Full-field strain measurement and identification of composites moduli at high strain rate with the Virtual Fields Method

Raphael Moulart (1) , Fabrice Pierron (1) , Stephen R. Hallett (2) , Michael R. Wisnom (2)

1 MSMP - Mechanics surfaces and materials processing
2 University of Bristol [Bristol]

The present paper deals with full-field strain measurement on glass/epoxy composite tensile specimens submitted to high strain rate loading through a split Hopkinson pressure bar (SHPB) device and with the identification of their mechanical properties. First, the adopted methodology is presented: the device, including an Ultra-High Speed camera, and the experimental procedure to obtain relevant displacement maps are described. The different full-field results including displacement, strain and acceleration maps for two mechanical tests are then addressed. The last part of the paper deals with an original procedure to identify stiffnesses on this dynamic case only using the actual strain and acceleration maps (without the applied force) by using the Virtual Fields Method. The results provide very promising values of Young's modulus and Poisson's ratio on a quasi-isotropic glass-epoxy laminate. The load reconstructed from the moduli and strains compares favourably with that from the readings.

Mots clés: Full-field measurement; High strain rate; UHS camera; Grid method; SHPB; Virtual Fields Method; Fibre composites

Domaines: Mécanique [physics.med-ph]; Mécanique des matériaux [physics.class-ph]; Mécanique des matériaux [physics.class-ph]; Mécanique des solides [physics.class-ph]; Mécanique des solides [physics.class-ph]; Mécanique des structures [physics.class-ph]; Mécanique des structures [physics.class-ph]

Raphael Moulart, Fabrice Pierron, Stephen R. Hallett, Michael R. Wisnom. Full-field strain measurement and identification of composites moduli at high strain rate with the Virtual Fields Method. Experimental Mechanics, 2011, 51 (4), pp.509-536. ⟨10.1007/s11340-010-9433-4⟩. ⟨hal-01064631⟩