Fatigue of Aircraft Structures最新文献

{"title":"Assessment of Sensor Technologies for Aircraft SHM Systems","authors":"A. Kurnyta, K. Dragan, M. Dziendzikowski","doi":"10.2478/fas-2013-0005","DOIUrl":"https://doi.org/10.2478/fas-2013-0005","url":null,"abstract":"Abstract SHM is a monitoring system which uses sensors, actuators and data transmission, acquisition and analysis, permanently integrated with the inspected object. The objective of SHM is to detect, localize, identify and predict development of fatigue fractures, increasing safety and reliability. This paper presents an assessment of sensor technologies used in aircraft SHM system. Due to the fact that most of these measurement methods are relatively new and still under development the present appraisal focuses on a number of parameters with reference to each method, including a sensor’s installation issues, reliability, power consumption, sensor infrastructure, sensitivity and cost and availability. The work is predominantly focused on the assessment ofpermanently bonded sensors, such as foil strain gages, Comparative Vacuum Monitoring (CVM), Piezo sensors (PZT), Eddy-Current Transducers (ECT). Finally, all these methods are briefly discussed.","PeriodicalId":37629,"journal":{"name":"Fatigue of Aircraft Structures","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2014-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2478/fas-2013-0005","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69203588","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}

{"title":"Micromechanical Properties and Stress Measurements with Diffraction Methods","authors":"Elżbieta Gadalińska, A. Baczmaňski","doi":"10.2478/fas-2013-0003","DOIUrl":"https://doi.org/10.2478/fas-2013-0003","url":null,"abstract":"Abstract Diffraction methods are commonly used for the determination of the elastic lattice deformation and distortion from the displacement and broadening of the diffraction peak. These methods enable researchers to measure stresses and elastic properties of polycrystalline materials. The main advantages of diffraction methods are their non-destructive character and the possibility of macrostress and microstress analysis for multiphase and anisotropic materials. Measurements are performed selectively only for crystallites contributing to the measured diffraction peak, i.e. for the grains having lattice orientations for which the Bragg condition is satisfied. When several phases are present in the sample, measurements of separate diffraction peaks allow for the behaviour of each phase to be investigated independently. This method can be applied without any limitations to flat specimens. Numerical calculations of residual stresses around the rivets imply a very high stress gradientin the case of tangential stresses as well in the case of radial stresses. Attempting to verify these predictions, the residual stress measurements with an X-ray diffractometer were performed on riveted samples after the riveting process. In addition, complementary measurements of strain values with strain gauges during the riveting process were performed as well as the finite elements modelling. The aim of these measurements was to determine the stress values around the rivets and to compare results obtained with different techniques. On the other hand, the multi-scale crystallographic model of elastoplastic deformation is very convenient for the study of elastoplastic properties in microscopic and macroscopic scales. Comparison of experimental data with model predictions allows us to understand the physical phenomena that occur during a sample’s deformation at the level of polycrystalline grains. Moreover, the micro and macro parameters of elastoplastic deformation can be experimentally established. It should be stated that the characterisation of the residual stress field and elastic properties is important in the study of the mechanical behaviour of polycrystalline materials, including plasticity and damage phenomena. In this work, a new analysis method of neutron diffraction results obtained during in-situ tensile load is proposed and tested. The methodology is based on the measurements of lattice strains during in-situ tensile testing for several hkl reflections and for different orientations of the sample with respect to the scattering vector. As the result, the full stress tensor for preferred texture orientations in function of the applied stress can be determined using the crystallite group method. The experimental data are presented and compared with the self-consistent model calculations performed for groups of grains selected by different hkl reflections.","PeriodicalId":37629,"journal":{"name":"Fatigue of Aircraft Structures","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2014-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69203529","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}

{"title":"Investigations into Load Spectra of UAVS Aircraft","authors":"M. Rodzewicz, D. Głowacki","doi":"10.2478/fas-2013-0004","DOIUrl":"https://doi.org/10.2478/fas-2013-0004","url":null,"abstract":"Abstract The paper contains a description of a novel approach to the load spectra estimation applied to UAVs. The authors have developed a number of tools in the LabVIEW environment enabling an in-depth analysis of flight-log data. One major achievement was the separation of the load spectra induced by steering and the load spectra induced by turbulence. The authors have shown a significant influence of both of the main load sources on the fatigue life of the UAV airframe, calculated based on the P-M hypothesis. This approach to fatigue testing of composite UAV airframes needs to take into account the rate of load variations as these may affect the fatigue life of tested structures. The paper presents several schemes of calculation algorithms and a number of well-illustrated examples of the tests and investigations results.","PeriodicalId":37629,"journal":{"name":"Fatigue of Aircraft Structures","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2014-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69203539","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}

