Dr Csaba Sinka

Senior Lecturer in Mechanics of Materials
Mechanics of Materials Research Group
PhD, DIC

T: +44 (0)116 252 2555
E: ics4@le.ac.uk

Location: Room 220, Michael Atiyah Building

Personal details

PhD, DIC

Admin

• Post-Graduate Research (PGR) Director – College of Science and Engineering
• Programme Director for MSC in Advanced Mechanical Engineering – Department of Engineering
• Programme Director for MSC in Advanced Engineering – Department of Engineering

Teaching

• EG1002 Engineering Design (2006-2016)
• EG3103 Mechanics of Structures 2 (2006-2016)

Publications

Selected publications

• Baserinia R., Sinka I.C. and Rajniak P., 2016. Air pressure effects on powder flow initiation in orifice flow. Powder Technology. Vol. 301, pp. 493-502.
• Sinka I.C., 2014. A model for the deformation of an ellipsoid subject to a large number of successive impacts with special reference to spheronisation. Powder Technology. Vol. 270, Part B, pp. 592-598.
• Shang C., Sinka I.C. and Pan J., 2013. Modelling of the break force of tablets under diametrical compression. International Journal of Pharmaceutics. Vol. 445, Issues 1–2, pp. 99-107.
• Shang C., Sinka I.C., Jayaraman B. and Pan J., 2013. Break force and tensile strength relationships for curved faced tablets subject to diametrical compression. International Journal of Pharmaceutics. Vol. 442, Issues 1–2, pp. 57-64.
• Shang C., Sinka I.C., Pan J., 2012. Constitutive model calibration for powder compaction using instrumented die testing. Experimental Mechanics. Vol. 52, Issue 7, pp. 903-916.
• Sinka I.C., 2007. Modelling powder compaction. KONA (Hosokawa Powder Technology Foundation, Japan). Invited review paper. Vol. 25, pp. 4-22.
• Cocks, A.C.F. and Sinka, I.C., 2007. Constitutive Modelling of Powder Compaction – I. Theoretical Concepts. Mechanics of Materials, Vol. 39, pp. 392-403.
• Sinka, I.C., and Cocks, A.C.F., 2007. Constitutive Modelling of Powder Compaction – II. Evaluation of Material Data. Mechanics of Materials, Vol. 39, pp. 404-416.
• Sinka, I.C., Schneider L.C.R. and Cocks, A.C.F., 2004. Measurement of the flow properties of powders with special reference to die fill. International Journal of Pharmaceutics. Vol. 280, Issues 1-2, pp. 27-38.
• Sinka, I.C., Cunningham, J.C. and Zavaliangos, A., 2003. The effect of wall friction in the compaction of pharmaceutical tablets with curved faces: A validation study of the Drucker-Prager Cap model. Powder Technology, Vol. 133, Issue. 1-3, pp. 33-43.
• Sinka, I.C., Cocks, A.C.F., Morrison, C.J. and Lightfoot, A., 2000. High Pressure Triaxial Facility for Powder Compaction. Powder Metallurgy, Vol. 43, No. 3, pp. 253-262.

Research

My area of research is the mechanics of granular and porous materials with applications to particle science and engineering. My work combines experimental characterisation, numerical analysis and theoretical research covering the following four themes: powder compaction, powder flow and die fill, particle transformations during processing, and formulation of complex products.

Grants (PI)

EPSRC EP/N025261/1 Virtual Formulation Laboratory for prediction and optimisation of manufacturability of advanced solids based formulations. 2016-2019.

Interests

A wide range of goods are manufactured by die compaction of powders. A major theme in my research is related to improving the fundamental understanding of the mechanics of powder compaction and developing appropriate constitutive laws in terms of the evolution of suitable state variables for the full range of compaction mechanisms and loading cycles.

The powder compaction process involves the formulation of a powder blend, which is then fed into a die and compressed using rigid punches.

The compact is then ejected and subject to post-compaction operations:

1. Powder flow

The details of the delivery process of powder into the die are important for achieving weight and content uniformity. A model shoe-die facility and high speed video system enabled a 
detailed study of the powder-air interaction and air pressure build-up during powder flow into constrained cavities:

The experimental facility is used to assess the flowability of powders, assist powder formulation design and selection of process parameters relevant to single station presses as well as high speed rotary presses.

http://www.youtube.com/watch?v=Qkj1J9GSJkQ

2. Compaction
The behaviour of particulate materials depends on the details of particle-particle interactions which involve elastic and plastic deformation and fracture.

• Theoretical tools (micromechanical models)
• Numerical modelling (material point method for particle impact)
• Experimental facilities (state of the art 700 MPa capacity triaxial testing system):

The constitutive models developed are implemented into finite element packages for practical applications.

3. An integrated approach to powder compaction
The relationships between material properties, process parameters and product performance is investigated through the development of an integrated process model developed for 
the manufacturing of pharmaceutical solid dosage forms.

The process model supports rational product, process and tool design.

http://www.youtube.com/watch?v=lvx56uUOQyo

4. Polymer biodegradation
A multi-physics modelling approach is developed to couple the mass transport and reaction equations that describe the hydrolysis process of biodegradable polymers used in
orthopaedic fixation devices.

Numerical results have established a biodegradation map illustrating regimes dominated by hydrolysis, auto-catalytic hydrolysis or monomer diffusion. The framework is extended to
model controlled drug release systems.

Supervision

Current PhD students and project titles (October2016)

1. Peter Polak. Understanding densification and crack propagation in pharmaceutical tablet manufacturing
2. Abdulrahman Alharbi: Modelling solid-solid and air-solid interactions for particulate handling and processing.
3. Muhanad Al-Sabbagh. Influence of contact strength between particles on the constitutive law for powder compaction and the strength of powder compacts
4. Amnani Binti Shamjuddin. Swelling and disintegration of multi-component polymeric structures
5. Hasan Elmsahli. Particle interactions and transformations using coupled DEM-CFD-PBM modelling
6. Reza Baserinia. Flow of fine and cohesive powders under controlled air pressure conditions
7. Lida Che. Numerical constitutive laws for powder compaction