scholarly journals Impacts of Thermal and Mechanical Cycles on Electro-Thermal Anti-Icing System of CFRP Laminates Embedding Sprayable Metal Film

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1589
Author(s):  
Rongjia Li ◽  
Wang Xu ◽  
Dalin Zhang
Keyword(s):  
Fatigue Life ◽  
Metal Film ◽  
Fatigue Testing ◽  
Aerodynamic Force ◽  
Testing Machine ◽  
Laminated Composite ◽  
Heating Element ◽  
Electric Resistance ◽  
Potential Threat ◽  
Mechanical Cycling

The aircraft electro-thermal anti-icing system that can guarantee flight safety may be affected by periodic heating and cyclic aerodynamic force during long-term flight missions, which seems to be a potential threat to ice protection. This paper aims to investigate the impacts of thermal and mechanical cycles on heating elements of the electro-thermal anti-icing system. Specimens were manufactured with CFRP (carbon fiber reinforced polymer) laminated composite, glass fiber prepreg and copper screen, in which sprayable metal film (SMF) was embedded as the heating element. The study focuses on electric resistance variation of SMF and functional fatigue life under the cycling load. Thermal cycling tests were carried out in an insulated chamber where the specimens were heated up to 80 °C and then cooled down to −55 °C for 1000 cycles. Mechanical cycling tests were conducted on a fatigue testing machine where the specimens were imposed on tension-compression loading for 106 cycles. Results showed that the electric resistance of SMF increased with the number of loading cycles. The resistance was increased by 20% and the heating power was decreased by 16.67% after 1000 thermal cycles. During the mechanical cycling tests, it was found that the heating element was destructed before the structural failure, which indicated that the fatigue life of function was lower than that of the structure.

Fatigue of NiTi for Dampers and Actuators

2012 ◽  
Vol 83 ◽  
pp. 18-27 ◽  
Author(s):  
Antonio Isalgue ◽  
Vicenç Torra ◽  
Fabio Casciati ◽  
Sara Casciati
Keyword(s):  
Fatigue Life ◽  
Martensitic Transformation ◽  
Size Effects ◽  
Main Parameter ◽  
Testing Machine ◽  
Constant Load ◽  
Thermomechanical Properties ◽  
Niti Wire ◽  
Mechanical Cycling ◽  
Thermal Actuation

The application of Shape Memory Alloy (SMA) devices to practical uses need well established performance. The reliable application in some areas, as dampers in engineering, needs a known, relatively long fatigue life (some million oscillations). The thermomechanical properties of SMA, based on their martensitic transformation, made them attractive to use for damping, taking advantage of the pseudoelastic window and hysteresis on transforming-retransforming. Due to size effects and to the fact that fatigue failure in metallic NiTi usually comes from a defect inducing crack growth, fatigue has to be studied for concrete applications, with the correct samples. The present work points out the possibility to apply NiTi to dampers and actuators. Testing machine experiments indicate that the main parameter controlling fatigue life is the effective stress on the NiTi wire. Long wire life (in the million cycle regime) can be achieved under limited stresses (around or under 200 MPa). Also, experiments have been done on thermal actuation of NiTi wire under traction at constant load. The results demonstrate that long actuator life (larger than 300000 cycles) can be achieved at low stresses (around 100 MPa), coherently with the mechanical cycling. From our results, NiTi is useful to effectively damp vibrations even at relatively low stresses and strains. The experimental results from facilities (cable No. 1 in ELSA-JRC, Ispra, Italy, and IFSTTAR test cable, near Nantes, France) confirm that NiTi wire is able to damp stayed cables.

