Semi-analytical FEM Analysis and Experimental Measurement for Propagating Guided Waves Modes in Rail

Laser vibrometer measurement of guided wave modes in rail track.

The ability to measure the individual modes of propagation is very beneficial during the development of guided wave ultrasound based rail monitoring systems. Scanning laser vibrometers can measure the displacement at a number of measurement points on the surface of the rail track. A technique for estimating the amplitude of the individual modes of propagation from these measurements is presente...

Rail Inspection with Guided Waves

The critical subject of transverse crack detection in a rail head is treated in this paper. Conventional bulk wave ultrasonic techniques often fail because of shelling and other surface imperfections that shield the defects that lie below the shelling. A guided wave inspection technique is introduced here that can send ultrasonic energy along the rail under the shelling with a capability of fin...

Propagating modes in gain-guided optical fibers.

Optical fibers in which gain-guiding effects are significant or even dominant compared with conventional index guiding may become of practical interest for future high-power single-mode fiber lasers. I derive the propagation characteristics of symmetrical slab waveguides and cylindrical optical fibers having arbitrary amounts of mixed gain and index guiding, assuming a single uniform transverse...

Observation of propagating edge spin waves modes

Bloch waves and non - propagating modes in photonic crystals

We investigate the propagation of electromagnetic waves in finite photonic band gap structures. We analyze the phenomenon of conduction and forbidden bands and we show that two regimes are to be distinguished with respect to the existence of a strong field near the interfaces. We precise the domain for which an effective medium theory is sounded.