Modified Railway Wheel Steels: Production and Evaluation of Mechanical Properties with Emphasis on Low-Cycle Fatigue Behavior

2009 ◽  
Vol 40 (7) ◽  
pp. 1557-1567 ◽  
Author(s):  
Johan Ahlström ◽  
Birger Karlsson
Keyword(s):  
Mechanical Properties ◽  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Cycle Fatigue ◽  
Railway Wheel ◽  
Railway Wheel Steels

Experimental Study of Viscoelastic Dampers under Large Deformation

2012 ◽  
Vol 166-169 ◽  
pp. 2226-2233 ◽  
Author(s):  
Gang Zhao ◽  
Peng Pan ◽  
Jia Ru Qian ◽  
Jin Song Lin
Keyword(s):  
Mechanical Properties ◽  
Experimental Study ◽  
Energy Dissipation ◽  
Low Cycle Fatigue ◽  
Loss Modulus ◽  
Fatigue Behavior ◽  
Fatigue Tests ◽  
Small Displacement ◽  
Loading Frequency ◽  
Cycle Fatigue

The paper presents an experimental study on a new type viscoelastic damper, which is expected to have better energy dissipation capability. Tests on the dampers’ mechanical properties, including shear storage modulus, shear loss modulus, and loss factor, were conducted using reduced scale specimens, and took strain amplitude, loading frequency and ambient temperature as test parameters. Aging tests, low cycle and high cycle fatigue tests were also conducted. Particularly, the low cycle fatigue behavior under a strain of 300% and the basic mechanical behavior under strains of 300%-420% were investigated. Test results suggest that the dependency of the mechanical properties on frequency and temperature is small, the energy dissipation capacity is stable for both large and small displacement, and the damper reaches a strain of 420% without failure.

An experimental investigation on low-cycle fatigue behavior of GO-NH2-reinforced epoxy adhesive

2020 ◽  
pp. 146442072097754
Author(s):  
Jamal Dabbagh ◽  
Bashir Behjat ◽  
Mojtaba Yazdani ◽  
Lucas FM da Silva
Keyword(s):  
Mechanical Properties ◽  
Graphene Oxide ◽  
Fatigue Life ◽  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Epoxy Adhesive ◽  
Cycle Fatigue ◽  
Hummers Method ◽  
Optimum Weight ◽  
Modified Hummers Method

In this study, the effect of adding functionalized aminated graphene oxide up to 0.3 wt% was experimentally investigated on the mechanical properties and fatigue behavior of an epoxy adhesive with intermediate toughness. Accordingly, graphene oxide was prepared by a modified Hummers method and was modified with 3-aminopropyltrimethoxysilane silane agent. Bulk samples were then prepared from neat and reinforced adhesive with different weight amounts of aminated graphene oxide. Dumbbell-shaped samples with a notch were used to limit displacement at break. The results showed the presence of 0.1 wt% and 0.3 wt% aminated graphene oxide nanoplatelets, as optimum weight percentages respectively for the mechanical properties and the fatigue life, improves the modulus of elasticity by 35% and the tensile strength by 44% as well as the fatigue life by about 72–241% under different cyclic loading conditions.

Low Cycle Fatigue of Electrodeposited Pure Nanocrystalline Metals

2007 ◽  
Vol 561-565 ◽  
pp. 1299-1302 ◽  
Author(s):  
Pasquale Cavaliere
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Fatigue Crack ◽  
Crack Propagation ◽  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Fatigue Crack Initiation ◽  
Size Variation ◽  
Load Ratio ◽  
Cycle Fatigue

The fatigue behavior of metals is strongly governed by the grain size variation. As the tensile strength, the fatigue limit increases with decreasing grain size in the microcrystalline regime. A different trend in mechanical properties has been demonstrated in many papers for metals with ultrafine (< 1 m) and nanocrystalline (< 100 nm) grain size in particular in the yield stress and fatigue crack initiation and growth. The fatigue behavior of electrodeposited nanocrystalline Ni (20 and 40 nm mean grain size) and nanocrystalline Co (20 nm) has been analyzed in the present paper by means of stress controlled tests. The monothonic mechanical properties of the materials were obtained from tensile tests by employing an Instron 5800 machine by measuring the strain with an extensometer up to 2.5% maximum strain. The strain gage specimen dimensions measured 20 mm length and 5 mm width, all the specimens were produced by electro-discharge machining. The low cycle fatigue tests were performed with specimens of the same geometry of the tensile ones in tension-tension with load ratio R=0.25. The fatigue crack propagation experiments were carried out by employing single edge notched specimens measuring 39 mm in length, 9.9 mm in width and with an electro-discharge machined edge-notch of 1 mm. All the endurance fatigue and crack propagation tests were performed at 10 Hz.

scholarly journals Low Cycle Fatigue Performance of Additively Processed and Heat-Treated Ti-6Al-7Nb Alloy for Biomedical Applications

Metals ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 122
Author(s):  
Maxwell Hein ◽  
David Kokalj ◽  
Nelson Filipe Lopes Dias ◽  
Dominic Stangier ◽  
Hilke Oltmanns ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Tensile Tests ◽  
Cyclic Fatigue ◽  
Recrystallization Annealing ◽  
Cycle Fatigue ◽  
Microstructural Investigation ◽  
Heat Treated ◽  
Stress Relieving

