Academic literature on the topic 'Mean stress method'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the lists of relevant articles, books, theses, conference reports, and other scholarly sources on the topic 'Mean stress method.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Journal articles on the topic "Mean stress method"
1
Papuga, Jan, Ivona Vízková, Maxim Lutovinov, and Martin Nesládek. "Mean stress effect in stress-life fatigue prediction re-evaluated." MATEC Web of Conferences 165 (2018): 10018. http://dx.doi.org/10.1051/matecconf/201816510018.
Full textAbstract:
The paper compares various methods for computing the equivalent stress amplitude for stress cycles of non-zero mean value in stress-life fatigue prediction. A set of 11 calculation methods is evaluated. In addition to formulations based on common static or fatigue properties, the Walker formula and the generalized Linear formula are included in the investigation. These two methods use an optimization routine to find the material parameters. The final response of the methods is compared and discussed. The Walker method provides a better solution. The generalized Linear method produces inferior results, i.e. the linear fit of the segment of the Haigh diagram is not an optimal solution.
2
Yamamoto, Norio, and Kazuyoshi Matsuoka. "Fatigue Assessment Method considering an Effect of Mean Stress." Journal of the Society of Naval Architects of Japan 2001, no. 190 (2001): 499–505. http://dx.doi.org/10.2534/jjasnaoe1968.2001.190_499.
Full text
3
Burger, Robert, and Yung-Li Lee. "Assessment of the Mean-Stress Sensitivity Factor Method in Stress-Life Fatigue Predictions." Journal of Testing and Evaluation 41, no. 2 (January 2013): 20120035. http://dx.doi.org/10.1520/jte20120035.
Full text
4
Munday, Edgar G. "The Effect of Mean Stress Components in High-Cycle, Biaxial Fatigue." International Journal of Mechanical Engineering Education 31, no. 2 (April 2003): 177–86. http://dx.doi.org/10.7227/ijmee.31.2.10.
Full textAbstract:
A new method is presented to obtain the effect of mean stress components in high-cycle, biaxial fatigue. It is assumed that the time-varying stress state can be represented as a superposition of mean components, and proportionally applied alternating components. The method takes into account the relative orientation of the mean and alternating principal stress axes by making the ‘equivalent mean stress’ depend on the alternating components as well as the mean stress components. The method correlates well with the available data. The new method is compared with three popular methods.
5
Wang, Yu Sheng, Wen Xuan Ma, Ming Li, and Hao Jin. "Method of Life Prediction of Engine Cylinder Cover." Advanced Materials Research 677 (March 2013): 236–40. http://dx.doi.org/10.4028/www.scientific.net/amr.677.236.
Full textAbstract:
Cylinder cover is an important component of the engine. It is damaged by low cycle thermal fatigue, high cycle thermal fatigue and creep in operation. Thus, the life and reliability of the cylinder cover are important criteria for engines. The temperature field and stress field of the cylinder cover are computed by the sequentially coupled analysis method: the elastic strain, plastic strain and creep strain of the dangerous point on the cylinder cover are analyzed in ten startup-working-shut down cycles; and it is proved in theory that low cycle thermal fatigue is the primary factor affecting the service life of the cylinder cover and the startup time of the engine is an appropriate parameter to estimate the life of thecylinder cover. The creep has little influence on the stress amplitude, and makes the mean stress increased. The relaxation is coexisting with creep in high temperature; it reduces the increase speed of mean stress. After finite cycles, the mean stress tends to constant gradually. Therefore, the creep-fatigue interaction can equal to thermo-mechanical fatigue whose stress amplitude and mean stress are constant. At last, the mean service life of cylinder is predicted.
6
IWASA, Masaki, and Toshio HATTORI. "Evaluation Method for Fatigue Strength of FRP/MetalAdhesive Joints Considering Mean Stress." Journal of The Adhesion Society of Japan 39, no. 5 (2003): 177–82. http://dx.doi.org/10.11618/adhesion.39.177.
Full text
7
Iwasa, Masaaki, and Toshio Hattori. "Evaluation Method for Fatigue Strength of FRP/Metal Adhesive Joints Considering Mean Stress." Journal of Engineering Materials and Technology 125, no. 4 (September 22, 2003): 402–5. http://dx.doi.org/10.1115/1.1605114.
Full textAbstract:
The fatigue strength of two types of FRP/metal adhesive joints at low temperature, a double lap joint and an embedded joint, was evaluated analytically and experimentally. First, the stress singularity parameters of the delamination edges under mechanical and thermal loadings were analyzed by FEM for various delamination lengths. The delamination propagation rate of the double lap joint under mechanical cyclic loadings at room temperature was measured. Using the relationship between the measured propagation rates and the analyzed ranges of stress singularity intensity, we estimated the fatigue strength of the embedded joint, which coincided well with the measured one. Second, we developed an evaluation method that separates the effects of temperature on fatigue strength into two effects: thermal residual stress and low temperature. Third, the fatigue strengths of the double lap joints were measured for various mean stresses. Fatigue limit of adhesive joints was experimentally measured and compared with analytical intensity of stress singularity. A method for evaluating the fatigue strength of adhesive joints by taking mean stress into account was developed.
8
Najem Clarke, Shima, David W. Goodpasture, Richard M. Bennett, J. Harold Deatherage, and Edwin G. Burdette. "Effect of Cycle-Counting Methods on Effective Stress Range and Number of Stress Cycles for Fatigue-Prone Details." Transportation Research Record: Journal of the Transportation Research Board 1740, no. 1 (January 2000): 49–60. http://dx.doi.org/10.3141/1740-07.
Full textAbstract:
Two important parameters in fatigue life evaluations of existing steel highway bridges are the number of stress cycles experienced and the effective stress range. The inaccuracies in predicting remaining fatigue life can be attributed to either one of these two parameters. However, the AASHTO guide specification has no provisions for the cycle-counting methods to be used to determine these two parameters. A sensitivity analysis that addresses the effects of cycle-counting methods on the effective stress range and the number of cycles for various fatigue-prone details in both main and secondary bridge members is described. A comparison of five cycle-counting methods (level-crossing counting, peak counting, simple-range counting, mean-crossing-peak counting, and rain-flow counting) by using a simple variable-amplitude strain-time history showed that both the stress range and the number of cycles are sensitive to cycle-counting methods. Two of the most commonly used cycle-counting techniques for highway bridge variable-amplitude loading are the mean-crossing-peak and the rainflow cycle-counting methods. A comparison of the two methods by using field data taken under normal traffic showed that the rainflow cycle-counting method is more conservative than the mean-crossing-peak method. The relationship between the mean-crossing-peak and the rainflow cycle-counting methods was determined in the form of a correlation coefficient and a linear regression line. There is a nearly perfect positive correlation between the two methods. Therefore, values obtained for the effective stress range and the number of cycles by the mean-crossing-peak method can be converted to values for the rainflow method.
