Academic literature on the topic 'CREEP ESTIMATION'

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Journal articles on the topic "CREEP ESTIMATION"

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Bloom, J. M. "Validation of Creep Crack Growth Life Estimation Methodology/Hot Reheat Steam Pipes." Journal of Pressure Vessel Technology 116, no. 3 (August 1, 1994): 331–35. http://dx.doi.org/10.1115/1.2929597.

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This paper documents a validation study of a creep crack growth life estimation methodology developed by Riedel and Rice, Saxena, and Bassani which has been implemented into a Babcock & Wilcox computer code. This computer code called PCCREEP was developed for estimation of remaining lives of fossil power plant components with both postulated and in-service determined defects. The initial validation was performed through comparisons with other computer codes. However, these comparisons were limited to continuous operating conditions (steady-state creep) and bulk creep deformation properties for secondary creep only. Even with the independent comparison with other available life estimation codes, the question still remained of how well can the creep crack growth methodology estimate actual field lives? This paper presents the results of a study of a life estimation scheme for hot reheat steam pipes having defects found in service. The initial survey was conducted by the Electric Power Research Institute (EPRI) of U.S. electric utility problems with hot reheat steam pipes. The primary reason for that study was three catastrophic failures of hot reheat steam pipes in 1979, 1985, and 1986. These pipes were seam-welded 1-1/4 Cr-1/2 Mo and 2-1/4 Cr-1 Mo. All these ruptures initiated from flaws (near the weld fusion line) which grew by a creep mechanism. This EPRI data base consisted of twelve pipes with flaws found from inspection. While several assumptions relating to material properties and operating conditions were required (due to insufficient information), predictions demonstrated that life estimation is possible provided material property data representative of the material condition for the component in question is available. Discussion is given regarding the significance of the postulated flaw location, constraint (stress triaxiality) effects for buried flaws, and the importance of weld metal, heat-affected zone, and base metal properties to the accuracy of the life estimations.
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Katinić, Marko, Dorian Turk, Pejo Konjatić, and Dražan Kozak. "Estimation of C* Integral for Mismatched Welded Compact Tension Specimen." Materials 14, no. 24 (December 7, 2021): 7491. http://dx.doi.org/10.3390/ma14247491.

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The C* integral for the compact tension (CT) specimen is calculated using the estimation equation in ASTM E1457-15. This equation was developed based on the assumption of material homogeneity and is not applicable to a welded CT specimen. In this paper, a modified equation for estimating the C* integral for a welded compact tension (CT) specimen under creep conditions is proposed. The proposed equation is defined on the basis of systematically conducted extensive finite element (FE) analyses using the ABAQUS program. A crack in the welded CT specimen is located in the center of the heat-affected zone (HAZ), because the most severe type IV cracks are located in the HAZ. The results obtained by the analysis show that the equation for estimating the C* integral in ASTM E1457-15 can underestimate the value of the C* integral for creep-soft HAZ and overestimate for creep-hard HAZ. Therefore, the proposed modified equation is suitable for describing the creep crack growth (CCG) of welded specimens.
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Abe, Fujio. "Creep modeling and creep life estimation of Gr.91." International Journal of Materials Research 103, no. 6 (June 2012): 765–73. http://dx.doi.org/10.3139/146.110769.

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Han, Bing, and Qiang Fu. "Study on the Estimation of Rock Rheological Parameters under Multi-level Loading and Unloading Conditions." MATEC Web of Conferences 213 (2018): 02003. http://dx.doi.org/10.1051/matecconf/201821302003.

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Determining reasonable rheological constitutive models based on laboratory rock creep test data and estimating rheological parameters are important means of studying rheological mechanical property of rocks. Previous rock uniaxial or triaxial compression creep tests mostly adopted the method of multi-level loading. In order to study the influence of unloading stress on the estimation of rock rheological parameters, rock triaxial creep tester RLW-2000 was used in this paper to carry out triaxial compression creep tests for granites in a given area with two different stress paths of multi-level loading and stepwise unloading. Study results indicate that rock rheological parameters obtained vary with different stress paths. The instantaneous elastic modulus and viscosity coefficient obtained through loading show a stepwise increase, while the viscoelastic modulus shows a progressive decrease.
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Abdul Ghafir, Mohammad Fahmi, Yi Guang Li, A. A. Wahab, Siti Nur Mariani Mohd Yunos, M. F. Yaakub, Siti Juita Mastura Mohd Salleh, Qamarul Ezani Kamarudin, and Mohd Fikri Mohd Masrom. "Impact of Operating and Health Conditions on a Helicopter Turbo-Shaft Hot Section Component Using Creep Factor." Applied Mechanics and Materials 225 (November 2012): 239–44. http://dx.doi.org/10.4028/www.scientific.net/amm.225.239.

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The paper investigates the effects of various gas turbine operating and health conditions on its hot section component’s creep life via a simple relative creep life parameter known as Creep Factor. Using the Creep Factor, the correlation between individual gas turbine operating and health parameter and component’s creep life was established and the weight of the impact was measured. Analytical-parametric-based creep life estimation model combined with the Creep Factor approach was developed and integrated with an existing engine performance model to allow the estimation of various hot section component creep lives and the computation of the Creep Factors. The impact analysis was carried out on the high pressure turbine blade of a model turbo-shaft helicopter engine. The results indicate that for a clean engine, the change in engine rotational speed was seen to provide the highest impact on changing the blade’s creep life consumption while for a degraded engine, the presence of compressor fouling has the highest threat in changing the blade’s creep life. The analysis also shows that the Creep Factor is a good indicator of creep life consumption and provides a good technique to rank the influencing factor according to the threat they imposed.
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Ohashi, Kayo, Jun-ichi Arai, and Toshiaki Mizobuchi. "Study on estimation of creep behaviour of concrete at early age considering temperature effect." MATEC Web of Conferences 289 (2019): 10010. http://dx.doi.org/10.1051/matecconf/201928910010.

