Foreign Object Damage and Fatigue Strength Loss in Compressor Blades

2008 ◽  
Author(s):  
Mickhail S. Nikhamkin ◽  
Leonid V. Voronov ◽  
Irina V. Semenova
Keyword(s):  
Fatigue Strength ◽  
Stress Concentration ◽  
Gas Turbine ◽  
Strength Loss ◽  
Fatigue Tests ◽  
Sensitivity Factor ◽  
Compressor Blades ◽  
Turbine Engine ◽  
Foreign Object Damage ◽  
Concentration Sensitivity

Foreign object damage (FOD) is always an all-important problem of gas turbine engines safety, reliability and operating costs. This paper describes experimental and numerical prediction investigations of FOD to compressor blades of gas turbine engine. Experimental modeling of FOD processes was done using a special plant on the base of a pneumatic gun. Real steel blades of a high-pressure compressor were impacted with spherical steel projectiles at the velocity about 200 m/s. Typical in-service damages as well as round dents, tears and bends were reproduced in the experiment. Numerical prediction analyses of the damage process were fulfilled by finite element method (FEM). Material behavior is described with elastic-plastic strain rate dependent model. We find the form and sizes of the calculated damages to be in good agreement with the experimental findings. Furthermore, the experimental and computational procedure for estimation of fatigue strength loss of damaged blades is proposed. It is based on study of stress concentration in damages. Stress concentration factor for different concentrator shapes was calculated using 3-D finite element analyses and refined via a stress concentration sensitivity factor. Stress concentration sensitivity factor was experimentally defined through fatigue tests of real blades with V-shape notches at leading edge. This technique supposes minimum laborious fatigue tests. Experimentally confirmed numerical methodology and model may be used for prediction study of FOD and fatigue strength loss of gas turbine engine blades.

Influence of chrome electroplating on fatigue strength of parts

2020 ◽  
pp. 112-119
Author(s):  
S. V. Malysh ◽  
I. M. Kovenskiy ◽  
L. Z. Chaugarova
Keyword(s):  
Fatigue Strength ◽  
Endurance Limit ◽  
Fatigue Tests ◽  
Compressor Blades ◽  
Turbine Engine ◽  
Engine Compressor ◽  
Electrodynamic Vibration ◽  
Chrome Layer ◽  
Standard Gas ◽  
Chrome Electroplating

The article is devoted to the results of studies, which have been conducted on parts with electrolytic chromium in order to determine the effect of the coating on fatigue strength of their. The work was performed in observance of standards, which are fixed in GOST RV 2840-001-2008. Samples for the tests were made from standard gas turbine engine compressor blades. We used a VEDS- 1500 electrodynamic vibration stand with an UMK-12K power amplifier to excite vibrations. It has been shown that the minimum endurance limit of 46 kgf/mm2 based on 2 ∙ 107 cycles, established on uncoated parts, didn't decrease during fatigue tests of compressor blades with an electroplated chrome layer. It should be stressed that the influence of the geometry of the chrome-plated part on the reduction of the endurance limit has been established.

THREE FACE ATTACHMENT RETROFIT AGAINST FATIGUE CRACKING AT STEEL GIRDER WEB PENETRATION

2018 ◽  
Vol 5 (2) ◽  
Author(s):  
Chihiro Sakamoto ◽  
Masahiro Sakano ◽  
Hideyuki Konishi ◽  
Takashi Fujii
Keyword(s):  
Fatigue Strength ◽  
Stress Concentration ◽  
Stress Reduction ◽  
Fatigue Cracking ◽  
Highway Bridges ◽  
Lower Surface ◽  
Strength Properties ◽  
Fatigue Tests ◽  
Lower Side ◽  
Steel Girder

Fatigue cracking in steel girder web penetration details is so dangerous that it can break steel girders. Since a number of highway bridges have such web penetration details in Japan, it is of urgent importance to grasp these fatigue strength properties. In this study, we investigate stress reduction effects of three face attachment retrofit through fatigue tests using a large girder specimen with web penetration details where cross beam lower flanges are connected to the lower surface of a slot by welding. As a result, there is very little difference between two and three face attachments about stress reduction effects, while they are more effective than one face attachment. The upper side attachment is more effective than the lower side attachment, while both side attachment is best. Two and three face both side attachments can reduce about 40% of stress concentration, while two and three face upper side attachments can reduce 50– 60%.

