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equivalent pre-crack size approach

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Series: ASM Handbook
Volume: 11B
Publisher: ASM International
Published: 15 May 2022
DOI: 10.31399/asm.hb.v11B.a0006910
EISBN: 978-1-62708-395-9
... 29 ) following Broberg’s work on stable crack growth ( Ref 30 – 32 ) and later extended to cover the ductile tearing of polymers ( Ref 33 , 34 ), is currently the approach that is most often employed. It is based on the hypothesis that the total energy involved in the ductile fracture of a pre...
Series: ASM Failure Analysis Case Histories
Volume: 3
Publisher: ASM International
Published: 01 December 2019
DOI: 10.31399/asm.fach.v03.c9001789
EISBN: 978-1-62708-241-9
... in a corrosive environment will occur using the rising step load (RSL) method and a reasonable exposure time. The stress intensity parameter K is conservative in that it assumes the presence of a sharp crack or defect; and is useful for design as it includes the effect of defect size. Once the K th of each...
Series: ASM Handbook Archive
Volume: 11
Publisher: ASM International
Published: 01 January 2002
DOI: 10.31399/asm.hb.v11.a0003509
EISBN: 978-1-62708-180-1
... to the problem under consideration. The level 1 approach is based on the CTOD design curve method, which forms the basis of the elastic-plastic fracture assessment procedure. This approach has a deliberate safety factor built into the calculations, and it results in computation of “tolerable” crack sizes...
Series: ASM Handbook Archive
Volume: 11
Publisher: ASM International
Published: 01 January 2002
DOI: 10.31399/asm.hb.v11.a0003546
EISBN: 978-1-62708-180-1
... of crack-tip plasticity should be small in comparison to the ligament size, b, and the crack depth, a . The latter condition is definitely violated in SSTGs because of the small crack sizes being considered. Thus, nonlinear analysis using the J -integral concepts ( Ref 16 , 17 ) is needed...
Series: ASM Handbook Archive
Volume: 11
Publisher: ASM International
Published: 01 January 2002
DOI: 10.31399/asm.hb.v11.a0003564
EISBN: 978-1-62708-180-1
... by sintering and followed by HIPing and by gas pressure sintering have the best impact resistance. For ball sizes of 6.35 mm (0.25 in.), the maximum contact pressure of 20 to 25 GPa (2.9 to 3.6 × 10 6 psi) was required to form surface ring cracks; for ball sizes of 12.7 mm (0.50 in.), 10 to 15 GPa (1.5 to 2.2...
Book Chapter

Series: ASM Handbook Archive
Volume: 11
Publisher: ASM International
Published: 01 January 2002
DOI: 10.31399/asm.hb.v11.a0003544
EISBN: 978-1-62708-180-1
... of subcritical crack growth in structures. Its magnitude depends on the applied nominal stress, geometry, and the crack size. Fracture mechanics methods are thus used to determine the crack-growth rates of pre-existing cracks under cyclic loading, where the subcritical crack growth from fatigue loading, da / dN...
Series: ASM Handbook
Volume: 11
Publisher: ASM International
Published: 15 January 2021
DOI: 10.31399/asm.hb.v11.a0006829
EISBN: 978-1-62708-295-2
... ): (Eq 7) % GS = N ( A > A t ) N Stating that: PSR: %GS = 0% MFR: 0% < %GS < 100% GSR: %GS = 100% Hence, by using this approach, the competition between fretting wear and fretting cracking as a function of the applied displacement can be better...
Series: ASM Handbook
Volume: 11
Publisher: ASM International
Published: 15 January 2021
DOI: 10.31399/asm.hb.v11.a0006775
EISBN: 978-1-62708-295-2
... particle shows multiple cracks and shattering. Courtesy of R. Holman, University of Tennessee In materials containing a dual distribution of particle sizes (for example, MnS inclusions and spheroidal carbides in a quenched and tempered steel), a dual-dimple size is often seen on the fracture surface...
Series: ASM Handbook Archive
Volume: 11
Publisher: ASM International
Published: 01 January 2002
DOI: 10.31399/asm.hb.v11.a0003538
EISBN: 978-1-62708-180-1
..., no debonding was observed for any of the second-phase particles. Fracture initiation was by cleavage in the larger solute-addition-rich phases. The smaller second phases may or may not subsequently crack, depending on their size, but no debonding at the interface of second phases with the matrix was observed...
Series: ASM Handbook
Volume: 11
Publisher: ASM International
Published: 15 January 2021
DOI: 10.31399/asm.hb.v11.a0006765
EISBN: 978-1-62708-295-2
... in the preceding step. A satisfactory grinding sequence may involve SiC papers with grit sizes of 240-, 320-, 400-, and 600-grit (P280, P400, P800, and P1200, respectively). This sequence is used in the “traditional” preparation approach. Fig. 8 Light micrograph showing cutting damage (arrows at left...
