Crack Propagation Test Results for Variable Amplitude Spectrum Loading in Surface Flawed D6ac Steel.

1971 ◽  
Author(s):  
H. A. Wood ◽  
T. L. Haglage
Keyword(s):  
Crack Propagation ◽  
Amplitude Spectrum ◽  
Test Results ◽  
Variable Amplitude ◽  
Spectrum Loading

Fatigue of Stabilized SS and 316 NG Alloy in PWR Environment

2006 ◽  
Author(s):  
Jussi P. Solin
Keyword(s):  
Stainless Steels ◽  
Fatigue Tests ◽  
Test Results ◽  
Constant Amplitude ◽  
Low Oxygen ◽  
Variable Amplitude ◽  
Variable Amplitude Fatigue ◽  
Reduction Factors

Strain controlled constant and variable amplitude fatigue tests for 316NG and Titanium stabilized stainless steels in low oxygen PWR waters were performed. The stabilized steel has been plant aged for 100 000 hours. Constant amplitude test results at 0,01 Hz sinusoidal straining comply with predicted lives according to the Fen approach for both materials. Spectrum straining both in air and in environment caused predicted life reduction factors (about 3) for the stabilized steel, but for the 316NG steel spectrum straining in environment resulted to a larger reduction in life.

Crack Propagation Versus Crack Initiation Lives of FPSO Weld Details

2010 ◽  
Author(s):  
Inge Lotsberg ◽  
Mamdouh M. Salama
Keyword(s):  
Crack Initiation ◽  
Crack Propagation ◽  
Fatigue Testing ◽  
Fatigue Cracks ◽  
Full Scale ◽  
Test Results ◽  
Inspection Strategy ◽  
Scale Test ◽  
Crack Initiation Life

Documentation of a long crack propagation phase is important for planning a sound inspection program for fatigue cracks in FPSOs. Test results of full scale FPSO weld details have shown that fatigue lives of FPSO details are governed by crack propagation and that crack propagation lives are several times that of the crack initiation life. However, some analysis packages predict a short crack propagation life until failure compared to the crack initiation life. These predictions are not consistent with full scale test results and thus cannot be relied on in developing inspection strategy. The reason for this inconsistency in analysis as compared with test results may be due to limitations in the analysis program packages. The paper presents analysis of fatigue testing data on several full scale FPSO weld details. The paper also discusses the effect of “shake-down’ that is not simulated in the full scale constant amplitude testing and would even lead to longer crack propagation lives under the actual long term loading on FPSOs.

Analysis and Experimental Verification of SCC Characteristics of Typical Chinese Steels for Pressure Vessels Under Wet H2S Environment

2006 ◽  
Author(s):  
Xuedong Chen ◽  
Jialing Jiang ◽  
Tiecheng Yang ◽  
Jiushao Hu ◽  
Zhibin Ai ◽  
...  
Keyword(s):  
Crack Propagation ◽  
Critical Concentration ◽  
Dynamic Control ◽  
Control Process ◽  
Critical Stress Intensity Factor ◽  
Pressure Vessels ◽  
Concentration Limit ◽  
Test Results ◽  
Hydrogen Induced Cracking ◽  
Chinese Standard

In this paper, the estimation expression of critical concentration for hydrogen-induced cracking and estimation expression of critical stress intensity factor KISCC for hydrogen-induced delayed brittle fracture of the three Chinese steels for pressure vessels — 16MnR, 15MnVR and 07MnCrMoVR in Chinese standard GB 6654 are derived first according to SCC mechanism and in combination with fracture mechanics techniques, and verified by comparison with test values. The estimation expressions of diffusion-dominated crack plateau growth rate da/dt of these three materials are derived using Gerberich model based on the analysis of dynamic control mechanism of hydrogen-induced crack propagation under wet H2S environment and the estimated values are verified with the test results for WOL specimens. And the effect of concentration limit and concentration of the medium at normal temperature on the dynamic control process of crack propagation is also discussed.

Fatigue Crack Propagation in Clad RR58 Sheet to DTD 5070A: Analysis and Correlation of Test Results

1969 ◽  
Vol 73 (700) ◽  
pp. 335-339 ◽  
Author(s):  
D. P. Rooke ◽  
N. J. F. Gunn ◽  
J. T. Ballett ◽  
F. J. Bradshaw
Keyword(s):  
Fatigue Crack ◽  
Crack Propagation ◽  
Aluminium Alloy ◽  
Fatigue Crack Propagation ◽  
Stress Level ◽  
Stress Conditions ◽  
Specimen Geometry ◽  
Aircraft Industry ◽  
Test Results ◽  
Obvious Advantage

In recent years there has been an increasing need for data on the rates of fatigue crack propagation in alloys of interest to the aircraft industry. In general alloys in which cracks grow slowly, under given stress conditions, have an obvious advantage over those in which cracks grow faster; there is more time to detect a crack before failure. It is possible that, in the future, quantitative crack propagation data may be used to give better estimates of the safe life of a structure. There is, however, a need to rationalise the presentation of such data and to study the effect of such parameters as specimen geometry and stress level. Some experiments to investigate the effect of varying some of these parameters in one clad aluminium alloy, DTD 5070A are described. It is a summary of work contained in two RAE Technical Reports.

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