System for monitoring the condition of structural elements

Abstract

A system for monitoring the condition of elongate structural elements, for example, railway rails, and a method of designing and manufacturing the system is disclosed. The method includes identifying and selecting suitable modes of propagation and signal frequencies that can be expected to travel large distances through an elongate structural element; designing a transducer that will excite the selected mode at the selected frequency; numerically modelling the transducer as attached to the elongate structural element; validating the transducer design by analysing a harmonic response of the selected mode of propagation to excitation by the transducer, and manufacturing one or more transducers for use in the system.

What is claimed is: 
     
         1 . A system for monitoring and detecting cracks or breaks in rails of a railway track, the system including a plurality of transducers defining transmitting and receiving stations of the system, characterised in that the transducers are located on the inner sides of the rails. 
     
     
         2 . The system of  claim 1  in which the plurality of transducers is in the form of a series of transducers located at predetermined spaced apart positions, with at least one transducer provided at each predetermined position, and with ultrasonic waves periodically being transmittable along the rail from one transducer used as a transmitter to a spaced apart transducer used as a receiver. 
     
     
         3 . The system of  claim 2  in which an array of the transducers is located at each predetermined position. 
     
     
         4 . The system of  claim 1  in which the plurality of transducers is in the form of a series of transducers located at predetermined spaced apart positions, with at least one transducer provided at each predetermined position, with ultrasonic waves periodically being transmittable along the rail from one transducer used as a transmitter, and reflected by a crack in the rail to the same transducer, which is also used as a receiver. 
     
     
         5 . The system of  claim 4  in which an array of the transducers is located at each predetermined position. 
     
     
         6 . The system of  claim 1 ,  claim 2  or  claim 4  in which the predetermined spaced apart positions are spaced apart by a distance of about 1 to 3 kilometres. 
     
     
         7 . The system of  claim 6  in which the predetermined spaced apart positions are spaced apart by a distance of about 2 kilometres. 
     
     
         8 . The system of  claim 6  in which an array of the transducers is located at each predetermined position.