Abstract :
Non-stationary phenomena arising in structures can 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
(p,, k,) and (pz, kJ of density and stiffness of smart material, this whole array traveling along the
bar with a suitable constant speed V. 0 1997 Elsevier Science Ltd. All rights reserved.
