P. Reymer, M. Kurdelski, A. Leski, A. Leśniczak, M. Dziendzikowski
Abstract The Su-22 fighter-bomber is a military aircraft used in the Polish Air Force (PLAF) since the mid 1980’s. By decision of the Ministry of National Defence Republic of Poland, the assumed service life for this type of aircraft was prolonged up to 3200 flight hours based on the Full Scale Fatigue Test (FSFT) results. The FSFT was conducted using the real load profile defined during the Operational Load Monitoring Program (OLM) and the 3200 hour service life was also based on this load profile. In order to assure safe operation of all the 18 Su-22 aircraft, the Individual Aircraft Tracking program was introduced. The program was based on the results of the FSFT as well as the analysis of the flight parameters recorded by the THETYS onboard flight recorder. In this paper, the authors present the methodology, assumed fatigue hypothesis and preliminary results of the IAT program for the Polish Su-22.
{"title":"Introduction of an Individual Aircraft Tracking Program for the Polish SU-22","authors":"P. Reymer, M. Kurdelski, A. Leski, A. Leśniczak, M. Dziendzikowski","doi":"10.1515/fas-2017-0008","DOIUrl":"https://doi.org/10.1515/fas-2017-0008","url":null,"abstract":"Abstract The Su-22 fighter-bomber is a military aircraft used in the Polish Air Force (PLAF) since the mid 1980’s. By decision of the Ministry of National Defence Republic of Poland, the assumed service life for this type of aircraft was prolonged up to 3200 flight hours based on the Full Scale Fatigue Test (FSFT) results. The FSFT was conducted using the real load profile defined during the Operational Load Monitoring Program (OLM) and the 3200 hour service life was also based on this load profile. In order to assure safe operation of all the 18 Su-22 aircraft, the Individual Aircraft Tracking program was introduced. The program was based on the results of the FSFT as well as the analysis of the flight parameters recorded by the THETYS onboard flight recorder. In this paper, the authors present the methodology, assumed fatigue hypothesis and preliminary results of the IAT program for the Polish Su-22.","PeriodicalId":37629,"journal":{"name":"Fatigue of Aircraft Structures","volume":"2017 1","pages":"101 - 108"},"PeriodicalIF":0.0,"publicationDate":"2017-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48148318","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Wojciech Wronicz, J. Kaniowski, Maciej Malicki, Paweł Kucio, R. Klewicki
Abstract Fatigue behaviour is one of the most important properties of modern airplanes and rivets influence it strongly. According to the literature, the NACA riveting offers a multiple increase in the fatigue life of joints. The aim of this paper is to investigate the benefits offered by the NACA riveting procedure with respect to the residual stress and strain distribution after riveting as well as rivet hole expansion. Experimental and numerical approaches were adopted. The conventional riveting with both the universal and countersunk rivets was compared with the NACA riveting. The countersunk angle and depth in the case of the NACA riveting was modified somewhat relative to the values met in the literature. For these three cases, strain gauge measurements during riveting, hole expansion measurements and FE calculations were performed. The hole expansion measurement with the use of Computer Tomography(CT) was proposed. Only the FE calculations unambiguously indicate better fatigue properties of the NACA riveting. The proposed method of hole expansion measurement requires further research to increase its accuracy.
