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Numerical simulation of adiabatic sh...

Lear, Matthew Houck.

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Numerical simulation of adiabatic shear bands and crack propagation in thermoviscoplastic materials.

紀錄類型:	書目-電子資源 : Monograph/item
正題名/作者:	Numerical simulation of adiabatic shear bands and crack propagation in thermoviscoplastic materials./
作者:	Lear, Matthew Houck.
面頁冊數:	103 p.
附註:	Source: Dissertation Abstracts International, Volume: 64-02, Section: B, page: 0800.
Contained By:	Dissertation Abstracts International64-02B.
標題:	Applied Mechanics. -
電子資源:	http://pqdd.sinica.edu.tw/twdaoeng/servlet/advanced?query=3082593

Numerical simulation of adiabatic shear bands and crack propagation in thermoviscoplastic materials.
Lear, Matthew Houck.

Numerical simulation of adiabatic shear bands and crack propagation in thermoviscoplastic materials. - 103 p.

Source: Dissertation Abstracts International, Volume: 64-02, Section: B, page: 0800.

Thesis (Ph.D.)--Virginia Polytechnic Institute and State University, 2003.

Plane strain deformations of an elastoplastic material are studied using numerical methods. In the first chapter, a meshless formulation of the static small strain elastic-plastic problem is formulated using the meshless local Petrov-Galerkin method. The code is validated against the small strain plasticity routines in the commercial finite element code ABAQUS for two basic configurations with loading, unloading, and reloading. The results are found to agree within 5%. The validated code is then used to analyze the stress intensity factor (SIF) in a double edge-cracked plate. Deformations of the plate are studied both with and without exploiting the symmetry conditions. The penalty method is used to enforce the essential boundary condition in the former case. When analyzing the deformations of the entire plate, the diffraction method is employed in order to introduce the discontinuity in the displacement field across the crack faces. The log-log and a higher order extrapolation technique due to Dally and Berger (1996) are used to calculate the SIF. It is found that the penalty method was inadequate to enforce the essential boundary conditions in the vicinity of the crack tip and that in this region the deformations were oscillatory. Consequently, the SIF calculation using the higher order technique was not accurate. It is also found that for a small plastic zone (3% of the cracked length) the SIFs do not differ significantly from their values for the corresponding linear elastic problem.Subjects--Topical Terms:

1018410
Applied Mechanics.

Numerical simulation of adiabatic shear bands and crack propagation in thermoviscoplastic materials.
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100 1 $a Lear, Matthew Houck. $3 1944620
245 1 0 $a Numerical simulation of adiabatic shear bands and crack propagation in thermoviscoplastic materials.
300 $a 103 p.
500 $a Source: Dissertation Abstracts International, Volume: 64-02, Section: B, page: 0800.
500 $a Chair: Romesh C. Batra.
502 $a Thesis (Ph.D.)--Virginia Polytechnic Institute and State University, 2003.
520 $a Plane strain deformations of an elastoplastic material are studied using numerical methods. In the first chapter, a meshless formulation of the static small strain elastic-plastic problem is formulated using the meshless local Petrov-Galerkin method. The code is validated against the small strain plasticity routines in the commercial finite element code ABAQUS for two basic configurations with loading, unloading, and reloading. The results are found to agree within 5%. The validated code is then used to analyze the stress intensity factor (SIF) in a double edge-cracked plate. Deformations of the plate are studied both with and without exploiting the symmetry conditions. The penalty method is used to enforce the essential boundary condition in the former case. When analyzing the deformations of the entire plate, the diffraction method is employed in order to introduce the discontinuity in the displacement field across the crack faces. The log-log and a higher order extrapolation technique due to Dally and Berger (1996) are used to calculate the SIF. It is found that the penalty method was inadequate to enforce the essential boundary conditions in the vicinity of the crack tip and that in this region the deformations were oscillatory. Consequently, the SIF calculation using the higher order technique was not accurate. It is also found that for a small plastic zone (3% of the cracked length) the SIFs do not differ significantly from their values for the corresponding linear elastic problem.
520 $a In the second chapter, a finite element formulation of the dynamic deformations of a microporous thermoviscoplastic solid is formulated. The heat conduction in a material is assumed to be governed by a hyperbolic heat equation; thus thermal and mechanical waves propagate with finite speeds. The formation and propagation of an adiabatic shear band (ASB) in plane strain tensile deformations is studied for eleven materials. A parametric study of the effect of the initial defect strength where the defect is assumed through an initially inhomogeneous distribution of porosity, the thermal conductivity, the thermal wave speed, and the applied strain-rate upon the ASB initiation and propagation is conducted. It is found that the susceptibility ranking for this configuration differs somewhat from that previously found for simple shear and torsion of thin-walled tubes.
520 $a In the final chapter, the formulation from the previous chapter is modified to permit the formation and propagation of brittle and ductile fracture. (Abstract shortened by UMI.)
590 $a School code: 0247.
650 4 $a Applied Mechanics. $3 1018410
650 4 $a Engineering, Mechanical. $3 783786
690 $a 0346
690 $a 0548
710 2 0 $a Virginia Polytechnic Institute and State University. $3 1017496
773 0 $t Dissertation Abstracts International $g 64-02B.
790 1 0 $a Batra, Romesh C., $e advisor
790 $a 0247
791 $a Ph.D.
792 $a 2003
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoeng/servlet/advanced?query=3082593