{"title":"Local Phenomena During Riveting Process","authors":"J. Kaniowski, Wojciech Wronicz","doi":"10.2478/fas-2013-0007","DOIUrl":"https://doi.org/10.2478/fas-2013-0007","url":null,"abstract":"Abstract The paper presents experimental and numerical study of the local phenomena during the riveting process. It is commonly accepted that technological factors of the riveting process has a strong influence on the fatigue life of riveted joints. The authors analysed the papers concerned the experimental researches of the riveting force influence on fatigue life. The magnitude of the life increase caused by the riveting force increase suggests the authors that this is not only the result of beneficial stress system but the change of the joint formation mechanism has taken place. This was an inspiration to undertake more detailed researches of the riveting process. The strain progress during the riveting process has been experimentally investigated for four types of aluminium rivets used in airframes. Measurements confirm very high strains near the driven head. For some types of rivets the reversal strain signal has been recorded. Several FE model has been use to investigate the riveting process. The axisymmetric and solid models were used. The agreement of experimental and numerical results in some cases were good, in other cases the numerical models demand further development. In any calculations, the reversal strain effect has not been obtained, This suggest that it is result of the phenomenon which has not been taken into account in numerical modelling. The working hypothesis has been assumed that during the riveting process adhesive joints (called cold welding) were formed and destroyed during the process, what was the reason of the observed reversal strain signal. The authors are going to continue this investigation.","PeriodicalId":37629,"journal":{"name":"Fatigue of Aircraft Structures","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2014-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69203659","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}

{"title":"Wireless Energy Supply to Aircraft Structural Health Monitoring Nodes Using Ultrasonic Lamb Waves","authors":"A. Kural","doi":"10.1515/fas-2014-0002","DOIUrl":"https://doi.org/10.1515/fas-2014-0002","url":null,"abstract":"Abstract This article is based on research done during the author’s PhD at Cardiff University, UK. A prototype of a novel wireless energy transmission system aimed at the use with wireless aircraft structural health monitoring (SHM) sensor nodes is described. The system uses ultrasonic guided plate waves (Lamb waves) to transmit energy along an aluminium plate, similar to those used in aircraft structures. Three types of piezoelectric transducers generating and receiving the ultrasonic vibration were compared. The Smart Material MFC M8528-P1 was found to achieve the best performance, allowing the transmission of 17 mW across a 54 cm distance, while being driven with a 20 V signal. Laser vibrometer imaging and LISA software simulation of the Lamb wave propagation in the experimental plate were also performed. Based on these, ideas for a further development of the system were proposed.","PeriodicalId":37629,"journal":{"name":"Fatigue of Aircraft Structures","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2014-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1515/fas-2014-0002","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67370226","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}

{"title":"Stress Analysis of the PZL M28’s Airframe Subjected to Repairs During Fatigue Tests","authors":"J. Brzęczek, Henryk Gruszecki, L. Pieróg, Franciszek Deszcz, J. Pietruszka","doi":"10.1515/fas-2014-0011","DOIUrl":"https://doi.org/10.1515/fas-2014-0011","url":null,"abstract":"Abstract The PZL M28’s service life is determined based on the fatigue tests of the wing and wing loads-carry-through structure. During the fatigue test, the first occurrence of significance was the appearance of a in the area of the wing where loads are applied from the strut. It was demonstrated during further activities that repairs of the wing and other basic assemblies enabled, when performed at an appropriate time, the airplane’s service life to be significantly increase. In the case of each design change implemented in the airframe subject to the fatigue testing, a stress analysis of the airframe was required in order to check if local changes, i.e. local repairs, did not affect the stress level in other tested areas. This helped to avoid significant stress redistribution in the airframe after the repair, so the fatigue test was still valid for all areas of interest.","PeriodicalId":37629,"journal":{"name":"Fatigue of Aircraft Structures","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2014-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1515/fas-2014-0011","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67370424","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}

