scholarly journals Effect of additive manufacturing on fatigue crack propagation of a gas turbine superalloy

2019 ◽  
Vol 23 ◽  
pp. 215-220
Author(s):  
Mattias Calmunger ◽  
Robert Eriksson ◽  
Thomas Lindström ◽  
Daniel Leidermark
Keyword(s):  
Fatigue Crack ◽  
Additive Manufacturing ◽  
Crack Propagation ◽  
Gas Turbine ◽  
Fatigue Crack Propagation

Three-Dimensional LEFM Prediction of Fatigue Crack Propagation in a Gas Turbine Disk Material at Component Near Conditions

2015 ◽  
Vol 138 (4) ◽  
Author(s):  
Christian Busse ◽  
David Gustafsson ◽  
Patrik Rasmusson ◽  
Björn Sjödin ◽  
Johan J. Moverare ◽  
...  
Keyword(s):  
Fatigue Crack ◽  
Crack Propagation ◽  
Gas Turbine ◽  
Plastic Flow ◽  
Fatigue Crack Propagation ◽  
Three Dimensional ◽  
Turbine Disk ◽  
Material Behavior ◽  
Linear Elastic ◽  
Disk Material

In this paper, the possibility to use linear elastic fracture mechanics (LEFM), with and without a superimposed residual stress field, to predict fatigue crack propagation in the gas turbine disk material Inconel 718 has been studied. A temperature of 400 °C and applied strain ranges corresponding to component near conditions have been considered. A three-dimensional crack propagation software was used for determining the stress intensity factors (SIFs) along the crack path. In the first approach, a linear elastic material behavior was used when analyzing the material response. The second approach extracts the residual stresses from an uncracked model with perfectly plastic material behavior after one loading cycle. As a benchmark, the investigated methods are compared to experimental tests, where the cyclic lifetimes were calculated by an integration of Paris' law. When comparing the results, it can be concluded that the investigated approaches give good results, at least for longer cracks, even though plastic flow was taking place in the specimen. The pure linear elastic simulation overestimates the crack growth for all crack lengths and gives conservative results over all considered crack lengths. Noteworthy with this work is that the 3D-crack propagation could be predicted with the two considered methods in an LEFM context, although plastic flow was present in the specimens during the experiments.

scholarly journals Degradation in Fatigue Crack Propagation Resistance of a Gas Turbine Vane after Long Term Service

2011 ◽  
Vol 278 ◽  
pp. 375-380
Author(s):  
Masakazu Okazaki ◽  
Motoki Sakaguchi ◽  
Yosuke Sasaki ◽  
Koichi Namba
Keyword(s):  
Fatigue Crack ◽  
Crack Propagation ◽  
Gas Turbine ◽  
Fatigue Crack Propagation ◽  
Trailing Edge ◽  
Propagation Resistance ◽  
Crack Propagation Resistance ◽  
Turbine Vane ◽  
Edge Part

Degree of long term degradation damage of a retired gas turbine vane made of a Ni-based superalloy which had been operating for about 20000 hrs in a land-based gas turbine, was experimentally evaluated, through an assessment on the change in fatigue crack propagation resistance. For the purpose, a new testing apparatus has been developed to measure the local area fatigue crack propagation resistance, by extracting the miniature size compact tension specimens from the vane, where the specimens were extracted from the leading and the trailing edge, respectively. It was shown, the propagation rate of the crack that grew at the trailing edge part was significantly higher that that at the leading edge part. It was also shown that the crack propagation rates in the miniature specimen were generally higher than those in the standard size specimen. In order to explore an possibility to recover the degradation damage, the effect of a simple reheat treatment on the fatigue crack propagation resistance was also investigated

scholarly journals Evaluation of Fatigue Crack Propagation in The Post-Service Gas Turbine Vane

2010 ◽  
Vol 4 (2) ◽  
pp. 131-142 ◽  
Author(s):  
Motoki SAKAGUCHI ◽  
Yosuke SASAKI ◽  
Masakazu OKAZAKI ◽  
Koichi NAMBA
Keyword(s):  
Fatigue Crack ◽  
Crack Propagation ◽  
Gas Turbine ◽  
Fatigue Crack Propagation ◽  
Turbine Vane

An Engineering Approach to Cumulative Damage Fracture Mechanics in Gas Turbine Disks

1979 ◽  
Author(s):  
C. G. Annis
Keyword(s):  
Fatigue Crack ◽  
Fracture Mechanics ◽  
Crack Propagation ◽  
Gas Turbine ◽  
Fatigue Crack Propagation ◽  
Stress Ratio ◽  
Cumulative Damage ◽  
Engineering Approach ◽  
Sigmoidal Curve ◽  
Turbine Disks

An empirical description of fatigue crack propagation (FCP) under complex loadings, typical of those experienced by gas turbine disks, is presented. This approach uses a three coefficient sigmoidal curve (SINH) to model the macroscopic effects on FCP of service overloads, dwells, and load sequencing, as well as basic influences of frequency, stress ratio, and temperature. The coefficients are then related to these growth-controlling parameters through simple, linear, empirical functions. Comparisons are made of this approach with more conventional methods, and the results of laboratory verification tests are presented.

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