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The research of our group.

for 20 years, our researchgroup 'Mechanics of Materials and Structures', a subgroup of 'Mechanical Construction and production' (Ghent University) is active in the mechanics of composite materials. The principal topic of research is the behaviour of these materials under impact and fatigue loading, both experimental and numerical (modelling).

Graduate thesis. 2003 - 2004

Study of the shear behaviour of composites

Depending on the outcome of a number of experiments on an unidirectional reinforced glass-epoxy, the behaviour under shear stress of this material is determined. Next, a damage model is developed, which is implemented in a finite elements program, 'Samcef'. After implementation, this model is verified with the previous experiments.

Furtermore, a method to measure displacements,'Digital Speckle Photography' was researched. From the displacements, the strains can be derived. This has been done in cooperation with the Bulgarian Academy of Sciences, Sofia.

Doctoral thesis. 2004 - 2008

Experimental and Numerical Study of Different Setups for Conducting and Monitoring Fatigue Experiments of Fibre-Reinforced Thermoplastics

There is an increase in the use of fibre-reinforced thermoplastic polymers in the industry, amongst others for aeronautical and automotive applications. However, these materials are not yet considered for load bearing parts, because such parts are often subjected to fatigue loads. The behaviour under fatigue loading conditions of these materials is very complicated and not yet completely understood. If these materials are used, then often very large safety factors are used, which causes the advantages of composites, for instance the high strength to weight ratio, to diminish. As such, there is a need for a better understanding of the mechanical behaviour of these composites under fatigue loading conditions.

This research consists of two approaches: on one hand, an extensive experimental program has been conducted so that a better understanding in the mechanical behaviour under various static and fatigue loading conditions is obtained. Besides the standard uni-axial tests, the bending and three-rail shear setups were also considered and new or modified designs, better suited for composite materials, were implemented.
On the other hand, several non-destructive observation techniques were proposed and assessed to what extent they can monitor the (damage) behaviour of the composite, in order to increase the confidence in the material. Optical fibre sensors with Bragg gratings were chosen to observe the deformations and the electrical resistance of the composite specimen was measured during the experiments to estimate the damage state of the material. The elastic properties such as stiffness and permanent deformation were also considered and special attention is paid to the peculiar behaviour of the Poisson’s ratio during hysteresis and fatigue tests.

Of course, both approaches were combined and the observation techniques were used as much as possible during the experiments. Moreover, all experimental findings were verified by finite-element simulations if applicable. Furthermore, finite-element modelling was also used for the design or the modifications of the various test setups, to determine the actual stress distributions in the specimen and to verify whether the setup itself could withstand the occurring loading conditions.

The material on which the research is conducted, is a carbon fibre reinforced polyphenylene sulphide (PPS), which is supplied bij Ten Cate in the Netherlands.

For the full version of my PhD, click here. This is a pdf-file and requires Adobe Acrobat Reader.

Publications

Publications in international journals of the Science Citation Index (SCI):
Unfortunately, I cannot place pdf-files of A1 articles on my site. If the DOI link is already available, you can click on the paper for the corresponding link. After it is published, you can find it on the web of science.
The following articles are already published or accepted:

