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Stress-Strain-Time Relations Under Radial Loadings and Plastic Strain Under Static Tension and Cyclic Torsion for Aluminum Alloy.

Record Type:	Electronic resources : Monograph/item
Title/Author:	Stress-Strain-Time Relations Under Radial Loadings and Plastic Strain Under Static Tension and Cyclic Torsion for Aluminum Alloy./
Author:	Wu, Shu-Liang Bob.
Description:	1 online resource (144 pages)
Notes:	Source: Dissertations Abstracts International, Volume: 42-07, Section: B.
Contained By:	Dissertations Abstracts International42-07B.
Subject:	Metallurgy. -
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=8201168click for full text (PQDT)
ISBN:	9798661370655

Stress-Strain-Time Relations Under Radial Loadings and Plastic Strain Under Static Tension and Cyclic Torsion for Aluminum Alloy.
Wu, Shu-Liang Bob.

Stress-Strain-Time Relations Under Radial Loadings and Plastic Strain Under Static Tension and Cyclic Torsion for Aluminum Alloy. - 1 online resource (144 pages)

Source: Dissertations Abstracts International, Volume: 42-07, Section: B.

Thesis (Ph.D.)--University of California, Los Angeles, 1981.

Includes bibliographical references

The objective of this study is to improve the prediction of the stress-strain-time relationship and the plastic strain under static tension and cyclic torsion of Aluminum alloys. Structural components are increasingly required to serve at elevated temperatures; therefore, a more representative stress-strain-time relation in this temperature range is essential for engineering structural analyses. At this temperature, the creep strain becomes significant and induces a redistribution of stress in a redundant structure. Many engineering polycrystalline metals undergo considerable inelastic deformation before cracks occur. The most significant example is the failure of the nuclear reactor fuel elements cladding which is due in part to the inelastic deformation of pellet and cladding interaction (PCI). This inelastic deformation also can be seen in a number of aircraft structures. The most common methods used in the stress-strain-time calculations are purely phenomenological. Since they neglect the physical mechanism of inelastic deformation, they often lead to an inaccurate estimate. The purpose of this research is to combine the micromechanisms and the nature of plastic flow to find the constitutive equations among the stress, strain and time to predict the creep deformation. It is hoped that the theory developed will be able to apply to other metals. Aluminum single crystal tests show that slip occurs along certain crystal directions on certain crystal planes. The slip planes are those of highest atomic density and the slip directions correspond to the densest atomic packing directions. In an f.c.c. crystal, there are four slip planes and on each of which there are three slip directions. The main difference between single crystals and polycrystals is the presence of grain boundaries in polycrystals. The most significant effect of the grain boundaries is the constraining of inelastic (plastic and creep) deformation by neighboring grains. Since grain boundaries have been estimated to be only a few atoms thick, they are considered as surfaces of zero thickness between two differently oriented crystals. Consider a fine grained polycrystal(reference 9) composed of a very large number of identical cube-shaped blocks each of which consists of 64 differently oriented crystals. This region is embedded in an infinite isotropic elastic medium. The polycrystal macroscopic stress and inelastic strain are assumed to equal the average stress and strain over the 64 crystals of the center cube-shaped block. Slip is considered to be the only source of inelastic deformation. The rate of creep strain of the component crystals is taken to depend on the resolved shear stress, and independent of the normal stress on the sliding plane. The method to calculate the inelastic relationship was developed by Lin et al. (references 1 to 10), in which the inelastic strains are replaced by an equivalent set of applied body and surface forces. This method satisfies the condition of equilibrium, the condition of continuity of displacement, and the stress-strain relation of the component crystals. The method is here applied to the study of creep and cyclic plastic deformation. This study, considering the deformation mechanism, the hardening behavior of single crystal, and their steady and transient creep, is to be developed to predict the creep deformation of Aluminum alloy 2618-T61 in part I of this research. In part II of this research, the plastic strain under static tension and cyclic torsion of the Aluminum alloy 14ST has been studied. The calculated results seem to agree reasonably well with test results.

