Structural Shape Estimation Using Shaped Sensors.
Final rept. 1 Feb 94-31 Jul 96,
MASSACHUSETTS INST OF TECH CAMBRIDGE
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The estimation of the global shape of intelligent structures using an array of shaped sensors is investigated. The design of these sensors and their functional requirements are discussed. It is found that certain spatially averaging strain sensors can be used to satisfy these requirements. The output and transfer function characteristics of spatially averaging sensors with arbitrary spatial weightings are given for a sinusoidal and exponential strain fields desirable spatial weightings are then identified. A number of integration schemes used to process sensor measurements and estimate global shape are described. These schemes are then used with spatially averaging sensors to estimate the shape of pinned-pinned and clamped-free beams. Evanescent components in the modeshapes of the clamped-free beam make it more difficult to estimate the shape at low frequencies while ensuring reduced observability of the sensors to higher order modes. A measurement near the root is determined to be important, as is the use of shaped sensors. Finally, an experiment using a clamped-free beam fitted with a number of point and shaped strain sensors was conducted to verify that accurate modeshape estimation can be performed.
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