Elżbieta Gadalińska, Andrzej Michałowski, Sławomir Czarnewicz
Abstract This work deals with the problem of X-ray stress determination on the samples dedicated to fatigue tests. A number of research studies point out the fact that the processing of hard, difficult to machine materials like nickel superalloys, reveals more than one trend of residual stress versus working parameters of behaviour (Lavella and Berruti, 2010). Many papers have shown that the residual stresses are dependent on a combination of a number of factors. When the above is taken into account simultaneously with the requirements of the internal General Electric specification for the fatigue tests samples preparation (Metallic test specimen preparation, low stress, 2017) the problem of turning and grinding parameters gathers significance. It is well known that the quality of the surface layer, produced during machining, is of vital importance for the fatigue life specially for the components of aircraft produced form nickel superalloys e.g. Inconel 718 (Kortabarri et al., 2011). That is why the surface layer’s properties are described in detail by the standards. The aim of the work is to determine one of the most influential features from the point of view of fatigue life, i.e. the stress state on the surface layer with one non-destructive method – the diffraction analysis.
{"title":"Determination of Stress Values in the Surface Layer of Inconel 718 Samples Dedicated to Fatigue Tests","authors":"Elżbieta Gadalińska, Andrzej Michałowski, Sławomir Czarnewicz","doi":"10.2478/fas-2019-0008","DOIUrl":"https://doi.org/10.2478/fas-2019-0008","url":null,"abstract":"Abstract This work deals with the problem of X-ray stress determination on the samples dedicated to fatigue tests. A number of research studies point out the fact that the processing of hard, difficult to machine materials like nickel superalloys, reveals more than one trend of residual stress versus working parameters of behaviour (Lavella and Berruti, 2010). Many papers have shown that the residual stresses are dependent on a combination of a number of factors. When the above is taken into account simultaneously with the requirements of the internal General Electric specification for the fatigue tests samples preparation (Metallic test specimen preparation, low stress, 2017) the problem of turning and grinding parameters gathers significance. It is well known that the quality of the surface layer, produced during machining, is of vital importance for the fatigue life specially for the components of aircraft produced form nickel superalloys e.g. Inconel 718 (Kortabarri et al., 2011). That is why the surface layer’s properties are described in detail by the standards. The aim of the work is to determine one of the most influential features from the point of view of fatigue life, i.e. the stress state on the surface layer with one non-destructive method – the diffraction analysis.","PeriodicalId":37629,"journal":{"name":"Fatigue of Aircraft Structures","volume":"2019 1","pages":"78 - 86"},"PeriodicalIF":0.0,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41509785","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}
Łukasz Lindstedt, M. Rodzewicz, C. Rzymkowski, K. Kędzior
Abstract One major problem associated with gliding is the safety of the crew during landings in the country outside the airfield. The analysis of glider-accident statistics shows that such out-landings may significantly influence the safety. Therefore, of vital importance are the crashworthiness properties of the glider fuselage structure. The subject of the study was the PW-5 glider fuselage made of composites and subjected to high loads typical of glider crashes. The aim was to provide experimental data for validation of a numerical model of the cockpit-pilot system during impact. Two experimental tests with the composite glider cockpit were performed using a typical car-crash track. During the first test the cockpit with a dummy inside was crashed onto the ground at the angle of 45 degrees at a speed of 55 km/h. Accelerations and deformations at chosen points in the cockpit as well as signals coming from the dummy sensors and forces in the seat belts were recorded. The second test was an impact into a concrete wall at a speed of about 80 km/h. The full-scale tests were accompanied by a number of quasi-static and dynamic laboratory tests on samples of composite material. The experimental tests provided valuable results for the parametrical identification of a simulation model developed using the MADYMO software.