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Clarifying the creep behaviour of concrete at early age not only improves the accuracy of temperature stress analysis but also contributes to prediction accuracy and control measures in cracks caused by thermal stress. However, most past researches on creep behaviour were investigated after 28 days. Currently, it is difficult to accurately perceive the creep behaviour of concrete at an early age in the test method of creep which is generally carried out. Therefore, it is necessary to evaluate the creep behaviour of concrete at early age and to establish a convenient test method to estimate the creep behaviour. Therefore, in this study, experiments were carried out for concrete at early age within one week. As the result of the experiments, it was shown that the creep strain is proportional to the load stress of concrete at an early age and the strain of specific creep decreases as the loaded age increases. In addition, based on the experimental results, an estimation equation for creep strain at early age was proposed. Within the scope of this experimental result, it was confirmed that the estimation equation proposed in this study accurately represented the creep behaviour of concrete at early age.
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N, Shivakumar, and Anbazhagan R. "Estimation of Inexpensive Creep Testing Machine." International Innovative Research Journal of Engineering and Technology 4, no. 3 (March 30, 2019): 4–8. http://dx.doi.org/10.32595/iirjet.org/v4i3.2019.80.

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Abe, Fujio. "Creep life estimation of Gr.91 based on creep strain analysis." Materials at High Temperatures 28, no. 2 (June 2011): 75–84. http://dx.doi.org/10.3184/096034011x13058176494936.

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Niu, Yu Jing, Hong Sheng Cai, Jin Feng Geng, Dong Fang Ma, Guo Dong Ma, Yong Feng Zhao, and Xu Yang. "Creep Properties and Life Estimation of P91 Steel with Low Hardness." Advanced Materials Research 842 (November 2013): 201–4. http://dx.doi.org/10.4028/www.scientific.net/amr.842.201.

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The creep properties and creep life estimation experiment was carried out on the P91 steel with low hardness (About 135HBHLD),and the creep life of P91 pipe was estimated.The result was that the ability for anti-plastic fracture, cracking and crack propagation of resistance to damage of high pressure steam conduit pipe with low hardness (About 135HBHLD) is very poor at 566°C and that the working life of low hardness zones (About 135HBHLD) from the creep crack propagation tests is about 5914 hours at 540°C.
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Holmström, S., Y. Li, P. Dymacek, E. Vacchieri, S. P. Jeffs, R. J. Lancaster, D. Omacht, et al. "Creep strength and minimum strain rate estimation from Small Punch Creep tests." Materials Science and Engineering: A 731 (July 2018): 161–72. http://dx.doi.org/10.1016/j.msea.2018.06.005.

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Dissertations / Theses on the topic "CREEP ESTIMATION"

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Leung, Chun-Pok. "Estimation of the Ct parameter for primary creep." Diss., Georgia Institute of Technology, 1988. http://hdl.handle.net/1853/15901.

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Abdul, Ghafir Mohammad Fahmi Bin. "Performance based creep life estimation for gas turbines application." Thesis, Cranfield University, 2011. http://dspace.lib.cranfield.ac.uk/handle/1826/7457.

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Accurate and reliable component life prediction is crucial to ensure both the safety and economics of gas turbine operations. In the pursuit of improved accuracy and reliability, current model-based creep life estimation methods have become more and more complicated and therefore demand huge amounts of work and significant amounts of computational time. Because of the underlying problems arising from current life estimation methods, this research aims to develop an alternative performance-based creep life estimation method that is able to provide a quick solution to creep life prediction while at the same time maintaining the achieved accuracy and reliability as that of the model-based method. Using an artificial neural network, the existing creep life prediction subprocesses and secondary inputs are ‘absorbed’ into simple parallel computing units that are able to create direct mapping between various gas turbine operating and health conditions or gas path sensors and creep life. The outcome of this research is the creation of three proposed neural-based creep life prediction architectures known as the Range-Based, Functional-Based and Sensor-Based. An integrated creep life estimation model was first developed and incorporated into an in-house performance simulation and diagnostics software. Using the integrated model, the effects of several operating and health parameters on a selected turbo-shaft engine model turbine blade’s creep life was initially performed using an introduced Creep Factor approach. The outcomes of this investigation were then used to populate input-output samples to train and validate the neural-based creep life prediction architectures. To ensure that the proposed neural architectures are able to achieve generalisation and produce accurate creep life prediction for both clean and degraded engine conditions, four-stage assessments were carried out. Finally, the effects of input uncertainties on the creep life prediction were investigated to assess how sensitive the proposed architectures are to different levels of uncertainty. The results show that all of the proposed neural architectures were able to produce accurate creep life predictions for both clean and degraded engine conditions. When comparing the three proposed architectures, the Sensor-Based architecture was found to be the most accurate in both conditions. Despite the accurate creep life prediction, it was also found that all of the proposed architectures were sensitive to input uncertainties with the Functional-Based architecture being the least sensitive to the uncertainty.
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Taherzadehboroujeni, Mehrzad. "Lifetime Estimation for Ductile Failure in Semicrystalline Polymer Pipes." Diss., Virginia Tech, 2019. http://hdl.handle.net/10919/91901.

