LASER-GENERATED AND RECORDED TRANSIENT BENDING WAVES IN COMPOSITE TUBES

Propagating bending waves are studied in three different composite tub es by holographic interferometry. A conical mirror is placed axially i nside the tubes. Axial illumination and observation directions make it possible to view the circumference of the tube, with a high sensitivi ty to radial deformation. It is shown how the deformation field can be numerically evaluated using a phase stepping and unwrapping technique . Transient bending waves in the tubes are both generated and recorded by the same pulsed laser, which makes the experiments easy to perform . Finite element simulations of the impacted tubes are compared to cor responding experiments. Both the geometry and the material properties of the tubes affect the wave propagation. For unidirectional composite tubes, the 0-deg and 90-deg directions have different dynamic behavio r. The proposed method could be used in nondestructive testing of tube s.