9
SUGAWARA, MOTOAKI, and KIYOHARU NAKANO. "A method of analyzing regional myocardial function : Mean wall stress-area strain relationship." Japanese Circulation Journal 51, no. 1 (1987): 120–24. http://dx.doi.org/10.1253/jcj.51.120.
Full text
10
Zhao, Ping, and Hong Wen Yan. "Application Research on Haigh Diagram in the Wind Turbine Fatigue Analysis." Applied Mechanics and Materials 190-191 (July 2012): 931–35. http://dx.doi.org/10.4028/www.scientific.net/amm.190-191.931.
Full textAbstract:
The influence of mean stress on fatigue has to be considered by means of Haigh diagram, the actual stress range is modified to damage-equivalent range. There are three main methods for creating Haigh diagram, such as experiment and empirical relationships and six points, which has the different application field. The creating and application of Haigh diagram in GL certification for wind turbines is studied, and the solving method for the mean stress sensitivity is given.
Dissertations / Theses on the topic "Mean stress method"
1
Jin, Hui, and Hao Wu. "Finite Element Modelling of Fracture in dowel-type timber connections." Thesis, Linnéuniversitetet, Institutionen för maskinteknik (MT), 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-34783.
Full textAbstract:
Dowel-type steel to timber connections are commonly used in timber structure. The load carrying capacity and the stress distribution within the connection area are complicated and the failure behavior of a connection depends on many parameters. The main purpose of this thesis was to verify, using the data obtained from previous experiments, the conventional design method of European Code 5(EC5) (hand calculation) for dowel type joints subjected to pure bending moment and other alternative design methods based on the finite element method (FEM) including the use of the mean stress approach and the extended finite element method (XFEM). Finite element models were created in the software ABAQUS. The models were then used to predict the load bearing capacity and compare this to the experimental results. In addition parametric studies were performed with modifications of material properties and other parameters. The closest prediction in relation to the test results was obtained using XFEM where the predicted capacity was 3.82% larger than the experimental result. An extension of the mean stress method going from a 2D-formulation to a 3D-formulation was verified as well. A general conclusion drawn from this work is that the numerical modelling approaches used should also be suitable for application to complex connections and situations involving other loading situations than pure tension.
2
Kocer, Bilge. "Vibration Fatigue Analysis Of Structures Under Broadband Excitation." Master's thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/12612061/index.pdf.
Full textAbstract:
The behavior of structures is totally different when they are exposed to fluctuating loading rather than static one which is a well known phenomenon in engineering called fatigue. When the loading is not static but dynamic, the dynamics of the structure should be taken into account since there is a high possibility to excite the resonance frequencies of the structure especially if the loading frequency has a wide bandwidth. In these cases, the structure&rsquos response to the loading will not be linear. Therefore, in the analysis of such situations, frequency domain fatigue analysis techniques are used which take the dynamic properties of the structure into consideration. Vibration fatigue method is also fast, functional and easy to implement. In this thesis, vibration fatigue theory is examined. Throughout the research conducted for this study, the ultimate aim is to find solutions to problems arising from test application for the loadings with nonzero mean value bringing a new perspective to mean stress correction techniques. A new method is developed to generate a modified input loading history with a zero mean value which leads in fatigue damage approximately equivalent to damage induced by input loading with a nonzero mean value. A mathematical procedure is proposed to implement mean stress correction to the output stress power spectral density data and a modified input loading power spectral density data is obtained. Furthermore, this method is improved for multiaxial loading applications. A loading history power spectral density set with zero mean but modified alternating stress, which leads in fatigue damage approximately equivalent to the damage caused by the unprocessed loading set with nonzero mean, is extracted taking all stress components into account using full matrixes. The proposed techniques&rsquo
efficiency is discussed throughout several case studies and fatigue tests.
3
Loret, Benjamin. "Problèmes numériques et théoriques de la géomécanique." Paris 6, 1986. http://www.theses.fr/1986PA066239.
Full textAbstract:
Traitement numérique des milieux infinis de la géomécanique: méthodes d'équations intégrales régulières et singulières pour les structures géotechniques en conditions dynamiques; méthode de couplage itérative éléments finis/équations intégrales (applications au demi-espace et demi-plan); vibration d'un pieu fiché dans le demi espace stratifié. Comportement frottant des milieux granulaires: algorithmes locaux d'intégration numérique pour matériaux élastoplastiques type Drucker-Prager; partie élastique déformation des sols; influence de la contrainte moyenne. Problèmes liés à l'anisotropie en grandes transformations (rotations plastiques). Etude de deux types de bifurcation sur les sables; conséquences macroscopiques de la structure granulaire des sables; non-linéarité incrémentale et localisation des déformations.
4
Laubscher, Liesel L. "The effect of different cropping methods on the meat quality of various game species." Thesis, Stellenbosch : University of Stellenbosch, 2009. http://hdl.handle.net/10019.1/4055.
Full textAbstract:
Thesis (MScAgric (Animal Sciences))--University of Stellenbosch, 2009.ENGLISH ABSTRACT: The production and especially the export of game meat from Southern African are steadily increasing and with this growth, it is inevitable that more emphasis is being placed on the quality of game meat. Research regarding the effect of different cropping methods on ante-mortem stress, and as a result, on meat quality in wild ungulates, is lacking and thus the purpose of this study was to investigate the effect of some of the commonly used cropping methods on the meat quality of red hartebeest, impala, gemsbok and kudu. Antemortem stress was measured using serum cortisol levels (nmol/L), a subjective stress score allocated to each animal as well as the rate and extent of pH decline in the M. longissimus dorsi. Special emphasis was also placed on the meat quality parameters drip loss, cooking loss, colour and Warner-Bratzler shear force (kg/1.27 cm diameter). The effect of day and night cropping on the meat quality of red hartebeest, gemsbok and kudu was investigated. An exponential decay model, y = a + b-ct, was fitted to the pH data of the gemsbok and red hartebeest, and pHu measurements taken at 24 hours post-mortem. Only pHu readings taken at 48 hours post-mortem were analysed in the kudu. Day-cropped kudu had a lower mean pHu (5.40 ± 0.030) than nightcropped kudu (5.48 ± 0.041). No differences in pHu were found for the red hartebeest although night-cropped gemsbok had a higher mean pHu (5.54 ± 0.013) than day-cropped gemsbok (5.49 ± 0.014). None of the constants of the exponential decay model differed for the red hartebeest although day-cropped gemsbok produced a lower constant than night-cropped gemsbok. Mean stress scores and cortisol levels were found to be higher in day-cropped animals for both the gemsbok and kudu while only cortisol levels were higher in die day-cropped red hartebeest. Stress score and cortisol levels were found to be correlated in all three species (red hartebeest: r = 0.51; gemsbok: r = 0.786; kudu: r = 0.823). No treatment differences in drip loss or cooking loss were found for either the red hartebeest or gemsbok, while day-cropped kudu had a higher mean drip loss % (2.76 ± 0.261%) than night-cropped kudu (1.36 ± 0.361%). Night-cropped gemsbok and kudu produced higher mean shear force values (gemsbok = 4.19 ± 0.138; kudu = 4.06 ± 0.237 kg/1.27 cm diameter) than day-cropped animals (gemsbok = 3.57 ± 0.154; kudu = 3.45 ± 0.171 kg/1.27 cm diameter). Colour differences indicated that day-cropped gemsbok and kudu produced lighter meat than night-cropped animals. The results indicate no difference in the effects of day and night cropping in red hartebeest although day-cropped gemsbok and kudu experienced more ante-mortem stress than their night-cropped counterparts. The effect of conventional hunting during the day and night cropping on impala meat was also investigated. No differences were found in pH45 or pHu (taken at 45 minutes and 24 hours post-mortem respectively) although the exponential decay model, y = a + b-ct, fitted to the pH data revealed differences in all the constants (day: a = 5.424 ± 0.039, b = 1.405 ± 0.034, c = -0.385 ± 0.022; night: a = 5.295 ± 0.033, b = 1.556 ± 0.029, c = -0.184 ± 0.019). No differences were found for drip loss, cooking loss or shear force although day-cropped animals produced higher a* and chroma values. The results indicate that, although conventional hunting caused a faster and more severe post-mortem pH decline, both treatments produced meat of similar quality.
