A full-engulfment engineering model, and its experimental and numerical verification, for the response of a rigid body to ground-shock

In this study, a new engineering model is presented which treats the motions of a rigid body to ground shock. A rigid body is defined as one whose deformations are small compared to the deformations of the surrounding media. The new model treats non-planar normal loads on the structure, tensile cut-off constraints at the upstream and downstream faces of the structure, and shear forces on the lateral surfaces of the structure. It assumes linear elastic material properties for all materials, and collinearity between reflected and transmitted particle velocities and stresses. An important feature of the model is that it incorporates the effects of wave diffraction around the rigid body through simple bounding arguments on the conditions which prevail in the shadow zone of the structure at early-times, intermediate-times, and late-times after the wave has engulfed the rigid body. The resulting expressions are uncomplicated, and provide bounds on the structure’s motion. The model was tested against a series of linear elastic finite element calculations and was found to be accurate, and able to explain the velocity overshoot which, while not widely known, accompanies the motions of rigid bodies under certain circumstances. The model was also tested against the results of a high-explosive test in sand, and a high explosive test in a competent shale, by treating the ground motion instrument canisters on the tests as rigid bodies. Again the model was found to be accurate, and accounted for the differences observed between finite difference predictions of the flow fields and the measured canisters’ responses. The model is expected to find application in aiding in the interpretation of ground motion measurements from explosion tests, in the design of ground motion transducers, and as an aid in the vulnerability analysis of underground Structures to the effects from large explosions.

Name thesis:degree_name

Ph. D.

Level thesis:degree_level

doctoral

Discipline thesis:degree_discipline

Engineering Mechanics

Department dc:contributor.department

Engineering Mechanics

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

1993

Author dc:creator

• Welch, Charles Robert

Chair dc:contributor.committeechair

• Cramer, Mark S.

Committee members dc:contributor.committeemember

• Reddy, Junuthula N.
• Rinehart, Eric
• Hendricks, Scott L.
• Morris, Don H.

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Language dc:language.iso

en

Dc Identifier Other

etd-09192008-063134

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/39400