Effective properties of smart elastic laminates and the screening phenomenon

Non-stationary phenomena arising in structures dan be effectively controlled via smart (intelligent) materials. The corresponding mathematical problems contain controls in the coefficients of hyperbolic equations, these controls depending both on position and time. When appropriately activated, such controls may provide 100% screening of some extended parts of the structure from the invasion of dynamic disturbances. For bars exposed to longitudinal vibrations, the material pattern producing such a screening effect can be the combination of rank-one laminar composites in space-time. Such a composite is described as an array of alternating segments with different pairs (rho(1), k(1)) and (rho(2), k(2)) of density and stiffness of smart material, this whole array traveling along the bar with a suitable constant speed V. (C) 1997 Elsevier Science Ltd. All rights reserved.