BSI PD IEC/TR 62048:2014
$198.66
Optical fibres. Reliability. Power law theory
| Published By | Publication Date | Number of Pages |
| BSI | 2014 | 70 |
This technical r eport is a guideline that gives formulae to estimate the reliability of fibre under a constant service stress based on a power law for crack growth.
NOTE Power law is derived empirically, but there are other laws which have a more physical basis (for example, the exponential law). All these laws generally fit short -term experimental data well but lead to different long -term predictions. The power law has been selected as a most reasonable representation of fatigue behaviour by the experts of several standard-formulating bodies.
PDF Catalog
| PDF Pages | PDF Title |
|---|---|
| 4 | CONTENTS |
| 7 | FOREWORD |
| 9 | INTRODUCTION |
| 10 | 1 Scope 2 Normative references 3 Symbols Tables Table 1 – Symbols |
| 12 | 4 General approach 5 Formula types |
| 13 | 6 Measuring parameters for fibre reliability 6.1 Overview 6.2 Length and equivalent length |
| 14 | 6.3 Reliability parameters 6.3.1 Overview 6.3.2 Proof-testing 6.3.3 Static fatigue |
| 15 | 6.3.4 Dynamic fatigue 6.4 Parameters for the low-strength region 6.4.1 Overview 6.4.2 Variable proof test stress |
| 16 | 6.4.3 Dynamic fatigue |
| 18 | Figures Figure 1 – Weibull dynamic fatigue plot near the proof test stress level |
| 19 | 6.5 Measured numerical values 7 Examples of numerical calculations 7.1 Overview |
| 20 | 7.2 Failure rate calculations 7.2.1 FIT rate formulae 7.2.2 Long lengths in tension |
| 21 | Figure 2 – Instantaneous FIT rates of 1 km fibre versus time for applied stress/proof test stress percentages (bottom to top): 10 %, 15 %, 20 %, 25 %, 30 % Figure 3 – Averaged FIT rates of 1 km fibre versus time for applied stress/proof test stress percentages (bottom to top): 10 %, 15 %, 20 %, 25 %, 30 % |
| 22 | 7.2.3 Short lengths in uniform bending Table 2 –FIT rates of 1 km fibre in Figures 2 and 3 at various times |
| 23 | Figure 4 – Instantaneous FIT rates of bent fibre with 1 m effective length versus time Figure 5 – Averaged FIT rates of bent fibre with 1 m effective length versus time for bend diameters (top to bottom): 10 mm, 20 mm, 30 mm, 40 mm, 50 mm |
| 24 | 7.3 Lifetime calculations 7.3.1 Lifetime formulae 7.3.2 Long lengths in tension Table 3 – FIT rates of 1 metre effective length bent fibre in Figures 4 and 5 at various times Table 4 – FIT rates of Table 3 neglecting stress versus strain non-linearity |
| 25 | 7.3.3 Short lengths in uniform bending Figure 6 – 1 km lifetime versus failure probability for applied stress/proof test stress percentages (top to bottom): 10 %, 15 %, 20 %, 25 %, 30 % Table 5 – 1 km lifetimes in years of Figure 6 for various failure probabilities |
| 26 | Figure 7 – Lifetimes of bent fibre with 1 m effective length versus failure probability for bend diameters (bottom-right to top-left): 10 mm, 20 mm, 30 mm, 40 mm, 50 mm Table 6 – Lifetimes of bent fibre with 1 m effective length in years of Figure 7 for various failure probabilities |
| 27 | 7.3.4 Short lengths with uniform bending and tension Table 7 – Lifetimes in years of Table 6 neglecting stress versus strain non-linearity |
| 28 | 8 Fibre weakening and failure 8.1 Crack growth and weakening Table 8 – Calculated results in case of bend plus 30 % of proof test tension for 30 years |
| 30 | 8.2 Crack fracture |
| 31 | 8.3 Features of the general results |
| 32 | 8.4 Stress and strain 9 Fatigue testing 9.1 Overview 9.2 Static fatigue |
| 33 | Figure 8 – Static fatigue – Applied stress versus time for a particular applied stress |
| 34 | 9.3 Dynamic fatigue 9.3.1 Overview 9.3.2 Fatigue to breakage Figure 9 – Static fatigue – Schematic data of failure time versus applied stress Figure 10 – Dynamic fatigue – Applied stress versus time for a particular applied stress rate |
| 36 | 9.3.3 Fatigue to a maximum stress 9.4 Comparisons of static and dynamic fatigue 9.4.1 Intercepts and parameters obtained 9.4.2 Time duration Figure 11 – Dynamic fatigue – Schematic data of failure time versus applied stress rate |
| 37 | 9.4.3 Dynamic and inert strengths |
| 38 | 9.4.4 Plot non-linearities 9.4.5 Environments |
| 39 | 10 Proof-testing 10.1 Overview 10.2 The proof test cycle |
| 40 | 10.3 Crack weakening during proof-testing Figure 12 – Proof-testing – Applied stress versus time |
| 41 | 10.4 Minimum strength after proof-testing 10.4.1 Overview 10.4.2 Fast unloading |
| 42 | 10.4.3 Slow unloading |
| 43 | 10.4.4 Boundary condition 10.5 Varying the proof test stress 11 Statistical description of strength by Weibull probability models 11.1 Overview 11.2 Strength statistics in uniform tension 11.2.1 Unimodal probability distribution |
| 45 | 11.2.2 Bimodal probability distribution 11.3 Strength statistics in other geometries 11.3.1 Stress non-uniformity |
| 46 | 11.3.2 Uniform bending |
| 47 | 11.3.3 Two-point bending 11.4 Weibull analysis for static fatigue before proof-testing |
| 49 | 11.5 Weibull analysis for dynamic fatigue before proof-testing Figure 13 – Static fatigue schematic Weibull plot |
| 50 | Figure 14 – Dynamic fatigue schematic Weibull plot |
| 51 | 11.6 Weibull distribution after proof-testing |
| 53 | 11.7 Weibull analysis for static fatigue after proof-testing |
| 55 | 11.8 Weibull analysis for dynamic fatigue after proof-testing |
| 56 | 12 Reliability prediction 12.1 Reliability under general stress and constant stress |
| 57 | 12.2 Lifetime and failure rate from fatigue testing |
| 58 | 12.3 Certain survivability after proof-testing |
| 59 | 12.4 Failures in time |
| 60 | 13 B-value – Elimination from formulae, and measurements 13.1 Overview 13.2 Approximate Weibull distribution after proof-testing 13.2.1 Overview 13.2.2 “Risky region” during proof-testing |
| 61 | 13.2.3 Other approximations |
| 63 | 13.3 Approximate lifetime and failure rate |
| 64 | 13.4 Estimation of the B-value 13.4.1 Overview 13.4.2 Fatigue intercepts 13.4.3 Dynamic fatigue failure stress 13.4.4 Obtaining the strength |
| 65 | 13.4.5 Stress pulse measurement 13.4.6 Flaw growth measurement |
| 66 | Annex A (informative) Statistical strength degradation map Figure A.1 – Schematic diagram of the statistical strength degradation map |
| 67 | Bibliography |
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BSI PD IEC/TR 62048:2014
Optical fibres. Reliability. Power law theory Published By Publication Date Number of Pages BSI 2014…
