Axial higher order modes cluster (A-HOMC) guided wave for pipe inspection

This paper reports the potential of Higher Order Modes Cluster Guided Waves (HOMC-GW) which are highly non-dispersive for axial testing in pipe over a couple of meters. The HOMC-GW is a recently explored phenomena which is found to occur at very high frequency-thickness product i.e. 15 MHz.mm to 35 MHz.mm. 2D ABAQUS finite element simulations were used to decide the optimal wedge angle which facilitates the generation of the HOMC-GW. Experiments were carried out on a 6 inch diameter mild steel pipe with machined pin hole type defects of various diameter and depth. A commercial 2.25 MHz, 1 inch diameter transducer mounted on a machined acrylic wedge was used. The potential of axially propagating HOMC-GW on pipe like structures is being brought into light. © 2010 American Institute of Physics.