{"title":"Impact Loads and Crash Safety of the Cockpit of a Composite Glider","authors":"Łukasz Lindstedt, M. Rodzewicz, C. Rzymkowski, K. Kędzior","doi":"10.2478/fas-2019-0005","DOIUrl":"https://doi.org/10.2478/fas-2019-0005","url":null,"abstract":"Abstract One major problem associated with gliding is the safety of the crew during landings in the country outside the airfield. The analysis of glider-accident statistics shows that such out-landings may significantly influence the safety. Therefore, of vital importance are the crashworthiness properties of the glider fuselage structure. The subject of the study was the PW-5 glider fuselage made of composites and subjected to high loads typical of glider crashes. The aim was to provide experimental data for validation of a numerical model of the cockpit-pilot system during impact. Two experimental tests with the composite glider cockpit were performed using a typical car-crash track. During the first test the cockpit with a dummy inside was crashed onto the ground at the angle of 45 degrees at a speed of 55 km/h. Accelerations and deformations at chosen points in the cockpit as well as signals coming from the dummy sensors and forces in the seat belts were recorded. The second test was an impact into a concrete wall at a speed of about 80 km/h. The full-scale tests were accompanied by a number of quasi-static and dynamic laboratory tests on samples of composite material. The experimental tests provided valuable results for the parametrical identification of a simulation model developed using the MADYMO software.","PeriodicalId":37629,"journal":{"name":"Fatigue of Aircraft Structures","volume":"2019 1","pages":"39 - 55"},"PeriodicalIF":0.0,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41414420","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}
Michał Sałaciński, R. Kowalski, Michał Szmidt, S. Augustyn
Abstract The fatigue test was carried out on an element of a rotor blade removed from the Mi-2 helicopter. The purpose of the test was to check the fatigue strength of the repaired rotor blade. Metal composite rotor blades have a metal spar in the form of a box and the trailing sections in the form of metallic honeycomb sandwich panels. The trailing sections are bonded to the spar. The repair had been carried out at the point where the trailing section became debonded from the spar at the Air Force Institute of Technology in Warsaw using a methodology developed for carrying out repairs of rotor blades’ damage. All types of the Mi family helicopters are equipped with metal composite rotors blades. Depending on MTOW (Maximum Take-Off Weight) and destination of helicopters, blades differ in dimensions, but their design solutions are practically the same. For this reason, the developed repair methodology can be used for all characteristic rotor blades structures for Mi helicopters. The fatigue test was performed at the Łukasiewicz - Institute of Aviation in Warsaw, using a hydraulically driven fatigue machine. The fatigue test was carried out by performing over 1.1 million load cycles. In repair places, upon completion of fatigue testing, no damage was found.
{"title":"A New Approach to Modelling and Testing the Fatigue Strength of Helicopter Rotor Blades during Repair Process","authors":"Michał Sałaciński, R. Kowalski, Michał Szmidt, S. Augustyn","doi":"10.2478/fas-2019-0006","DOIUrl":"https://doi.org/10.2478/fas-2019-0006","url":null,"abstract":"Abstract The fatigue test was carried out on an element of a rotor blade removed from the Mi-2 helicopter. The purpose of the test was to check the fatigue strength of the repaired rotor blade. Metal composite rotor blades have a metal spar in the form of a box and the trailing sections in the form of metallic honeycomb sandwich panels. The trailing sections are bonded to the spar. The repair had been carried out at the point where the trailing section became debonded from the spar at the Air Force Institute of Technology in Warsaw using a methodology developed for carrying out repairs of rotor blades’ damage. All types of the Mi family helicopters are equipped with metal composite rotors blades. Depending on MTOW (Maximum Take-Off Weight) and destination of helicopters, blades differ in dimensions, but their design solutions are practically the same. For this reason, the developed repair methodology can be used for all characteristic rotor blades structures for Mi helicopters. The fatigue test was performed at the Łukasiewicz - Institute of Aviation in Warsaw, using a hydraulically driven fatigue machine. The fatigue test was carried out by performing over 1.1 million load cycles. In repair places, upon completion of fatigue testing, no damage was found.","PeriodicalId":37629,"journal":{"name":"Fatigue of Aircraft Structures","volume":"2019 1","pages":"56 - 67"},"PeriodicalIF":0.0,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47529737","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 Historical operational usage data give a ground for fatigue damage estimation. Quality of sensors and recorders two or more decades ago were lower then modern one. Lack of resolution in nz-level measurement and recording leads to some errors in fatigue damage calculations. In this paper author propose a method to improve the accuracy of fatigue damage calculations for archived data. The method takes advantage of typical distribution of accumulated cycles for aircrafts. Small correction in representative nz value taken in calculations can reduce the error in fatigue damage assessment.
