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Dynamic vertical displacements in pl...

Sykora, David Wayne.

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Dynamic vertical displacements in planar geosystems.

紀錄類型:	書目-電子資源 : Monograph/item
正題名/作者:	Dynamic vertical displacements in planar geosystems./
作者:	Sykora, David Wayne.
出版者:	Ann Arbor : ProQuest Dissertations & Theses, : 1993,
面頁冊數:	256 p.
附註:	Source: Dissertations Abstracts International, Volume: 55-10, Section: B.
Contained By:	Dissertations Abstracts International55-10B.
標題:	Civil engineering. -
電子資源:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=9413611

Dynamic vertical displacements in planar geosystems.
Sykora, David Wayne.

Dynamic vertical displacements in planar geosystems. - Ann Arbor : ProQuest Dissertations & Theses, 1993 - 256 p.

Source: Dissertations Abstracts International, Volume: 55-10, Section: B.

Thesis (Ph.D.)--The University of Texas at Austin, 1993.

This item must not be sold to any third party vendors.

This dissertation considers a method for approximating the variation of vertical displacements in space and time produced by dynamic loads in isotropic soil and rock media with complex planar geometry using the direct displacement formulation of the finite element method. Hysteretic material behavior is represented through the use of complex shear moduli. The important distinction is that the formulation allows planar (two-dimensional) geosystems with three-dimensional loads (i.e., synthetic sources) to be solved using a two-dimensional finite element model. The procedure involves condensing the three-dimensional dynamic stiffness matrices into equivalent two-dimensional matrices, representing the load function in the out-of-plane direction with a Fourier expansion, solving the system of equations in the wavenumber domain, and then using an inverse transform to obtain displacements. These types of problems cannot be solved analytically and normally would be solved using a laborious 3-D numerical approximation. The mathematical formulation was implemented in a computer code, compiled and run on CRAY Y-MP supercomputers, and validated using closed-form solutions for axi-symmetric problems. The results of computations proved that the formulation and implementation are correct and well suited for analysis of planar geosystems. The results of a parametric analysis provided recommended thresholds for system variables to maintain two different levels of desired accuracy. Two general problems were analyzed with results calculated using the new computer code f buried layers (continuous and discontinuous) and sloping ground. Practical findings were made for the use of surface waves to determine the variation of stiffness in these systems. In the case of sloping ground, comparisons were also made with field measurements of dynamic displacements. In general, good agreement exists between field data and numerical approximations. Sufficient evidence was collected to show that the spectral analysis of surface waves can be accurately and reliably applied to these types of geosystems. The results also suggest that the method can be applied to the analysis of geosystems with more complex geometries.Subjects--Topical Terms:

860360
Civil engineering.
Subjects--Index Terms:

finite element

Dynamic vertical displacements in planar geosystems.
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100 1 $a Sykora, David Wayne. $3 3546592
245 1 0 $a Dynamic vertical displacements in planar geosystems.
260 1 $a Ann Arbor : $b ProQuest Dissertations & Theses, $c 1993
300 $a 256 p.
500 $a Source: Dissertations Abstracts International, Volume: 55-10, Section: B.
500 $a Publisher info.: Dissertation/Thesis.
500 $a Advisor: Roesset, Jose M.
502 $a Thesis (Ph.D.)--The University of Texas at Austin, 1993.
506 $a This item must not be sold to any third party vendors.
506 $a This item must not be added to any third party search indexes.
520 $a This dissertation considers a method for approximating the variation of vertical displacements in space and time produced by dynamic loads in isotropic soil and rock media with complex planar geometry using the direct displacement formulation of the finite element method. Hysteretic material behavior is represented through the use of complex shear moduli. The important distinction is that the formulation allows planar (two-dimensional) geosystems with three-dimensional loads (i.e., synthetic sources) to be solved using a two-dimensional finite element model. The procedure involves condensing the three-dimensional dynamic stiffness matrices into equivalent two-dimensional matrices, representing the load function in the out-of-plane direction with a Fourier expansion, solving the system of equations in the wavenumber domain, and then using an inverse transform to obtain displacements. These types of problems cannot be solved analytically and normally would be solved using a laborious 3-D numerical approximation. The mathematical formulation was implemented in a computer code, compiled and run on CRAY Y-MP supercomputers, and validated using closed-form solutions for axi-symmetric problems. The results of computations proved that the formulation and implementation are correct and well suited for analysis of planar geosystems. The results of a parametric analysis provided recommended thresholds for system variables to maintain two different levels of desired accuracy. Two general problems were analyzed with results calculated using the new computer code f buried layers (continuous and discontinuous) and sloping ground. Practical findings were made for the use of surface waves to determine the variation of stiffness in these systems. In the case of sloping ground, comparisons were also made with field measurements of dynamic displacements. In general, good agreement exists between field data and numerical approximations. Sufficient evidence was collected to show that the spectral analysis of surface waves can be accurately and reliably applied to these types of geosystems. The results also suggest that the method can be applied to the analysis of geosystems with more complex geometries.
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650 4 $a Geophysics. $3 535228
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710 2 $a The University of Texas at Austin. $3 718984
773 0 $t Dissertations Abstracts International $g 55-10B.
790 $a 0227
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792 $a 1993
793 $a English
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=9413611