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The aim of this study is to develop a combined experimental and analytical framework for accelerated lifetime estimates of semi-crystalline plastic pipes which is sensitive to changes in structure, orientation, and morphology introduced by processing conditions. To accomplish this task, high-density polyethylene (HDPE) is chosen as the exemplary base material. As a new accelerated test protocol, several characterization tests were planned and conducted on as-manufactured HDPE pipe segments. Custom fixtures are designed and developed to admit uniaxial characterization tests. The yield behavior of the material was modeled using two hydrostatic pressure modified Eyring equations in parallel to describe the characterization test data collected in axial tension and compression. Subsequently, creep rupture failure of the pipes under hydrostatic pressure is predicted using the model. The model predictions are validated using the experimental creep rupture failure data collected from internal pressurization of pipes using a custom-designed, fully automatic test system. The results indicate that the method allows the prediction of pipe service lifetimes in excess of 50 years using experiments conducted over approximately 10 days instead of the traditional 13 months. The analytical model is joined with a commercial finite element package to allow simulations including different thermal-mechanical loading conditions as well as complicated geometries. The numerical model is validated using the characterization test data at different temperatures and deformation rates. The results suggest that the long-term performance of the pipe is dominated by the plastic behavior of the material and its viscoelastic response is found to play an insignificant role in this manner. Because of the potential role of residual stresses on the long-term behavior, the residual stress across the wall thickness is measured for three geometrically different HDPE pipes. As expected, the magnitude of tensile and compressive residual stresses are found to be greater in pipes with thicker walls. The effect of the residual stress on the long-term performance of the pipes is investigated by including the residual stress measurements into the numerical simulations. The residual stress slightly accelerates the failure process; however, for the pipe geometries examined, this acceleration is insignificant.
Doctor of Philosophy
The use of plastic pipes to carry liquids and gases has greatly increased in recent decades, primarily because of their moderate costs, long service lifetimes, and corrosion resistance compared with materials such as corrugated steel and ductile iron. Before these pipes can be effectively used, however, designers need the capability to quickly predict the service lifetime so that they can choose the best plastic material and pipe design for a specific application. This capability also allows manufacturers to modify materials to improve performance. The aim of this study is to develop a combination of experiments and models to quickly predict the service lifetime of plastic pipes. High-density polyethylene (HDPE) was chosen as the plastic material on which the model was developed. Several characterization tests are planned and conducted on as-manufactured HDPE pipe segments. The yielding behavior of the material is modeled and the lifetime predictions are evaluated. The predictions are validated by experimental data captured during pipe burst tests conducted in the lab. The results indicate that the method allows the accurate prediction of pipe service lifetimes in excess of 50 years using experiments conducted over approximately 10 days instead of the traditional 13 months, resulting in significant savings in time (and consequently costs) and making it possible to introduce new materials into production more rapidly.
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Toufexis, Dimitrios. "Aircraft maintenance and development of a performance-based creep life estimation for aero engine." Thesis, Cranfield University, 2012. http://dspace.lib.cranfield.ac.uk/handle/1826/7750.

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For any machine designed to generate power, or to fulfill its functions in general, maintenance actions will have an impact on many aspects of its overall capabilities, especially its performance and the length of its useful life. Since these are vital in order to generate maximum profit, the maintenance actions that affect them must be given serious consideration. For this reason, this research aims to propose a method that will enhance the cost saving potential with more accurately determined maintenance intervals and greater exploitation of the remaining life of the components by utilizing the capabilities of condition based monitoring. Initially, the research focuses on the description and the understanding of maintenance methods as they are performed within the aviation industry, but it also aims to investigate the state of the art Condition Based Monitoring Maintenance (CBMM) and its associated advantaged relating to the older methods. The thesis begins by describing the fundamental aviation maintenance management domains, paying particular attention to CBMM, and continues with the diagnostic and prognostic methods that are in use in order to support the condition monitoring concept. Next, a description is given of the actual implementations of the CBMM process, with the presentation of the maintenance enhancement systems, namely the Central Maintenance System and the Aircraft Condition Monitoring System. Lastly, a case study is presented of the estimation of the remaining useful life of a turbine blade, as it relates to the primary failure mode of creep. The case study endorses the use of the condition monitoring diagnostic methods discussed previously and also aims to demonstrate the predictive capabilities of the Engine Usage Diagnostics at both the design and the into-service stage. The created/simulated engine performance models concern several operating conditions of the engine while the impact of each of those on the remaining useful life of the blade is investigated. The benefit of this research is that it proposes a practical, effective, and relatively easy way to perform maintenance by predicting the need according to the usage. Additionally, the data required have already been measured, which paves the way for the creation of more intelligent engine control units. The contribution and innovation of the research is demonstrated by the fact that no similar approaches to creep life prediction have been published for the same type of engine, namely the CFM56 5B2. Last but not least, the results are presented in the most beneficial form of remaining hours before the failure.
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Hösthagen, Anders. "Thermal Crack Risk Estimation and Material Properties of Young Concrete." Licentiate thesis, Luleå tekniska universitet, Byggkonstruktion och brand, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-65495.

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This thesis presents how to establish a theoretical model to predict risk of thermal cracking in young concrete when cast on ground or an arbitrary construction. The crack risk in young concrete is determined in two steps: 1) calculation of temperature distribution within newly cast concrete and adjacent structure; 2) calculation of stresses caused by thermal and moisture (due to self-desiccation, if drying shrinkage not included) changes in the analyzed structure. If the stress reaches the tensile strength of the young concrete, one or several cracks will occur. The main focus of this work is how to establish a theoretical model denoted Equivalent Restraint Method model, ERM, and the correlation between ERM models and empirical experiences. A key factor in these kind of calculations is how to model the restraint from any adjacent construction part or adjoining restraining block of any type. The building of a road tunnel and a railway tunnel has been studied to collect temperature measurements and crack patterns from the first object, and temperature and thermal dilation measurements from the second object, respectively. These measurements and observed cracks were compared to the theoretical calculations to determine the level of agreement between empirical and theoretical results. Furthermore, this work describes how to obtain a set of fully tested material parameters at CompLAB (test laboratory at Luleå University of Technology, LTU) suitable to be incorporated into the calculation software used. It is of great importance that the obtained material parameters describe the thermal and mechanical properties of the young concrete accurately, in order to perform reliable crack risk calculations.  Therefore, analysis was performed that show how a variation in the evaluated laboratory tests will affect the obtained parameters and what effects it has on calculated thermal stresses.
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Dauk, Philip Carl. "Estimation in creel surveys under non-standard conditions." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/NQ51851.pdf.

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Luky, Robin. "Predikce creepového poškození polymerních trubek." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2012. http://www.nusl.cz/ntk/nusl-230310.

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A new methodology of polymer pipe lifetime estimation taking into account residual stresses is described in this thesis. Engineering equations derived based on numerical simulations of a hydrostatic pressure test are proposed. Residual lifetime calculations were performed for different loading conditions using experimental data of a creep crack propagation in studied material and stress distribution in the pipe wall. The effects which significantly influence lifetime estimation were quantified with special focus on residual stresses.
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Turner, Jacqueline. "LATE SPRING SURVEY AND RICHNESS ESTIMATION OF THE AQUATIC BENTHIC INSECT COMMUNITY IN THE UPPER PORTION OF THE LUSK CREEK WATERSHED." OpenSIUC, 2012. https://opensiuc.lib.siu.edu/theses/935.