Effect of Slag Composition on Fatigue Life of High Speed Wheel Steel

2013 ◽  
Vol 675 ◽  
pp. 264-269
Author(s):  
Yu Tang
Keyword(s):  
Fatigue Life ◽  
High Speed ◽  
Fatigue Testing ◽  
Testing Machine ◽  
Oxide Inclusion ◽  
Wheel Steel ◽  
Al2o3 Content ◽  
Confocal Laser ◽  
Composition Analysis ◽  
In Situ Observation

In order to improve fatigue life of wheel steel, secondary-refining process was done with Al-deoxidation and slag of high basicity, high Al2O3 content and low oxidizing property. By morphology observation and composition analysis with FESEM, it is found that during LF-VD process, by slag-steel-inclusion interaction, Al2O3 inclusions could transform to MgO-Al2O3 spinel, and later on to CaO-MgO-Al2O3 inclusions, which are inclined to be eliminated by floatation, lowering T[O] content to 0.0007%, enhancing fatigue life of wheel steel. By In-Situ observation with CONFOCAL laser scanning microscope, it is found that MnS precipitates during solidification process, which would core oxide inclusion to form MnS-oxide complex inclusion, contributing to fatigue life improvement of wheel steel. By INSTRON fatigue testing machine, it is found that by successful inclusion control, tested samples achieve ultra-high cycle of 108 above, realizing experimental purpose of improving fatigue life of wheel steel, boosting domestic production process of CRH high speed wheel steel.

A Study on Fatigue Behavior of SM490A Steel under Low Temperature

2007 ◽  
Vol 353-358 ◽  
pp. 142-145 ◽  
Author(s):  
Ki Weon Kang ◽  
Byeong Choon Goo ◽  
J.H. Kim ◽  
Heung Seob Kim ◽  
Jung Kyu Kim
Keyword(s):  
Fatigue Life ◽  
Low Temperature ◽  
Test Temperature ◽  
Fatigue Testing ◽  
Fatigue Behavior ◽  
Testing Machine ◽  
Fatigue Tests ◽  
Static Strength ◽  
Experimental Results ◽  
Railway Vehicle

This paper deals with the fatigue behavior and its statistical properties of SM490A steel at various temperatures, which is utilized in the railway vehicle. For these goals, the tensile ad fatigue tests were performed by using a servo-hydraulic fatigue testing machine at three temperatures: +20°C, -10°C and -40°C. The static strength and fatigue limits of SM490A steel were increased with decreasing of test temperature. The probabilistic properties of fatigue behavior are investigated by means of probabilistic stress-life (P-S-N) curve and they are well in conformance with the experimental results regardless of temperature. Also, based on P-S-N curves, the variation of fatigue life is investigated and as the temperature decreases, the variation of fatigue life increases moderately.

Fatigue Damage Mechanism Analyses of Oriented Sheets of Polymethyl Methacrylate Glasses

2011 ◽  
Vol 462-463 ◽  
pp. 36-41
Author(s):  
Wei Guo Guo ◽  
Xiao Qiong Zhang ◽  
J. Su
Keyword(s):  
Fatigue Life ◽  
Polymethyl Methacrylate ◽  
Fatigue Testing ◽  
Testing Machine ◽  
Damage Mechanism ◽  
Materials Testing ◽  
Compression Tests ◽  
Static Compression ◽  
Lower Amplitude ◽  
Notch Edge

To understand the damage mechanism and obtain the fatigue life of the oriented sheets of polymethyl methacrylate (PMMA) glasses, the quasi-static compression tests and the constant amplitude fatigue testing with two notch stress concentration factors are carried out respectively, using the CSS44100 electromechanical universal materials testing machines and a MTS servohydraulic testing machine. The damage region and fracture section of the deformed and failed sheet samples are examined with the aid of an optical microscopy. The results show that, 1) the oriented PMMA glasses drawn through vertical bi-direction have remarkable thermomechanical anisotropic characteristic, that is, it has the higher hardness and strength along the normal direction of the sheet panel, it will burst out and scatters into bigger pieces under the perforation; 2) the S-N curve of the oriented sheet specimens shows that its fatigue life is not sensitive on the notch at lower amplitude stress levels; and 3) the crack initiation of the oriented PMMA glasses often originates the interbeds area or mid region of the notch edge under fatigue cycle loading.

scholarly journals Analysis of Torque Maintenance and Fracture Resistance after Fatigue in Retention Screws Made of Different Metals for Screw-Retained Implant-Borne Prosthesis Joints