{"title":"Experimental and Numerical Study of NACA and Conventional Riveting Procedure","authors":"Wojciech Wronicz, J. Kaniowski, Maciej Malicki, Paweł Kucio, R. Klewicki","doi":"10.1515/fas-2017-0012","DOIUrl":"https://doi.org/10.1515/fas-2017-0012","url":null,"abstract":"Abstract Fatigue behaviour is one of the most important properties of modern airplanes and rivets influence it strongly. According to the literature, the NACA riveting offers a multiple increase in the fatigue life of joints. The aim of this paper is to investigate the benefits offered by the NACA riveting procedure with respect to the residual stress and strain distribution after riveting as well as rivet hole expansion. Experimental and numerical approaches were adopted. The conventional riveting with both the universal and countersunk rivets was compared with the NACA riveting. The countersunk angle and depth in the case of the NACA riveting was modified somewhat relative to the values met in the literature. For these three cases, strain gauge measurements during riveting, hole expansion measurements and FE calculations were performed. The hole expansion measurement with the use of Computer Tomography(CT) was proposed. Only the FE calculations unambiguously indicate better fatigue properties of the NACA riveting. The proposed method of hole expansion measurement requires further research to increase its accuracy.","PeriodicalId":37629,"journal":{"name":"Fatigue of Aircraft Structures","volume":"2017 1","pages":"157 - 170"},"PeriodicalIF":0.0,"publicationDate":"2017-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43543561","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Wojciech Wdowiński, E. Szymczyk, J. Jachimowicz, G. Moneta
Abstract The motivation of the article is fatigue and fretting issue of the compressor rotor blades and disks. These phenomena can be caused by high contact pressures leading to fretting occurring on contact faces in the lock (blade-disk connection, attachment of the blade to the disk). Additionally, geometrical notches and high cyclic loading can initiate cracks and lead to engine failures. The paper presents finite element static and modal analyses of the axial compressor 3rd rotor stage (disk and blades) of the K-15 turbine engine. The analyses were performed for the original trapezoidal/dovetail lock geometry and its two modifications (new lock concepts) to optimize the stress state of the disk-blade assembly. The cyclic symmetry formulation was used to reduce modelling and computational effort.
{"title":"Design and Strength Analysis of Curved-Root Concept for Compressor Rotor Blade in Gas Turbine","authors":"Wojciech Wdowiński, E. Szymczyk, J. Jachimowicz, G. Moneta","doi":"10.1515/fas-2017-0011","DOIUrl":"https://doi.org/10.1515/fas-2017-0011","url":null,"abstract":"Abstract The motivation of the article is fatigue and fretting issue of the compressor rotor blades and disks. These phenomena can be caused by high contact pressures leading to fretting occurring on contact faces in the lock (blade-disk connection, attachment of the blade to the disk). Additionally, geometrical notches and high cyclic loading can initiate cracks and lead to engine failures. The paper presents finite element static and modal analyses of the axial compressor 3rd rotor stage (disk and blades) of the K-15 turbine engine. The analyses were performed for the original trapezoidal/dovetail lock geometry and its two modifications (new lock concepts) to optimize the stress state of the disk-blade assembly. The cyclic symmetry formulation was used to reduce modelling and computational effort.","PeriodicalId":37629,"journal":{"name":"Fatigue of Aircraft Structures","volume":"2017 1","pages":"137 - 155"},"PeriodicalIF":0.0,"publicationDate":"2017-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46180524","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Following the damage tolerance philosophy in aircraft design and operation, one of the most significant stages of maintenance is non-destructive testing of structures. It is, therefore, essential to use testing methods sensitive to particular damage types occurring in aircraft structures during operation. In this paper, the authors present a study on selection and comparison of methods of information fusion applied to testing the results of inspection of composite structures used in aircraft elements, obtained using various ultrasonic methods. The presented approach of fusion of ultrasonic scans allows for enhancement of damage detection and identification due to the presence of different parts of information about detected damage obtained from different initial information sources in a single resulting set. Such an approach can be helpful at the decision-making stage during inspection of aircraft elements and structures. Besides the methodology, the GUI-based software for performing fusion of various types of ultrasonic data is presented.