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The Lusk Creek Watershed, located in Pope County, IL, long has been recognized as a high quality area and as biologically significant. Yet, surveys of the macroinvertebrate fauna have been limited. Thus, a survey of the benthic insect community in the upper portion of Lusk Creek was conducted from May 2003 to April 2005. Eleven sites were selected and characterized by physical properties and water chemistry. Insect distribution patterns, abundance, and diversity (richness, evenness) were examined. A total of 20,888 specimens, mostly immatures, were examined during the study and represented eight orders. The Diptera, by far, was the most common order, with 18,590 specimens, almost all of which were members of the Chironomidae and Simuliidae. The EPT (Ephemeroptera, Plecoptera, Trichoptera) combined were common with 1,550 specimens but paled in comparison to the Diptera. The Coleoptera was represented by 647 specimens, almost all of which were members of Stenelmis (n = 612). The Shannon diversity index (H') showed that the H' values for individual sites were similar to those reported for other relatively undisturbed streams. Analyses of richness suggested that as many as 37 taxa were unobserved, indicating the survey was incomplete.
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Nascimento, Lucas Deroide do. "Estimativa da fluência de geotêxteis não tecidos de poliéster por meio de ensaios convencionais e acelerados." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/18/18132/tde-10072017-091037/.

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O método convencional de ensaios para a obtenção das curvas de fluência de geossintéticos pode necessitar de períodos de até 10.000 horas. Entretanto, a utilização de ensaios acelerados têm se mostrado bastante eficiente, especialmente para avaliar rapidamente a qualidade do material. Estudos bem sucedidos realizados por diversos autores, utilizaram o método Stepped Isothermal Method (SIM) para acelerar a fluência nos geotêxteis. Neste trabalho, com base neste método foi estimada a fluência de dois geotêxteis com 300 g/m² do tipo não tecido de poliéster (PET) de fibra curta e contínua. Neste estudo, foi analisada a fluência causada por carregamentos de 5, 10, 20, 40 e 60% da carga que causa a ruptura do material. Com base nos resultados conclui-se que os valores de deformação por fluência obtidos são satisfatórios, pois as previsões de alcance de até 355 anos estão próximos aos valores encontrados na literatura internacional. Ainda, para o tempo de 100 anos ficou evidenciado que para o geotêxtil não tecido do tipo PET, de fibra curta ou contínua, o comportamento mecânico do geotêxtil é mais influenciado pela deformação inicial do que pela fluência.
The conventional method of tests to achieve the geosynthetic creep curves may require times of up to 10,000 hours. However, the use of accelerated tests have shown to be very effective, especially for rapidly assessing the quality of the material. Successful studies by various authors used the Stepped Isothermal Method Method (SIM) to accelerate creep in geotextiles. In this work, based on this method was estimated creep of two non-woven geotextiles of polyester with 300 g/m², short or continuous fiber. In this study, creep caused by loads of 5, 10, 20, 40 and 60% of the rupture load of the material was analyzed. Based on the results, it is concluded that the creep strain values obtained are satisfactory, because up to 355 years range forecasts are close to those found in the literature. Still, for the 100-year time, it became evident that for the nonwoven geotextile type PET with short or continuous fiber, the mechanical behavior of the geotextile is more influenced by the initial deformation than by creep.
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Bonini, Nick. "Comparison of VNIR Derivative and Visible Fluorescence Spectroscopy Methods for Pigment Estimation in an Estuarine Ecosystem: Old Woman Creek, Huron, Ohio." Kent State University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=kent1382838748.

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Books on the topic "CREEP ESTIMATION"

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W, Tichler J., and Commission of the European Communities. Directorate-General for Science, Research and Development., eds. Estimation of the residual service lifetime of structures by periodic non-destructive inspection of the structural material, in particular under creep conditions. Luxembourg: Commission of the European Communities, 1985.

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Ockerman, Darwin J. Simulation of streamflow and estimation of ground-water recharge in the upper Cibolo Creek Watershed, south-central Texas, 1992-2004. Reston, Va: U.S. Geological Survey, 2007.

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Ockerman, Darwin J. Simulation of streamflow and estimation of ground-water recharge in the upper Cibolo Creek Watershed, south-central Texas, 1992-2004. Reston, Va: U.S. Geological Survey, 2007.

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Ockerman, Darwin J. Simulation of streamflow and estimation of ground-water recharge in the upper Cibolo Creek Watershed, south-central Texas, 1992-2004. Reston, Va: U.S. Geological Survey, 2007.

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Ockerman, Darwin J. Simulation of streamflow and estimation of ground-water recharge in the upper Cibolo Creek Watershed, south-central Texas, 1992-2004. Reston, Va: U.S. Geological Survey, 2007.

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United States. Environmental Protection Agency. Great Lakes National Program Office and Purdue University, eds. Use of the Black Creek Database to analyze techniques for estimating nonpoint source loadings from small watersheds. Chicago, Ill: U.S. Environmental Protection Agency, Great Lakes National Program Office, 1991.

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Andreasen, David C. Estimation of areas contributing recharge to selected public-supply wells in designated metro core areas of Upper Wicomico River and Rockawalking Creek basins, Maryland. Baltimore, Md: Maryland Geological Survey, 2001.

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Gupta, Saurabh Kumar. Estimation of Life Of Turbine Blade Considering Effect of Creep. LAP LAMBERT Academic Publishing, 2021.

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Book chapters on the topic "CREEP ESTIMATION"

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Pavlović, Ana, Ted Donchev, and Diana Petkova. "Analytical Estimation of the Creep Behaviour of Basalt FRP Bars Below the Creep Rupture Limit." In Lecture Notes in Civil Engineering, 739–46. Cham: Springer Nature Switzerland, 2023. http://dx.doi.org/10.1007/978-3-031-32519-9_72.

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Chuang, Tze-jer. "A Generic Model for Creep Rupture Lifetime Estimation on Fibrous Ceramic Composites." In Fracture Mechanics of Ceramics, 441–57. Boston, MA: Springer US, 1992. http://dx.doi.org/10.1007/978-1-4615-3348-1_29.

