A crack-opening-displacement technique for crack length measurement in fatigue crack growth rate testing—development and evaluation

1977 ◽  
Vol 9 (1) ◽  
pp. 159-166 ◽  
Author(s):  
A.M. Sullivan ◽  
T.W. Crooker
Keyword(s):  
Growth Rate ◽  
Fatigue Crack ◽  
Crack Growth Rate ◽  
Fatigue Crack Growth ◽  
Crack Length ◽  
Crack Growth ◽  
Crack Opening ◽  
Opening Displacement ◽  
Rate Testing ◽  
Crack Length Measurement

Effects of a Single Overload on Fatigue Crack Growth of Type 316 Stainless Steel

2021 ◽  
Author(s):  
Koji Miyoshi ◽  
Masayuki Kamaya
Keyword(s):  
Growth Rate ◽  
Stainless Steel ◽  
Fatigue Crack ◽  
Crack Growth Rate ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Crack Opening ◽  
Constant Amplitude ◽  
Single Overload ◽  
Tensile Overload

Abstract The effect of a single overload on the fatigue crack growth rate was investigated for Type 316 stainless steel. Fatigue crack growth tests were conducted by controlling strain and load. Tensile and compressive overloads were applied during constant amplitude cycling. The overload ratio, which was defined as the ratio of overload size to baseline constant amplitude, was also changed. The constant amplitude tests were conducted at the strain or the stress ratio of −1.0 which was defined as the ratio of the minimum value to the maximum value. The crack opening point was obtained by the unloading elastic compliance method. The crack growth rate increased after the single compressive overload. The accelerating rate increased with the overload ratio. In contrast, not only the acceleration but also the retardation of the crack growth rate was observed for some tensile overload cases. The crack growth rate increased for relatively small tensile overload cases and decreased for relatively large tensile overload cases. The change in the crack opening level was examined. The crack growth rates after tensile and compressive single overloads correlated with the effective strain and stress intensity factor ranges both for load and strain controlling modes.

Investigation of the fatigue crack growth rate in heatresistant nickel alloys

2021 ◽  
pp. 48-63
Author(s):  
I. A. Khodinev ◽  
S. A. Monin ◽  
P. V. Ryzhkov
Keyword(s):  
Growth Rate ◽  
Fatigue Crack ◽  
Crack Growth Rate ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Fatigue Crack Growth Rate ◽  
Elevated Temperatures ◽  
Crack Opening ◽  
Cyclic Crack Resistance ◽  
Inconel 625

The results of tests on the FCGR (fatigue crack growth rate) of compact specimens of eccentric tension using a crack opening (COD) sensor under conditions of an asymmetric loading cycle R=0.1 at room and elevated temperatures are presented. The relationship between the conditions of force loading of preliminary growth of the initial fatigue crack is considered. The values of the effective stress intensity factor Keff were obtained, which is an important estimate for interpreting the observed character of crack growth. A comparison of the properties of the cyclic crack resistance of the VZh175-ID alloy with the properties of foreign analogues Rene 88DT, Inconel 625 SLM and domestic ones - EP741NP, EK151-ID is presented. The influence of the test temperature on the growth rate is shown. The hypothesis about the linear dependence of the parameters of the Paris equation is tested.

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