Active vibration control of composite laminated cylindrical shells via surface-bonded magnetostrictive layers

Active vibration control of composite laminated shells has been studied via embedded magnetostrictive layers. Magnetostriction targets the coupled strains or stresses; hence it is very important to develop a layerwise theory for laminates to determine the coupled strains and stresses accurately. The present layerwise theory satisfies the continuity conditions of transverse shear stresses and in-plane displacements at the interfaces of neighboring layers. This higher order layerwise theory has an advantage over the equivalent single layer theory and provides an intuitively correct computational model, which follows Newton's third law in perfect bonding conditions for laminated materials. The displacements of the layerwise theory combine classical thin shell theory and the displacements caused by the transverse shear stresses which satisfy the condition of zero transverse shear stresses at the free surface. Laminated composite shells with surface layers of magnetostrictive Terfenol-D particles have been studied. The direct and converse effects of these properties of smart materials are exploited here. Negative velocity feedback and constant gain controllers are used to achieve effective vibration suppression. The numerical results show that vibration suppression of the shell with magnetostrictive layers can be achieved by negative velocity feedback constant gain controllers.