In biomedical engineering, laser powder bed fusion is an advanced manufacturing technology, which enables, for example, the production of patient-customized implants with complex geometries. Ti-6Al-7Nb shows promising improvements, especially regarding biocompatibility, compared with other titanium alloys. The biocompatible features are investigated employing cytocompatibility and antibacterial examinations on Al2O3-blasted and untreated surfaces. The mechanical properties of additively manufactured Ti-6Al-7Nb are evaluated in as-built and heat-treated conditions. Recrystallization annealing (925 °C for 4 h), β annealing (1050 °C for 2 h), as well as stress relieving (600 °C for 4 h) are applied. For microstructural investigation, scanning and transmission electron microscopy are performed. The different microstructures and the mechanical properties are compared. Mechanical behavior is determined based on quasi-static tensile tests and strain-controlled low cycle fatigue tests with total strain amplitudes εA of 0.35%, 0.5%, and 0.8%. The as-built and stress-relieved conditions meet the mechanical demands for the tensile properties of the international standard ISO 5832-11. Based on the Coffin–Manson–Basquin relation, fatigue strength and ductility coefficients, as well as exponents, are determined to examine fatigue life for the different conditions. The stress-relieved condition exhibits, overall, the best properties regarding monotonic tensile and cyclic fatigue behavior.

Characteristics of Wheel Tread for Property Improvement of Railway Wheel

2006 ◽  
Vol 326-328 ◽  
pp. 1075-1078
Author(s):  
Seok Jin Kwon ◽  
Jung Won Seo ◽  
Hyun Mu Hur ◽  
Sung Tae Kwon
Keyword(s):  
Fracture Toughness ◽  
Low Temperature ◽  
Impact Energy ◽  
Low Cycle Fatigue ◽  
Maintenance Cost ◽  
Railway Vehicle ◽  
Cycle Fatigue ◽  
Railway Wheel ◽  
Mechanics Characteristics ◽  
Wheel Material

Despite of improvement of wheel material for railway vehicle, the damages of railway wheel have been occurred in service running. Because of wheel damage with spalling, shelling and thermal crack, the maintenance cost for the railway wheel has increased. The railway wheel had standardized but the chemical composition, the mechanical property and the hardness with respect to railway wheel is merely established. In order to reduce wheel damage, it is necessary to reinforce the standard of railway wheel. In present study, the fracture mechanics characteristics of railway wheel such as low cycle fatigue, fracture toughness, impact energy depended on low temperature and so on have tested. The result shows that the standard of railway wheel has to supplement fracture toughness and impact energy depended on low temperature etc.

Effects of Surface Finish and Loading Conditions on the Low Cycle Fatigue Behavior of Austenitic Stainless Steel in PWR Environment for Various Strain Amplitude Levels

2009 ◽  
Author(s):  
Jean Alain Le Duff ◽  
Andre´ Lefranc¸ois ◽  
Jean Philippe Vernot
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Strain Amplitude ◽  
Surface Finish ◽  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Complex Loading ◽  
Loading Conditions ◽  
Test Results ◽  
Cycle Fatigue

In February/March 2007, The NRC issued Regulatory Guide “RG1.207” and Argonne National Laboratory issued NUREG/CR-6909 that is now applicable in the US for evaluations of PWR environmental effects in fatigue analyses of new reactor components. In order to assess the conservativeness of the application of this NUREG report, Low Cycle Fatigue (LCF) tests were performed by AREVA NP on austenitic stainless steel specimens in a PWR environment. The selected material exhibits in air environment a fatigue behavior consistent with the ANL reference “air” mean curve, as published in NUREG/CR-6909. LCF tests in a PWR environment were performed at various strain amplitude levels (± 0.6% or ± 0.3%) for two loading conditions corresponding to a simple or to a complex strain rate history. The simple loading condition is a fully reverse triangle signal (for comparison purposes with tests performed by other laboratories with the same loading conditions) and the complex signal simulates the strain variation for an actual typical PWR thermal transient. In addition, two various surface finish conditions were tested: polished and ground. This paper presents the comparisons of penalty factors, as observed experimentally, with penalty factors evaluated using ANL formulations (considering the strain integral method for complex loading), and on the other, the comparison of the actual fatigue life of the specimen with the fatigue life predicted through the NUREG report application. For the two strain amplitudes of ± 0.6% and ± 0.3%, LCF tests results obtained on austenitic stainless steel specimens in PWR environment with triangle waveforms at constant low strain rates give “Fen” penalty factors close to those estimated using the ANL formulation (NUREG/6909). However, for the lower strain amplitude level and a triangle loading signal, the ANL formulation is pessimistic compared to the AREVA NP test results obtained for polished specimens. Finally, it was observed that constant amplitude LCF test results obtained on ground specimens under complex loading simulating an actual sequence of a cold and hot thermal shock exhibits lower combined environmental and surface finish effects when compared to the penalty factors estimated on the basis of the ANL formulations. It appears that the application of the NUREG/CR-6909 in conjunction with the Fen model proposed by ANL for austenitic stainless steel provides excessive margins, whereas the current ASME approach seems sufficient to cover significant environmental effects for representative loadings and surface finish conditions of reactor components.

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