Untitled - Society of Naval Architects and Marine Engineers

275 Pages·2003·4.01 MB·English

Table of Contents

1.0 Introduction 1

2.0 Background 12
2.1 Identification of critical fatigue-sensitive details 12
2.2 Types of fracture behavior 15
2.3 Fracture mechanics analysis 16

3.0 Fracture Experiments 35
3.1 Specimen fabrication, residual stress, and materials characterization 35
3.2 I-beams with structural details in bending 41
3.3 Box-beams with stiffened shell in bending 45
3.4 Cope-hole and CCT specimens in tension 47

4.0 Analyses of Experiments 98
4.1 PD6493 calculations 100
4.2 Plastic limit-load calculations for propagating cracks 111
4.3 Finite-element analyses to calculate applied J 112
4.4 J estimation schemes 115
4.5 Predicting crack propagation by the J-R curve analysis 121
4.6 Landes' normalization method 125
4.7 Predicting crack propagation by the crack opening angle 129

5.0 Guidelines for Application of Ductile Fracture Models to Ship Structures 180
5.1 Specification of steel and filler metal 180
5.2 Fracture mechanics test methods 183
5.3 Recommended ductile fracture models 185

6.0 Conclusions and Recommendations for Further Research 191

Appendix 1: Selected J-R Curves for the HSLA-80 and EH-36 Material
Appendix 2: Experimental Data from I-Beam Experiments
Appendix 3: Experimental Data from Box-Beam Experiments
Appendix 4: Experimental Data from Cope-Hole Experiments
Appendix 5: Sample Stress Intensity Factor Calculation
Appendix 6: Limit-Load Predictions for I-Beam and Box-beam Specimens

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Acknowledgements

This work was supported by the interagency Ship Structure Committee under contract
DTCG23-92-C-EO1031 The authors are grateful for the guidance of the Project Technical
Committee, especially the Chairman Walter Reuter of Idaho National Engineering
Laboratory and the Technical Advisor John Landes of the University of Tennessee. Stanley
Rolfe of the University of Kansas served as a consultant to Lehigh University on this project
and provided overall guidance on fracture mechanics assessment of ship structure,
particularly on the use of CTOD. Harold Reemsnyder of Bethlehem Steel Corporation
provided valuable insight and advice, particularly on the application of PD6493. In addition
to the authors, many others at Lehigh have contributed to this research, especially Bruce
Somers and Dayan Xiao. Professors John Fisher and Richard Roberts provided guidance
and advice. Several undergraduate students at Lehigh University contributed to the project,
especially Kenneth Gilvary and Kenneth George. The authors are also grateful for the work
of the technical staff at the ATLSS Laboratory and Fritz Laboratory, especially David
Schnalzer who fabricated many of the specimens and the photography of Richard Sopko.
Most of the test specimens were fabricated at Ingalls Shipbuilding.

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