{"title":"Improving the Accuracy of Fatigue Damage Calculations for Archived Data","authors":"A. Leski","doi":"10.2478/fas-2019-0011","DOIUrl":"https://doi.org/10.2478/fas-2019-0011","url":null,"abstract":"Abstract Historical operational usage data give a ground for fatigue damage estimation. Quality of sensors and recorders two or more decades ago were lower then modern one. Lack of resolution in nz-level measurement and recording leads to some errors in fatigue damage calculations. In this paper author propose a method to improve the accuracy of fatigue damage calculations for archived data. The method takes advantage of typical distribution of accumulated cycles for aircrafts. Small correction in representative nz value taken in calculations can reduce the error in fatigue damage assessment.","PeriodicalId":37629,"journal":{"name":"Fatigue of Aircraft Structures","volume":"2019 1","pages":"113 - 120"},"PeriodicalIF":0.0,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45825638","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}
D. Nowakowski, Marta Baran, J. Lisiecki, S. Kłysz, P. Synaszko
Abstract The objective of the research presented in this paper was to determine the honeycomb core compliance of a sandwich structure of the horizontal stabilizer of the MiG-29 fighter jet in the static compression test. The study of the specimen was conducted based on the ASTM C365/C365M standard. The article presents the results of experimentally determined dependencies and strength parameters, i.e. the force-displacement dependence, the compressive modulus and the honeycomb core deformations.
{"title":"Examination of Honeycomb Core Compliance in Sandwich Structure","authors":"D. Nowakowski, Marta Baran, J. Lisiecki, S. Kłysz, P. Synaszko","doi":"10.2478/fas-2019-0003","DOIUrl":"https://doi.org/10.2478/fas-2019-0003","url":null,"abstract":"Abstract The objective of the research presented in this paper was to determine the honeycomb core compliance of a sandwich structure of the horizontal stabilizer of the MiG-29 fighter jet in the static compression test. The study of the specimen was conducted based on the ASTM C365/C365M standard. The article presents the results of experimentally determined dependencies and strength parameters, i.e. the force-displacement dependence, the compressive modulus and the honeycomb core deformations.","PeriodicalId":37629,"journal":{"name":"Fatigue of Aircraft Structures","volume":"2019 1","pages":"19 - 27"},"PeriodicalIF":0.0,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42540517","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 purpose of this paper is to present the design of a data recorder for flight tests of a full-scale aircraft and an UAV. The recorder is built based on the Arduino microprocessor platform and LabVIEW development environment. The data recorder will be used mainly for helicopter flight tests.
{"title":"Low-Cost Data Acquisition Unit for Flight Tests","authors":"Błażej Morawski, D. Głowacki, Anna Głowacka","doi":"10.2478/fas-2019-0012","DOIUrl":"https://doi.org/10.2478/fas-2019-0012","url":null,"abstract":"Abstract The purpose of this paper is to present the design of a data recorder for flight tests of a full-scale aircraft and an UAV. The recorder is built based on the Arduino microprocessor platform and LabVIEW development environment. The data recorder will be used mainly for helicopter flight tests.","PeriodicalId":37629,"journal":{"name":"Fatigue of Aircraft Structures","volume":"2019 1","pages":"121 - 130"},"PeriodicalIF":0.0,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48691826","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}
P. Kamińska, Jarosław Ziemkiewcz, P. Synaszko, K. Dragan
Abstract This paper presents two techniques of active thermography i.e. the pulsed thermography technique and the step heating technique. The aim of this article is to compare these two techniques and present the possibilities, advantages and limitations of their use in the context of non-destructive testing of composite materials. The experimental section presents the results of tests carried out on samples of the polymer composites reinforced with glass fiber.