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Sri Krishna Sudhamsu, Kambhammettu, and Chebolu Lakshmana Rao. "Creep Failure Estimation of Nickel-Based Superalloys Using Unified Mechanics Theory (UMT)." In Recent Advances in Applied Mechanics, 737–43. Singapore: Springer Singapore, 2022. http://dx.doi.org/10.1007/978-981-16-9539-1_56.

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Sonoya, Keiji, Masaki Kitagawa, and Ippei Omata. "Estimation of Creep-Fatigue Life From Creep and Fatigue Data (Extrapolation of Best-Fit Equation of Sus304 to Other Materials)." In Low Cycle Fatigue and Elasto-Plastic Behaviour of Materials—3, 775–80. Dordrecht: Springer Netherlands, 1992. http://dx.doi.org/10.1007/978-94-011-2860-5_122.

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Ha, Je Chang, Joon Hyun Lee, Tabuchi Masaaki, and A. Toshimitsu Yokobori. "Estimation of Creep Crack Growth Properties Using Circumferential Notched Round Bar Specimen for 12CrWCoB Rotor Steel." In Key Engineering Materials, 397–402. Stafa: Trans Tech Publications Ltd., 2005. http://dx.doi.org/10.4028/0-87849-978-4.397.

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Basnayake, K., U. B. Attanayake, M. LaViolette, and M. Chynoweth. "Creep and shrinkage estimation for low-heat concrete mix used in the 2nd Avenue network arch bridge." In Bridge Safety, Maintenance, Management, Life-Cycle, Resilience and Sustainability, 1638–44. London: CRC Press, 2022. http://dx.doi.org/10.1201/9781003322641-202.

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Ozeki, Go, Toshimitsu A. Yokobori, Masaaki Tabuchi, Masao Hayakawa, and Kamran Nikbin. "Testing and Estimation Methods of Crack Growth Life for Alloy 617 under Strain-Controlled Creep-Fatigue Conditions Using Circular Sharp Notched Round Bar Specimen." In Advances in Accelerated Testing and Predictive Methods in Creep, Fatigue, and Environmental Cracking, 42–62. 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959: ASTM International, 2023. http://dx.doi.org/10.1520/stp164320210094.

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Kaneko, Hideaki, Toshio Sakon, Hitoshi Kaguchi, Takanori Nakazawa, Nobuhiro Fujita, and Hiroyoshi Ueda. "Study on Fracture Mechanism and a Life Estimation Method for Low Cycle Creep-Fatigue Fracture of Type 316 Stainless Steels." In Low Cycle Fatigue and Elasto-Plastic Behaviour of Materials—3, 229–34. Dordrecht: Springer Netherlands, 1992. http://dx.doi.org/10.1007/978-94-011-2860-5_38.

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Tipton, A. A. "Method for Estimating the Remaining Life of Steam Turbine Casings from a Creep Rupture Standpoint." In Materials for Advanced Power Engineering 1994, 529–37. Dordrecht: Springer Netherlands, 1994. http://dx.doi.org/10.1007/978-94-011-1048-8_44.

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Alarcon, Vladimir J., and Gretchen F. Sassenrath. "Sensitivity of Nutrient Estimations to Sediment Wash-off Using a Hydrological Model of Cherry Creek Watershed, Kansas, USA." In Computational Science and Its Applications -- ICCSA 2015, 457–67. Cham: Springer International Publishing, 2015. http://dx.doi.org/10.1007/978-3-319-21470-2_33.

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Conference papers on the topic "CREEP ESTIMATION"

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Morris, Andy, Iain Palmer, Chris Maharaj, and John Dear. "ARCMAC Optical Creep Monitoring: Developments in Image Analysis Techniques and Creep Measurement Validation." In ASME 2010 Pressure Vessels and Piping Division/K-PVP Conference. ASMEDC, 2010. http://dx.doi.org/10.1115/pvp2010-25617.

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Power station steam pipes operate at high temperatures (approximately 570°C) and pressures, and estimation of remaining life is critical in avoiding pipe failure. In estimating remaining life, creep rate for both parent pipe material and weldments is an important metric. A number of optical strain methods have been investigated to measure creep strain, including digital image correlation (DIC) and E.ON’s auto-reference creep management and control (ARCMAC) system. The ARCMAC system measures point to point strain by capturing and analysing images of a pair of inconel gauges. Recently, a modified ARCMAC image capture system has been developed using a DSLR camera, providing higher resolution images and lower costs compared to the existing system. Experimental results from the modified ARCMAC system show reduced accuracy compared to the existing system, likely due to distortion caused by lower quality lens components. However, by calculating and applying a correction for this distortion during image processing, it has been shown that accuracy of the modified system becomes significantly better than the existing system. The processing of ARCMAC images has previously been carried out manually by the user. In order to improve the repeatability and a speed of ARCMAC image processing, a computational code has been developed to carry out the procedure automatically. As well as reducing processing time substantially, the selection of image processing parameters has been standardised, improving accuracy significantly. ARCMAC results from creep tests carried out to simulate in-service conditions and measure creep under controlled conditions are also presented. These creep experiments form part of efforts to develop the ARCMAC system to be used to measure strain on-load rather than during the outage, allowing for more regular readings and more accurate creep rate estimation.
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Ainsworth, Robert A. "Design and Assessment for Creep-Fatigue and Creep-Fatigue Crack Growth." In ASME 2016 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/pvp2016-63313.

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Creep-fatigue assessments require inputs for both creep damage and fatigue damage. Then these damage terms are combined using some form of interaction diagram to enable estimation of the creep-fatigue life. Similarly, creep-fatigue crack growth assessments need separate calculations of creep crack growth, fatigue crack growth and again possibly some allowance for interaction in order to obtain the total crack growth. A consequence of these approaches is that uncertainties in creep calculations, uncertainties in fatigue calculations and uncertainties in the form of interaction all lead to significant uncertainties in the overall lifetime or crack growth assessment. This paper first briefly describes how creep-fatigue and creep-fatigue crack growth assessments are performed using the UK R5 procedure and contrasts the methods with those in other codes. Then, the paper presents the guidance in R5 on addressing the many uncertainties in these assessments and discusses the use of probabilistic methods in order to avoid over-conservative lifetime and crack growth estimates.
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Prakash, Raghu V. "Estimation of Creep-Fatigue Damage Through Indentation Test Method." In ASME 2011 International Mechanical Engineering Congress and Exposition. ASMEDC, 2011. http://dx.doi.org/10.1115/imece2011-63445.

