VERTICAL MOTION OF RIGID FOOTINGS.

Abstract

This work deals with the vertical mode of vibration of a rigid circular footing resting on a plane soil surface and excited by a vertical time-dependent force in the axis of symmetry. It is assumed that the subsoil can be considered as a perfectly elastic, isotropic, and homogeneous half space. First an approximate theoretical solution is developed for the steadystate motion of the above half-space model. This solution differs from previously published solutions in that it includes all frequencies of excitation. It is then shown how the transient response due to a pulse-type loading can be calculated from the steady-state solution by a simple Fourier technique, and a computer program using this technique is presented. Parallel with the above development it is shown that the elastic half-space model behaves very similarly to a simple damped oscillator, and the author proposes the use of a simplified analog of the mass-spring-dashpot type for practical calculations. The above theoretical results are supported by the presentation of both steady-state and impact tests performed by other researchers. (Author)

Document Details

Document Type
Technical Report
Publication Date
Jun 01, 1965
Accession Number
AD0469600

Entities

People

  • John Lysmer

Organizations

  • University of Michigan

Tags

Communities of Interest

  • Air Platforms

DTIC Thesaurus Topics

  • Computer Programs
  • Computers
  • Doppler Effect
  • Excitation
  • Frequency
  • Frequency Shift
  • Impact Tests
  • Oscillators
  • Steady State
  • Symmetry
  • Vibration

Readers

  • Control Systems Engineering.
  • Structural Dynamics.

Technology Areas

  • Space