Affiliations: ESTIG, Instituto Politécnico de
Bragança, Campus de Sta. Apolónia, Bragança,
Portugal | IDMEC, Instituto Superior Técnico, Universidade
Técnica de Lisboa, Lisboa, Portugal
Note: [] Correctonding author: J.V. Araújo dos Santos, Instituto
Superior Técnico, Universidade Técnica de Lisboa, Av. Rovisco
Pais, 1049-001 Lisboa, Portugal. E-mail: viriato@ist.utl.pt
Abstract: This paper describes several interferometric techniques and their
applications in structural damage identification. With that objective in mind,
damaged aluminum beams with clamped-free and free-free boundary conditions are
analyzed. Different damages cases are inflicted by creating small cuts
perpendicular to the beams longitudinal axis, being the damage, therefore,
characterized by the dimensions of these cuts. The out-of-plane displacement
field of modal response is measured with an electronic speckle pattern
interferometric system. The static and dynamic rotation fields, defined as the
spatial derivative of the displacement field, are measured with two different
speckle shearography systems. Second and third order spatial derivatives of the
displacement field, which are related to the bending moment and shear force,
are computed by differentiation techniques. The cuts locations are determined
by looking for maximum values and/or perturbations of damage indicators based
on bending moments and shear forces. This method is validated by comparing its
results with numerical ones, from which the most suitable interferometric
technique is chosen.
