PIEZOELECTRIC CABLE: GOES TO GREAT LENGTHS FOR PRESSURE SENSING

A long, small diameter piezoelectric cable has become available for use as a sensor device. The long length of the cable is exciting in that measurement can take place anywhere along its length. This is an excellent characteristic when measuring the dynamic behaviour of a continuous system. Measuring at a point (for example using strain gauges) is often not satisfactory as the point may or may not correspond to a node (or nodes) associated with one or more modes of vibration of the system. By monitoring over a length however, this problem is overcome. The disadvantage with measuring over a length is that the output signal is a summation of all the events along the length and a quantity that does not indicate an exact position.