Introduction of Developing Fatigue Load Spectrum for Full-Scale Fatigue Test of Composite Aircraft

2020 ◽  
Vol 21 (3) ◽  
pp. 681-692
Author(s):  
Young-Sik Joo ◽  
Won-Jun Lee ◽  
Bo-Hwi Seo ◽  
Seung-Gyu Lim
Keyword(s):  
Fatigue Test ◽  
Full Scale ◽  
Load Spectrum ◽  
Fatigue Load

scholarly journals Introduction of Fatigue Markers in Full Scale Fatigue Test of an Aircraft Structure

2012 ◽  
Vol 2012 (4) ◽  
pp. 29-37 ◽  
Author(s):  
Andrzej Leski ◽  
Sylwester Kłysz ◽  
Janusz Lisiecki ◽  
Gabriel Gmurczyk ◽  
Piotr Reymer ◽  
...  
Keyword(s):  
Fatigue Crack ◽  
Crack Propagation ◽  
Fatigue Test ◽  
Crack Propagation Rate ◽  
Propagation Rate ◽  
Full Scale ◽  
Life Assessment ◽  
Load Spectrum ◽  
Preliminary Load ◽  
Different Levels

Abstract Air Force Institute of Technology participates in the service life assessment programme SEWST. The aim of this programme, funded by the Polish Ministry of Defense, is to modify the operation system of PZL-130 "Orlik" TC-II turbo propelled trainer aircraft. The structural part of the programme is focused on the Full Scale Fatigue Test of the whole airframe to be conducted at the VZLU in the Czech Republic. The load spectrum for the test was developed by the AFIT based on the flight test results. The basic load block represents 200 simulated flight hours and consists of 194 flights showing different levels of severity. At the end of the Full Scale Fatigue Test a teardown inspection is planned during which it would be most beneficial to be able to determine crack propagation rate by means of a crack surface inspection. Markers are usually visible on most fatigue crack surfaces, however they occur randomly therefore it is almost impossible to conclude anything about the crack history. Since the preliminary load block consisted of separate flights (flight loads together with landing and taxing loads) showing significantly different levels of severity, the easiest way to modify the load block was to change the order of flights within the block. Hence a pilot programme was started at the AFIT which was focused on the determination of the influence of flight sequence on crack appearance. Several load blocks were determined using various techniques of rearranging the order of flights within the preliminary load spectrum. This approach ensured the preservation of the initial severity of the load block and simultaneously enabled a significant increase in the probability of the markers occurrence introducing neither artificial underloads nor overloads that would most probably affect the crack propagation rate. Fatigue crack surfaces were inspected using Scanning Electron Microscope. As a result of the investigations a series of images were obtained showing the specimen microstructure with visible markers arranged in the desired sequences. Based on the obtained pictures the most promising load block arrangements were chosen for the Full Scale Fatigue Test.

scholarly journals ZL-130TCII Fracture Markers Solution for Full-Scale Fatigue Test

2011 ◽  
Vol 2011 (3) ◽  
pp. 22-27
Author(s):  
Sylwester Kłysz ◽  
Janusz Lisiecki ◽  
Dariusz Zasada ◽  
Gabriel Gmurczyk ◽  
Andrzej Leski
Keyword(s):  
Fracture Surface ◽  
Fatigue Test ◽  
Aluminium Alloys ◽  
Full Scale ◽  
Load Spectrum ◽  
Full Scale Tests ◽  
Change Spectrum ◽  
Pilot Tests

ZL-130TCII Fracture Markers Solution for Full-Scale Fatigue TestIn the context of PZL-130TC-II full-scale fatigue test, several strategies of fatigue loadings that create fracture surface markings were considered. One block of spectrum is made of 200 flights. By reordering those flights, a block which should create a fracture marker, was developed. It was very important that reordering the load spectrum or adding overloads or underloads did not change spectrum severity. Pilot tests of aluminium alloys specimens were carried out to finalise appropriate marker intervals before commencing full-scale tests. The experiment was conducted with the MTS machine with 810.23 system. The results and conclusions are presented within this paper.

Full-Scale Fatigue Test of Trough-to-Deck Plate Joints in Steel Orthotropic Deck

2013 ◽  
Vol 671-674 ◽  
pp. 1035-1039
Author(s):  
Xiu Wei Wang ◽  
Liang Tang ◽  
Chun Sheng Wang ◽  
Gao Liu
Keyword(s):  
Fatigue Test ◽  
Fatigue Cracks ◽  
Sudden Change ◽  
Longitudinal Direction ◽  
Failure Criteria ◽  
Full Scale ◽  
Fatigue Load ◽  
Deck Plate ◽  
Weld Toe ◽  
Steel Orthotropic Deck

Trough-to-deck plate joints in steel orthotropic deck are very sensitive to fatigue. A full-scale fatigue test of steel orthotropic deck was conducted to study the fatigue performance of trough-to-deck plate joints between two diaphragms. The test panel has three spans of 1.0m+3.5m+1.0m in the longitudinal direction and five troughs with the width of 3.0m in the transverse direction. At the end of the fatigue test, the cycles of the fatigue load reached to six million and no fatigue cracks were found by naked eye at the trough-to-deck plate joints. Based on the failure criteria of the measured stresses with a sudden change, it is confirmed that the fatigue strength of trough-to-deck plate welded joints with deck plate failure is similar to design category 71 in the Eurocode using the measured stresses at a distance of ten millimeters from the weld toe.

scholarly journals The Definition of the Load Spectrum for SU-22 Fighter-Bomber Full Scale Fatigue Test