{"title":"Enhancement of Damage Detectability in Aircraft Structures Using the Fusion of NDT Results","authors":"Marcin Zapłotny, A. Katunin, K. Dragan","doi":"10.1515/fas-2017-0005","DOIUrl":"https://doi.org/10.1515/fas-2017-0005","url":null,"abstract":"Abstract Following the damage tolerance philosophy in aircraft design and operation, one of the most significant stages of maintenance is non-destructive testing of structures. It is, therefore, essential to use testing methods sensitive to particular damage types occurring in aircraft structures during operation. In this paper, the authors present a study on selection and comparison of methods of information fusion applied to testing the results of inspection of composite structures used in aircraft elements, obtained using various ultrasonic methods. The presented approach of fusion of ultrasonic scans allows for enhancement of damage detection and identification due to the presence of different parts of information about detected damage obtained from different initial information sources in a single resulting set. Such an approach can be helpful at the decision-making stage during inspection of aircraft elements and structures. Besides the methodology, the GUI-based software for performing fusion of various types of ultrasonic data is presented.","PeriodicalId":37629,"journal":{"name":"Fatigue of Aircraft Structures","volume":"2017 1","pages":"55 - 74"},"PeriodicalIF":0.0,"publicationDate":"2017-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48536807","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract This review was presented on the 34 Conference of the International Committee on Aeronautical Fatigue and Structural Integrity, Helsinki, Finland, June 1-2, 2015. It contains description of main works and investigations in fatigue of aircraft structures performed in Poland during the years 2013 and 2014.
{"title":"Review of Aeronautical Fatigue Investigations in Poland (2013-2014)","authors":"A. Niepokólczycki, A. Leski, K. Dragan","doi":"10.1515/fas-2016-0001","DOIUrl":"https://doi.org/10.1515/fas-2016-0001","url":null,"abstract":"Abstract This review was presented on the 34 Conference of the International Committee on Aeronautical Fatigue and Structural Integrity, Helsinki, Finland, June 1-2, 2015. It contains description of main works and investigations in fatigue of aircraft structures performed in Poland during the years 2013 and 2014.","PeriodicalId":37629,"journal":{"name":"Fatigue of Aircraft Structures","volume":"2016 1","pages":"48 - 5"},"PeriodicalIF":0.0,"publicationDate":"2016-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1515/fas-2016-0001","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67370869","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract This paper presents the results of the quantitative evaluation of the degree of damage caused by plastic strain accumulated in static tensile tests and creep tests. To detect changes in the structure of the material and in order to determine the degradation of the materials, nondestructive methods were used, namely the ultrasonic and eddy current methods. In ultrasonic testing, attenuation and acoustic birefringence were used as damage indicators. In the case of the eddy current method, changes in the phase angle of impedance were observed in the material. The material tested was Inconel 718 alloy. Inconel alloys are often find application in extreme working conditions including in the power engineering industry, aviation and aerospace. A new type of specimen with the variable cross-sectional area of the measuring part was used in the tests. This allowed researchers to obtain a continuous distribution of plastic strain and enabled analysis of the material with respect to different damage degrees. The correlation between the degree of damage, expressed by the measure of deformation, and the value of nondestructive indicators was determined. On the basis of it, the dependence indicating the ability to nondestructive evaluation of the degradation degree of the material, subjected to loads exceeding the yield limit was obtained.
