Implementation of the direct evaluation of strains using a phase analysis code for random patterns

Jérôme Molimard (1, 2, 3, 4, 5, 6)

1 MPE-ENSMSE - Département Mécanique et Procédés d'Elaboration
2 LTDS - Laboratoire de Tribologie et Dynamique des Systèmes
3 DB2M-ENSMSE - Département Biomécanique et Biomatériaux
4 IFRESIS - Institut Fédératif de Recherche en Sciences et Ingénierie de la Santé
5 CIS-ENSMSE - Centre Ingénierie et Santé
6 LCG-ENSMSE - UMR 5146 - Laboratoire Claude Goux

A new approach for decoding directly strains from surfaces encoded with random patterns has been developed and validated. It is based on phase analysis of small region of interest. Here we adapt to random patterns new concepts proposed by Badulescu (2009) on the grid method. First metrological results are encouraging: resolution is proportional to strain level, being 9% of the nominal value, for a spatial resolution of 9 pixels (ZOI 64×64 pixels2). Random noise has to be carefully controlled. A numerical example shows the relevance of the approach. Then, first application on a carbon fiber reinforced composite is developed. Fabric intertwining is studied using a tensile test. Over-strains are clearly visible, and results connect well with the previous studies

Mots clés: Strain measurement; Phase analysis; Composite fabrics

Domaines: Biomécanique [physics.med-ph]; Biomécanique [physics.med-ph]; Matériaux

Jérôme Molimard. Implementation of the direct evaluation of strains using a phase analysis code for random patterns. Optics and Lasers in Engineering, 2011, 49 (9), pp.1194-1200. ⟨10.1016/j.optlaseng.2011.04.016⟩. ⟨hal-00620854⟩