2015 ◽  
Vol 2015 (7) ◽  
pp. 28-33
Author(s):  
Piotr Reymer ◽  
Marcin Kurdelski ◽  
Andrzej Leski ◽  
Krzysztof Jankowski
Keyword(s):  
Service Life ◽  
Fatigue Test ◽  
Air Force ◽  
Monitoring Program ◽  
Full Scale ◽  
Load Spectrum ◽  
Load Spectra ◽  
Load Monitoring ◽  
Wing Sweep ◽  
Definition Of

Abstract The Su-22 fighter-bomber is a military aircraft used in the Polish Air Force since the mid 1980’s. By the decision of the Polish Ministry of Defense the predicted service life for this type of aircraft will be extended to 3200 flight hours. Due to the fact that some aircraft were nearing the end of the service life guaranteed by the manufacturer, the actual service life, determined based on the flight profile in the Polish Air Force, had to be validated. Consequently, the Full Scale Fatigue Test (FSFT) had to be carried out in order to verify that the required service life was attainable. This article describes the process of preparation of the load spectra used in the Su-22 FSFT. Due to the fact that the Su-22 has a variable sweep wing the whole test was divided into three Stages (landing, flight and flap loads) carried out at different wing sweep angles (30°/45°/30°). The spectra were developed using the historical data gathered from Flight Data Recorders (FDR), strain signals acquired during the Operational Load Monitoring program (OLM) and aerodynamic calculations.

scholarly journals Fatigue Load Spectrum of Highway Bridge Vehicles in Plateau Mountainous Area Based on Wireless Sensing

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Li Rui ◽  
Xie Xiaoyu ◽  
Duan Xueyan
Keyword(s):  
Low Cost ◽  
Mineral Resources ◽  
Highway Bridges ◽  
Equivalent Model ◽  
Distribution Model ◽  
Mountainous Area ◽  
Wireless Sensing ◽  
Mountainous Areas ◽  
Load Spectrum ◽  
Fatigue Load

In Yunnan and other plateau mountainous areas, hydropower and mineral resources are abundant, and there are relatively many vehicles used for the transportation of large hydropower facilities. The widespread phenomenon of vehicle overload causes severe fatigue among the drivers. However, there is no reference vehicle load spectrum for fatigue analysis in the existing research. The application of wireless sensing technology to bridge health monitoring is favorable for the entire monitoring system’s low-cost and intelligent development. In this study, wireless sensors are used to collect sensing data in the measured area and perform preliminary filtering processing. The data collected by the sensing layer is aggregated at the TD gateway layer to realize local short-term storage of monitoring data, and 3G wireless transmission is used for the effective processing of the data. The clustering method is used to classify the vehicle models based on investigating the most representative expressway traffic flow information in Yunnan Province. Moreover, the weighted probability distribution model of different vehicle models is established through statistical analysis, which simplifies the composition’s fatigue intensity spectrum model. The selection of five vehicles of the equivalent model followed by a six-axle vehicle has the most significant impact on bridge damage as the standard fatigue vehicle. The research results establish a basis for the fatigue design of highway bridges in plateau and mountainous areas and provide data to establish vehicle fatigue load spectra in national highway regions.

Health Monitoring of the Aircraft Structure during a Full Scale Fatigue Test with Use of an Active Piezoelectric Sensor Network

2015 ◽  
Vol 220-221 ◽  
pp. 328-332
Author(s):  
Michal Dziendzikowski ◽  
Krzysztof Dragan ◽  
Artur Kurnyta ◽  
Sylwester Klysz ◽  
Andrzej Leski
Keyword(s):  
Signal Processing ◽  
Damage Detection ◽  
Crack Growth ◽  
Fatigue Test ◽  
Piezoelectric Sensor ◽  
Full Scale ◽  
Growth Monitoring ◽  
Aircraft Structure ◽  
System Functioning ◽  
Signal Processing Methods

The paper presents an approach to develop a system for fatigue crack growth monitoring and early damage detection in the PZL – 130 ORLIK TC II turbo-prop military trainer aircraft structure. The system functioning is based on elastic waves propagation excited in the structure by piezoelectric PZT transducers. In the paper, a built block approach for the system design, signal processing as well as damage detection is presented. Description of damage detection capabilities are delivered in the paper and some issues concerning the proposed signal processing methods and their application to crack growth estimation models are discussed. Selected preliminary results obtained during the Full Scale Fatigue Test thus far are also presented.

Investigation on Parameter Contribution to the Property of Weld Joint AA5052-H112 Sheets in Friction Stir Spot Welding under Fatigue Load and Failure Mode

2020 ◽  
Vol 899 ◽  
pp. 117-125
Author(s):  
Armansyah ◽  
Juri Saedon ◽  
Hwi Chie Ho ◽  
Shahriman Adenan
Keyword(s):  
Fatigue Test ◽  
Failure Mode ◽  
Weld Joint ◽  
Spot Welding ◽  
Dwell Time ◽  
Welded Joint ◽  
Friction Stir Spot Welding ◽  
Spindle Speed ◽  
Fatigue Load ◽  
Friction Stir

In an initiative to reveal the property of welded joint, investigation and assessment of the welding parameters in friction stir spot welding (FSSW) was carried out. In this study, the AA5052-H112 sheets with 2mm thickness was welded using cylindrical tool pin profile under different combinations of main process parameters i.e. spindle speed, tool depth, and dwell time. The fatigue test under cyclical load condition was performed to investigate the dynamic behavior of the welded joint. Failure mode analysis on the fracture of the weld joint after fatigue test was took also consideration. Finally, results from the test were evaluated using analysis of variance (ANOVA) to deter-mine statistically significant factors and associated percentage contribution together with the generation of main effects plots. From ANOVA results, dwell time had the highest influence on fatigue load with a PCR of 52.8%, followed by the spindle speed 37.1%, and then tool depth 6%.

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