{"title":"Evaluation of Damage Degree of Inconel 718 using Nondestructive Indicators of Damage","authors":"J. Krysztofik","doi":"10.1515/fas-2016-0003","DOIUrl":"https://doi.org/10.1515/fas-2016-0003","url":null,"abstract":"Abstract This paper presents the results of the quantitative evaluation of the degree of damage caused by plastic strain accumulated in static tensile tests and creep tests. To detect changes in the structure of the material and in order to determine the degradation of the materials, nondestructive methods were used, namely the ultrasonic and eddy current methods. In ultrasonic testing, attenuation and acoustic birefringence were used as damage indicators. In the case of the eddy current method, changes in the phase angle of impedance were observed in the material. The material tested was Inconel 718 alloy. Inconel alloys are often find application in extreme working conditions including in the power engineering industry, aviation and aerospace. A new type of specimen with the variable cross-sectional area of the measuring part was used in the tests. This allowed researchers to obtain a continuous distribution of plastic strain and enabled analysis of the material with respect to different damage degrees. The correlation between the degree of damage, expressed by the measure of deformation, and the value of nondestructive indicators was determined. On the basis of it, the dependence indicating the ability to nondestructive evaluation of the degradation degree of the material, subjected to loads exceeding the yield limit was obtained.","PeriodicalId":37629,"journal":{"name":"Fatigue of Aircraft Structures","volume":"2016 1","pages":"55 - 64"},"PeriodicalIF":0.0,"publicationDate":"2016-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1515/fas-2016-0003","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67371227","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Electropolishing is the sole reliable method of removing the outer layer of the specimen without changing its stress state. This feature of the electropolishing procedure allows researchers to investigate the in-depth stress distribution. Developing of the method in a diffraction laboratory is crucial because there is no universal theory for the electropolishing procedure allowing the removal of the layers of different thickness. This is due to the multiplicity of different factors affecting the electropolishing results. A factor of vital importance from the point of view of indepth stress measurements is the thickness of the electropolishing layer. Hence the importance of the procedures for the electropolishing of a layer of a precisely defined thickness. This work deals with the problem of the selection of the parameters in the electropolishing process for two types of materials: stainless steel and aluminium alloy. The tests of mutual correlation of current intensity, voltage applied and time of the procedure and its results are presented in the paper.
{"title":"Electropolishing Procedure Dedicated to In-Depth Stress Measurements with X-Ray Diffractometry","authors":"Elżbieta Gadalińska, Wojciech Wronicz","doi":"10.1515/fas-2016-0004","DOIUrl":"https://doi.org/10.1515/fas-2016-0004","url":null,"abstract":"Abstract Electropolishing is the sole reliable method of removing the outer layer of the specimen without changing its stress state. This feature of the electropolishing procedure allows researchers to investigate the in-depth stress distribution. Developing of the method in a diffraction laboratory is crucial because there is no universal theory for the electropolishing procedure allowing the removal of the layers of different thickness. This is due to the multiplicity of different factors affecting the electropolishing results. A factor of vital importance from the point of view of indepth stress measurements is the thickness of the electropolishing layer. Hence the importance of the procedures for the electropolishing of a layer of a precisely defined thickness. This work deals with the problem of the selection of the parameters in the electropolishing process for two types of materials: stainless steel and aluminium alloy. The tests of mutual correlation of current intensity, voltage applied and time of the procedure and its results are presented in the paper.","PeriodicalId":37629,"journal":{"name":"Fatigue of Aircraft Structures","volume":"2016 1","pages":"65 - 72"},"PeriodicalIF":0.0,"publicationDate":"2016-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67371295","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract The paper proposes a method of calculating the maximum displacement in the aircraft metal structure repaired by CPBR (bonded composite patch repair). The calculations were made based on specimens. The specimens were prepared according to the current requirements used in aviation. The 2024-T3 alloy metal sheet was a structure. To repair the structure used the boron-epoxy composite patch in prepreg technology was used. The metal structure was modeled as an isotropic elastic body. The metal structure coated with the composite patch was modeled as an orthotropic structure. Based on this, the stress was determined in the metal structure. The size opening displacement in the metal structure was determined based on the model of linear elastic fracture mechanics for the plane stress state. The calculation results were verified by measuring the displacement in laboratory conditions. The laboratory tests made it possible to demonstrate the accuracy of the proposed approach.
