THE VIRTUAL FIELDS METHOD

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The VFM

Applications: problem type

Applications: materials

Professor Michel GREDIAC

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University Degrees

• 1983 - Engineering Degree from École Nationale Supérieure d’Arts et Métiers in Paris (France).
• 1983 - Master of Science (DEA) in Mechanical Engineering from Paris VI University (France).
• 1984 - "Agregation" in Mechanical Engineering.
• 1989 - PhD (Doctorat) in Mechanical Engineering from University of Lyon (France).
• 1993 - ‘Habilitation à Diriger les Recherches’ (HDR) from University of Lyon, France (French degree necessary to supervise PhD students and apply to a professor chair).

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Professional Positions

• 1988- Lecturer at Ecole Nationale d'Ingénieurs de Saint-Etienne (France)
• 1991- Assistant professor at Jean Monnet University, Saint-Etienne (France)
• 1994- Research professor at École Nationale Supérieure des Mines de Saint-Étienne (France)
• 1997- Professor at Blaise Pascal University, Clermont-Ferrand (France)

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Administrative function

2003- Head of the network of 21 French research groups involved in full-field measurement techniques and identification (http://www.ifma.fr/lami/gdr2519/)

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Research interests

• Use of full-field measurement techniques in experimental solid mechanics (displacement, strain, temperature measurement).
• Development of the Virtual Fields Method, devoted to the identification of constitutive parameters from full-field measurements.
• Composite materials and structures: design, optimization and characterization.
• Reinforcement of metallic structures with composite materials

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Scientific activity

• Co-Chairman and organizer of "Photomechanics 2006", conference held in July 2007 in Clermont-Ferrand (France) – 128 participants from 17 countries.
• 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 Mechanics Society (AFM)
• Member of the British Society for Strain Measurement (BSSM)
• Member of the Society for Experimental Mechanics (SEM)

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Journal editing

• Member of the editorial board and council of the international journal “Strain” (Blackwell Publishing).
• Invited editor for special issues of Mecanique et Industries (Elsevier) on Full-Field Measurement methods and Identification, 2003.
• Invited editor for the Photomechanics 2006 special issue of the journal “Strain" (Blackwell Publishing).

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Reviewing

Regular reviewer for International Journal of Solids and Structures, Composites Science and Technology, Composites Part A, Optics and Lasers in Engineering (Elsevier), Experimental Mechanics (Springer).

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Publications

• 51 publications in international refereed journals + 3 in press
• 12 publications in French refereed journals
• 3 invited lectures
• 70 communications in international conferences with proceedings
• 53 communications in national conferences with proceedings

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Publications in international journals (August 2007)