{"title":"Comparison of Pulse Thermography (PT) and Step Heating (SH) Thermography in Non-Destructive Testing of Unidirectional GFRP Composites","authors":"P. Kamińska, Jarosław Ziemkiewcz, P. Synaszko, K. Dragan","doi":"10.2478/fas-2019-0009","DOIUrl":"https://doi.org/10.2478/fas-2019-0009","url":null,"abstract":"Abstract This paper presents two techniques of active thermography i.e. the pulsed thermography technique and the step heating technique. The aim of this article is to compare these two techniques and present the possibilities, advantages and limitations of their use in the context of non-destructive testing of composite materials. The experimental section presents the results of tests carried out on samples of the polymer composites reinforced with glass fiber.","PeriodicalId":37629,"journal":{"name":"Fatigue of Aircraft Structures","volume":"2019 1","pages":"102 - 87"},"PeriodicalIF":0.0,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41419905","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}
Rafał Luziński, Jarosław Ziemkiewicz, P. Synaszko, A. Żyluk, K. Dragan
Abstract Carbon fiber reinforced plastics (CFRPs) are widely used in aerospace structures due to their high stiffness, strength and good fatigue properties. They are however vulnerable to loads perpendicular to their plane and, while impacted, can suffer significant internal damage decreasing their overall strength. Detecting and sizing such damage is an important task of the non-destructive inspection (NDI) methods. This study was conducted to detect and quantify damage in a set of six impacted even rectangular CFRP specimens designed from a MiG-29 vertical stabilizer’s skin. The inspection was done using the ultrasonic (UT) method (based on mobile scanner – MAUS V) and the pulsed infrared thermographic (IRT) method. Each specimen’s inside and outside (impacted) surface was inspected separately with IRT, while the outside surface was then inspected with UT. UT provided the most precise measurements of the damage area, while the IRT inspection of the outside surface (which would be accessible on a real aircraft structure) provided underestimated values due to the damage’s depth and geometry.
{"title":"A Comparison of Composite Specimens Damage area Measurements Performed using Pulsed Thermography and Ultrasonic NDT Methods","authors":"Rafał Luziński, Jarosław Ziemkiewicz, P. Synaszko, A. Żyluk, K. Dragan","doi":"10.2478/fas-2019-0007","DOIUrl":"https://doi.org/10.2478/fas-2019-0007","url":null,"abstract":"Abstract Carbon fiber reinforced plastics (CFRPs) are widely used in aerospace structures due to their high stiffness, strength and good fatigue properties. They are however vulnerable to loads perpendicular to their plane and, while impacted, can suffer significant internal damage decreasing their overall strength. Detecting and sizing such damage is an important task of the non-destructive inspection (NDI) methods. This study was conducted to detect and quantify damage in a set of six impacted even rectangular CFRP specimens designed from a MiG-29 vertical stabilizer’s skin. The inspection was done using the ultrasonic (UT) method (based on mobile scanner – MAUS V) and the pulsed infrared thermographic (IRT) method. Each specimen’s inside and outside (impacted) surface was inspected separately with IRT, while the outside surface was then inspected with UT. UT provided the most precise measurements of the damage area, while the IRT inspection of the outside surface (which would be accessible on a real aircraft structure) provided underestimated values due to the damage’s depth and geometry.","PeriodicalId":37629,"journal":{"name":"Fatigue of Aircraft Structures","volume":"2019 1","pages":"68 - 77"},"PeriodicalIF":0.0,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46743793","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}
P. Reymer, Wojciech Zieliński, Łukasz Piątkowski, M. Dziendzikowski, A. Kurnyta, Rafał Wrąbel, Tomasz Cichocki, A. Leśniczak, M. Kurdelski, K. Dragan
Abstract This paper presents a general concept of the Full Scale Fatigue Test of the Mi-24 helicopter including the test layout and load distribution, as well as describes the milestones to be achieved. Additionally, some initial work conducted in order to determine both the mass and load distribution in the structure is described. The main goal of the test is to verify the low cycle fatigue life of the helicopter structure (fuselage, tail boom, wings and landing gear). The test will be divided into two main stages at which flight and landing loads will be applied. The authors demonstrate the general test concept, the helicopter’s structure fixture and the arrangement of the hydraulic actuators at both stages in order to achieve representative loads during the test. The proposed concept is based on AFIT’s previous experience in full scale structural testing, available literature and the experience of the test staff.