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Maria Beatriz Bello Taborda ◽  
Gabriela Sumie Yaguinuma Gonçalves ◽  
Cecília Alves de Sousa ◽  
Wirley Gonçalves Assunção
Keyword(s):  
Fracture Resistance ◽  
Fatigue Testing ◽  
Testing Machine ◽  
Compression Testing ◽  
Testing Methods ◽  
Mechanical Cycling ◽  
Universal Testing ◽  
Grade 5 ◽  
Alloy Material ◽  
Connection Type

Purpose. The aim was to evaluate the effect of different metallic alloys used in the manufacture of retention screws for universal cast to long abutment (UCLA) abutments for external hexagon (HE) and Morse taper (MT) connection implants, as well as of mechanical cycling on torque maintenance and fracture resistance through electromechanical fatigue testing by mastication followed by compression testing. Methods. Sixty implants were used, 30 MT and 30 HE, with their respective titanium UCLA abutments and retention screws of 5 different materials (n = 6): Ti cp grade 2, Ti cp grade 4, Ti cp grade 4 hard, Ti grade 5—Ti6Al4V and surgical steel (DSP® Biomedical). The assemblies were positioned in an electromechanical masticatory fatigue testing machine. The fracture strength test was performed by compression testing in a universal testing machine EMICDL-200. Results. The cycled screws and new screws of each alloy group for each connection type were evaluated, obtaining the maximum force (FM), in order to verify the effect of mechanical cycling. The data were tabulated and submitted to appropriate statistical analysis (α = 0.05). Conclusion. It was concluded that for the MT, the alloy with the best performance was steel, both in the maintenance of torque and in the compression test, and cycling negatively influenced the maintenance of preload for this connection. The alloy material did not influence torque maintenance for HE. The new screws that were subjected to EMIC showed higher strength. The alloy with the lowest strength was Ti grade 2.

scholarly journals Some aspects of fretting fatigue under cyclic normal loading

2019 ◽  
Vol 1 (1) ◽  
Author(s):  
Farshad Abbasi ◽  
G. H. Majzoobi
Keyword(s):  
Fatigue Life ◽  
Fatigue Testing ◽  
Normal Load ◽  
Testing Machine ◽  
Low Frequency ◽  
Load Condition ◽  
Fretting Fatigue ◽  
Normal Loading ◽  
Drastic Effect ◽  
Fretting Damage

Fretting fatigue has been studied mainly under constant normal loading, as it requires simple equipment which can be assembled on a universal fatigue testing machine. Recently, we [1] have introduced an innovative fretting fatigue apparatus in which the contact pressure can independently be varied during the test. In a recent publication [2] we have investigated the effect of normal load frequency on fretting fatigue life of Al7075-T6 under cyclic normal load condition. It was found that the low frequency of normal load has drastic effect on fretting fatigue life. The effect, however, gradually diminishes with the frequency increase and vanishes at the frequency of around 80Hz. In another publication [3] we have compared the results of constant normal loading with those of in phase, 90° and 180° degrees out-of-phase loadings. It was found that the constant normal loading has the least fretting damage, while the maximum fretting damage occurs by in-phase loading. The results also showed that the out-of-phase loading had improving effect on fretting fatigue life with respect to the in-phase condition. Recently, Ciaverella [4] has published a discussion on our publications [2, 3]. He believes that some of our experimental results needs further discussion. Therefore, the objective of this article is to answer three main points he has raised in his article [4]. We hope that this discussion could lead to some progress.

scholarly journals Rotary Fatigue Testing Machine to Determine the Fatigue Life of NiTi alloy Wires and Endondontic Files

2015 ◽  
Vol 114 ◽  
pp. 500-505 ◽  
Author(s):  
André Carvalho ◽  
Manuel Freitas ◽  
Luis Reis ◽  
Diogo Montalvão ◽  
Manuel Fonte
Keyword(s):  
Fatigue Life ◽  
Fatigue Testing ◽  
Niti Alloy ◽  
Testing Machine

Effect of Slag Composition on Total Oxygen of High Speed Wheel Steel

2013 ◽  
Vol 690-693 ◽  
pp. 114-117
Author(s):  
Yu Tang
Keyword(s):  
Fatigue Life ◽  
High Speed ◽  
Fatigue Testing ◽  
Testing Machine ◽  
Wheel Steel ◽  
Al2o3 Content ◽  
Inclusion Interaction ◽  
Secondary Refining ◽  
Positive Factor ◽  
Improve Fatigue

