J. L. Davis

Bio: J. L. Davis is an academic researcher from Picatinny Arsenal. The author has contributed to research in topics: Boundary value problem & Viscoelasticity. The author has an hindex of 1, co-authored 1 publications receiving 9 citations.

On wave propagation in viscoelastic media

Abstract: A mathematical analysis is made of the problem of wave propagation in a one-dimensional bounded viscoelastic medium under prescribed boundary conditions. Closed form expressions are obtained for viscoelastic waves for the case of a relaxation function involving a single relaxation time. An expression for the phase velocity as a function of ratio of relaxation frequency to frequency of applied periodic displacement is obtained for the steady state part of the solution. The generalization to a relaxation function involving a finite number of relaxation times is discussed, and a method is sketched out for solving the more general integropartial differential equation of motion. Comments are made on the molecular interpretation of viscoelastic models.

Frequency-dependent seismic attenuation in the inner core 1. A viscoelastic interpretation

Abstract: [1] Using reference source time functions, broadband velocity waveforms of PKIKP in the distance range 150–180° are inverted for a viscoelastic model of inner core attenuation. A mean Qα at 1 Hz of 307 ± 90 is determined from 345 available PKIKP ray paths. Both global and regional results find a depth-dependent attenuation in the deep inner core, with anisotropic attenuation resolved in regional results. Attenuation is much stronger in the upper 300 km of the inner core. The preferred model of viscoelastic attenuation is frequency dependent, with very weak velocity dispersion. Our data do not resolve any hemispherical differences of attenuation in the deep inner core.

Equivalences and Contrasts of Thermo-Elasticity and Thermo-Viscoelasticity: A Comprehensive Critique

Abstract: Similarities and differences between thermo-elasticity and thermo-viscoelas- ticity are critically examined and evaluated. Topics include, among others, constitutive relations, Poisson's ratio, energy dissipation, temperature effects on material properties, thermal expansions, loading histories, failure criteria, lifetimes, 1–D beams, torsion, columns, plates, motions in time of neutral axes and shear centers, computational issues, wave propagation, torsional divergence, control reversal, aerodynamic derivatives, flutter and experimental determinations of viscoelastic properties. The full, partial or no possible applications of the elastic/viscoelastic correspondence principle, including approximate approaches, are analyzed and discussed.

Coupled 1-D stress and thermal waves in temperature dependent nonlinear elastic and viscoelastic media*

Abstract: A general analysis is formulated for the closed loop coupled thermal and displacement viscoelastic 1-D wave problem. The proper inclusion of the highly temperature sensitive viscoelastic material p...