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Dynamic stiffness matrices for homogeneous viscoelastic halfplanes

Dasgupta, Gautam; Chopra, Anil K.

UCB/EERC-77/26, Earthquake Engineering Research Center, University of California, Berkeley, 1977-11, 121 pages (535/D3/77/26)

Analytical expressions and numerical results are presented for the complex-valued, dynamic (frequency dependent), flexibility influence coefficients for a homogeneous, isotropic, linearly viscoelastic halfspace in plane strain or generalized plane stress. These influence coefficients, defined for uniformly spaced nodal points at the surface of the halfspace, are obtained from solutions of two boundary value problems associated with harmonically time-varying stresses uniformly distributed between two adjacent nodal points. Numerical values for these coefficients are presented for a viscoelastic halfspace of constant hysteretic material. A method is developed to determine from these results the dynamic stiffness matrix associated with the nodal points at the base of a surface-supported structure for the halfspace. The resulting dynamic stiffness matrix is shown to be superior compared to the one determined from an available procedure which is based on solutions of displacement boundary-value problems for the halfspace.

Available online: http://nisee.berkeley.edu/documents/EERC/EERC-77-26.pdf (29 MB)