THE VIRTUAL FIELDS METHOD

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The VFM

Applications: problem type

Applications: materials

Professor Fabrice PIERRON

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University Degrees

• 1989 - Engineering Degree from École Nationale Supérieure d’Électricité et de Mécanique in Nancy (France), major in Mechanical Engineering.
• 1990 - Master of Science (DEA) in Mechanics and Thermodynamics from Institut National Polytechnique de Lorraine.
• 1994 - PhD (Doctorat) in Macromolecular Materials and Composites from Lyon University, France, obtained with the highest grade.
• 1998 - ‘Habilitation à Diriger les Recherches’ (HDR) from Clermont-Ferrand University, France (French degree necessary to supervise PhD students and apply for a professorial position).

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Professional Positions

• 1994 - Lecturer at École Nationale Supérieure des Mines de Saint-Étienne (France), in the Mechanical and Materials Engineering Department led by Professor Georges Verchery and then by Professor Alain Vautrin.
• 1999 - Professor at École Nationale Supérieure d’Arts et Métiers (ENSAM) in Châlons en Champagne (France). Head of the Mechanical Engineering and Manufacturing Research Group.
• 2004-05 - Sabbatical, Department of Aerospace Engineering, University of Bristol, UK.
• 2006 - Promoted to first class professor.

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Main administrative duties

• Head of the "Identification from Full-Field Measurements" group within the Mechanical Engineering and Manufacturing Research Group (LMPF, certified by the French Ministry for Research) including 11 academic staff, 3 technical and administrative staff and 11 PhD students.
• Elected member of the Administration Board of ENSAM

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Research interests

Mechanical testing and machining of composites:

• PhD on the Iosipescu shear test for composite materials. Design of a new fixture and application to thick composites. 18 months spent at the University of Bath (UK).
• Work on the shear strength of composite materials using the Iosipescu and 10° off-axis tensile test (use of oblique tabs).
• Mechanical testing of composite materials: design of new tests and fixtures, optimisation of existing tests.
• Machining of composite materials.

Design of composite structures:

• Durability of composite structures: moisture effect and fatigue.
• Work on the prediction of the failure load of composite pin-joints.
• Design of composite structures: replacement of metallic systems by composite components (function integration). Collaborations with companies in the automotive and railway industry.

Use of full-field optical measurements and heterogeneous tests for advanced material testing:

• Development of the Virtual Fields Method (identification technique dedicated to full-field measurements).
• Application of the VFM to different situations: anisotropic elasticity, heterogeneous materials, elasto-plasticity, wood, vibration damping, high strain rate testing etc.
• Measurement of thermal dissipation in cyclically tested materials using infrared thermography.

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International experience

• 3 years at the University of Bath as an undergraduate (exchange student) and postgraduate (European grant for PhD).
• Director of ENSAM double degree programme with the UK and Ireland (MSc level).
• Broad experience of undergraduate student exchanges (ERASMUS/SOCRATES, UK, USA, Germany etc.).
• 1 year sabbatical at the University of Bristol (UK), 2004-05.
• Wide range of international research collaborations (University of Bristol, University of Loughborough, GB, University of South Carolina, USA, UTAD, Portugal, etc.).

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Industrial collaborations

GEC Alsthom and Alstom, Renault, Hexcel composites, Saint-Gobain, Ifremer, SNCF, ONERA, Astrium (UK), Airbus UK, GKN Technology (UK) etc.

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Scientific animation

• Co-Chairman and organizer of the “Composites Testing and Model Identification” (CompTest2003) conference held in January 2003 in Châlons en Champagne (France) – 100 participants from 15 countries. Invited editor for a CompTest2003 special issue of the journal “Composites Part A”.
• Co-Chairman of the “Composites Testing and Model Identification” (CompTest2004) conference held in September 2004 in Bristol (UK) – 140 participants from 25 countries.
• Co-Chairman of the “Composites Testing and Model Identification” (CompTest2006) conference held in April 2006 in Porto (Portugal).
• Co-Chairman of the “Composites Testing and Model Identification” (CompTest2008) conference held in October 2008 in Dayton (Ohio, USA).
• Co-chair of the organizing committee of the French Conference on Mechanics (1200 participants) held in Troyes in Sept. 2005.
• Leader of a French network on composites including 5 ENSAM research groups (2002-2005).
• Member of the scientific committee and/or session organizer of a number of national and international conferences.

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Affiliation to Societies

• Member of the French Society for Composite Materials (AMAC)
• Member of the French Society for the Mechanics of Materials (MECAMAT)
• Member of the French Mechanics Society (AFM)
• Member of the British Society for Strain Measurement (BSSM)
• Co-opted member of the National Technical Committee (NATCO)
• Member of the Society for Experimental Mechanics (SEM)
  • President of the Technical Division entitled “Inverse Problem Approaches”

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Journal editing

• Member of the editorial board and council of the international journal “Strain” (Blackwell Publishing).
• Invited editor for the CompTest2003 and CompTest2004 special issues of the journal “Composites Part A” (Elsevier).
• Invited editor for special issues of Experimental Mechanics (Springer) on Inverse problems and Composites Part A (Elsevier) on full-field measurements applied to composites, 2006-2007.