AFRIKAANSE OPSOMMING: Die produksie en veral die uitvoer van wildsvleis vanuit Suidelike Afrika is gedurig aan die toeneem en met hierdie groei is dit onvermydelik dat meer klem op die gehalte van wildsvleis gelê word. Daar is ’n tekort aan navorsing oor die uitwerking van verskillende oesmetodes op ante mortem stres en gevolglik ook vleisgehalte van verskillende wildspesies en dus was die doel van dié studie om die uitwerking van sommige van die gewildste oesmetodes op die vleisgehalte van rooihartebees, gemsbok, koedoe en rooibok te ondersoek. Ante mortem stres is gemeet deur die gebruik van serum-kortisolvlakke (nmol/L), ʼn subjektiewe strestelling wat aan elke dier gegee is asook die tempo en vlak van pH-daling in die M. longissimus dorsi. Spesiale klem is gelê op die vleisgehalteparameters drupverlies, kookverlies, kleur en Warner-Bratzlerskeurwaarde (kg/1.27 cm deursnee). Die uitwerking van dag- en nag-oes op die vleisgehalte van rooihartebees, gemsbok en koedoe is ondersoek. ’n Eksponensiële vervalkurwe, y = a + b-ct, is aan die pH-data van die gemsbokke en rooihartebeeste gepas en pHu-metings is op 24 uur ná dood geneem. Net pHu-lesings op 48 uur ná dood in die koedoe is geanaliseer. Koedoes wat in die dag geoes is, het ’n laer pHu (5.40 ± 0.030) gehad as koedoes wat in die nag geoes is (5.48 ± 0.041). Daar was geen verskille in pHu vir die rooihartebeeste nie, alhoewel die gemsbokke wat in die nag geoes is, ’n hoër pHu (5.54 ± 0.013) gehad het as gemsbokke wat in die dag geoes is (5.49 ± 0.014) . Geeneen van die konstantes van die eksponensiële vervalkurwe het verskil in die geval van rooihartebeeste nie terwyl gemsbokke wat in die dag geoes is ʼn hoër konstante a en ʼn laer konstante c getoon het as gemsbokke wat in die nag geoes is. Gemiddelde strestellings en kortisolvlakke was hoër in die geval van gemsbokke en koedoes wat in die dag geoes is terwyl net die kortisolvlakke hoër was in die rooihartebeeste wat in die dag geoes is. Daar is ook bevind dat die strestelling en kortisolvlakke gekorreleer was in al drie spesies (hartebees: r = 0.51; gemsbok: r = 0.786; koedoe: r = 0.823). Geen verskille in drupverlies of kookverlies is aangetref vir die rooihartebeeste of gemsbokke nie, alhoewel koedoes wat in die dag geoes is ʼn hoër gemiddelde drupverlies % (2.76 ± 0.261%) getoon het in vergelyking met koedoes wat in die nag geoes is (1.36 ± 0.361%). Gemsbokke en koedoes wat in die nag geoes is, het ’n hoër gemiddelde skeurwaarde gehad (gemsbokke = 4.19 ± 0.138; koedoes = 4.06 ± 0.237 kg/1.27 cm deursnee) as diere wat in die dag geoes is (gemsbokke = 3.57 ± 0.154; koedoes = 3.45 ± 0.171 kg/1.27 cm deursnee). Kleurverskille het aangedui dat gemsbokke en koedoes wat in die dag geoes is, ligter gekleurde vleis geproduseer het as diere wat in die nag geoes is. Die resultate dui aan dat daar by rooihartebeeste geen verskil is tussen die uitwerking van dag-oes en nag-oes nie, maar dat die dag-oes van gemsbokke en koedoes meer voordoodse stres veroorsaak het as nag-oes. Die uitwerking van konvensionele jag gedurende die dag- en nag-oes op die vleisgehalte van rooibokke is ook ondersoek. Geen verskille is aangetref in pH45 of pHu (geneem op 45 minute en 24 uur ná dood onderskeidelik) nie, alhoewel die eksponensiële vervalkurwe, y = a + b-ct, wat gepas is aan die pH-data verskille getoon het in al die konstantes (dag: a = 5.424 ± 0.039, b = 1.405 ± 0.034, c = -0.385 ± 0.022; nag: a = 5.295 ± 0.033, b = 1.556 ± 0.029, c = -0.184 ± 0.019). Geen verskille is aangetref ten opsigte van drupverlies, kookverlies of skeurkrag nie. Diere volgens die konvensionele maniere geoes het wel hoër a*-en chroma-waardes getoon. Die resultate dui daarop dat, alhoewel konvensionele jag ʼn vinniger en meer ekstreme pH-daling veroorsaak het, albei behandelinge tot dieselfde vleisgehalte gelei het.
5
VÁVRA, Miroslav. "Výpočet prostorové distribuce srážek různými metodami a vyhodnocení rozdílu v úhrnech srážek na vybraném povodí." Master's thesis, 2013. http://www.nusl.cz/ntk/nusl-154479.