In order to improve fatigue life of wheel steel, secondary-refining process is done with Al-deoxidation and slag of high basicity, high Al2O3 content and low oxidizing property. By slag-steel-inclusion interaction, harmful inclusions could be controlled well to be eliminated by floation, lowering T[O] content to 0.0007% in round billets, enhancing fatigue life of wheel steel. It is found that (Al2O3) in slag is positive factor for decrease of T[O], while (CaO)/(Al2O3), (SiO2) in slag and [Al]s in molten steel is negative factor for it. As a result, by INSTRON fatigue testing machine, tested steel samples achieve ultra-high cycle of 108 above, realizing experimental purpose of improving fatigue life of wheel steel.

Analysis of Static Stress in an Alloy Wheel of the Passengercar

2015 ◽  
Vol 16 ◽  
pp. 17-25 ◽  
Author(s):  
S. Nallusamy ◽  
N. Manikanda Prabu ◽  
K. Balakannan ◽  
Gautam Majumdar
Keyword(s):  
Fatigue Life ◽  
Aluminium Alloy ◽  
Fatigue Test ◽  
Fatigue Testing ◽  
Testing Machine ◽  
Manufacturing Companies ◽  
Passenger Cars ◽  
Element Analysis ◽  
Static And Dynamic Analysis ◽  
Alloy Wheel

The vehicle may be towed without the engine but it is not possible without the wheels. Road wheel is a significant structural member of the vehicular suspension system that supports the static and dynamic loads encountered during vehicle operation. As in the case of an automobile wheel maximum load is applied on the alloy wheel. Proper analysis of the alloy wheel plays a significant role for the safety of the passenger cars. Alloy wheels which are intended for normal use on passenger cars, undergo three tests and have to pass before going into the production: Dynamic Cornering Fatigue Test, Dynamic Radial Fatigue Test and Impact Test. Most of aluminium alloy wheels manufacturing companies have done several testing of their product however information of their method on simulation test is often kept limited. During a part of research a static and fatigue analysis of aluminum alloy wheel A356.0 was carried out using FEA package. The 3-D model was imported from CATIA into ANSYS using the appropriate format. Finite element analysis (FEA) is carried out by simulating the test conditions to analyze stress distribution and fatigue life of the aluminium alloy wheel rim of passenger car. Experimental analyses are carried out by radial fatigue testing machine for evaluation of fatigue life under influence of camber angle. The test indicates that integrating FEA and nominal stress method is a good and efficient method to predict alloy wheels fatigue life. In this paper by observing the results of both static and dynamic analysis the aluminium alloy is suggested as better material.

scholarly journals Flexural Fatigue Behaviors of Silicon Carbide Recycled Concrete in Corrosive Environments

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Jinzhi Zhou ◽  
Tiantian Fu ◽  
Chuheng Zhong ◽  
Kun Peng ◽  
Ziyang Shuang
Keyword(s):  
Silicon Carbide ◽  
Fatigue Life ◽  
Failure Probability ◽  
Fatigue Testing ◽  
Testing Machine ◽  
Fatigue Tests ◽  
Recycled Concrete ◽  
Flexural Fatigue ◽  
Corrosive Environments ◽  
The Relationship

An experimental study on the flexural fatigue behaviors of recycled concrete (RC) and silicon carbide recycled concrete (SiCRC) was conducted. The immersion time was 0 d, 30 d, 60 d, and 90 d in 5% NaCl solution for these two kinds of recycled concrete specimens, respectively, and then, four-point flexural fatigue tests were performed by MTS fatigue testing machine. The fatigue life for varying stress levels ranging from 0.9 to 0.6 was obtained. The fatigue life was given considering the failure probability according to the fatigue life and stress level of the specimen via the logarithmic normal distribution and Weibull distribution, respectively. The relationship between fatigue life and failure probability was also obtained. The fatigue life with failure probability of 1% and 50% was further predicted. The results showed that the fatigue life of RC and SiCRC increased in corrosive environments. The fatigue life of SiCRC is higher than that of RC, and the incorporation of SiCRC can improve the fatigue life of recycled concrete.

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