  • Modelling the nonlinear shear stress-strain response of glass fibre-reinforced composites. Part I: Experimental results. Composites Science and Technology 66 (2006) 1455-1464, Van Paepegem W., De Baere I. and Degrieck J.
  • Modelling the nonlinear shear stress-strain response of glass fibre-reinforced composites. Part II: Model development and finite element simulations.Composites Science and Technology 66 (2006) 1465-1478, Van Paepegem W., De Baere I. and Degrieck J.
  • Poisson's ratio as a sensitive indicator of (fatigue) damage in fibre-reinforced plastics. Fatigue & Fracture of Engineering Materials & Structures 30 (4): 269-276 APR 2007, Van Paepegem W., De Baere I., Lamkanfi E. and Degrieck J..
  • The use of rivets for electrical resistance measurement on carbon fibre-reinforced thermoplastics, Smart Materials and Structures 16 (2007) 1821-1828, De Baere I., Van Paepegem W., and Degrieck J. DOI-link
  • Design of mechanical clamps with extra long wedge grips for static and fatigue testing of composite materials in tension and compression, Experimental Techniques 32 (3) 62-69 (May-June 2008),, De Baere I., Van Paepegem W., and Degrieck J. DOI-link
  • Comparison of different identification techniques for measurement of quasi-zero Poisson's ratio of fabric reinforced laminates, Composites part A, 38 (9) pp. 2047-2054 (2007), De Baere I., Van Paepegem W., Degrieck J., Sol H., Van Hemelrijck D. and Petreli A. DOI-link
  • Strain monitoring in thermoplastic composites with optical fibre sensors: embedding process, visualization with micro-tomography and fatigue results, Journal of Thermoplastic Composite Materials 2007;20 453-472 , De Baere I., Voet E., Van Paepegem W., Vlekken J., Cnudde V., Masschaele B. and Degrieck J. link
  • On the feasibility of a three-point bending setup for the validation of (fatigue) damage models for thin composite laminates. Polymer Composites 29 (10) pp 1067-1076 (2008), De Baere I., Van Paepegem W. and Degrieck J. DOI-link
  • On the design of end tabs for quasi-static and fatigue testing of fibre-reinforced composites Polymer Composites Volume 30, Issue 4, Pages 381-390, April 2009, De Baere I., Van Paepegem W. and Degrieck J. DOI-link
  • On the feasibility of optical fibre sensors for strain monitoring in thermoplastic composites under fatigue loading conditions Optics and Lasers in Engineering 47 (2009) 403-411, special issue for OPTIMESS 2007, De Baere I., Luyckx G., Voet E., Van Paepegem W. and Degrieck J. DOI-link
  • Design of a modified three-rail shear test for shear fatigue of composites. Polymer Testing 27 (2008) 346-359, De Baere I., Van Paepegem W. and Degrieck J. DOI-link
  • Electrical resistance measurement for in-situ monitoring of fatigue of carbon fabric composites, International Journal of Fatigue volume 32 (2010), pp197-207., De Baere I., Van Paepegem W. and Degrieck J. DOI-link
  • Modelling the nonlinear shear stress-strain behaviour of a carbon fabric reinforced polyphenylene sulphide from rail shear and [(+45°,-45°)]4s tensile test.
    Polymer Composites volume 30 issue 7 pp1016-1026 (2009), De Baere I., Van Paepegem W. and Degrieck J. DOI-link
  • Comparison of different set-ups for fatigue testing of thin composite laminates in bending.International Journal of Fatigue 31(2009) pp 1095-1101, De Baere I., Van Paepegem W. and Degrieck J. DOI-link
  • Monitoring fatigue damage in fibre-reinforced plastics through the Poisson's ratio degradation, International Journal of Fatigue International Journal of Fatigue volume 32 (2010), Van Paepegem W., De Baere I., Lamkanfi E. and Degrieck J. DOI-link
  • Comparison of the modified three-rail shear test and the [(+45°,-45°)]ns tensile test for pure shear fatigue loading of carbon fabric thermoplastics. Fatigue and Fracture of Engineering Materials & Structures. Vol. 31 (6) Pages: 414-427 (JUN 2008). De Baere I., Van Paepegem W. and Degrieck J.
  • On the nonlinear evolution of the Poisson's ratio under quasi-static loading for a carbon fabric-reinforced thermoplastic. Part I: influence of the transverse strain sensor. Polymer Testing 28 (2009) 196 - 203. De Baere I., Van Paepegem W. and Degrieck J. DOI-link
  • On the nonlinear evolution of the Poisson's ratio under quasi-static loading for a carbon fabric-reinforced thermoplastic. Part II: Analytical Explanation. Polymer testing Volume 28, Issue 3, May 2009, Pages 324-330 De Baere I., Van Paepegem W. and Degrieck J. DOI-link
  • Van Paepegem W., De Baere I., Lamkanfi E. and Degrieck J., Monitoring fatigue damage in fibre-reinforced plastics through the Poisson's ratio degradation, International Journal of Fatigue International Journal of Fatigue volume 32 (2010), pp184-196.Van Paepegem W., De Baere I., Lamkanfi E. and Degrieck J DOI-link

Articles in book volumes:
  • Van Paepegem W., De Baere I., Lamkanfi E., Luyckx G. and Degrieck J., Numerical modelling of fatigue in textile polymer composites. Accepted chapter for Computational & Experimental Analysis of Damaged Materials, 2007; ISBN: 978-81-7895-308-3 Editor: Dimitrios G. Pavlou. Research Signpost, India.
  • Van Paepegem W., De Baere I., Lamkanfi E., Luyckx G. and Degrieck J. Research directions in the fatigue testing of polymer composites. Accepted chapter for Composite Materials Research Progress 2007; ISBN: 978-1-60021-994-8 Editor Lucas P. Durand. Nova Science Publishers, Inc., New York, United States of America.