Full textAbstract:
This thesis engages various methods of calculation of the spatial distribution of precipitation and the evaluation of differences in totals of rainfall in a chosen catchment. The aim of this work was to choose suitable methods for the calculation of areal rainfall and subsequently to create those methods. Most methods were developed in the GIS program. The next objective was to explore differences in monthly precipitation from hydrological years 2006 and 2007 calculated in the catchment by chosen methods. Chosen methods for the calculation of the spatial distribution of precipitation in the catchment were: arithmetic mean, Thiessen polygons, isohyetal method and inverse distance weighting method. (IDW). As a suitable catchment was selected the catchment of the Kopaninský stream where relatively dense rainfall measurement network is installed. During the solution of this thesis the area of interest had to be extended by the area between the used rain gauges which was delimited in the GIS program. The reason for an enlargement was a fact that a decomposition of rain gauges in the catchment of the Kopaninský stream did not permit the creation of isohyetal lines in this whole catchment. During the calculation and the comparison of results of individual methods was found that results of used methods were surprisingly nearly the same. It was also stated that not even sufficient dense rain gauges network does not guarantee 100% exactness for calculating the amount of the precipitation in the selected area because of their extraordinary variability.
6
Yang, Yeong-Ming, and 楊永名. "The influences and effects of electric-discharged parameters and EDMed-surface character on residual stress by means of EDM- Hole- Drilling Method." Thesis, 1996. http://ndltd.ncl.edu.tw/handle/30670204070024945072.
Full textBooks on the topic "Mean stress method"
1
Smith, S. Jerrod (Stephen Jerrod), 1977-, Geological Survey (U.S.), and Oklahoma Water Resources Board, eds. Methods for estimating flow-duration and annual mean-flow statistics for ungaged streams in Oklahoma. Reston, Va: U.S. Dept. of the Interior, U.S. Geological Survey, 2009.
Find full text
2
Grandin, Temple, ed. Improving animal welfare: a practical approach. 3rd ed. Wallingford: CABI, 2021. http://dx.doi.org/10.1079/9781789245219.0000.
Full textAbstract:
Abstract The third edition of this book contains a total of 20 chapters (including 3 new chapters), including the implementation of an effective animal welfare programme; the importance of measurement to improve the welfare of livestock, poultry and fish; the social and ethical importance of agricultural animal welfare; the implementation of effective animal-based measurements for assessing animal welfare on farms and slaughter plants; how to improve livestock handling and reduce stress; painful husbandry procedures in livestock and poultry; the importance of good stockmanship and its benefits to animals; in-farm considerations of animal behaviour and emotions; improving livestock, poultry and fish welfare in slaughter plants with auditing programmes and animal-based measures; recommended on-farm euthanasia practices; welfare during transport of livestock and poultry; animal well-being on organic farms; a practical approach on sustainability for supply chain managers of meat, dairy and other animal proteins; the effect of economic factors on the welfare of livestock and poultry; practical approaches for changing and improving animal care and welfare; successful technology transfer of behavioural and animal welfare research to the farm and slaughter plant; technological innovations for individualized animal care and welfare; technology designed to enhance poultry welfare; precision livestock farming and technology in swine welfare and practical methods for improving the welfare of horses, donkeys and mules. There is also a list of videos that will allow students to see different types of farms and technology for raising broiler chickens, cattle, laying hens and pigs. This book provides practical information which will enable veterinarians, managers, animal scientists and policy makers to improve welfare. It will be especially useful for training animal welfare specialists.
3
Inc, Game Counselor. Game Counselor's Answer Book for Nintendo Players. Redmond, USA: Microsoft Pr, 1991.
Find full text
4
Sepowski, Stephen J., ed. The Ultimate Hint Book. Old Saybrook, CT: The Ultimate Game Club Ltd., 1991.
Find full text
5
Slomka, Piotr J., Guido Germano, and Daniel S. Berman. Gated SPECT MPI Processing and Quantitation. Oxford University Press, 2015. http://dx.doi.org/10.1093/med/9780199392094.003.0007.
Full textAbstract:
Gated MPS provides an accurate and reproducible method for measuring myocardial perfusion at stress and rest as well as LVEF, EDV, ESV and diastolic function. It also provides a means of assessing regional wall motion abnormality, either at rest or post-stress. These functions and perfusion measurements obtained from gated MPS complement each other in CAD diagnosis as well as risk stratification. This chapter presents a comprehensive review of techniques used in gated SPECT processing to quantify function and perfusion, including the latest techniques and developments.
6
Estimation of slow crack growth parameters for constant stress-rate test data of advanced ceramics and glass by the individual data and arithmetic mean methods. Cleveland, Ohio: Lewis Research Center, National Aeronautics and Space Administration, 1997.
Find full text
7
Cates, M. Complex fluids: the physics of emulsions. Oxford University Press, 2017. http://dx.doi.org/10.1093/oso/9780198789352.003.0010.
Full textAbstract:
These lectures start with the mean field theory for a symmetric binary fluid mixture, addressing interfacial tension, the stress tensor, and the equations of motion (Model H). We then consider the phase separation kinetics of such a mixture: coalescence, Ostwald ripening, its prevention by trapped species, coarsening of bicontinuous states, and the role of shear flow. The third topic addressed is the stabilization of emulsions by using surfactants to reduce or even eliminate the interfacial tension between phases; the physics of bending energy, which becomes relevant in the latter case, is then presented briefly. The final topic is the creation of long-lived metastable emulsions by adsorption of colloidal particles or nanoparticles at the fluid–fluid interface; alongside spherical droplets, these methods can be used to create a range of unconventional structures with potentially interesting properties that are only now being explored.
8
McBurney, John W., Ilene S. Ruhoy, and Andrew T. Weil, eds. Integrative Neurology. Oxford University Press, 2020. http://dx.doi.org/10.1093/med/9780190051617.001.0001.
Full textAbstract:
Over the past decade, there has been increasing interest in alternative methods of treatment for many diseases. Physicians have recognized the limitations in the conventional use of pharmaceuticals and surgical intervention. Integrative approaches to patient care combine evidence-based conventional care with the best of evidence-based alternative care. Neurologists, in particular, manage many patients who have difficult-to-treat symptoms and disorders and can greatly benefit from integrative medicine. Many neurologists in practice have been incorporating alternative means of treatment in conjunction with current standards of care and experiencing improved patient response and satisfaction. This text covers some of the more commonly seen disease states in neurology and discusses integrative approaches to treatment and management. It also addresses the importance of self-care for the neurologist as stress and burnout are problematic for neurologists, further impairing patient care and the critical patient–doctor relationship.
9
Williamon, Aaron, Terry Clark, and Mats Küssner. Learning in the spotlight. Oxford University Press, 2017. http://dx.doi.org/10.1093/acprof:oso/9780199346677.003.0014.
Full textAbstract:
The skills needed to perform music well and to communicate effectively as a performer are truly multifaceted. Increasingly, new methods and technologies are enabling a better understanding of how musicians perform and some of the reasons great performances are so compelling. Yet, optimizing performance skills can still be an elusive task for musicians. Implicit in this is the need for performers to attain a high level of self-awareness regarding their skills and behaviours, appropriate development of those skills and behaviours, and effective implementation of them within high-stress performance situations. This chapter provides an overview of self-regulated learning and examines its relevance to enhancing musical performance. To assist musicians in applying self-regulatory processes to their own assessment, development and review of performance skills, the authors introduce an approach widely used in sport—performance profiling—as a means of facilitating effective ‘self-regulated performing’.
