMMC Composites”, 26th Tech. conf., American Society of Composites, 2011.
  16. Bejjani R, Attia H, Balazinski M, Shi B, “A New Design of Quick Stop Device for Research on Chip Formation”, Transactions of NAMRI/SME,  vol. 38 pp.269-274, 2010.

Other academic papers

  1. Bachir E., Bejjani R.”Ultrasonic Assisted Turning of Titanium Alloy: An Experimental and FEM Study”, VMPT2020, McMaster Canada (reviewed, cancelled presentation), 2020.
  2. Salame C., Bejjani R.”Optimization of cryogenic machining for aerospace alloys using finite element simulation”, VMPT2020, McMaster Canada (reviewed, cancelled presentation), 2020.
  3. Al Fleety A.H., Bejjani R.”Tribo-Device to Evaluate Friction acting on cutting tools”, VMPT2020, McMaster, Canada (reviewed, cancelled presentation), 2020.
  4. Skordaris G., Bouzakis K.-D., Charalampous P., Kotsanis T., Bouzakis E., Bejjani R., Effect of PVD coating’s mechanical properties and adhesion on the milling performance of coated cemented carbide inserts, 13th THE “A” Coatings conference October 2017
  5. Bejjani R., Odelros S., Öhman S., Collin M. “Machining different workpiece materials and the effect on worn surfaces’ topography in textured alfa alumina coated tools”- Virtual Machining Process Tech 2017.
  6. Odelros S., Kaplan B. Kritikos M., Bejjani R., Norgren S. “Study of tool wear and chemical interaction during machining of Ti6Al4V” ”- 19th Plansee Conference (Nov 2016).
  7. Bejjani R, Balazinski M, Attia H, ”Analysis of crack initiation and evolution when turning titanium MMC using a quick stop device and finite element simulation”. 2nd  Intl. Conf. Virtual Machining Process Tech./CIRP, 2013.
  8. Bejjani R , Balazinski M., Attia H, Kishawy H,” A study on adiabatic shear banding in chip segmentation when cutting TiMMC” , 1st Intl. Conf. Virtual Machining Process Tech./CIRP, 2012.
  9. Bejjani R,  et.al, “Chip morphology Study of Titanium metal matrix composites”, 23rd Canadian Congress of Applied Mechanics, pp. 499-502, 2011.
  10. Bejjani R, Shi B, Attia H, Balazinski M, Kishawy H, “Machinability of titanium metal matrix composites”, Proceedings CIRP 2nd conf. Process Machine Interactions. C12,  2010.

Awards & Patents

  • European Patent : 5164846.6- (Accepted, pat. Pending 2016): enhancement of performance for coated cutting tools with surface engineering
  • Award: Key Scientific Article contributing to excellence in scientific and engineering research (Advances in Engineering Ltd) for : Bejjani R, et al., “Multi-scale study of initial tool wear on textured alumina coating, and the effect of inclusions in low alloyed steel”, Tribology Intl. 2015

Academic degrees

Ph.D., M.E., Mechanical engineering, Manufacturing, Polytechnique Montréal,  Cot. NRC- Aerospace Manufacturing Technology Center,  Canada, 2007-2012
Executive MBA,  ESCP-EAP & ESA, 2005