Results are described of a theoretical and experimental investigation of the effects of collision damage in the form of elasto-plastic lateral bending and local indentations, on the stiffness and strength of tubular steel bracing members. Full-scale tests have been carried out on two pairs of nominally identical braces obtained from the BP West Sole Platform, recently removed from the North Sea following completion of service. One tube from each pair was tested to collapsl under compres sive load in an initially undamaged condition while the second was tested to collaple following application of simulated collis:·.on dama,.:,e, thus providing a direct indication of damage effects. Results were found to correlate satisfactorily with theoretical analysis and with four tests on small-scale tUbes representing as closely as possible the fullscale experiments. The relationship between collision loads and damage deformations was examined.

An experimental study of passive damping in rotating composite I-beams is presented. Damping is augmented in a Gr/Ep I-beam using a co-curable viscoelastic material layer in the flanges of the I-beam. This study examines the effects of variable visco-elastic material thickness in the flange in improving passive damping performance. Experimentation is carried out in both a non-rotating, and rotating condition in the vaccuum chamber.

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