10
Burns, Tom, and Mike Firn. Research and development. Edited by Tom Burns and Mike Firn. Oxford University Press, 2017. http://dx.doi.org/10.1093/med/9780198754237.003.0029.
Full textAbstract:
This chapter covers the spectrum of routine monitoring, audit, service evaluation, and formal research. Routine monitoring is an essential task for all mental health professionals, and techniques to make it more palatable are explored, including using routine data for clinical supervision and monitoring team targets. Regular audit is described as an essential tool for logical service development and quality improvement. In the discussion of research, the importance of choosing the correct methodology and of paying attention to detail are stressed. In community psychiatry, sampling bias, regression to the mean, and the Hawthorne effect pose important risks. The hierarchy of research methods is outlined with randomized controlled trials (RCTs) at the top, preferably with either single- or double-blinding. Careful statistics and systematic reviews support evidence-based practice. In addition to experimental quantitative trials, there is a place for cohort and case control trials, as well as for qualitative trials to generate hypotheses.
Book chapters on the topic "Mean stress method"
1
Scholle, Markus, Marcel Mellmann, Philip H. Gaskell, Lena Westerkamp, and Florian Marner. "Multilayer Modelling of Lubricated Contacts: A New Approach Based on a Potential Field Description." In Springer Tracts in Mechanical Engineering, 359–75. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-60124-9_16.
Full textAbstract:
AbstractA first integral approach, derived in an analogous fashion to Maxwell’s use of potential fields, is employed to investigate the flow characteristics, with a view to minimising friction, of shear-driven fluid motion between rigid surfaces in parallel alignment as a model for a lubricated joint, whether naturally occurring or engineered replacement. For a viscous bilayer arrangement comprised of immiscible liquids, it is shown how the flow and the shear stress along the separating interface is influenced by the mean thickness of the layers and the ratio of their respective viscosities. Considered in addition, is how the method can be extended for application to the more challenging problem of when one, or both, of the layers is a viscoelastic material.
2
Rossmanith, H. P., R. E. Knasmillner, and A. Shukla. "Experimental Investigation of Dynamic Contact Problems by Means of the Method of Caustics." In Experimental Stress Analysis, 407–16. Dordrecht: Springer Netherlands, 1986. http://dx.doi.org/10.1007/978-94-009-4416-9_45.
Full text
3
Papuga, Jan, Ivona Vízková, Maxim Lutovinov, and Martin Nesládek. "Comparison of Several Optimized Methods for Mean Stress Effect Evaluating the Stress-Life Prediction." In Structural Integrity, 231–37. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-13980-3_30.
Full text
4
Catalano, Chiara, Salvatore Pasta, and Riccardo Guarino. "A Plant Sociological Procedure for the Ecological Design and Enhancement of Urban Green Infrastructure." In Future City, 31–60. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-75929-2_3.
Full textAbstract:
AbstractUrban green infrastructure could represent an important mean for environmental mitigation, if designed according to the principles of restoration ecology. Moreover, if suitably executed, managed and sized, they may be assimilated to meta-populations of natural habitats, deserving to be included in the biodiversity monitoring networks. In this chapter, we combined automatised and expert opinion-based procedures in order to select the vascular plant assemblages to populate different microhabitats (differing in terms of light and moisture) co-occurring on an existing green roof in Zurich (Switzerland). Our results lead to identify three main plant species groups, which prove to be the most suitable for the target roof. These guilds belong to mesoxeric perennial grasslands (Festuco-Brometea), nitrophilous ephemeral communities (Stellarietea mediae) and drought-tolerant pioneer species linked to nutrient-poor soils (Koelerio-Corynephoretea). Some ruderal and stress-tolerant species referred to the class Artemisietea vulgaris appear to fit well with local roof characteristics, too. Inspired by plant sociology, this method also considers conservation issues, analysing whether the plants selected through our procedure were characteristic of habitats of conservation interest according to Swiss and European laws and directives. Selecting plant species with different life cycles and life traits may lead to higher plant species richness, which in turn may improve the functional complexity and the ecosystem services provided by green roofs and green infrastructure in general.
5
Macura, P. "Study of Flow of Metal and Stress Conditions at Rolling by Means of Optical Methods." In Optical Methods in Dynamics of Fluids and Solids, 293–99. Berlin, Heidelberg: Springer Berlin Heidelberg, 1985. http://dx.doi.org/10.1007/978-3-642-82459-3_37.
Full text
6
Cucinotta, Filippo, Marcello Raffaele, and Fabio Salmeri. "A Topology Optimization Method for Stochastic Lattice Structures." In Lecture Notes in Mechanical Engineering, 235–40. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-70566-4_38.
Full textAbstract:
AbstractStochastic lattice structures are very powerful solutions for filling three-dimensional spaces using a generative algorithm. They are suitable for 3D printing and are well appropriate to structural optimization and mass distribution, allowing for high-performance and low-weight structures. The paper shows a method, developed in the Rhino-Grasshopper environment, to distribute lattice structures until a goal is achieved, e.g. the reduction of the weight, the harmonization of the stresses or the limitation of the strain. As case study, a cantilever beam made of Titan alloy, by means of SLS technology has been optimized. The results of the work show the potentiality of the methodology, with a very performing structure and low computational efforts.
7
van Santen, Victor M., Hussam Amrouch, Thomas Wild, Jörg Henkel, and Andreas Herkersdorf. "Thermal Management and Communication Virtualization for Reliability Optimization in MPSoCs." In Dependable Embedded Systems, 181–205. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-52017-5_8.
Full textAbstract:
AbstractThis chapter covers the interdependencies of temperature and the reliable operation of multiprocessor systems on chip (MPSoC). Starting with the assessment of temperature values for the different cores either through measurement or estimation, it is shown which methods on system level can be applied to balance the thermal stress in the system and thus to come to an evenly distributed probability of errors. Special focus is given to task migration as a system-level means, which is supported by an on-chip interconnect virtualization technique that eases fast and transparent switch-over of communication channels. Overall, it is shown how mechanisms on different levels of the system stack can be combined to cooperate across layers for improving system reliability.
8
Hämäläinen, Heikki, and Pertti Huttunen. "Estimation of Acidity in Streams by Means of Benthic Invertebrates: Evaluation of Two Methods." In Acidification in Finland, 1051–70. Berlin, Heidelberg: Springer Berlin Heidelberg, 1990. http://dx.doi.org/10.1007/978-3-642-75450-0_53.
