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 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.

Damage Mechanism Analysis of Carbon Fiber Composites under Compressive Load

2018 ◽  
Vol 775 ◽  
pp. 36-42 ◽  
Author(s):  
Xun Lai He ◽  
Jun Hui Yin ◽  
Zhen Qian Yang ◽  
Hong Wei Liu
Keyword(s):  
Carbon Fiber ◽  
Failure Mode ◽  
Fiber Composite ◽  
Testing Machine ◽  
Compressive Load ◽  
Damage Mechanism ◽  
Fiber Composites ◽  
Carbon Fiber Composites ◽  
Carbon Fiber Composite ◽  
Static Compression

Carbon fiber composite material with light weight, high strength, corrosion resistance and other characteristics of its impact damage mechanism is different from the traditional metal materials. In this paper, the quasi-static compression of carbon fiber composites was carried out by using a material testing machine to analyze the damage mechanism. The Hopkinson bar technology was used to test the dynamic mechanical properties. The damage mechanism of the carbon fiber composites under dynamic compressive loading was studied. Stress - Strain relationship of composites under Quasi - static and dynamic compressive load. It is found that the main failure mode of out-of-plane direction of carbon fiber composite laminates is brittle shear failure, while the in-plane failure mode shows the properties of brittle materials.

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.

Dynamic Compression Behavior of Lotus-Type Porous Iron

2010 ◽  
Vol 658 ◽  
pp. 193-196
Author(s):  
Masakazu Tane ◽  
Tae Kawashima ◽  
Keitaro Horikawa ◽  
Hidetoshi Kobayashi ◽  
Hideo Nakajima
Keyword(s):  
Split Hopkinson Pressure Bar ◽  
Dynamic Compression ◽  
Testing Machine ◽  
Porous Iron ◽  
Compression Tests ◽  
Hopkinson Pressure Bar ◽  
Static Compression ◽  
Plateau Stress ◽  
Stress Region ◽  
Quasi Static Compression

Dynamic and quasi-static compression tests were conducted on lotus-type porous iron with porosity of about 50% using the split Hopkinson pressure bar method and universal testing machine, respectively.　In the dynamic compression parallel to the pore direction, a plateau stress region appears where deformation proceeds at nearly constant stress, while the plateau stress region does not appear in the quasi-static compression. The plateau stress region is probably caused by the buckling deformation of matrix iron which occurs only in the dynamic compression. In contrast, the compression perpendicular to the orientation direction of pores exhibits no plateau-stress regions in the both dynamic and quasi-static compression.

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.

Micromechanical Study on High-Temperature Behavior of ZrO2 Particle-Dispersed Ni Composites

2007 ◽  
Vol 340-341 ◽  
pp. 95-100 ◽  
Author(s):  
Hideaki Tsukamoto ◽  
Andrei G. Kotousov
Keyword(s):  
High Temperature ◽  
Creep Behavior ◽  
Fatigue Testing ◽  
Testing Machine ◽  
Temperature Behavior ◽  
Laser Sensor ◽  
Compression Tests ◽  
Creep Tests ◽  
Zro2 Particle ◽  
High Temperature Behavior

This paper aims to investigate high temperature behavior of ZrO2 particle-dispersed Ni composites. The tension-compression tests under constant stress rates as well as creep tests including stress-dip tests were performed using a high-temperature material testing set up, which consists of an electric-hydraulic fatigue testing machine, electric furnace and extensometer with a laser sensor. ZrO2 particle-dispersed Ni composites were fabricated by using the powder metallurgical methods. The results obtained from the experimental study show that ZrO2 particles remarkably strengthen the composite and there exists a reasonable correlation between the tensioncompression stress-strain relation and the creep behavior. In addition, the creep behavior has been examined based on the micromechanical concept, which takes into account the diffusional mass flow at the interface between the particles and matrix. Some numerical analysis based on this concept demonstrates that even a little amount of ZrO2 particles can effectively increase the creep resistance of the composites

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.

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