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Creep, creep-fatigue damage is often estimated through in-situ metallography, tensile testing of specimens. However, these methods require specimen preparation which includes specimen extraction from critical components. Automated ball indentation testing has been used as an effective tool to determine the mechanical properties of metallic materials. In this work, the tensile properties of materials subjected to controlled levels of damage in creep, creep-fatigue is studied. It is found that the tensile properties such as yield strength and UTS deteriorates with creep damage, whereas the same specimens show an improved UTS values (at the cost of ductility) when subjected to creep-fatigue interactions.
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Lee, Hoomin, Seok-Jun Kang, Jae-Boong Choi, and Moon-Ki Kim. "Creep Life Prediction of HR3C Steel Using Creep Damage Models." In ASME 2017 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/pvp2017-65923.

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The world’s energy market demands more efficient power plants, hence, the operating conditions become severe. For thermal plants, Ultra Super Critical (USC) conditions were employed with an operating temperature above 600°C. In such conditions, the main failure mechanism is creep rupture behavior. Thus, the accurate creep life prediction of high temperature components in operation has a great importance in structural integrity evaluation of USC power plants. Many creep damage models have been developed based on continuum damage mechanics and implemented through finite element analysis. The material constants in these damage models are derived from several accelerated uniaxial creep experiments in high stress conditions. In this study, the target material, HR3C, is an austenitic heat resistant steel which is used in reheater/superheater tubes of an USC power plant built in South Korea. Its creep life was predicted by extrapolating the creep rupture times derived from three different creep damage models. Several accelerated uniaxial creep tests have been conducted in various stress conditions in order to obtain the material constants. Kachanov-Rabotnov, Liu-Murakami and the Wen creep damage models were implemented. A comparative assessment on these three creep damage models were performed for predicting the creep life of HR3C steel. Each models require a single variable to fit the creep test curves. An optimization error function were suggested by the authors to quantify the best fit value. To predict the long term creep life of metallic materials, the Monkman-Grant model and creep rupture property diagrams were plotted and then extrapolated over an extended range. Finally, it is expected that one can assess the remaining lifetime of UCS power plants with such a valid estimation of long-term creep life.
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Won, Min-Gu, Jae-Boong Choi, and Nam-Su Huh. "Estimations of C* and COD for Non-Idealized Axial Through-Wall Cracks in Cylinders Under Creep Conditions." In ASME 2014 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/pvp2014-28902.

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The present paper provides C*-integral and COD for non-idealized through-wall cracks in cylinders under creep conditions. These solutions are based on detailed 3-dimensional Finite Element (FE) analyses which can be used for structural integrity assessment of nuclear piping. To cover a practical interest range, two types of creep conditions and two types of estimation methods were considered. Furthermore, axial through-wall crack model with internal pressure was considered. As for creep conditions, secondary creep (Norton creep), primary-secondary creep (RCC-MR creep) were considered. To estimate C*-integral and COD for non-idealized axial through-wall crack, GE/EPRI and ERS method were used and the results were compared with numerical solutions. Finally, an appropriate estimating methods for each creep condition were suggested.
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Yaguchi, Masatsugu, Sosuke Nakahashi, and Koji Tamura. "Estimation of Creep Strength of Grade 91 Steel Welded Joint in Time Region Over 100,000 Hours." In ASME 2018 Symposium on Elevated Temperature Application of Materials for Fossil, Nuclear, and Petrochemical Industries. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/etam2018-6720.

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A creep strength of welded joint of ASME Grade 91 steel in a region exceeding 100,000 hours was examined in this work. Creep tests were conducted on the steel used at USC plants for long-term, and remaining creep life of the material for operating condition was calculated on a fitting curve using Larson-Miller parameter. Total creep life of the material, which means a creep life at initial state, was presumed to be a summation of the service time at the plants and the remaining creep life. The estimation was conducted for welded joints used at five plants for long-term, and all results lay within 99% confidential band by the creep life evaluation curve of the material proposed by Japanese committee in 2015, while a significant heat-heat variation of creep strength was found even in the region exceeding 100,000 hours. Creep tests on base metals related to each welded joint were also conducted, and the estimation results of the total creep life of the base metals were compared to those of the welded joints. It was suggested that the heat-heat variation of the welded joints eminently depends on the creep life property of the corresponding base metal.
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Kobayashi, Toshimi, Toru Izaki, Junichi Kusumoto, and Akihiro Kanaya. "A Study on Estimation of Internal Pressure Creep Life Using Small Punch Creep (SPC) Tests for Boiler Pipes." In ASME 2009 Pressure Vessels and Piping Conference. ASMEDC, 2009. http://dx.doi.org/10.1115/pvp2009-77336.

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The small punch creep (SPC) test is possible to predict residual creep life at a high accuracy. But, the results of SPC tests cannot be compared with uniaxial creep or internal pressure creep results directly. In this report, the relationship between SPC test results and uniaxial creep test results in ASME A335 P11 (1.25Cr-0.5Mo Steel) was studied. The obtained relationship between SPC load and equivalent uniaxial creep stress formed a simple linear equation under the wide range of test temperature and test period. Then, the SPC results can be compared with uniaxial results by converting SPC loads to the equivalent uniaxial creep stresses. The relationship between SPC test results and internal pressure creep tests results was also studied. The internal creep life of as-received P11 pipe was almost same as SPC result when the hoop stress was converted to the SPC load. The creep lives of internal pressure creep influenced materials also showed good correspondence with SPC results. Therefore SPC can estimate the residual life of internal pressure creep influenced materials.
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Quintana, Osvaldo D., Antonio Aquino, Rubén Löpez, Jean Marie Désir, and Eduardo M. B. Campello. "Inverse Estimation of Thermal Properties of Concrete During Hydrating Process." In Ninth International Conference on Creep, Shrinkage, and Durability Mechanics (CONCREEP-9). Reston, VA: American Society of Civil Engineers, 2013. http://dx.doi.org/10.1061/9780784413111.057.

