Transient response of sandwich viscoelastic beams, plates, and shells under impulse loading

The transient response of sandwich beams, plates, and shells with viscoelas tic layers tinder impulse loading is studied using the finite element metho d. The viscoelastic material behavior is represented by a complex modulus m odel. AR efficient method using the fast Fourier transform is proposed This method is based on the trigonometric representation of the input signals a nd the matrix of the transfer functions. The present approach makes it poss ible to preserve exactly the frequency dependence of the storage and loss m oduli of viscoelastic materials. The logarithmic decrements ave determined using the steady state vibrations of sandwich structures to characterize th eir damping properties. Test problems and numerical examples are given to d emonstrate the validity, and application of the approach suggested in this paper.