... half that of Haynes 25. Thus, current heart valve designs that use Nitinol should incorporate lessons learned from analyses of the BSCC heart valve to assess the likelihood of premature valve failure due to repeated loading. Bjork-Shiley short cracks Haynes 25 Nitinol threshold heart valves...

.... The long and short cracks are very different in characteristics of closure behavior under random loading. Crack growth of short and long cracks under random loading can be well described by the crack closure concept. The effects of random spectrum or random block length on crack opening load and crack...

... includes some geometrical aspects for the description of crack coalescence. fatigue short cracks crack simulation optical microscopy low carbon steel Journal of ASTM International, NovJDec. 2004, Vol. 1, No. 10 Paper ID JAI19048 Available online at www.astrn.org Joachim Hi~necke 1 and Dieter...

.... fracture testing SE(B) constraint plastic eta factor local plasticity short cracks welds undermatch welds J-R curves weld joint geometry gamma factor Gerard P. Mercier The Effect of Localized Plasticity and Crack Tip Constraint in Undermatched Welds Reference: Mercier, G. P., "The Effect...

... this methodology for the assessment of components gives rise to two problems. The first problem concerns geometry: real stress concentrations have complex shape and cannot be modelled as notches of simple profile. The second problem concerns notch size: can short notches be modelled in the same way as short cracks...

... fracture mechanics short cracks modelling Robert Akid THE ROLE OF STRESS-ASSISTED LOCALIZED CORROSION IN THE DEVELOPMENT OF SHORT FATIGUE CRACKS REFERENCE: Akid, R. "The Role of Stress-Assisted Localized Corrosion in the Development of Short Fatigue Cracks," Effects of the Environment...

... The kinetics of short cracks at notches were studied in 2014-T6511 Al-Cu alloy extruded bar stock under modified versions of FALSTAFF and TWIST load spectra. Experiments were conducted on test coupons of different thickness and at different stress levels. The effects of these and other...

... of cracks of an engineering size (≃ 1 mm). Though formulated in terms of a cumulative damage calculation, it is based on the consideration of short crack growth behavior. The main features are: • Consideration of load sequence dependent crack opening and closing levels controlled by the elasto-plastic...

... mechanics mechanical properties microcracks microscopy short cracks small cracks test methods James M. Larsen, 1 Jay R. Jira, ~ and Kakkaveri S. Ravichandran I Measurement of Small Cracks by Photomicroscopy: Experiments and Analysis REFERENCE: Larsen, J. M., Jira, J. R., and Ravichandran, K. S...

... to the measurement of closure, crack shape, and to automation of small-crack testing. automation crack propagation displacements fatigue materials fracture mechanics interferometry lasers mechanical properties microcracks short cracks small cracks test methods William N. Sharpe, Jr., 1 Jay R...

... to nonconservative lifetime estimates of a component that contains very small cracks. One major reason for this discrepancy may be traced to the fact that different closure levels are found at the same applied Δ K level for long and short cracks, respectively. Much effort has been given to the generation...

... to evaluate the effect of an R -value equal to 0.1, considering frequencies of 0.01 and 1.0 Hz. The crack is allowed to grow to a final length of 46 μm. The plastic zone in front of the crack tip is approximately equal to the initial crack length, yielding conditions associated with short cracks...

... The fatigue crack growth behavior of physically short cracks (0.2 ≤ a ≤ 1 mm), intermediate cracks (1 < a ≤ 2 mm), and long cracks (2 < a < 25 mm) at near-threshold and threshold levels was investigated with single-edge-notched-type specimens using four materials with stress...

... microcracks short cracks small cracks test methods James M. Larsen,^ James C. Williams,^ and Anthony W. Thompson^ Crack-Closure Effects on the Growth of Small Surface Cracks in Titanium-Aluminum Alloys REFERENCE: Larsen, J. M., Williams, J. C., and Thompson, A. W., "Crack-Closure Effects on the Growth...

... Single-edged notched specimens, 2.3 mm thick, of 2024-T3 aluminum were cyclicly loaded at R ratios of 0.5, 0.0, −1.0, and −2.0. The notch roots were periodically inspected with an optical microscope and with acetate replicas in order to locate the initiation of very short cracks. The loads...

...-element analysis of fatigue crack advance in plane strain. It is shown that the numerical analysis consistently underpredicts the magnitude of crack closure for both long and short cracks, particularly at near-threshold levels; an observation attributed to the fact that the numerical procedures can only...

... Plasticity induced crack closure and its effect on the fatigue growth of short cracks is investigated numerically. A plane stress finite-element analysis is used to simulate a nonpropagating crack of length 65 μm in a single-edge-cracked specimen under two stress levels and two values of stress...

... were concluded to be the primary features contributing to crack closure. crack closure crack propagation fatigue (materials) fracture mechanics mechanical properties minicomputers microcracks short cracks small cracks surface cracks test methods titanium alloys Jay R. Jira,^ Tusit...

... initiation crack growth J integral life prediction microshrinkage porosity SG irons short cracks fatigue life M. S. Starkey^ and P. E. Irving^ Prediction of Fatigue Life of Smootii Specimens of SG Iron by Using a Fracture Mechanics Approacii REFERENCE: Starkey, M. S. and Irving, P. E...

..., resulting in a pseudo-crack. The present paper introduces and analyzes an extensive data set pertinent to this so-called short-crack problem. Included are results for notched plates made from two aluminum alloys and a steel. These plates, which contain either circular or one of two different elliptical...