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Eno, D. R., G. A. Young, and T. L. Sham. "A Unified View of Engineering Creep Parameters." In ASME 2008 Pressure Vessels and Piping Conference. ASMEDC, 2008. http://dx.doi.org/10.1115/pvp2008-61129.

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Creep data are often analyzed using derived engineering parameters to correlate creep life (either time to rupture, or time to a specified strain) to applied stress and temperature. Commonly used formulations include Larson-Miller, Orr-Sherby-Dorn, Manson-Haferd, and Manson-Succop parameterizations. In this paper, it is shown that these parameterizations are all special cases of a common general framework based on a linear statistical model. Recognition of this fact allows for statistically efficient estimation of material model parameters and quantitative statistical comparisons among the various parameterizations in terms of their ability to fit a material database, including assessment of a stress-temperature interaction in creep behavior. This provides a rational basis for choosing the best parameterization to describe a particular material. Furthermore, using the technique of maximum likelihood estimation to estimate model parameters allows for a statistically proper treatment of runouts in a test database via censored data analysis methods, and for construction of probabilistically interpretable upper and lower bounds on creep rate. Comparisons are made to a generalization of the commonly used Larson-Miller parameterization (namely, the Mendelson-Roberts-Manson parameterization), which is comparable in complexity to the Manson-Haferd parameter, but utilizes a reciprocal temperature dependence. The general framework for analysis of creep data is illustrated with analysis of Alloy 617 and HAYNES® 230® alloy (Alloy 230) test data.
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Teramae, Tetsuo. "A Study on the Creep Rupture Life Estimation of Internally Pressurized Welded Pipe Joints." In ASME 2006 Pressure Vessels and Piping/ICPVT-11 Conference. ASMEDC, 2006. http://dx.doi.org/10.1115/pvp2006-icpvt-11-94036.

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A study had been conducted to establish the precise method estimating the creep rupture life of welded steam pipe joints used for thermal power plants. Firstly, basic creep data of 2.25CrlMo low alloy steel, such as rupture time, minimum creep strain rate, and creep crack growth rate, had been obtained on mother material, fine-grained heat affected zone (HAZ), coarse-grained HAZ, and weld metal. Secondly, internally pressurized creep rupture test had been conducted on the pipe specimens of mother material, seam welded joint and girth welded joint. Whereas girth welded pipe joints showed longer lives than those of mother material pipes, seam welded pipe joints showed shorter rupture lives. To clarify the effect of fine-grained HAZ on the rupture life of the seam welded pipe joint, an analytical study had been performed taking the difference of creep deformation between fine-grained HAZ and mother material into account. The analytical creep rupture life had agreed quite well with experimental one. Finally, internally pressurized creep rupture test had been conducted on the specimens of the seam welded pipe joints with a semi-elliptical notch introduced along the outer HAZ of weld line. Creep rupture life of these specimens was calculated as the sum of crack incubation time and crack growth time. It was shown that the calculated creep rupture life had agreed quite well with the experimental result.
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Reports on the topic "CREEP ESTIMATION"

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Chuang, Tze-jer. Estimation of power-law creep parameters from bend test data. Gaithersburg, MD: National Bureau of Standards, 1985. http://dx.doi.org/10.6028/nbs.ir.85-2997.

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Cramer, Grant R., and Nirit Bernstein. Mechanisms for Control of Leaf Growth during Salinity Stress. United States Department of Agriculture, September 1994. http://dx.doi.org/10.32747/1994.7570555.bard.

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In the project "Mechanisms for Control of Leaf Growth during Salinity Stress" ionic and enzymatic changes in the cells and cell walls of the expanding region of salt-stressed maize leaves were evaluated. Conventional numerical techniques for REG estimation were reevaluated; 'Greens' method was recommended and applied throughout the project for growth intensity estimation. Salinity slowed leaf development and reduced leaf size, but increased cell development within the leaf-growing zone. Leaf elongation rate was most affected by salinity from the region of maximal growth to the distal end; the basal region was largely unaffected. Creep assays indicated that the physical properties of the cell wall were not altered. Furthermore, pH or protein concentrations in the apoplastic space were not altered. Salinity decreased in half the concentrations of putative oligosaccharides in both the apoplast and the Golgi vesicles, suggesting that salinity reduced oligosaccharide biosynthesis. Salinity significantly increased solute concentrations in the vacuoles, but the ion concentrations tested remain unchanged in the vacuole. Most importantly, salinity increased the ion concentrations in the apoplast, particularly Cl-concentrations. The evidence obtained clearly points to the biochemical and ionic components of the apoplast as otential factors controlling leaf elongation of salt-stressed plants.
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McNab, Henry W., Julia O’Shields, Michael Bowker, and Stanley Zarnoch. Estimating recreation use in Bent Creek Experimental Forest. Asheville, NC: U.S. Department of Agriculture, Forest Service, Southern Research Station, 2023. http://dx.doi.org/10.2737/srs-rp-67.

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Pradhan, Nawa Raj. Estimating growing-season root zone soil moisture from vegetation index-based evapotranspiration fraction and soil properties in the Northwest Mountain region, USA. Engineer Research and Development Center (U.S.), September 2021. http://dx.doi.org/10.21079/11681/42128.