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Reviewing

Regular reviewer for Composites Science and Technology, Composites Part A (Elsevier), Journal of Composite Materials (Sage), Experimental Mechanics (Springer) etc.

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Publications

• 53 publications in international refereed journals plus 1 submitted
• h-factor: 14
• 8 publications in French refereed journals
• 7 invited lectures
• 85 communications in international conferences with proceedings
• 44 communications in national conferences with proceedings
• 37 communications in conferences without proceedings

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Publications in international journals (January 2009)

1994

1. Grédiac M., Pierron F., Vautrin A.
   The Iosipescu in-plane shear test applied to composites: a new approach based on displacement field processing
   Composites Science and Technology, vol. 51, n° 3, pp 409-417, 1994.
2. Pierron F., Vautrin A.
   Accurate comparative determination of the in-plane shear modulus of T300/914 using the Iosipescu and 45° off-axis tests
   Composites Science and Technology, vol. 52, n° 1, pp 61-72, 1994.

1995

3. Pierron F., Vautrin A., Harris B.
   The Iosipescu in-plane shear test: validation on an isotropic material
   Experimental Mechanics, vol. 35, n° 2, pp 130-136, 1995.

1996

4. Pierron F., Vautrin A.
   The 10° off-axis tensile test: a critical approach
   Composites Science and Technology, vol. 56, n° 4, pp 483-488, 1996.

1997

5. Pierron F., Vautrin A.
   Measurement of the in-plane shear strength of unidirectional composites with the Iosipescu test
   Composites Science and Technology, vol. 57, n° 12, pp 1653-1660, 1997.
6. Pierron F., Vautrin A.
   New ideas on the measurement of the in-plane shear strength of unidirectional composites
   Journal of Composite Materials, vol. 31, n° 9, pp 889-895, 1997.
7. Pierron F., Vautrin A.
   Discussion of "Experimental Strain Analysis of the Iosipescu Shear Test Specimen" (Adams D. F. et Lewis E. Q.)
   Experimental Mechanics, vol. 37, n° 1, pp 11-12, 1997.

1998

8. Grédiac M., Pierron F.
   A T-shaped specimen for the direct characterization of orthotropic materials
   International Journal for Numerical Methods in Engineering, vol. 41, pp 293-309, 1998.
9. Pierron F., Alloba E., Surrel Y., Vautrin A.
   Whole-field assessment of the effects of boundary conditions on the strain field in off-axis tensile testing of unidirectional composites
   Composites Science and Technology, vol. 58, pp 1939-1947, 1998.
10. Pierron F.
    Saint-Venant effects in the Iosipescu specimen
    Journal of Composite Materials, vol. 32, n° 22, pp 1986-2015, 1998.

1999

11. Pierron F.
    Discussion of the article "Biaxial testing of unidirectional carbon-epoxy composite using biaxial Iosipescu test fixture"
    Journal of Composite Materials, vol. 33, n° 8, pp 683-687, 1999.
12. Grédiac M., Pierron F., Surrel Y.
    Novel procedure for complete in-plane composite characterization using a single T-shaped specimen
    Experimental Mechanics, vol. 39, n° 2, pp 142-149, 1999.

2000

13. Pierron F., Cerisier F., Grédiac M. A numerical and experimental study of woven composite pin-joints
    Journal of Composite Materials, vol. 34, n° 12, pp 1028-1054, 2000.
14. Pierron F., Zhavoronok S., Grédiac M.
    Identification of the through-thickness properties of thick laminated tubes using the virtual fields method
    International Journal of Solids and Structures, vol. 37, n° 32, pp 4437-4453, 2000.
15. Pierron F., Grédiac M.
    Identification of the through-thickness moduli of thick composites from whole-field measurements using the Iosipescu fixture
    Composites Part A: Applied Science and Manufacturing, vol. 31, n° 4, pp 309-318, 2000.

2001

16. Grédiac M., Auslender F., Pierron F.
    Using the virtual fields method to identify the through-thickness moduli of thick composites with a nonlinear shear response
    Composites Part A: Applied Science and Manufacturing, vol. 32, n° 12, pp. 1713-1725, 2001.