Electronic reproduction.
Ann Arbor, Mich. :
ProQuest,
2023

Mode of access: World Wide Web

ISBN: 9798661370655Subjects--Topical Terms:

535414
Metallurgy.
Index Terms--Genre/Form:

542853
Electronic books.

Stress-Strain-Time Relations Under Radial Loadings and Plastic Strain Under Static Tension and Cyclic Torsion for Aluminum Alloy.
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100 1 $a Wu, Shu-Liang Bob. $3 3698992
245 1 0 $a Stress-Strain-Time Relations Under Radial Loadings and Plastic Strain Under Static Tension and Cyclic Torsion for Aluminum Alloy.
264 0 $c 1981
300 $a 1 online resource (144 pages)
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500 $a Source: Dissertations Abstracts International, Volume: 42-07, Section: B.
500 $a Publisher info.: Dissertation/Thesis.
502 $a Thesis (Ph.D.)--University of California, Los Angeles, 1981.
504 $a Includes bibliographical references
520 $a The objective of this study is to improve the prediction of the stress-strain-time relationship and the plastic strain under static tension and cyclic torsion of Aluminum alloys. Structural components are increasingly required to serve at elevated temperatures; therefore, a more representative stress-strain-time relation in this temperature range is essential for engineering structural analyses. At this temperature, the creep strain becomes significant and induces a redistribution of stress in a redundant structure. Many engineering polycrystalline metals undergo considerable inelastic deformation before cracks occur. The most significant example is the failure of the nuclear reactor fuel elements cladding which is due in part to the inelastic deformation of pellet and cladding interaction (PCI). This inelastic deformation also can be seen in a number of aircraft structures. The most common methods used in the stress-strain-time calculations are purely phenomenological. Since they neglect the physical mechanism of inelastic deformation, they often lead to an inaccurate estimate. The purpose of this research is to combine the micromechanisms and the nature of plastic flow to find the constitutive equations among the stress, strain and time to predict the creep deformation. It is hoped that the theory developed will be able to apply to other metals. Aluminum single crystal tests show that slip occurs along certain crystal directions on certain crystal planes. The slip planes are those of highest atomic density and the slip directions correspond to the densest atomic packing directions. In an f.c.c. crystal, there are four slip planes and on each of which there are three slip directions. The main difference between single crystals and polycrystals is the presence of grain boundaries in polycrystals. The most significant effect of the grain boundaries is the constraining of inelastic (plastic and creep) deformation by neighboring grains. Since grain boundaries have been estimated to be only a few atoms thick, they are considered as surfaces of zero thickness between two differently oriented crystals. Consider a fine grained polycrystal(reference 9) composed of a very large number of identical cube-shaped blocks each of which consists of 64 differently oriented crystals. This region is embedded in an infinite isotropic elastic medium. The polycrystal macroscopic stress and inelastic strain are assumed to equal the average stress and strain over the 64 crystals of the center cube-shaped block. Slip is considered to be the only source of inelastic deformation. The rate of creep strain of the component crystals is taken to depend on the resolved shear stress, and independent of the normal stress on the sliding plane. The method to calculate the inelastic relationship was developed by Lin et al. (references 1 to 10), in which the inelastic strains are replaced by an equivalent set of applied body and surface forces. This method satisfies the condition of equilibrium, the condition of continuity of displacement, and the stress-strain relation of the component crystals. The method is here applied to the study of creep and cyclic plastic deformation. This study, considering the deformation mechanism, the hardening behavior of single crystal, and their steady and transient creep, is to be developed to predict the creep deformation of Aluminum alloy 2618-T61 in part I of this research. In part II of this research, the plastic strain under static tension and cyclic torsion of the Aluminum alloy 14ST has been studied. The calculated results seem to agree reasonably well with test results.
533 $a Electronic reproduction. $b Ann Arbor, Mich. : $c ProQuest, $d 2023
538 $a Mode of access: World Wide Web
650 4 $a Metallurgy. $3 535414
655 7 $a Electronic books. $2 lcsh $3 542853
690 $a 0794
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710 2 $a University of California, Los Angeles. $3 626622
773 0 $t Dissertations Abstracts International $g 42-07B.
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=8201168 $z click for full text (PQDT)