The Development and Testing of a Gas Turbine Engine Foreign Object Damage (FOD) Detection System

2010 ◽  
Author(s):  
D. N. Cardwell ◽  
K. S. Chana ◽  
M. T. Gilboy
Keyword(s):  
Gas Turbine ◽  
Eddy Current ◽  
Engine Speed ◽  
Detection System ◽  
Acoustic Emissions ◽  
Gas Turbine Engine ◽  
Current Sensor ◽  
Foreign Object ◽  
Turbine Engine ◽  
Foreign Object Damage

This paper details the development of a prototype in-flight foreign object damage (FOD) detection system through various stages, resulting in a system capable of detecting objects as small as one gram (1g) mass. The system comprises an eddy current sensor based tip timing system and acoustic emissions vibration sensors controlled through a digital signal processor (DSP). QinetiQ have developed light weight, contamination-immune eddy current tip timing sensors for use in engine health management. Engine tests confirmed these sensors’ potential for detecting FOD events. FOD detection algorithms were developed and implemented in a prototype DSP that was built and tested on an uninstalled gas turbine engine. The trials showed that the prototype DSP FOD detection system could detect dynamic FOD events at full engine speed. Further work was carried out to enhance the FOD detection system, overcoming limitations in the previous system through the implementation of enhanced algorithms and its extension to accept four eddy current sensor inputs as well as a vibration signal input from an acoustic emissions (AE) sensor. An algorithm that computes engine speed from the tip timing data was also implemented to alleviate the need for a separate 1/rev signal. A number of engine trials were successfully completed in order to validate the system. The speed algorithm has been successfully validated on engine trials and comparisons with a conventional optical based 1/rev showed the DSP-generated 1/rev signals to be almost identical to the conventional system. Typically, the error was in the region of 0.03% speed. The investigations culminated in a test series designed to ascertain the system’s sensitivity to foreign object impacts. These demonstrated that the system was capable of detecting objects down to one gram (1g) mass introduced at low speed into the engine intake.

Stress concentration in sloping cooling circuits of a disk of a gas-turbine engine

1998 ◽  
Vol 30 (3) ◽  
pp. 299-302
Author(s):  
V. I. Kravchenko ◽  
S. V. Kobel'skii ◽  
P. P. Voroshko ◽  
E. V. Petrov
Keyword(s):  
Stress Concentration ◽  
Gas Turbine ◽  
Gas Turbine Engine ◽  
Turbine Engine

Development of a Touch Probing System for Gaging the Compressor Blades of the GTE

2018 ◽  
Vol 769 ◽  
pp. 242-249
Author(s):  
Nikolay Vladimirovich Ruzanov ◽  
Michael Alexandrovich Bolotov ◽  
Vadim Andreevich Pechenin ◽  
Ekaterina Robertovna Matek
Keyword(s):  
Mathematical Models ◽  
Gas Turbine ◽  
Strain Gage ◽  
Simulation Modeling ◽  
Gas Turbine Engine ◽  
Compressor Blades ◽  
Reference Element ◽  
Turbine Engine ◽  
Optimum Configuration ◽  
Engine Compressor

The article describes the touch probing system with the strain gage as the main measuring element. The device has small geometric dimensions and it was developed to measure the gas turbine engine compressor blades. To select the optimum configuration of the probing system, mathematical models of two principal configurations were developed. Simulation modeling of the force of the measured surface impact on the measuring tip was carried out in the Ansys environment for these assemblies. On the basis of practical experiments, the diagram of the deviation of the probe on the resistance of the strain gage was constructed. Reference element were measured to determine the accuracy of the designed touch probing system.

Research of Fatigue Limit and Stress Concentration on Structural Steel with Double-Notches

2009 ◽  
Vol 419-420 ◽  
pp. 849-852
Author(s):  
Sheng Wu Wang ◽  
Shu Juan Sun ◽  
Ai Ling Wen ◽  
Wei Da Wang ◽  
Shinichi Nishida
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Fatigue Strength ◽  
Stress Concentration ◽  
Fatigue Limit ◽  
Three Dimensional ◽  
Fatigue Tests ◽  
Notched Specimen ◽  
Blind Hole ◽  
Element Method

The fatigue limit of parts and components that have the multi-notches is important data for the design and manufacture of machinery and traffic equipment which are operated under the high speed or pressure. In this paper the rotating bending fatigue tests have been carried out to investigate the fatigue limit of specimen with double-notch that is constructed of step and blind hole, and analyzed the effect of stress concentrations at the double-notched bottoms on the fatigue limits, using three-dimensional elastic finite element method. Firstly, the fatigue tests of 8 group specimens have been performed for examining the of fatigue limits of the single-notched specimen and double-notched specimen, respectively. Additionally, the stress field interactions between two stress fields by the blind hole notch and step are discussed using three-dimensional elastic finite element method. The main results obtained in this study are as follows: The fatigue limit of the double-notched specimen are down comparison with the fatigue limit of the single-notched specimen; the fatigue limit of the double-notch specimen is insensitive to distance between the blind hole and step for the low carbon structure steel with better ductility; for the high-strength steel, superposition and intensification of the stress concentration by the blind hole and step mutually may be avoided so that their adverse effects on the fatigue strength may be become to minimize, as take appropriate distance between the blind hole and step. The results are significant for the design of engineering design of the multi-notched parts, and the study of fatigue strength.

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