Proceedings of Conferences on Web of Science:
  • The use of optical fibres for fatigue testing of fibre-reinforced thermoplastics. 4th International Conference Emerging Technologies in Non-Destructive Testing, (ETNDT 4) 2 – 4 april 2007, Stuttgart, Germany, De Baere I., Voet E., Van Paepegem W., Degrieck J. and Vlekken J.
  • Electrical resistance measurement on carbon fibre-reinforced thermoplastics with rivets as electrodes. 4th International Conference Emerging Technologies in Non-Destructive Testing, (ETNDT 4) 2 – 4 april 2007, Stuttgart, Germany, De Baere I., Van Paepegem W. and Degrieck J.
  • Monitoring of a curved beam test structure using Braggg sensors and acoustic emission. 4th International Conference Emerging Technologies in Non-Destructive Testing, (ETNDT 4) 2 – 4 april 2007, Stuttgart, Germany, 9. Luyckx G., Degrieck J., De Baere I., De Waele W., Van Paepegem W. and Verbeke T.
  • Fusion Bonding of Carbon Fabric Reinforced Polyphenylene Sulphide by Hot-Tool Welding. 17th International Conference on Composite Materials (ICCM-17), 27-31 July 2009, Edinburgh, United Kingdom.De Baere I., Van Paepegem W. and Degrieck J.
  • Large scale slamming tests on composite buoys for wave energy applications. 17th International Conference on Composite Materials (ICCM-17), 27-31 July 2009, Edinburgh, United Kingdom.Blommaert C., Van Paepegem W., Dhondt P., De Backer G., Degrieck J., De Rouck J., Vantorre M., Van Slycken J., De Baere I., De Backer H., Vierendeels J., De Pauw P., Matthys S. and Taerwe L..
  • Meso-scale modeling in thermoplastic 5-harness satin weave composite. 17th International Conference on Composite Materials (ICCM-17), 27-31 July 2009, Edinburgh, United Kingdom.Daggumati S., De Baere I., Van Paepegem W., Degrieck J., Xu J., Lomov S.U., Verpoest I..
  • Fatigue testing of fibre reinforced thermoplastics: different testing and instrumentation strategies. 17th International Conference on Composite Materials (ICCM-17), 27-31 July 2009, Edinburgh, United Kingdom.Van Paepegem W., De Baere I. and Degriek, J.
  • Fatigue and Impact Testing of Textiel Reinforced Thermoplastic Composites for Aerospace Applications. International Conference on Latest Advances in High-Tech Textiles and Textile-Based Materials, 23-25 September 2009, Ghent, Belgium.Van Paepegem W., De Baere I. and Degriek, J.
  • Fusion bonding of carbon fabric reinforced polyphenylene sulphide.14th International Conference on Experimental Mechanics (ICEM-14), July 4 -9, 2010, Poitiers, FranceDe Baere I, Van Paepegem W. and Degrieck J. DOI-link
  • Pre-fatigue influence on quasi -static tensile properties of Ti-6Al-4V in thin-sheet form.14th International Conference on Experimental Mechanics (ICEM-14), July 4 -9, 2010, Poitiers, FranceGalan Lopez, J. Verleysen P., De Baere I. and Degrieck J DOI-link