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A soil moisture retrieval method is proposed, in the absence of ground-based auxiliary measurements, by deriving the soil moisture content relationship from the satellite vegetation index-based evapotranspiration fraction and soil moisture physical properties of a soil type. A temperature–vegetation dryness index threshold value is also proposed to identify water bodies and underlying saturated areas. Verification of the retrieved growing season soil moisture was performed by comparative analysis of soil moisture obtained by observed conventional in situ point measurements at the 239-km2 Reynolds Creek Experimental Watershed, Idaho, USA (2006–2009), and at the US Climate Reference Network (USCRN) soil moisture measurement sites in Sundance, Wyoming (2012–2015), and Lewistown, Montana (2014–2015). The proposed method best represented the effective root zone soil moisture condition, at a depth between 50 and 100 cm, with an overall average R2 value of 0.72 and average root mean square error (RMSE) of 0.042.
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Dietiker, B. Geoscientific studies of Champlain Sea sediments, Bilberry Creek, Ottawa, Ontario: firm ground depth estimation through microtremor horizontal-to-vertical spectral ratios (HVSR). Natural Resources Canada/ESS/Scientific and Technical Publishing Services, 2020. http://dx.doi.org/10.4095/326172.

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Liu and Nixon. L52305 Probabilistic Analysis of Pipeline Uplift Resistance. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), June 2010. http://dx.doi.org/10.55274/r0000002.

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To investigate the feasibility of probabilistic analyses of the peak uplift resistance in frozen soils by varying parameters that are known to be important for the development of the uplift resistance under the upward movement of a pipe. A buried pipeline will be subjected to a variety of forces, both internal and external, including the interaction of the pipe with the surrounding soil. The soil-pipe interaction in permafrost regions have to account for the behavior of frozen and unfrozen soil, and transitions between the two as the pipeline traverses in a discontinuous permafrost zone. The variations in the properties and behavior of frozen soils are expected to be substantial in three dimensions of the Right-of-Way (ROW) and with time (seasonal fluctuations and changes with the history of pipeline operation). Given the uncertainties with frozen soil properties and the changes in behavior with time and location, a large variation in soil-pipe interaction characteristics can exist. The uplift resistance of a pipeline is one of these soil-pipe interactions that can be impacted by a variation in soil condition and state. A need was identified to outline the use of a probabilistic analysis of pipe uplift resistance in an attempt to capture the magnitude of these variations and uncertainties of frozen soil and the impact on the soil-pipe interaction. The probabilistic analysis allows the designer of a pipeline to consider a range of uplift resistance to a certain confidence level that would represent the likely values that a pipe may be subjected to. The work presented in this report is more focused on the methodology of the probabilistic approach, rather than the analysis itself for a specific design case, even though an example is provided for illustration purposes. A series of numerical simulations using Fast Lagrangian Analysis of Continua (FLAC) were completed varying one parameter with each run to develop a library of peak uplift resistances for a variety of different temperatures, soil properties and pipe parameters. The FLAC model was previously developed for PRC, a summary of this report is provided here to outline important parameters that were used to complete this analysis. The simulations were used to develop a correlation of peak uplift resistance as a function of soil tensile strain limit, modulus of deformation, and creep of frozen soils. Each of these parameters is dependent of the pipeline conditions such as temperature, displacement rate, and effective frozen cover depth. It is noted that the scope of the work was to develop a probabilistic method of estimating peak uplift resistance in frozen soils. Even though some sensitivity analysis were carried out, as outlined later in this report, to assess the impacts of the variable, detailed uncertainty analysis or risk assessment were not performed.
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Lacerda Silva, P., G. R. Chalmers, A. M. M. Bustin, and R. M. Bustin. Gas geochemistry and the origins of H2S in the Montney Formation. Natural Resources Canada/CMSS/Information Management, 2022. http://dx.doi.org/10.4095/329794.

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The geology of the Montney Formation and the geochemistry of its produced fluids, including nonhydrocarbon gases such as hydrogen sulfide were investigated for both Alberta and BC play areas. Key parameters for understanding a complex petroleum system like the Montney play include changes in thickness, depth of burial, mass balance calculations, timing and magnitudes of paleotemperature exposure, as well as kerogen concentration and types to determine the distribution of hydrocarbon composition, H2S concentrations and CO2 concentrations. Results show that there is first-, second- and third- order variations in the maturation patterns that impact the hydrocarbon composition. Isomer ratio calculations for butane and propane, in combination with excess methane estimation from produced fluids, are powerful tools to highlight effects of migration in the hydrocarbon distribution. The present-day distribution of hydrocarbons is a result of fluid mixing between hydrocarbons generated in-situ with shorter-chained hydrocarbons (i.e., methane) migrated from deeper, more mature areas proximal to the deformation front, along structural elements like the Fort St. John Graben, as well as through areas of lithology with higher permeability. The BC Montney play appears to have hydrocarbon composition that reflects a larger contribution from in-situ generation, while the Montney play in Alberta has a higher proportion of its hydrocarbon volumes from migrated hydrocarbons. Hydrogen sulphide is observed to be laterally discontinuous and found in discrete zones or pockets. The locations of higher concentrations of hydrogen sulphide do not align with the sulphate-rich facies of the Charlie Lake Formation but can be seen to underlie areas of higher sulphate ion concentrations in the formation water. There is some alignment between CO2 and H2S, particularly south of Dawson Creek; however, the cross-plot of CO2 and H2S illustrates some deviation away from any correlation and there must be other processes at play (i.e., decomposition of kerogen or carbonate dissolution). The sources of sulphur in the produced H2S were investigated through isotopic analyses coupled with scanning electron microscopy, energy dispersive spectroscopy, and mineralogy by X-ray diffraction. The Montney Formation in BC can contain small discrete amounts of sulphur in the form of anhydrite as shown by XRD and SEM-EDX results. Sulphur isotopic analyses indicate that the most likely source of sulphur is from Triassic rocks, in particular, the Charlie Lake Formation, due to its close proximity, its high concentration of anhydrite (18-42%), and the evidence that dissolved sulphate ions migrated within the groundwater in fractures and transported anhydrite into the Halfway Formation and into the Montney Formation. The isotopic signature shows the sulphur isotopic ratio of the anhydrite in the Montney Formation is in the same range as the sulphur within the H2S gas and is a lighter ratio than what is found in Devonian anhydrite and H2S gas. This integrated study contributes to a better understanding of the hydrocarbon system for enhancing the efficiency of and optimizing the planning of drilling and production operations. Operators in BC should include mapping of the Charlie Lake evaporites and structural elements, three-dimensional seismic and sulphate ion concentrations in the connate water, when planning wells, in order to reduce the risk of encountering unexpected souring.
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