For example, one can use active control to counteract buckling in compressively-loaded members, which is one of the most important factors limiting the overall strength and stability of a structure. By sensing deflections while they are still small, it is possible to apply only a small amount of force to counteract the buckling.
The thin beam shown on the left (edge view on the right) is a composite steel column that incorporates strain gauges and piezo-ceramic actuators, which permit it to actively resist buckling. This active column can support more than 5 times the maximum load for a passive structure of the same dimensions and composition. We have used columns like this to demonstrate that a model truss bridge with actively stabilized members can support greater loads than would be possible without active control.
Potential applications for buckling-controlled active members include structures that can support large transient loads, such airplane landing gear and earthquake-resistant bridges and buildings; and counteracting wave-induced metal fatigue in ships.
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Last modified July 23, 1995