Viscoelastic damping and piezo-electric control of structures subjected to aerodynamic noise

The possibility of material damping due to viscoelastic material property degradation with time have been analyzed by Yi et al. (1996). Additional control of deformations and/or stresses by the introduction of elastic or viscoelastic piezo devices has bee shown most advan-tageous in an number of vibration and aero-viscoelastic problems by Beldica et al. (1998a, b, 1999) and Hilton et al. (1997). Viscoelastic material properties of piezoelectric devices have been demonstrated experimentally by Vinogradov & Holloway (1997, 1999) and Vinogradov & Schumaker (2001). In addition to decreases in viscoelastic relaxation moduli with time, failure stresses for viscoelastic materials also decrease with time, although in a manner not similar to that of the moduli (Dillard & Brinson 1983, Hiel et al. 1991). Hilton & Ariarat-nam (1994) have formulated invariant failure criteria for anisotropic materials leading to the prediction of deterministic or probabilistic structural survival times. Yi et al. (1999) have formulated finite element protocols for viscoelastic piezo stress and strain analyses. Finally, Beldica et al. (1999) have carried out FE parallel computations on piezo viscoelastic beams subjected to bending and torsion using ABAQUS. However, ABAQUS currently is limited to 16 parallel processors and does not utilize the full capabilities of modern supercomputers