{"title":"Mi-24 Helicopter Full Scale Fatigue Test Concept","authors":"P. Reymer, Wojciech Zieliński, Łukasz Piątkowski, M. Dziendzikowski, A. Kurnyta, Rafał Wrąbel, Tomasz Cichocki, A. Leśniczak, M. Kurdelski, K. Dragan","doi":"10.2478/fas-2019-0002","DOIUrl":"https://doi.org/10.2478/fas-2019-0002","url":null,"abstract":"Abstract This paper presents a general concept of the Full Scale Fatigue Test of the Mi-24 helicopter including the test layout and load distribution, as well as describes the milestones to be achieved. Additionally, some initial work conducted in order to determine both the mass and load distribution in the structure is described. The main goal of the test is to verify the low cycle fatigue life of the helicopter structure (fuselage, tail boom, wings and landing gear). The test will be divided into two main stages at which flight and landing loads will be applied. The authors demonstrate the general test concept, the helicopter’s structure fixture and the arrangement of the hydraulic actuators at both stages in order to achieve representative loads during the test. The proposed concept is based on AFIT’s previous experience in full scale structural testing, available literature and the experience of the test staff.","PeriodicalId":37629,"journal":{"name":"Fatigue of Aircraft Structures","volume":"2019 1","pages":"11 - 18"},"PeriodicalIF":0.0,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42281282","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 In this work, the authors continue researching issues related to fatigue of aircraft structures made of fabrics. Parachute systems are widely used in military, sport and recreational aviation. Braking parachutes as well as skydiving and troop parachutes are characterized by the repeated use of parachute canopies, which are exposed to wear and fatigue. Until now, parachutes were difficult to design aviation systems due to their complex and unsteady opening characteristics, large changes in the geometry of canopies, suspension lines and tape risers as well as exposure to stochastic atmospheric turbulence. The fatigue of the canopy fabric, suspension lines and tape risers is a problem that must be addressed by textile designers and designers of reusable parachute systems. The authors of this work demonstrate the complexity of operating a parachute in hard multiple use conditions and propose ways to extend the parachute’s service life without compromising safety.
{"title":"Fatigue Degradation of the Ram-Air Parachute Canopy Structure","authors":"K. Szafran, Ireneusz Kramarski","doi":"10.2478/fas-2019-0010","DOIUrl":"https://doi.org/10.2478/fas-2019-0010","url":null,"abstract":"Abstract In this work, the authors continue researching issues related to fatigue of aircraft structures made of fabrics. Parachute systems are widely used in military, sport and recreational aviation. Braking parachutes as well as skydiving and troop parachutes are characterized by the repeated use of parachute canopies, which are exposed to wear and fatigue. Until now, parachutes were difficult to design aviation systems due to their complex and unsteady opening characteristics, large changes in the geometry of canopies, suspension lines and tape risers as well as exposure to stochastic atmospheric turbulence. The fatigue of the canopy fabric, suspension lines and tape risers is a problem that must be addressed by textile designers and designers of reusable parachute systems. The authors of this work demonstrate the complexity of operating a parachute in hard multiple use conditions and propose ways to extend the parachute’s service life without compromising safety.","PeriodicalId":37629,"journal":{"name":"Fatigue of Aircraft Structures","volume":"2019 1","pages":"103 - 112"},"PeriodicalIF":0.0,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44466995","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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