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The lateral buckling characteristics of flexible composite beams are actively controlled by activating sets of shape memory alloy (NITINOL) fibers which are embedded along the mid-plane of these beams.With such active control capabilities, the beams can be manufactured from light weight sections without compromising their elastic stability. This feature will be invaluable in building light weight structures that have high resistance to failure due to buckling.Finite element models are developed to analyze the mechanical and thermal characteristics of the composite beams. The models account for the individual contributions of the matrix, the NITINOL fibers and the shape memory effect to the overall performance of the composite beams. A closed-loop computer-controlled system is built to validate the finite element model. The system is used to control the lateral buckling of a composite beam which is 40.6 cm long, 5.1 cm wide and .25 cm thick which is reinforced with two NITINOL-55 fibers that are 0.55 mm in diameter.The results obtained confirm the validity of the developed theoretical model and indicate that the buckled beams can be brought back completely to their unbuckled configuration by proper activation of the shape memory effect. Also, the results obtained suggest that reinforcing the beams with NITINOL fibers is effective in enhancing their lateral buckling characteristics.

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