2002

17. Grédiac M., Toussaint E., Pierron F.
    Special virtual fields for the direct determination of material parameters with the virtual fields method. 1- Principle and definition
    International Journal of Solids and Structures, vol. 39, n° 10, pp. 2691-2705, 2002.
18. Grédiac M., Toussaint E., Pierron F.
    Special virtual fields for the direct determination of material parameters with the virtual fields method. 2- Application to in-plane properties
    International Journal of Solids and Structures, vol. 39, n° 10, pp. 2707-2730, 2002.
19. Pierron F., Poirette Y., Vautrin A.
    A novel procedure for identification of 3D moisture diffusion parameters on thick composites: theory, validation and experimental results
    Journal of Composite Materials, vol. 36, n°19, pp. 2219-2244, 2002.

2003

20. El Mansori M., Pierron F., Paulmier D.
    Reduction of tool wear in metal cutting using external electromotive sources
    Surface and Coatings Technology, vol. 163-164C, pp. 472 - 477, 2003.
21. Grédiac M., Toussaint E., Pierron F.
    Special virtual fields for the direct determination of material parameters with the virtual fields method. 3- Application to the bending rigidities of anisotropic plates
    International Journal of Solids and Structures, vol. 40, n° 10, pp. 2401-2419, 2003.
22. Giraudeau A., Pierron F.
    Simultaneous identification of stiffness and damping properties of isotropic materials from forced vibrating plates
    Comptes rendus Mécanique, vol. 331, n° 4, pp. 259-264, 2003.

2004

23. Grédiac M., Pierron F.
    Numerical issues in the virtual fields method
    International Journal for Numerical Methods in Engineering, vol. 59, n° 10, pp. 1287-1312, 2004.
24. Chalal H., Meraghni F., Pierron F., Grédiac M.
    Direct identification of the damage behaviour of composite materials using the virtual fields method
    Composites Part A: Applied Science and Manufacturing, vol. 35, n° 7-8, pp. 841-848, 2004.
25. Ghidossi P., El Mansori M., Pierron F.
    Edge machining effects on the failure of polymer matrix composite coupons
    Composites Part A: Applied Science and Manufacturing, vol. 35, n° 7-8, pp. 989-999, 2004.
26. Xavier J.C., Garrido N.M., Oliveira M., Morais J.L., Camanho P.P., Pierron F.
    A comparison between the Iosipescu and off-axis shear test methods for the characterization of Pinus Pinaster Ait.
    Composites Part A: Applied Science and Manufacturing, vol. 35, n° 7-8, pp. 827-840, 2004.
27. Avril S., Grédiac M., Pierron F.
    Sensitivity of the virtual fields method to noisy data
    Computational Mechanics, vol. 34, n° 6, pp. 439-452, 2004.

2005

28. Giraudeau A., Pierron F.
    Identification of stiffness and damping properties of thin isotropic vibrating plates using the Virtual Fields Method. Theory and simulations
    Journal of Sound and Vibration, vol. 284, n° 3-5, pp. 757-781, 2005.

2006

29. Toussaint E., Grédiac M., Pierron F.
    The virtual fields method with piecewise virtual fields
    International Journal of Mechanical Sciences, vol. 48, n° 3, pp. 256-264, 2006.
30. Grédiac M., Pierron F.
    Applying the Virtual Fields Method to the identification of elasto-plastic constitutive parameters
    International Journal of Plasticity, vol. 22, pp. 602-627, 2006.
31. Moulart R., Avril S., Pierron F.
    Identification of the through-thickness rigidities of a thick laminated composite tube
    Composites Part A: Applied Science and Manufacturing, vol. 37, n° 2, pp. 326-336, 2006.
32. Chalal H., Avril S., Pierron F., Meraghni F.
    Experimental identification of a nonlinear model for composites using the grid technique coupled to the virtual fields method
    Composites Part A: Applied Science and Manufacturing, vol. 37, n° 2, pp. 315-325, 2006.
33. Ghidossi P., El Mansori M., Pierron F.
    Influence of specimen preparation by machining on the failure of polymer matrix off-axis tensile coupons
    Composites Science and Technology, vol. 66, pp. 1857-1872, 2006.
34. Pannier Y., Avril S., Rotinat R., Pierron F.
    Identification of elasto-plastic constitutive parameters from statically undetermined tests using the virtual fields method
    Experimental Mechanics, vol. 46, n° 6, pp. 735-755, 2006.
35. Grédiac M., Pierron F., Avril S., Toussaint E.
    The virtual fields method for extracting constitutive parameters from full-field measurements: a review
    Strain: an International Journal for Experimental Mechanics, vol. 42, pp. 233-253, 2006.
36. Giraudeau A., Guo B., Pierron F.
    Stiffness and damping identification from full field measurements on vibrating plates
    Experimental Mechanics, vol. 46, n° 6, pp. 777-787, 2006.

