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Transient Excitation of an Elastic Half-Space by a Point Load Traveling on the Surface


Gakenheimer, David Charles (1969) Transient Excitation of an Elastic Half-Space by a Point Load Traveling on the Surface. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/5FEH-EG57.


The propagation of transient waves in an elastic half-space excited by a traveling normal point load is investigated. The load is suddenly applied and then it moves rectilinearly at a constant speed along the free surface. The displacements are computed for all points of the half-space as well as for all load speeds. The disturbance is analyzed by using multi-integral transforms and an inversion scheme based on the well-known Cagniard technique. This reduces the displacements to single integral and algebraic contributions, each of which is identified as the disturbance behind a specific wave front. The same solution is valid for all load speeds, even though the wave front geometry varies greatly, depending on the speed of the load relative to the body wave speeds. Moreover, the surface displacements are obtained from the interior ones, but only after the Rayleigh waves are computed by a separate calculation. Then, by taking advantage of the form of the exact solution, wave front expansions and Rayleigh wave approximations are computed for all load speeds. Several other analytical results are obtained for restricted values of the load speed. In particular, when it exceeds both of the body wave speeds the steady-state displacement field is separated from the transient one and reduced to algebraic form. Also, for the limit case of zero load speed a new representation of the interior displacements for Lamb's point load problem is displayed in terms of single integrals.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:(Applied Mechanics)
Degree Grantor:California Institute of Technology
Division:Engineering and Applied Science
Major Option:Applied Mechanics
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Miklowitz, Julius
Thesis Committee:
  • Unknown, Unknown
Defense Date:1 July 1968
Record Number:CaltechETD:etd-03022006-134535
Persistent URL:
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:837
Deposited By: Imported from ETD-db
Deposited On:03 Mar 2006
Last Modified:29 Apr 2024 20:55

Thesis Files

PDF (Gakenheimer_dc_1969.pdf) - Final Version
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