SMART STRUCTURES AND MATERIALS （智能结构和材料）.pdfVIP

SMART STRUCTURES AND MATERIALS SMART STRUCTURES AND MATERIALS SMART SYSTEMS/ STRUCTURES Definition of Smart Systems/ Structures The definition of smart structures was a topic of controversy from the late 1970’s to the late 1980’s. In order to arrive at a consensus for major terminology, a special workshop was organised by the US Army Research Office in 1988, in which ‘sensors’, ‘actuators’, ‘control mechanism’ and ‘timely response’ were recognised as the four qualifying features of any smart system or structure (Rogers, 1988). In this workshop, following definition of smart systems/ structures was formally adopted (Ahmad, 1988). “A system or material which has built-in or intrinsic sensor(s), actuator(s) and control mechanism(s) whereby it is capable of sensing a stimulus, responding to it in a predetermined manner and extent, in a short/ appropriate time, and reverting to its original state as soon as the stimulus is removed” According to Vardan and Vardan (2000), smart system refers to a device which can sense changes in its environment and can make an optimal response by changing its material properties, geometry, mechanical or electromagnetic response. Both the sensor and the actuator functions with their appropriate feedback must be properly integrated. It should also be noted that if the response is too slow or too fast, the system could lose its application or could be dangerous (Takagi, 1990). Previously, the words ‘intelligent’, ‘adaptive’ and ‘organic’ were also used to characterize smart systems and materials. For example, Crawley and de Luis (1987) defined ‘intelligent structures’ as the structures possessing highly distributed actuators, sensors and processing networks. Similarly, Professor H. H. Robertshaw