Subcritical Crack Growth in Silica Optical Fibers in Wide Range of Crack Velocities

Muraoka, Mikio; Abé, Hiroyuki

doi:10.1111/j.1151-2916.1996.tb07879.x

Cited by 46 publications

(48 citation statements)

References 19 publications

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“…15) (3) Figure 6 shows the dierence from the results for bulk silica specimens for a wide range of crack velocities. 16) The data agreed with the exponential law rather than the power law for a wide range of da/dt. The eect of annealing is also shown.…”

Section: Delayed Failure In Silica Glass Berssupporting

confidence: 69%

An extension of fracture mechanics/technology to larger and smaller cracks/defects

Abé

2009

Proceedings of the Japan Academy. Ser. B: Physical and Biologic

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Fracture mechanics/technology is a key science and technology for the design and integrity assessment of the engineering structures. However, the conventional fracture mechanics has mostly targeted a limited size of cracks/defects, say of from several hundred microns to several tens of centimeters. The author and his group has tried to extend that limited size and establish a new version of fracture technology for very large cracks used in geothermal energy extraction and for very small cracks/defects or damage often appearing in the combination of mechanical and electronic components of engineering structures. Those new versions are reviewed in this paper.

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Section: Delayed Failure In Silica Glass Berssupporting

confidence: 69%

An extension of fracture mechanics/technology to larger and smaller cracks/defects

Abé

2009

Proceedings of the Japan Academy. Ser. B: Physical and Biologic

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“…However, Helfinstine and Gulati 18 (data shown in reference 19) made particularly extensive and careful measurements and found best agreement with the simple exponential, model 2. Muraoka and Abé 20 found similar results for both annealed and unannealed indentation cracks.…”

Section: Stress Dependencesupporting

confidence: 67%

Chemical Kinetics Models for the Fatigue Behavior of Fused Silica Optical Fiber

Matthewson

1998

MRS Proc.

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There have been numerous studies of the fatigue and strength behavior of fused silica optical fibers. However, no coherent model has emerged that self-consistently describes the simultaneous effects of stress, temperature and activity of the corroding species (e.g. water). A power law degradation kinetics model (relating the crack growth rate to the applied stress intensity factor, K I ) is widely used although various exponential forms based on chemical rate theory have also been proposed. The dependence of fatigue on parameters such as humidity, pH and temperature, has usually been treated in an empirical manner. Sometimes it is even ignoredfor example, the service environment is often assumed to be the same as the proof test environment when making lifetime predictions, thus avoiding the need for understanding the humidity dependence; this assumption is often unjustified. This paper reviews the dependence of fatigue on environmental factors and highlights some of the inconsistencies in published data. It is then attempted to present a coherent kinetics model that simultaneously accounts for stress temperature, humidity, etc. Several possible forms of the model are compared to a range of experimental data of several different types. The comparison is made using fitting techniques that account for correlation between fit parameters. It is found that a simple exponential form of the degradation kinetics model gives the best overall description of the temperature, humidity and pH effects on static and dynamic fatigue. It should be noted that the exponential form predicts shorter lifetimes than the ubiquitous power law model. Therefore, under some circumstances, the predictions of "worst case" models based on power law kinetics are unduly optimistic.

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“…There is less information available for weak fiber, probably because the increased scatter leads to inconclusive results (as is the case for the data considered here). However, there is evidence from slow crack growth measurements that the simple exponential form of equation (15) gives a better description than the other two [11,12]. Certainly, there is no evidence that Model 3, equation (16), fits any data best which is encouraging since it gives very pessimistic lifetime predictions.…”

Section: Calculation Of Spt Diagrams For Exponential Fatigue Kineticsmentioning

confidence: 80%

“…Figure 1b shows a log-log dynamic fatigue plot for these data where the points are the (geometric) mean of the data for each rate and the error bars are a 95% confidence interval for the mean. The solid line is found by fitting the power law fatigue equation (11) to the data using methods specified in FOTP-28. From the slope of the line the fatigue parameter n is found to be 19 with a 95% confidence interval from 13 to 36.…”

Section: Resultsmentioning

confidence: 99%

Strength-probability-time diagrams using power law and exponential kinetics models for fatigue

Matthewson

2006

SPIE Proceedings

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Strength-Probability-Time (SPT) diagrams provide an intuitively pleasing method for presenting reliability data based on extrapolations from accelerated fatigue testing data. If power-law crack growth kinetics are assumed the calculations required to generate the SPT diagram are particularly simple. However, if exponential or other more complex forms are used, this is not the case. If the accelerated data are for dynamic fatigue measurements (strength as a function of stressing rate) the SPT diagram can only be determined after numerical integration of the crack growth equations, followed by non-linear regression to the fatigue data. However, we have developed software to perform this task. In this paper we describe the methods used and show sample results of lifetime predictions using SPT diagrams. Also, the effect of using different crack growth kinetics models on predicted lifetimes is discussed.

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Subcritical Crack Growth in Silica Optical Fibers in Wide Range of Crack Velocities

Cited by 46 publications

References 19 publications

An extension of fracture mechanics/technology to larger and smaller cracks/defects

An extension of fracture mechanics/technology to larger and smaller cracks/defects

Chemical Kinetics Models for the Fatigue Behavior of Fused Silica Optical Fiber

Strength-probability-time diagrams using power law and exponential kinetics models for fatigue

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