1. Grédiac M.
   Principe des travaux virtuels et identification/Principle of virtual work and identification
   Comptes Rendus de l'Académie des Sciences, , vol. 302, pp 1-5, 1989.
2. Grédiac M., Vautrin A.
   A new method for determination of bending rigidities of thin anisotropic plates
   Journal of Applied Mechanics, vol. 57, pp 964-968, 1990.
3. Grédiac M., Hachani A., Vautrin A.
   Applying a quadriaxial extensometer to the strain analysis of anisotropic structures
   Composites Structures, vol. 17, pp 37-49, 1991.
4. Grédiac M., Vautrin A.
   Mechanical characterization of anisotropic plates : experiments and results
   European Journal of Mechanics/A Solids, vol. 12, n° 6, pp 819-838, 1993.
5. Grédiac M., Vautrin A. and Verchery G.
   A general method for data averaging of anisotropic elastic constants
   Journal of Applied Mechanics, vol. 60, pp 614-618, 1993.
6. Grédiac M.
   Four-point bending tests on off-axis composites
   Composite Structures, vol. 24, n° 3, pp 89-98, 1993.
7. Grédiac M.
   A finite element study of the transverse shear in honeycomb cores
   International Journal of Solids and Structures, vol. 30, n° 3, pp 1777-1788, 1993.
8. 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.
9. Benkeddad A., Grédiac M., Vautrin A.
   On the transient hygroscopic stresses in laminated composite plates
   Composite Structures, vol. 30, pp 201-205, 1995.
10. Grédiac M.
    The use of heterogeneous strain fields for the characterization of composite materials
    Composite Science and Technology, vol. 56, pp 841-846, 1996.
11. Benkeddad A., Grédiac M., Vautrin A.
    Computing of transient hygroscopic stresses in laminated plates
    Composite Science and Technology, vol. 56, pp 869-876, 1996.
12. Grédiac M.
    On the direct determination of invariant parameters governing the bending of anisotropic plates
    Experimental Mechanics, vol. 33, n°27, pp 3969-3982, 1996.
13. Grédiac M., Paris P. A.
    Direct identification of elastic constants of anisotropic plates by modal analysis : theoretical and numerical aspects
    Journal of Sound and Vibration, vol. 195, n° 3, pp 401-415, 1996.
14. Grédiac M.
    A method for surface reconstruction from slope or curvature of rectangular areas
    Applied Optics, vol. 36, pp 4823-4829, 1997.
15. 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.
16. Grédiac M., Fournier N., Paris P.A., Surrel Y.
    Direct identification of elastic constants of anisotropic plates by modal analysis : experiments and results
    Journal of Sound and Vibration, vol. 210, n° 5, pp 645-659, 1998.
17. Surrel Y., Fournier N., Grédiac M. Paris P.A.
    Phase-stepped deflectometry applied to shape measurement of bent plates
    Experimental Mechanics, vol. 39, n° 1, pp 66-70, 1999.
18. 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.
19. Grédiac M., Fournier N., Paris P.A., Surrel Y. Direct measurement of invariant parameters of composite plates
    Journal of Composite Materials, vol. 33, n° 20, pp 1939-1965, 1999.
20. Grédiac M., Fournier N., Paris P.A., Surrel Y. A procedure for designing laminated plates with required stiffness properties. Application to thin quasi-isotropic quasi-homogeneous laminates
    Journal of Composite Materials, vol. 33, n° 21, pp 2017-2040, 1999.
21. 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.
22. Grédiac M.
    On the design of some particular orthotropic plates with non-standard ply orientations
    Journal of Composite Materials, vol. 34, n° 19, pp 1665-1693, 2000.
23. 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.
24. 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.
25. Dufort L., Grédiac M. and Surrel Y.
    Experimental evidence of the cross section warping in short composite beams under three point bending
    Composite Structures, vol. 51, pp 37-47, 2001.
26. Grédiac M.
    On the stiffness design of thin woven composites
    Composite Structures, vol. 51, pp 245-255, 2001.
27. Dufort L., Drapier S., Grédiac M.
    Closed-form solution for the cross-section warping in short beams under three point bending
    Composite Structures, vol. 52, pp 233-246, 2001.
28. 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, vol. 32, n° 12, pp. 1713-1725, 2001.
29. Grédiac M., Dufort L.
    Experimental evidence of parasitic effects in the shear test on sandwich beams
    Experimental Mechanics, vol. 42, n° 2, pp. 186-193, 2002.
30. Sierra-Ruiz V., Destrebecq J.F., Grédiac M.
    The transfer length in concrete structures repaired with composite materials: a surveyof some analytical models and simplified approaches
    Composite Structures, vol. 55, pp. 445-454, 2002.
31. 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.
32. 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.
33. 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.
34. Racana N., Grédiac M., Gourvès R.
    Pull-out response of corrugated geotextile strips
    Geotextiles and Geomembranes, vol. 21, n° 5, pp. 265-337, 2004.
35. Grédiac M.
    The use of full-field measurement methods in composite material characterization : interest and limitations
    omposites Part A, vol. 35, pp. 751-761, 2004.
36. 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.
37. 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, vol. 35, n° 7-8, pp. 841-848, 2004.
38. Muller M., Toussaint E., Destrebecq J.F. and Grédiac M.
    {Experimental and numerical study of concrete specimens strengthened with composite plates
    Composites Part A, vol. 35, n° 7-8, pp. 885-893, 2004.
39. Grédiac M., Alzina A., Marquis D.
    {Optimal design of a multiperforated plate
    Journal of Composite Materials, vol. 38, n° 16, pp. 1401-1423, 2004.
40. Piro J.L., Grédiac M.
    {OpProducing and transferring low-spatial-frequency grids for measuring displacement fields with moiré and grid methods
    Experimental Techniques, vol. 28, n° 4, pp. 23-26, 2004.
41. 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.
42. 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.
43. Toussaint E., Destrebecq J.F., Grédiac M.
    A refined study of the crack propagation in cement-based composite beams under bending
    Cement and Concrete Composites, vol. 27, n° 6, pp. 399-411, 2005.
44. Mathias J.D., Balandraud X., Grédiac M.
    Applying a genetic algorithm to the optimization of composite patches
    Computers and Structures, vol. 84, pp. 823--834, 2006.
45. Mathias J.D., Balandraud X., Grédiac M.
    Experimental investigation of composite patches with a full-field measurement method
    Composites Part A, vol. 37, n°2, pp. 602-627, 2006.
46. 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.
47. Mathias J.D., Grédiac M. and Balandraud X.
    On the bidirectional stress distribution in rectangular bonded composite patches
    International Journal of Solids and Structures, vol. 43, pp. 6921-6947, 2006.
48. Toussaint E., Destrebecq J.F., Grédiac M.
    Rheological effects in reinforced concrete beams strengthened with CFRP-composite plates
    Archives of Civil Engineering, vol. 52, n°2, 2006.
49. 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.
50. Destrebecq J.F., Grédiac M., Sierra-Ruiz V.
    The transfer length in reinforced concrete structures strengthened with composite plates: experimental study and modelling
    Composites Science and Technology, vol. 67, pp. 3-4, 2006.
51. Muller M., Toussaint E., Destrebecq J.F., Grédiac M.
    Investigation into the time dependent behaviour of reinforced concrete specimens strengthned with externally bonded CFRP plates
    Composites Part B, vol. 38, n°4, pp. 417-428, 2007.
52. 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.
53. Mathias J.D., Grédiac M., Balandraud X.
    On the design of composite patches to reinforce damaged wings
    AIAA Journal2007, accepted.
54. Paluch B., Grédiac M., Faye A.
    Combining a finite element programme and a genetic algorithm to optimize composite structures with variable thickness
    Composite Structures2007, accepted.
55. Pastor M.L., Balandraud X., Grédiac M., Robert J.L.
    On the fatigue response of aluminium specimens reinforced with carbon-epoxy patches
    Composite Structures2007, accepted.