{"title":"Comparison of Selected Rivet and Riveting Instructions","authors":"J. Kaniowski","doi":"10.1515/fas-2014-0004","DOIUrl":"https://doi.org/10.1515/fas-2014-0004","url":null,"abstract":"Abstract Sheet metal parts are widely used in airframes. Most sheet metal parts used in aircraft assembly are joined using rivets. A number of riveting parameters directly influence fatigue properties of a structure. These include a rivet length, driven head diameter, tolerance of a rivet hole and a rivet shank diameter, and a protective layer among others. Unfavourable selection or change of these parameters can lead to stress concentrations and early crack nucleation. Crack growth can cause failure of a whole structure. The selection of the riveting process parameters is usually described in a company’s internal instruction (process specifications). Some parameters can be defined in an aircraft's technical specifications. Riveting instructions among other production documentation are part of a company's closely guarded know-how. The author obtained access to two riveting instructions used in Poland and three such documents used in western Europe. The author was permitted to publish the comparison of the parameters from these documents but he is not supposed to reveal any other information. For the reasons stated above, the following cryptonyms were used in the article: Poland-1, Poland-2, West-1, West-2 and West-3. The quality of a joint also depends on rivets parameters that are defined in rivets standards. For this reason, selected rivets defined in the Polish and Russian industry standards as well as western standards are compared in this paper. Tolerances of a rivet and a hole diameter, clearances between a rivet and a hole, rivet lengths anticipated for driven head formation as well as driven head dimensions are taken into account.","PeriodicalId":37629,"journal":{"name":"Fatigue of Aircraft Structures","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2014-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1515/fas-2014-0004","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67370326","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}

{"title":"Comparison of the Flight Loads Spectra of Two Business Jets","authors":"L. K. Kliment, K. Rokhsaz","doi":"10.1515/fas-2014-0001","DOIUrl":"https://doi.org/10.1515/fas-2014-0001","url":null,"abstract":"Abstract Operational flight loads have been analyzed from two business jets, a Global 5000 and a Global Express XRS. It is shown that both airframes were subjected to nearly the same number of ground-air-ground cycles, even though the flight times were much different. Flights have been divided into various phases, and loads and turbulence data have been categorized by altitude bands within each phase. Cumulative occurrences of incremental vertical gust load factors have been compared and shown to be comparable for the two airframes. Maneuver load factors have been shown to spread over a wider range of values for the 5000 in every phase. This has been confirmed through comparison of combined loads with those from a CRJ100 and an ERJ-145XR. Derived gust velocities, obtained from the load factors are presented in the form of exceedance spectra. These results from both aircraft are shown to agree well","PeriodicalId":37629,"journal":{"name":"Fatigue of Aircraft Structures","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2014-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67369795","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}

{"title":"Selected Aspects Related to the Applied Loads Control During Fatigue Tests of a Metallic Airframe","authors":"J. Brzęczek, Jerzy Chodur, J. Pietruszka","doi":"10.1515/fas-2014-0010","DOIUrl":"https://doi.org/10.1515/fas-2014-0010","url":null,"abstract":"Abstract Service life of the PZL M28 is computed based on the results of the full-scale fatigue tests of the structure [1]. As the PZL M28 is a commuter category airplane according to the 14 CFR Part 23 and CS-23 regulations, the test objects are: (1) wing and wing load carry-through structure, (2) empennage and attached fuselage structure. Additionally, there are fatigue tests carried out for the landing gear and other selected elements including control system elements. The aircraft load carry-through structure is metallic and the cabin is unpressurized. The fatigue tests are conducted stage-by-stage. As tests progress, it is possible to extend the aircraft target service life, applying the safe life philosophy with reference to the primary components of the load carry-through structure. The article brings into attention the issue of the applied loads control in conducting fatigue tests of the metallic airframe.","PeriodicalId":37629,"journal":{"name":"Fatigue of Aircraft Structures","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2014-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1515/fas-2014-0010","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67370360","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}

{"title":"Simulating Crack Propagation of a Selected Structural Component of the PZL-130 Orlik TC-II Aircrafts","authors":"Krzysztof Jankowski, P. Reymer","doi":"10.1515/fas-2014-0013","DOIUrl":"https://doi.org/10.1515/fas-2014-0013","url":null,"abstract":"Abstract This paper presents the process of estimating crack propagation within a selected structural component of the PZL-130 Orlik TC-II using a numerical model. The model is based on technical drawings and measurements of the real structure. The proper definition of the geometry, including the location and size of the gap between elements, is significant for mesh generation. During the simulation process the gap is combined node by node. Each time, the strain energy release rate (G) is calculated. The stress intensity factor and geometry correction factor are defined for consecutive crack lengths, and used further on to estimate crack propagation.","PeriodicalId":37629,"journal":{"name":"Fatigue of Aircraft Structures","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2014-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67370587","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}