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Fatigue - OSTI GOV

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Last Updated: 04 June 2022

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SIESTA a Fatigue Solution: User's and Theory Manual.

"It is divided into two parts: the first as a user manual and the second as a theory manual. " Customers have requested the use of technologies in particular reports, so the American Society of Mechanical Engineers and Boiler Pressure Vessel Code fatigue requirements have been enforced. The Rain?ow Cycle Counting Method is suitable for proportional loading. Several veri?cation examples are listed, as well as comparisons to experimental results. ".

Source link: https://www.osti.gov/biblio/1868847


Fatigue analysis of the Spallation Neutron Source 2 MW target design

"The first project is the Protoon Power Upgrade, which will double the power capacity of the SNS accelerator system in order to enable the operation of a new second neutron source target station, which is the second project. " The fatigue analysis in this report is an investigation of the PPU 2 MW target mercury vessel's ability to withstand failure from cyclic loading from the pulsed 60 Hz proton beam and thermal changes from disrupted operation. The most robust design to date in terms of resistance to fatigue failure is a 1. 2 MW target design that meets the minimum fatigue life expected for combined thermal and pulse loading for a jet-flow target design operating at 1. 4 MWu2014 the most robust design to date in terms of resistance to fatigue failure. Overall, the PPU 2 MW target model is expected to have greater resistance to fatigue loss than previous target designs. ".

Source link: https://www.osti.gov/biblio/1798609


An Artificial-Intelligence and Machine-Learning-Based Methodology to Conduct Seemingly Strain-Controlled Fatigue Test in a Pressurized-Water-Reactor-Test-Loop-Autoclave, While Not Controlling the Strain

"In general, low cycle fatigue analysis of pressurized water reactor components requires strain-controlled fatigue testing results such as strain curves. " Because of the difficulties of using an extensometer inside an autoclave, we were able to use an outside-autoclave displacement sensor that measures pull-rod-specimen assembly displacement. However, we found that a pull-rod-based fatigue testing could lead to significant cyclic strain amplitudes and rates in comparison to the intended cyclic strain amplitudes and rates, as well as other desirable cyclic strain amplitudes and rates in our study. To enhance the pull-rod-control based fatigue testing method, we recommend using a k-means clustering algorithm in this paper, such that the gage-area strain amplitude and rates can safely be achieved. We report the fatigue test results for both 316 SS base and 81/182 dissimilar-metal-weld specimens in support of this.

Source link: https://www.osti.gov/biblio/1845869


Role of deformation twinning in fatigue of CrCoNi medium-entropy alloy at room temperature

Low cycle fatigue was recorded on cylindrical samples of CrCoNi alloy with electropolished surfaces. " Thinest deformation twins were used at the end of a difficult phase of cycle-cyclic tension, with well-developed persistent slip markings consisting of extrusions and intrusions. In addition, localized cyclic plastic strain and stress concentrations near deformation twins contributed not only to early, well-developed PSMs, but also to the introduction of TWIP and TRIP plasticity at low macroscopic stress amplitudes. ".

Source link: https://www.osti.gov/biblio/1860593


An investigation into the effects of cyclic strain rate on the high cycle and very high cycle fatigue behaviors of wrought and additively manufactured Inconel 718

"This report examines the effects of test frequency and VHCF behaviors of both wrought and laser beam-powder bed fusion produced Inconel 718 in machined/polished surface condition, stressing on the effects of test frequency. " Whether or not the manufacturing process, the corrected stress-life fatigue results from 20 kHz were found to conform to the one obtained from conventional testing at 5 Hz, implying no effect of cyclic strain rate on Inconel 718's fatigue behavior. The findings of this research show that ultrasonic fatigue testing can be used to expedite AM material analysis to keep up with the latest demand; however, the applied stress may have to be addressed;.

Source link: https://www.osti.gov/biblio/1867811


Preliminary description of a new creep-fatigue design method that reduces over conservatism and simplifies the high temperature design process

"The paper includes the first description of a new creep-fatigue design scheme for structural components in high temperature nuclear service. " For the EPP-SMT design procedure's, the development of the flow chart required extrapolating SMT test results as a result of hold time and follow-up factor. The paper proposes the preliminary design charts for Alloy 617 at temperatures between 800°C and 950°C by combining two extrapolation techniques developed in previous research. By evaluating the design life of two sample geometries under different loading conditions, the paper also provides a comparative comparison between the EPP-SMT design method and the new ASME creep-fatigue design methods. The report also states that the EPP-SMT design process can account for the effects of primary load on creep-fatigue life by using a set, bounding value of follow-up when designing the design charts. ".

Source link: https://www.osti.gov/biblio/1656610


Initial microstructural model for creep-fatigue damage in Grade 91 steel

"This paper describes an initial Crystal Plasticity Finite Element Method (Methonism Method) model for cyclic plasticity and damage in Grade 91 steel. "The aim of this study is to establish a framework for modeling creep-fatigue interaction in Grade 91 steel in order to help anticipate the onset of damage in high temperature microreactor components. ".

Source link: https://www.osti.gov/biblio/1658589


Notch insensitivity in fatigue failure of chopped carbon fiber chip-reinforced composites using experimental and computational analysis

"This paper explores the notch effect on the fatigue failure of chopped carbon fiber chip-reinforced sheet molding compound composites by using both experimental and numerical techniques. " We get a much better fit in the normalized S-N diagram for all the notched specimens with different hole diameters after considering the consequences of this spatial distribution by using a new fatigue damage parameter to normalize the results. SMC composites under tension-tension fatigue loading produce notch-insensitivity, making this model of composites a more viable substitute in joints or similar situations, according to the next section. A computational micromechanics model predicting the fatigue behavior of notched SMC composites is used on this basis.

Source link: https://www.osti.gov/biblio/1799257


Fatigue-resistant high-performance elastocaloric materials made by additive manufacturing

"Elastocaloric cooling, a solid-state cooling system, displays the latent heat released and absorbed by stress-induced phase transitions. Nanocomposite microstructures made of a nickel-rich intermetallic compound interspersed within a binary alloy matrix have been formed by the use of a localized molten atmosphere and near-eutectic mixing of elemental powders. Implementing additive manufacturing to elastocaloric cooling materials allows for precise microstructure control of high-performance metallic refrigerants with long fatigue life. ".

Source link: https://www.osti.gov/biblio/1577117

* Please keep in mind that all text is summarized by machine, we do not bear any responsibility, and you should always check original source before taking any actions

* Please keep in mind that all text is summarized by machine, we do not bear any responsibility, and you should always check original source before taking any actions