NEW CONTINUOUS SENSORS FOR CONDITION MONITORING OF MACHINES AND STRUCTURES

摘要

Conventionally, machinery condition monitoring is done using many sensors. The drawback of using many sensors is that signal processing and data acquisition is expensive. The continuous sensor was developed for efficient and reliable health monitoring of structures and to reduce the number of wires and channels of data acquisition needed to monitor large areas. The continuous sensor uses highly distributed interconnected sensors to form a sensor that produces a signal that is the combined output of the individual sensors. Processing of the signal from the continuous sensors enables in-situ real-time condition monitoring. The concept of continuous sensors was implemented with new types of continuous sensors based on accelerometers and strain gauges. The information from the sensors can represent anomalous structural events that might occur at multiple locations. The advantage of having a combined signal is that hallmark events can be detected at any sensor, but only one channel of data acquisition is needed. In another embodiment, a new continuous sensor was developed based on carbon nanotube thread. Strain in the nanotube thread leads to a change in the electrical resistance, which indicates the potential for use as a strain or crack sensor. The nanotube thread can be embedded into structures to provide a continuous strain signal which can be processed to detect high strains and damage. Overall, continuous sensors represent a new approach to efficiently monitor large structures for damage.