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Numerical modeling of 3-dimensional ...

Settgast, Randolph Richard.

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Numerical modeling of 3-dimensional surface separation.

Record Type:	Electronic resources : Monograph/item
Title/Author:	Numerical modeling of 3-dimensional surface separation./
Author:	Settgast, Randolph Richard.
Description:	118 p.
Notes:	Source: Dissertation Abstracts International, Volume: 67-04, Section: B, page: 2068.
Contained By:	Dissertation Abstracts International67-04B.
Subject:	Applied Mechanics. -
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3212882
ISBN:	9780542635113

Numerical modeling of 3-dimensional surface separation.
Settgast, Randolph Richard.

Numerical modeling of 3-dimensional surface separation. - 118 p.

Source: Dissertation Abstracts International, Volume: 67-04, Section: B, page: 2068.

Thesis (Ph.D.)--University of California, Davis, 2006.

Embedding cohesive surfaces into finite element analysis is a widely used technique for the numerical simulation of surface separation (i.e., crack propagation). The cohesive zone method applies cohesive tractions to the separating surfaces to simulate the effects of rupturing material. Typically, a traction-separation law is used to relate the magnitude of the cohesive tractions to the distance between the separating surfaces. Use of this simple relation results in a potentially overly simplistic theory, as issues such as crack-tip constraint levels are inherently ignored. In this study, the "Cohesive Continuum Framework" (CCF) is presented as a new 3-dimensional method for calculating the response of material undergoing the separation process. The CCF presents the concept of a kinematic tensor that includes contributions from the standard deformation gradient, gap vector, and a length scale. This tensor is used to update a material state using the same constitutive law as the surrounding bulk material. This material state is then used to generate cohesive stresses that are applied to the body. As the definition of such a tensor requires certain assumptions be made regarding the configuration of the rupturing material, two separate formulations are presented in this study. The Finite Thickness Layer Formulation (FTLF) assumes that the rupture process occurs across a layer of material with non-zero thickness, while the Surface Based Formulation (SBF) assumes that the rupture process occurs across a 2-dimensional surface. The CCF also specifies that a material rupture function be defined in order to quantify the progression towards complete rupture of a particular material state in a particular direction. The CCF is implemented in an explicit 3-dimensional finite element code. Various analyses using both linear elastic and Gurson void growth constitutive relations are presented in order to display basic features of the CCF. A 3-point bend specimen is simulated, and provides good agreement with experimental results. The results of presented analyses indicate that the Cohesive Continuum Framework provides the natural ability to capture any dependencies on stress triaxiality near the crack tip, and represents a substantial contribution to the state of the art in computational fracture mechanics.

ISBN: 9780542635113Subjects--Topical Terms:

1018410
Applied Mechanics.

Numerical modeling of 3-dimensional surface separation.
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100 1 $a Settgast, Randolph Richard. $3 1919901
245 1 0 $a Numerical modeling of 3-dimensional surface separation.
300 $a 118 p.
500 $a Source: Dissertation Abstracts International, Volume: 67-04, Section: B, page: 2068.
500 $a Adviser: Mark M. Rashid.
502 $a Thesis (Ph.D.)--University of California, Davis, 2006.
520 $a Embedding cohesive surfaces into finite element analysis is a widely used technique for the numerical simulation of surface separation (i.e., crack propagation). The cohesive zone method applies cohesive tractions to the separating surfaces to simulate the effects of rupturing material. Typically, a traction-separation law is used to relate the magnitude of the cohesive tractions to the distance between the separating surfaces. Use of this simple relation results in a potentially overly simplistic theory, as issues such as crack-tip constraint levels are inherently ignored. In this study, the "Cohesive Continuum Framework" (CCF) is presented as a new 3-dimensional method for calculating the response of material undergoing the separation process. The CCF presents the concept of a kinematic tensor that includes contributions from the standard deformation gradient, gap vector, and a length scale. This tensor is used to update a material state using the same constitutive law as the surrounding bulk material. This material state is then used to generate cohesive stresses that are applied to the body. As the definition of such a tensor requires certain assumptions be made regarding the configuration of the rupturing material, two separate formulations are presented in this study. The Finite Thickness Layer Formulation (FTLF) assumes that the rupture process occurs across a layer of material with non-zero thickness, while the Surface Based Formulation (SBF) assumes that the rupture process occurs across a 2-dimensional surface. The CCF also specifies that a material rupture function be defined in order to quantify the progression towards complete rupture of a particular material state in a particular direction. The CCF is implemented in an explicit 3-dimensional finite element code. Various analyses using both linear elastic and Gurson void growth constitutive relations are presented in order to display basic features of the CCF. A 3-point bend specimen is simulated, and provides good agreement with experimental results. The results of presented analyses indicate that the Cohesive Continuum Framework provides the natural ability to capture any dependencies on stress triaxiality near the crack tip, and represents a substantial contribution to the state of the art in computational fracture mechanics.
590 $a School code: 0029.
650 4 $a Applied Mechanics. $3 1018410
650 4 $a Engineering, Civil. $3 783781
650 4 $a Engineering, Mechanical. $3 783786
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710 2 0 $a University of California, Davis. $3 1018682
773 0 $t Dissertation Abstracts International $g 67-04B.
790 1 0 $a Rashid, Mark M., $e advisor
790 $a 0029
791 $a Ph.D.
792 $a 2006
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3212882