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A Quantitative Weld Sizing Criterion for Welded Connections in Lightweight Shipboard Structures : = Modeling, Validation, and Structural Applications.

Record Type:	Electronic resources : Monograph/item
Title/Author:	A Quantitative Weld Sizing Criterion for Welded Connections in Lightweight Shipboard Structures :/
Reminder of title:	Modeling, Validation, and Structural Applications.
Author:	Lu, Hanqing.
Description:	1 online resource (204 pages)
Notes:	Source: Dissertations Abstracts International, Volume: 83-05, Section: B.
Contained By:	Dissertations Abstracts International83-05B.
Subject:	Engineering. -
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=28845274click for full text (PQDT)
ISBN:	9798471101227

A Quantitative Weld Sizing Criterion for Welded Connections in Lightweight Shipboard Structures : = Modeling, Validation, and Structural Applications.
Lu, Hanqing.

A Quantitative Weld Sizing Criterion for Welded Connections in Lightweight Shipboard Structures :Modeling, Validation, and Structural Applications. - 1 online resource (204 pages)

Source: Dissertations Abstracts International, Volume: 83-05, Section: B.

Thesis (Ph.D.)--University of Michigan, 2021.

Includes bibliographical references

Rampant welding-induced distortions in construction of modern lightweight shipboard structures not only increase production cost, but also cause structural integrity concerns in service. Numerous recent studies have shown that overwelding in complying with the existing empirical-based fillet weld sizing criteria is the key contributor. Fillet-welded connections are widely used in the construction of marine structures. However, due to the complex stress state in fillet-welded connections and the lack of an effective means to relate the stress state at a joint to failure conditions observed in standardized component tests, existing weld sizing criteria in Codes and Standards used today were largely based on design experiences and observations from limited test data, dating back to decades ago. Therefore, a more quantitative mechanics-based weld sizing criterion must be developed for not only enabling the cost-effective construction of lightweight ship structures, but also ensuring structural safety in service. In this study, a traction stress based mesh-insensitive method is introduced for characterizing the complex stress state and its relationship to weld failure conditions in fillet-welded components. The insights gained enable the development of a closed-form solution for relating weld throat shear stress state to remotely applied loading conditions, which in turn leads to an effective traction stress based failure criterion serving as a mechanics basis for achieving quantitative weld sizing. To support and validate the analytical developments, a comprehensive testing program using over 200 standard longitudinal and transverse shear joint specimens was carried out. The test results have proven the effectiveness of the closed-form failure criterion in predicting both failure angle and correlating joint strength test data. A careful observation of the test data obtained in this study suggests that certain nonlinear effects such as plate-to-plate contact can be important in certain type of test configurations. This leads to the development of a new analytical formulation for incorporating the nonlinear effects to further generalize the effective traction stress based weld sizing failure criterion for a broader range of structural applications. To further validate the effectiveness of the developed quantitative weld sizing failure criterion, a large number of well-known full-scale test data available from past and recent literature on hollow structural section (HSS) joints have been analyzed in detail. The results show that the correlations between the predicted failure loads with the proposed failure criterion and the measured loads offer as much as 60% improvement over those predicted by the existing Codes and Standards, confirming the validity of the proposed failure criterion resulted from this study. Finally, within the context of these standard shear test specimens and full-scale HSS connections, it can be shown that the quantitative weld sizing criterion proposed in this study can result in a weld size reduction as much as 40%, compared with the existing empirical-based weld sizing criteria used today, which can be very beneficial for welding-induced distortion control in the construction of lightweight shipboard structures.

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

Mode of access: World Wide Web

ISBN: 9798471101227Subjects--Topical Terms:

586835
Engineering.
Subjects--Index Terms:

Fillet weldIndex Terms--Genre/Form:

542853
Electronic books.

A Quantitative Weld Sizing Criterion for Welded Connections in Lightweight Shipboard Structures : = Modeling, Validation, and Structural Applications.
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502 $a Thesis (Ph.D.)--University of Michigan, 2021.
504 $a Includes bibliographical references
520 $a Rampant welding-induced distortions in construction of modern lightweight shipboard structures not only increase production cost, but also cause structural integrity concerns in service. Numerous recent studies have shown that overwelding in complying with the existing empirical-based fillet weld sizing criteria is the key contributor. Fillet-welded connections are widely used in the construction of marine structures. However, due to the complex stress state in fillet-welded connections and the lack of an effective means to relate the stress state at a joint to failure conditions observed in standardized component tests, existing weld sizing criteria in Codes and Standards used today were largely based on design experiences and observations from limited test data, dating back to decades ago. Therefore, a more quantitative mechanics-based weld sizing criterion must be developed for not only enabling the cost-effective construction of lightweight ship structures, but also ensuring structural safety in service. In this study, a traction stress based mesh-insensitive method is introduced for characterizing the complex stress state and its relationship to weld failure conditions in fillet-welded components. The insights gained enable the development of a closed-form solution for relating weld throat shear stress state to remotely applied loading conditions, which in turn leads to an effective traction stress based failure criterion serving as a mechanics basis for achieving quantitative weld sizing. To support and validate the analytical developments, a comprehensive testing program using over 200 standard longitudinal and transverse shear joint specimens was carried out. The test results have proven the effectiveness of the closed-form failure criterion in predicting both failure angle and correlating joint strength test data. A careful observation of the test data obtained in this study suggests that certain nonlinear effects such as plate-to-plate contact can be important in certain type of test configurations. This leads to the development of a new analytical formulation for incorporating the nonlinear effects to further generalize the effective traction stress based weld sizing failure criterion for a broader range of structural applications. To further validate the effectiveness of the developed quantitative weld sizing failure criterion, a large number of well-known full-scale test data available from past and recent literature on hollow structural section (HSS) joints have been analyzed in detail. The results show that the correlations between the predicted failure loads with the proposed failure criterion and the measured loads offer as much as 60% improvement over those predicted by the existing Codes and Standards, confirming the validity of the proposed failure criterion resulted from this study. Finally, within the context of these standard shear test specimens and full-scale HSS connections, it can be shown that the quantitative weld sizing criterion proposed in this study can result in a weld size reduction as much as 40%, compared with the existing empirical-based weld sizing criteria used today, which can be very beneficial for welding-induced distortion control in the construction of lightweight shipboard structures.
533 $a Electronic reproduction. $b Ann Arbor, Mich. : $c ProQuest, $d 2023
538 $a Mode of access: World Wide Web
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650 4 $a Naval engineering. $3 3173824
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653 $a Failure criterion
653 $a Weld sizing
653 $a Lightweight
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