2007

37. Pierron F., Green B., Wisnom M.R.
    Full-field assessment of the damage process of laminated composite open-hole tensile specimens. Part I: methodology
    Composites Part A: Applied Science and Manufacturing, vol. 38, pp. 2307–2320, 2007.
38. Pierron F., Green B., Wisnom M.R., Hallett S.R.
    Full-field assessment of the damage process of laminated composite open-hole tensile specimens. Part II: experimental results
    Composites Part A: Applied Science and Manufacturing, vol. 38, pp. 2321–2332, 2007.
39. Avril S., Pierron F.
    General framework for the identification of elastic constitutive parameters from full-field measurements
    International Journal of Solids and Structures, vol. 44, pp. 4978-5002, 2007.
40. Maquin F., Pierron F.
    Experimental evidence of the microplasticity threshold in steel from heat dissipation measurements
    Comptes rendus Mécanique, vol. 335, n° 3, pp. 168-174, 2007.
41. Pierron F., Vert G., Burguete R., Avril S., Rotinat R., Wisnom M.
    Identification of the orthotropic elastic stiffnesses of composites with the virtual fields method: sensitivity study and experimental validation
    Strain: an International Journal for Experimental Mechanics, vol. 43, n° 3, pp. 250-259, 2007.
42. Kim J.-H., Pierron F., Wisnom M., Syed-Muhamad K., Identification of the local stiffness reduction of a damaged composite plate using the virtual fields method, Composites Part A: Applied Science and Manufacturing, vol. 38, n° 9, pp. 2065-2075, 2007.
43. Kim J.-H., Pierron F., Grédiac M., Wisnom M.
    A procedure for producing reflective coatings on plates to be used for full-field slope measurements by a deflectometry technique
    Strain: an International Journal for Experimental Mechanics, vol. 43, pp. 138-144, 2007.
44. Xavier J., Avril S., Pierron F., Morais J.L.
    Novel experimental approach for the characterisation of the LR stiffness parameters of clear wood using a single specimen
    Holzforschung, vol. 61, pp. 573-581, 2007.
45. Moulart R., Rotinat R., Pierron F., Lerondel G.
    On the realization of microscopic grids for local strain measurement by direct interferometric photolithography
    Optics and Lasers in Engineering, vol. 45, n° 12, pp. 1131-1147, 2007.

2008

46. Avril S., Pierron F., Pannier Y., Rotinat R.
    Stress reconstruction and constitutive parameter identification in elastoplasticity using measurements of deformation fields
    Experimental Mechanics, vol. 48, n° 4, pp. 403-419, 2008.
47. Avril S., Huntley J.M., Pierron F., Steele D.D.
    3D heterogeneous stiffness identification using MRI and the virtual fields method Experimental Mechanics, vol. 48, n° 4, pp. 479-494, 2008.
48. Sutton M.A., Yan J., Avril S., Pierron F., Adeeb S.M.
    Identification of heterogeneous parameters in a welded specimen: constant stress and virtual fields method for material property estimation
    Experimental Mechanics, vol. 48, n° 4, pp. 451-464, 2008.
49. Avril S., Bonnet M., Bretelle A.-S., Grédiac M., Hild F., Ienny P., Latourte F., Lemosse D., Pagano S., Pagnacco E., Pierron F.
    
    Identification from measurements of mechanical fields
    Experimental Mechanics, vol. 48, n° 4, pp. 381-402, 2008.
50. Avril S., Pierron F., Yan J., Sutton M.
    Identification of viscoplastic parameters and characterization of Lüders behaviour using Digital Image Correlation and the Virtual Fields Method
    Mechanics of Materials, vol. 40, n° 9, pp. 729-742, 2008.

2009

51. Maquin F., Pierron F.
    Heat dissipation measurements in low stress cyclic loading of metallic materials: from internal friction to micro-plasticity
    Mechanics of Materials, vol. 41, n° 8, pp. 928–942, 2009.
52. Moulart R., Rotinat R., Pierron F.
    Full-field evaluation of the onset of microplasticity in a steel specimen
    Mechanics of Materials, vol. 41, n° 11, pp. 1207-1222, 2009.
53. Commin L., Rotinat R., Pierron F., Masse J.-E., Barrallier L.
    Identification of shear bands in AZ31 friction stir welds and laser beam welds
    Materials Science and Technology, 2009. Accepted.
54. Pierron F.
    A novel method for measuring the through-thickness shear moduli of anisotropic plates from surface deformation measurements
    Composites Part A: Applied Science and Manufacturing, 2009. Accepted.
55. Xavier J., Avril S., Pierron F., Morais J., Lousada J.
    Evaluation of the stiffness radial variability of P. pinaster within the stem
    Composites Part A: Applied Science and Manufacturing, 2009. Accepted.
56. Kim J.H., Pierron F., Wisnom M., Avril S.
    Local stiffness reduction in impacted composite plates from full-field measurements
    Composites Part A: Applied Science and Manufacturing, 2009. Accepted.