Full text
9
Zünd, Daniel, and Luís M. A. Bettencourt. "Street View Imaging for Automated Assessments of Urban Infrastructure and Services." In Urban Informatics, 29–40. Singapore: Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-15-8983-6_4.
Full textAbstract:
AbstractMany forms of ambient data in cities are starting to become available that allows tracking of short-term urban operations, such as traffic management, trash collections, inspections, or non-emergency maintenance requests. However, arguably the greatest promise of urban analytics is to set up measurable objectives and track progress toward systemic development goals connected to human development and sustainability over the longer term. The challenge for such an approach is the connection between new technological capabilities, such as sensing and machine learning and local knowledge, and operations of residents and city governments. Here, we describe an emerging project for the long-term monitoring of sustainable development in fast-growing towns in the Galapagos Islands through the convergence of these methods. We demonstrate how collaborative mapping and the capture of 360-degree street views can produce a general basis for a broad set of quantitative analytics, when such actions are coupled to mapping and deep-learning characterizations of urban environments. We map and assess the precision of urban assets via automatic object classification and characterize their abundance and spatial heterogeneity. We also discuss how these methods, as they continue to improve, can provide the means to perform an ambient census of urban assets (buildings, vehicles, services) and environmental conditions.
10
Tuomi, Aarni, Iis Tussyadiah, and Mark Ashton. "Covid-19 and Instagram: Digital Service Innovation in Top Restaurants." In Information and Communication Technologies in Tourism 2021, 464–75. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-65785-7_45.
Full textAbstract:
AbstractGovernments across the world have imposed strict rules on social distancing to curb the spread of Covid-19. In particular, restaurants have been impacted by government-mandated lockdowns. This study adopts a mixed methods approach to explore how Finnish high-profile restaurants used Instagram as a means for service innovation and diffusion during nine weeks of government-mandated lockdown. Comparatively analysing 1,119 Instagram posts across two time-stamps (2019 and 2020) and across 45 restaurants, as well as conducting five semi-structured interviews with restaurant managers, it is found that while the overall number of Instagram posts and likes on posts stayed relatively similar to the year prior, the number of comments increased significantly, suggesting a move towards a more didactic and dyadic form of Instagram communication. In addition, four digital service innovation strategies are identified: launching new service offerings and introducing new elements to existing service offerings, fostering social relationship with customers, exploring novel streams of revenue, and reinvigorating the brand’s image. Implications to service innovation theory and practice are discussed, along with suggestions for future research.
Conference papers on the topic "Mean stress method"
1
Asada, Seiji, Takeshi Ogawa, Makoto Higuchi, Hiroshi Kanasaki, and Yasukazu Takada. "Study on Mean Stress Effects for Design Fatigue Curves." In ASME 2016 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/pvp2016-63796.
Full textAbstract:
In order to develop new design fatigue curves for austenitic stainless steels, carbon steels and low alloy steels and a new design fatigue evaluation method that are rational and have a clear design basis, the Design Fatigue Curve (DFC) subcommittee was established in the Atomic Energy Research Committee in the Japan Welding Engineering Society. Mean stress effects for design fatigue curves are to be considered in the development of design fatigue curves. The Modified Goodman approach for mean stress effects is used in the design fatigue curves of the ASME B&PV Code. Tentative design fatigue curves were developed and studies on the effect of mean stress and design factors are on-going. Development of design fatigue curves, effect of mean stress and design factors is needed to establish a new fatigue design evaluation method. The DFC subcommittee has studied correction approaches for mean stress effects and the approaches of modified Goodman, Gerber, Peterson and Smith-Watson-Topper were compared using test data in literature. An appropriate approach for mean stress effects are discussed in this paper.
2
Zhang, Bin, and Torgeir Moan. "Mean Stress Effect on Fatigue of Welded Joint in FPSOs." In 25th International Conference on Offshore Mechanics and Arctic Engineering. ASMEDC, 2006. http://dx.doi.org/10.1115/omae2006-92056.
Full textAbstract:
This paper deals with the mean stress effect on the fatigue life of welded joints in FPSOs. Mean stresses in structural details of FPSOs are composed of residual stresses and mean stresses induced by external service loading conditions. Mean stresses, both the residual stresses and those induced by external load, affect on the fatigue life of structural details. Fatigue strength decreases as tensile mean stress increases. Under compressive mean stresses, fatigue lives are increased. Different fatigue analysis procedures to account for mean stress effect, i.e. JBP, JTP, DNV CN30.7 and IIW procedure, are used to compare the fatigue test data of different specimens representing different typical welded connections in ship-shaped structures from HHI in Korea. In this paper these procedures are compared and an improved procedure explicitly considering of the mean stress effect is also proposed. The fatigue strength of welded joints of FPSO is affected by the initial condition as well as possible redistribution (shake-down) of the residual stresses. The initial condition of welding residual stress and its re-distribution by static preload and cyclic load in the small scale specimens are evaluated with FE analyses and analytical equations, also compared with the test results obtained from measurement based on ordinary sectioning method.
3
Gyekenyesi, Andrew L., and George Y. Baaklini. "Thermoelastic Stress Analysis: A NDE Tool for Residual Stress Assessment of Metallic Alloys." In ASME Turbo Expo 2000: Power for Land, Sea, and Air. American Society of Mechanical Engineers, 2000. http://dx.doi.org/10.1115/2000-gt-0424.
Full textAbstract:
The primary objective of this report involves studying and developing various experimental techniques for accurate measurement of the mean stress effect in Thermoelastic Stress Analysis (TSA, also recognized as SPATE: Stress Pattern Analysis by Thermal Emission). The analysis of cyclic mean stresses at the coupon level directly relates to the measurement of residual stresses in structures. In a previous study by the authors1, it was shown that cyclic mean stresses significantly influenced the TSA results for titanium and nickel based alloys, although, difficulties were encountered concerning the quantification of the mean stress effect because of large test-to-test variations. This study continues the effort of accurate direct measurements of the mean stress effect by implementing various experimental modifications. In addition, a more in-depth analysis is included which involves analyzing the second harmonic of the temperature response. By obtaining the amplitudes of the first and second harmonics, the stress amplitude and the mean stress at a given point on a structure subjected to a cyclic load can be simultaneously obtained. The rather complex analysis of the temperature response involves obtaining the first and second harmonic amplitudes for 16384 infrared detectors (128 × 128 focal plane array). Upon establishing a protocol for mean stress measurements in the laboratory using the TSA technique, the next step is to utilize the method to assess residual stress states in complex structures during manufacturing and life.
4
Lee, Hyeong Y., Kamran M. Nikbin, and Noel P. O’Dowd. "Simplified Method for Profiling Residual Stress Distributions in Plate and Pipe Components." In 2004 International Pipeline Conference. ASMEDC, 2004. http://dx.doi.org/10.1115/ipc2004-0648.