Proceedings of Conferences:
  • Modelling the nonlinear shear stress-strain response of glass fibre-reinforced composites. Third International Conference on Advanced Computational Methods in Engineering. Gent, Belgium. 30 May - 2 June 2005, De Baere I., Van Paepegem W. and Degrieck J.
  • Modelling the nonlinear shear stress-strain response of glass fibre-reinforced composites. 12th European Conference on Composite Materials. Biarritz, France. 29 August - 1 September 2006, De Baere I., Van Paepegem W. and Degrieck J.
  • Monitoring of Fatigue, Impact and Wear in Cetex TPC. Workshop on Cetex thermoplastic composites in honour of Willem van Dreumel. TUDelft, Delft, The Netherlands, 14 June 2006. Invited presentation. Degrieck, J. et al.
  • On the feasibility of optical fibre sensors for strain monitoring in thermoplastic composites under fatigue loading conditions. 3rd Workshop on Optical Measurement Techniques for Structures and Systems (OPTIMESS 2007) 28 – 30 May, Leuven, Belgium. De Baere I., Voet E., Van Paepegem W., Degrieck J. and Vlekken J.
  • Analysis of a curved composite test specimen zith Fibre Bragg Gratings. 3rd Workshop on Optical Measurement Techniques for Structures and Systems (OPTIMESS 2007) 28 – 30 May, Leuven, Belgium. Luyckx G., De Baere I., W. De Waele, Degrieck J., Van Paepegem W., Vlekken J., Verbeke T.
  • Comparison of different setups for fatigue testing of thin composite laminates in bending, International Conference on Damage tolerance of Aircraft Structures (DTAS), on 25-28 September 2007, Delft, The Netherlands De Baere I., Van Paepegem W. and Degrieck J.
  • A clamped three-point bending setup for fatigue of thin composite laminates, 13th European Conference on Composite Materials (ECCM-13) June 2 - 5, 2008 Stockholm, Sweden. De Baere, I., Van Paepegem, W. and Degrieck, J.
  • A modified three-rail shear test for fatigue of composite laminates, 13th European Conference on Composite Materials (ECCM-13) June 2 - 5, 2008 Stockholm, Sweden. De Baere, I., Van Paepegem, W. and Degrieck, J.
  • High strain measurements during fatigue cycling in fibre reinforced thermoplastic composites using imbedded draw tower fibre bragg grating sensors. 13th European Conference on Composite Materials (ECCM-13) June 2 - 5, 2008 Stockholm, Sweden. Voet, E., Luyckx G., De Baere I., Degrieck J, Bartelt H., Vlekken J. and Jacobs E.
  • Fatigue testing of carbon fabric thermoplastics: different testing and instrumentation strategies. SAMPE EUROPE 28th International Conference (SEICO 08), Composites Forever, Affortable, Durable, Sustainable and Creatable. March 31st – April 2nd. 2008, Paris, France.De Baere I., Van Paepegem W., Voet E. and Degrieck, J.
  • A clamped three-point bending setup for fatigue of thin composite laminates. 13th European Conference on Composite Materials (ECCM-13) June 2 - 5, 2008 Stockholm, Sweden.De Baere I., Van Paepegem W., and Degrieck, J.
  • A modified three-rail shear test for fatigue of composite laminates. 13th European Conference on Composite Materials (ECCM-13) June 2 - 5, 2008 Stockholm, Sweden.De Baere I., Van Paepegem W., and Degrieck, J.
  • High strain measurements during fatigue cycling in fibre reinforced thermoplastic composites using imbedded draw tower fibre Bragg grating sensors. 13th European Conference on Composite Materials (ECCM-13) June 2 - 5, 2008 Stockholm, Sweden.Voet E., Luyckx G., De Baere I., Degrieck J., Bartelt H., Vlekken J. and Jacobs E
  • High Strain monitoring during Fatigue Loading of Thermoplastic Composites using imbedded draw Tower Fibre Bragg Grating Sensors. 3rd International Conference “Smart Materials, Structures and Systems”, CIMTEC, June 8 to 13, 2008, Florence, Italy.Voet E., Luyckx G., De Baere I. and Degrieck J.
  • On the nonlinear evolution of the Poisson’s ratio under quasi-static loading for a carbon fabric-reinforced thermoplastic. 14th European Conference on Composite Materials (ECCM-14), 7 – 10 June 2010, Budapest, HungaryDe Baere I., Van Paepegem W. and Degrieck J
  • Comparison of Slamming Wave Impact of a Rigid and Deformable Composite Cylinder with Numerical Simulation and Experimental Validation14th European Conference on Composite Materials (ECCM-14), 7 – 10 June 2010, Budapest, HungaryVepa K.S., Van Nuffel D., De Baere I., Degrieck J. , Van Paepegem W. and Vierendeels J
  • Finite element modeling of thermal stress in ITER prototype optical windows and its influencing parameters12th International Ceramics Congress CIMTEC 2010, June 6-11, Montecatini Terme, ItalyJacobs M., Van Oost G., Degrieck J., De Baere I., Gusarov A. and Massaut V
  • Effect of flax fibre reinforcement on the riding comfort of composite racing bicycle frames8th Conference of the International Sports Engineering Association (ISEA) 12 – 16 July 2010, Vienna, Austria.Ghosh AK, De Baere I., Vanwalleghem J. , De Thaeye J.,Van paepegem W. and Degrieck J

Articles and Poster from the FirW PhD symposium.You need acrobat to view the files.
  • Experimental and Theoretical Study of the Mechanical Behaviour of Fibre-Reinforced Thermoplastics under Fatigue Loading Conditions. paper - poster
  • Design of a Three- and Four-Point Bending Setup for Fatigue Testing of Fibre-Reinforced Thermoplastics. paper - poster
  • Optical fibres and electrical resistance measurement for in-situ monitoring of composite fatigue. paper - poster
  • A clamped three-point bending setup for fatigue of thin composite laminates. paper - poster