ABSTRACT
An approach, based on so called Virtual Distortion Method, to dynamic analysis of physically nonhnear (elasto-visco-plastic, piece-wise linear) truss structures is presented. Then, this dynamic analysis is applied to optimal design of adaptive structures (equipped with special devices allowing control of local yield limits) for improved impact absorption. The discussed strategy of damage protection initiates actuators just before collapse of local section of the structure protecting each structural element against the local failure (plastic behaviour).
The second application of adaptive structure presented in this paper is shape control of railway track over a bridge. The concept of adaptive railway track, with sleepers initially elevated (with the curvature tailored according to the detected, coming train) and then yielding in a controlled way (by opening valves in hydraulic pistons) under moving train is discussed. The problem formulated as shape control requiring the minimum mean square measure of the track deflection gives, as a side effect, a significant reduction of the corresponding mean square measure of the dynamic contact forces between track and wheels.