Full textAbstract:
A comprehensive review of through thickness transverse residual stress distributions in a range of as-welded and mechanically bent components made up of a range of steels has been carried out. The geometries consisted of welded pipe butt joints, pipe on plate joints, tubular Y-joints, tubular T-joints and T-plate joints as well as in cold bent tubes and pipes and the collected data cover a range of engineering steels including ferritic, austenitic, C-Mn and Cr-Mo steels. Measured residual stress data, normalised with respect to the parent material yield stress, have shown a good linear correlation versus the normalised crack depth (of upto half thickness) of the region containing the residual stress resulting from the welding or cold-bending operation. The proposed simplified generic residual stress profiling based on a family of linear distribution lines, derived from the mean statistical linear fit of all the analysed data, is shown to provide different levels of conservatism on the calculated stress intensity factors. Whereas the profiles in assessment procedures are fixed and case specific the proposed linear method can be varied by a combination of mean and bending shifts from the mean regression line to produce lower or higher safety factors on stress intensity factor values depending on the level of safety required.
5
Hong, Jeong K. "Evaluation of Weld Root Failure Using Battelle Structural Stress Method." In ASME 2010 29th International Conference on Ocean, Offshore and Arctic Engineering. ASMEDC, 2010. http://dx.doi.org/10.1115/omae2010-20387.
Full textAbstract:
Weld related fatigue failure is one of the most common concerns in welded structures. From the fatigue design point of view, weld toe failure is preferable to weld root failure. Base plate thickness is a controlling parameter for weld toe failure, while weld metal size is a controlling parameter for weld root failure. However, controlling the weld metal size is not easy because the actual weld penetration and weld leg size vary along a weld and from weld to weld. Therefore, analyzing fatigue test data for weld root failure tends to enlarge scatter band due to variability in weld penetration and weld leg size when the nominal weld size is considered. The structural stress based weld fatigue master S-N curve adopted by 2007 ASME section VIII Div. 2 and new API 579/ASME FFS-1 was constructed by incorporating only clearly defined weld toe fatigue data. In this article, a simplified structural stress procedure was developed and a design master S-N curve for weld root failure was established based on the published fatigue test data. Consequently, the mean design master S-N curve for weld root failure is downshifted relative to the mean master S-N curve for weld toe failure, and has a wider scatter band. To be conservative, a crack path along weld throat is recommended for structural stress calculation. Also, the transverse shear stress effects on structural stress calculation can be ignored.
6
Bhattacharya, Anindya, Shailan Patel, Sachin Bapat, Michael P. Cross, and Hardik Patel. "Stress Classification at Cylindrical Intersections Using Primary Structure Method: A Parametric Study Using Finite Element Method." In ASME 2016 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/pvp2016-63154.
Full textAbstract:
Stress classification at shell and nozzle interface has always been an interesting and challenging problem for Engineers. Basic shell theory analyses shell stresses as membrane with local bending stresses developed at locations of discontinuity and load applications. Since in a shell structure, bending stresses develop to mainly maintain compatibility of deformation and membrane stresses to equilibrate the applied load, a simple stress classification will be to categorize the bending stresses as secondary stresses. This is because by definition, secondary stresses develop to maintain compatibility of deformation and primary stresses develop to maintain equilibrium with the applied load. This simplified analysis can result in errors as in real world 100% primary stress as well as 100% secondary stress is rare if not impossible. The widespread use of Finite Element Analysis has made this problem become even more challenging. In this paper the work done by Chen and Li [1], using the two step primary structure method has been used to analyze the problem of stress classification of a shell and nozzle. This paper is a continuation of the author’s previous work on this topic [21]. In the previous paper, the sensitivity of modelling and the effect of the same on the results were investigated. However, the various approaches adapted in the paper [21], were not exactly in the true spirit of the method i.e in all the models, stresses in the vessels and nozzles were checked separately and compared against the stresses in the vessel and nozzle in the original model where by “original “model we mean the model with the vessel and nozzle modelled together i.e. connected along the space curve of intersection in all six degrees of freedom. The spirit of the method requires that the comparison has to be with reference to maximum M+B stresses in the original and reduced structure ( a “reduced” structure means where the vessel and the nozzle are not connected along some degrees of freedom along the space curve of intersection) and not individually in the vessels and nozzles and the M+B stresses have to be evaluated anywhere on the structure and not just at and close to the space curve of intersection. It is because of these reasons that [21] in not exactly in spirit of the method. In other words, the development of this paper was motivated by the fact that the previous paper did not use the exact spirit of the method and hence to investigate how its exact implementation changes results. This is the approach followed in this paper. A point to note; not in spirit of the method does not necessarily mean that the approach taken in [21] was not correct. It’s just that it was not in line with the way this method was defined by Chen and Li [1] and the present authors used their subjective approach to the problem. Additionally, this paper investigates the effect of geometric parameters like D/T, d/t and t/T on the results which was not investigated in the previous paper.
7
Ubulom, Iroizan. "Application of Spectral Method for Vibration-Induced High-Cycle Fatigue Evaluation of an HP Turbine Blade." In ASME Turbo Expo 2020: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/gt2020-14477.
Full textAbstract:
Abstract A method of fluid-structure interaction coupling is implemented for a forced-response, vibration-induced fatigue life estimation of a high-pressure turbine blade. Two simulations approaches; a two-way (fully-coupled) and one-way (uncoupled) methods are implemented to investigate the influence of fluidsolid coupling on a turbine blade structural response. The fatigue analysis is performed using the frequency domain spectral moments estimated from the response power spectral density of the two simulation cases. The method is demonstrated in light of the time-domain method of the rainflow cycle counting method with mean stress correction. Correspondingly, the mean stress and multiaxiality effects are also accounted for in the frequency domain spectral approach. In the mean stress case, a multiplication coefficient is derived based on the Morrow equation, while the case of multiaxiality is based on a criterion which reduces the triaxial stress state to an equivalent uniaxial stress using the critical plane assumption. The analyses show that while the vibration-induced stress histories of both simulation approaches are stationary, they violate the assumption of normality of the frequency domain approaches. The stress history profile of both processes can be described as platykurtic with the distributions having less mass near its mean and in the tail region, as compared to a Gaussian distribution with an equal standard deviation. The fully-coupled method is right leaning with positive skewness while the uncoupled approach is left leaning with negative skewness. The directional orientation of the principal axes was also analyzed based on the Euler angle estimation. Although noticeable differences were found in the peak distribution of the normal stresses for both methods, the predicted Euler angle orientations were consistent in both cases, depicting a similar orientation of the critical plane during a crack initiation process. It is shown that the fatigue life estimation was conservative in the fully-coupled solution approach.
8
Fan, Zhichao, Xuedong Chen, Ling Chen, and Jialing Jiang. "Fatigue-Creep Damage Evolution Model and Life Prediction Methods Under Stress Controlled Mode." In ASME 2007 Pressure Vessels and Piping Conference. ASMEDC, 2007. http://dx.doi.org/10.1115/creep2007-26151.