Series: ASM Handbook
Volume: 11A
Publisher: ASM International
Published: 30 August 2021
DOI: 10.31399/asm.hb.v11A.a0006803
EISBN: 978-1-62708-329-4
..., then there is no need for a probabilistic analysis. Thus, the first goal of any researcher performing probabilistic analysis should be: What question am I trying to answer? In many aeronautical studies, the probabilistic analysis starts with an assumed through-wall crack. In some nuclear industry and many gas pipeline...
Series: ASM Handbook
Volume: 11A
Publisher: ASM International
Published: 30 August 2021
DOI: 10.31399/asm.hb.v11A.a0006808
EISBN: 978-1-62708-329-4
... deoxidation of the weld pool. The most common approach for eliminating hydrogen cold cracking—after ensuring that a low-hydrogen process is being used and that the base metal and filler metals are properly cleaned—is to employ preheating. The use of carbon equivalent (CE) formulas ( Ref 9 ) in conjunction...
Series: ASM Handbook
Volume: 11
Publisher: ASM International
Published: 15 January 2021
DOI: 10.31399/asm.hb.v11.a0006754
EISBN: 978-1-62708-295-2
... or corrosion damage; find crack origin(s); take better photos than may be possible outside of the lab; allow the investigation to proceed Before subsequent destructive testing Ultrasonic testing Document presence or absence and size and orientation of secondary cracks Before subsequent destructive...
Series: ASM Handbook Archive
Volume: 11
Publisher: ASM International
Published: 01 January 2002
DOI: 10.31399/asm.hb.v11.a0001818
EISBN: 978-1-62708-180-1
... of nozzles 1 and 2 and continued down the shell. Drain grooves had been arc gouged at the nozzle sites, and examination of the fracture surface at the grooves revealed short, flat segments of fracture area indicative of pre-existing cracks. These features were consistent with crack indications found...
Series: ASM Handbook
Volume: 11
Publisher: ASM International
Published: 15 January 2021
DOI: 10.31399/asm.hb.v11.a0006756
EISBN: 978-1-62708-295-2
... characterization approaches and categorization methods of damage mechanism are also covered. damage mechanism damage modes damage failure analysis THE PRINCIPAL TASK OF A FAILURE ANALYST during a physical-cause investigation is to identify the sequence of events involved in the failure. Technical...
Series: ASM Handbook
Volume: 11B
Publisher: ASM International
Published: 15 May 2022
DOI: 10.31399/asm.hb.v11B.a0006934
EISBN: 978-1-62708-395-9
... macroscopic fracture. Crazes and cracks develop in a similar manner. Nevertheless, in contrast to cracks and despite the small size of fibrils (~5 to 50 nm in diameter), crazes can carry stress due to the fibrillar network within a craze ( Ref 34 ). Fig. 7 Representation of craze morphology. Adapted...
Series: ASM Handbook Archive
Volume: 11
Publisher: ASM International
Published: 01 January 2002
DOI: 10.31399/asm.hb.v11.a0003521
EISBN: 978-1-62708-180-1
... test(s) can be performed to confirm or eliminate possible explanations and refine knowledge about the observed damage? Asking questions, much like the Socratic method in philosophy, is an essential part of failure analysis, because a recipe approach (i.e., following a prescribed set of procedures...
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.modes.c9001459
EISBN: 978-1-62708-234-1
..., and aircraft manufacturers and others have been responsible for a great many developments in connection with the investigation of fatigue failures, especially the fatigue testing of full-size components. Fatigue Crack Characteristics The most important characteristic of a fatigue failure, and one...
Series: ASM Handbook
Volume: 11B
Publisher: ASM International
Published: 15 May 2022
DOI: 10.31399/asm.hb.v11B.a0006941
EISBN: 978-1-62708-395-9
... that the equivalency between time and temperature holds best for amorphous polymers. However, further testing and study has shown that classes of polymers have different constants to be applied to the extrapolation. The approach assumes that the viscoelastic time-dependent function is f(t,T). The topic...
Series: ASM Handbook
Volume: 11B
Publisher: ASM International
Published: 15 May 2022
DOI: 10.31399/asm.hb.v11B.a0006943
EISBN: 978-1-62708-395-9
... of the order of a few micrometers or 10 −6 meters. A schematic relation between the resolution and the size scale for various examinations is presented in Fig. 2 . Higher resolution is required to identify smaller features of interest as length scale decreases and approaches nanometer values. Fig. 2...