{"title":"Approach to Critical Crack Opening Displacement Modeling of Damage in Metal Sheets after Composite Patch Bonded Repair","authors":"Michał Sałaciński, A. Leski, M. Stefaniuk","doi":"10.1515/fas-2016-0009","DOIUrl":"https://doi.org/10.1515/fas-2016-0009","url":null,"abstract":"Abstract The paper proposes a method of calculating the maximum displacement in the aircraft metal structure repaired by CPBR (bonded composite patch repair). The calculations were made based on specimens. The specimens were prepared according to the current requirements used in aviation. The 2024-T3 alloy metal sheet was a structure. To repair the structure used the boron-epoxy composite patch in prepreg technology was used. The metal structure was modeled as an isotropic elastic body. The metal structure coated with the composite patch was modeled as an orthotropic structure. Based on this, the stress was determined in the metal structure. The size opening displacement in the metal structure was determined based on the model of linear elastic fracture mechanics for the plane stress state. The calculation results were verified by measuring the displacement in laboratory conditions. The laboratory tests made it possible to demonstrate the accuracy of the proposed approach.","PeriodicalId":37629,"journal":{"name":"Fatigue of Aircraft Structures","volume":"2016 1","pages":"104 - 110"},"PeriodicalIF":0.0,"publicationDate":"2016-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67371501","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Maciej Malicki, Elżbieta Gadalińska, Maciej Chmiel
Abstract In the previous work [1] it was shown that strain hardening had considerable impact on the hardness of Inconel 718. In order to verify the weakening of the material associated with the damage mechanism in the tested material, the hardness tests were performed on the stretched specimen which was subsequently heat treated. The tests revealed that, after heat treatment, the measured hardness was reduced with an increasing degree of the plastic deformation present prior to heat treatment.
{"title":"The Impact of Damage in Anneling Inconel 718 on Hardness Measured by the Vickers Method","authors":"Maciej Malicki, Elżbieta Gadalińska, Maciej Chmiel","doi":"10.1515/fas-2016-0007","DOIUrl":"https://doi.org/10.1515/fas-2016-0007","url":null,"abstract":"Abstract In the previous work [1] it was shown that strain hardening had considerable impact on the hardness of Inconel 718. In order to verify the weakening of the material associated with the damage mechanism in the tested material, the hardness tests were performed on the stretched specimen which was subsequently heat treated. The tests revealed that, after heat treatment, the measured hardness was reduced with an increasing degree of the plastic deformation present prior to heat treatment.","PeriodicalId":37629,"journal":{"name":"Fatigue of Aircraft Structures","volume":"2016 1","pages":"92 - 96"},"PeriodicalIF":0.0,"publicationDate":"2016-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67371616","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Elżbieta Gadalińska, Wojciech Wronicz, Maciej Malicki
Abstract Measuring the in-depth stress state is of vital importance for materials scientists. Strain gauges methods are capable of yielding information only about the surface stress state. Diffraction methods using synchrotron or neutron radiation, which allow totally non-destructive stress measurements inside the material, are not widely available. In this context, the best widely available method combines the X-ray diffraction stress measurements and gradual removal of the outer layer by means of electropolishing. Here, this method was applied to the specimen made of 1H13 stainless steel cut with under water on a corundum cut-off wheel. The idea was to investigate how deeply an additional stress state resulting from cutting was introduced and whether the technique of combining of X-ray diffractometry and electropolishing can be used widely for determining the stress state inside the specimen.
{"title":"The In-Depth Stress Distribution for 1H13 Specimen after Cutting","authors":"Elżbieta Gadalińska, Wojciech Wronicz, Maciej Malicki","doi":"10.1515/fas-2016-0005","DOIUrl":"https://doi.org/10.1515/fas-2016-0005","url":null,"abstract":"Abstract Measuring the in-depth stress state is of vital importance for materials scientists. Strain gauges methods are capable of yielding information only about the surface stress state. Diffraction methods using synchrotron or neutron radiation, which allow totally non-destructive stress measurements inside the material, are not widely available. In this context, the best widely available method combines the X-ray diffraction stress measurements and gradual removal of the outer layer by means of electropolishing. Here, this method was applied to the specimen made of 1H13 stainless steel cut with under water on a corundum cut-off wheel. The idea was to investigate how deeply an additional stress state resulting from cutting was introduced and whether the technique of combining of X-ray diffractometry and electropolishing can be used widely for determining the stress state inside the specimen.","PeriodicalId":37629,"journal":{"name":"Fatigue of Aircraft Structures","volume":"2016 1","pages":"73 - 79"},"PeriodicalIF":0.0,"publicationDate":"2016-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67371396","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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