Full textAbstract:
Damage evolution of stress controlled fatigue-creep interaction actually is the ductility exhaustion process induced by cyclic creep and static creep. Based on the ductility dissipation theory and effective stress concept of the continuum damage mechanism (CDM), a new fatigue-creep interaction damage evolution model and life prediction method under stress control mode are proposed, in which mean strain is the damage parameter to define damage variable D, and mean strain rate at half life is the control factor related to fracture lives. As for 1.25Cr0.5Mo steel, stress-controlled fatigue-creep tests with different combination of stress amplitudes and mean stresses at 540°C were conducted to investigate fatigue-creep interaction. The results of damage descriptions indicate that, the damage model and mean strain parameter are applicable to describe damage evolution of cyclic creep-static creep interaction when ductility exhaustion is dominant. The life prediction results are found to be quite satisfactory relative to test data with a ±1.25 error factor, which is much better than that for the Frequency Separation method (FS) and Strain Energy Frequency Modified approach (SEFS). Further more, it is found that, when stress amplitudes are less than mean stresses, drastic interaction between cyclic creep and static creep will accelerate the material damage rate, so that the damage exponent reaches its peak value.
9
Itoh, Takamoto, Masao Sakane, Takahiro Hata, and Takanori Hirai. "Evaluation of Strain and Stress Ranges for Proportional and Non-Proportional Fatigue." In ASME 2005 Pressure Vessels and Piping Conference. ASMEDC, 2005. http://dx.doi.org/10.1115/pvp2005-71640.
Full textAbstract:
In non-proportional multiaxial fatigue, principal directions of strains and stresses change during a cycle. In such a case, strain and stress ranges and mean strain and stress cannot be easily determined. Developing an appropriate method of determining the ranges and mean values are needed for the design of pressure vessels. This paper proposes a method for calculating the strain and stress ranges and mean values in non-proportional multiaxial loading. Based on the method proposed, non-proportional strain and stress ranges are derived and the accuracy of life prediction method using the ranges is discussed for type 304 stainless steel fatigued under 14 non-proportional strain paths.
10
Noban, Mohammad, and Hamid Jahed. "A Fast Method for Ratchetting Strain Prediction." In ASME 2006 Pressure Vessels and Piping/ICPVT-11 Conference. ASMEDC, 2006. http://dx.doi.org/10.1115/pvp2006-icpvt-11-93719.
Full textAbstract:
A time efficient method for predicting ratchetting strain is proposed. By finding the ratchetting rate, at only a few cycles, the ratchetting strain of any cycle can be determined. It is shown that a trajectory of the origin of stress may be defined in the deviatoric stress space as the ratchetting progresses. The method for obtaining this trajectory from a standard uniaxial asymmetric cyclic loading is presented. At the beginning, this trajectory coincides with the initial stress origin and approaches the mean stress, displaying a power law relationship with the number of loading cycles. This path defines a moving frame of reference for stress tensor calculations. Ratchetting rates for different cyclic loading are calculated with the knowledge of this frame of reference and through utilizing a constitutive cyclic plasticity model which incorporates deviatoric stresses and back stresses that are measured with respect to this moving frame. The proposed model is used to predict ratchetting strain of 1070 steel under single step constant amplitude and multi-step loading. The method is also applied to non-proportional loading. Results obtained agree with the available experimental measurements.
Reports on the topic "Mean stress method"
1
Hutchinson, M. L., J. E. L. Corry, and R. H. Madden. A review of the impact of food processing on antimicrobial-resistant bacteria in secondary processed meats and meat products. Food Standards Agency, October 2020. http://dx.doi.org/10.46756/sci.fsa.bxn990.
Full textAbstract:
For meat and meat products, secondary processes are those that relate to the downstream of the primary chilling of carcasses. Secondary processes include maturation chilling, deboning, portioning, mincing and other operations such as thermal processing (cooking) that create fresh meat, meat preparations and ready-to-eat meat products. This review systematically identified and summarised information relating to antimicrobial resistance (AMR) during the manufacture of secondary processed meatand meat products (SPMMP). Systematic searching of eight literature databases was undertaken and the resultantpapers were appraised for relevance to AMR and SPMMP. Consideration was made that the appraisal scores, undertaken by different reviewers, were consistent. Appraisal reduced the 11,000 initially identified documents to 74, which indicated that literature relating to AMR and SPMMP was not plentiful. A wide range of laboratory methods and breakpoint values (i.e. the concentration of antimicrobial used to assess sensitivity, tolerance or resistance) were used for the isolation of AMR bacteria.The identified papers provided evidence that AMR bacteria could be routinely isolated from SPMMP. There was no evidence that either confirmed or refuted that genetic materials capable of increasing AMR in non-AMR bacteria were present unprotected (i.e. outside of a cell or a capsid) in SPMMP. Statistical analyses were not straightforward because different authors used different laboratory methodologies.However, analyses using antibiotic organised into broadly-related groups indicated that Enterobacteriaceaeresistant to third generation cephalosporins might be an area of upcoming concern in SPMMP. The effective treatment of patients infected with Enterobacteriaceaeresistant to cephalosporins are a known clinical issue. No AMR associations with geography were observed and most of the publications identified tended to be from Europe and the far east.AMR Listeria monocytogenes and lactic acid bacteria could be tolerant to cleaning and disinfection in secondary processing environments. The basis of the tolerance could be genetic (e.g. efflux pumps) or environmental (e.g. biofilm growth). Persistent, plant resident, AMR L. monocytogenes were shown by one study to be the source of final product contamination. 4 AMR genes can be present in bacterial cultures used for the manufacture of fermented SPMMP. Furthermore, there was broad evidence that AMR loci could be transferred during meat fermentation, with refrigeration temperatures curtailing transfer rates. Given the potential for AMR transfer, it may be prudent to advise food business operators (FBOs) to use fermentation starter cultures that are AMR-free or not contained within easily mobilisable genetic elements. Thermal processing was seen to be the only secondary processing stage that served as a critical control point for numbers of AMR bacteria. There were significant linkages between some AMR genes in Salmonella. Quaternary ammonium compound (QAC) resistance genes were associated with copper, tetracycline and sulphonamide resistance by virtue of co-location on the same plasmid. No evidence was found that either supported or refuted that there was any association between AMR genes and genes that encoded an altered stress response or enhanced the survival of AMR bacteria exposed to harmful environmental conditions.
2
A method for estimating mean and low flows of streams in national forests of Montana. US Geological Survey, 1985. http://dx.doi.org/10.3133/wri854071.
Full text
3
Methods for estimating monthly mean concentrations of selected water-quality constituents for stream sites in the Red River of the North basin, North Dakota and Minnesota. US Geological Survey, 1991. http://dx.doi.org/10.3133/wri914086.
Full text