Relevant bibliographies by topics / Cylindrical estimates

Academic literature on the topic 'Cylindrical estimates'

Author: Grafiati
Published: 10 December 2022
Last updated: 28 January 2023

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Journal articles on the topic "Cylindrical estimates"

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Becker, Fabian, and Christian Hopmann. "Stiffness Estimates for Composites with Elliptic Cylindrical Voids." Materials 13, no. 6 (March 17, 2020): 1354. http://dx.doi.org/10.3390/ma13061354.

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A two-step homogenization procedure is presented to investigate the stiffness of a unidirectional continuous fiber-reinforced composite material containing voids of different shapes and volume contents. Since the Mori–Tanaka scheme is limited to moderate volume contents of the inhomogeneity phase, fiber and matrix are homogenized with semi-empirical relations with use of the adjusted fiber volume content in a first step. In the second step, the Mori–Tanaka scheme is applied to obtain the homogenized stiffness tensor of a transversely isotropic material containing voids aligned with the fiber direction. The voids are modelled with infinite length, but an elliptic base characterized by the aspect ratio. The tensor components of the Eshelby tensor for this case are presented in closed form for a transversely isotropic material depending on the aspect ratio and matrix material properties. The scheme is solved directly for easy implementation and the use of fast calculations of the effective engineering constants of a composite material containing voids. Experimental results from literature for different void contents and shapes are compared to the predicted moduli with cylindrical voids. From the results it is further concluded that the aspect ratio of the void and the manufacturing process of the composite should be considered.
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Abe, Ken, Yoshikazu Giga, Katharina Schade, and Takuya Suzuki. "On the Stokes resolvent estimates for cylindrical domains." Journal of Evolution Equations 17, no. 1 (September 6, 2016): 17–49. http://dx.doi.org/10.1007/s00028-016-0350-6.

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Andrews, Ben, and Mat Langford. "Cylindrical estimates for hypersurfaces moving by convex curvature functions." Analysis & PDE 7, no. 5 (September 27, 2014): 1091–107. http://dx.doi.org/10.2140/apde.2014.7.1091.

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Ji, Zhengchao. "Cylindrical estimates for mean curvature flow in hyperbolic spaces." Communications on Pure & Applied Analysis 20, no. 3 (2021): 1199. http://dx.doi.org/10.3934/cpaa.2021016.

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Langford, Mat, and Stephen Lynch. "Sharp one-sided curvature estimates for fully nonlinear curvature flows and applications to ancient solutions." Journal für die reine und angewandte Mathematik (Crelles Journal) 2020, no. 765 (August 1, 2020): 1–33. http://dx.doi.org/10.1515/crelle-2019-0010.

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AbstractWe prove several sharp one-sided pinching estimates for immersed and embedded hypersurfaces evolving by various fully nonlinear, one-homogeneous curvature flows by the method of Stampacchia iteration. These include sharp estimates for the largest principal curvature and the inscribed curvature (“cylindrical estimates”) for flows by concave speeds and a sharp estimate for the exscribed curvature for flows by convex speeds. Making use of a recent idea of Huisken and Sinestrari, we then obtain corresponding estimates for ancient solutions. In particular, this leads to various characterisations of the shrinking sphere amongst ancient solutions of these flows.
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Pipoli, Giuseppe, and Carlo Sinestrari. "Cylindrical estimates for mean curvature flow of hypersurfaces in CROSSes." Annals of Global Analysis and Geometry 51, no. 2 (September 29, 2016): 179–88. http://dx.doi.org/10.1007/s10455-016-9530-4.

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Gavrilenko, G. D., A. S. Sitnik, and V. I. Matsner. "On lower-bound estimates of critical loads for cylindrical shells." International Applied Mechanics 42, no. 10 (October 2006): 1145–50. http://dx.doi.org/10.1007/s10778-006-0186-9.

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Osakue, Edward E., and Lucky Anetor. "Revised Lewis Bending Stress Capacity Model." Open Mechanical Engineering Journal 14, no. 1 (July 31, 2020): 1–14. http://dx.doi.org/10.2174/1874155x02014010001.

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Background: During operation, cylindrical gearset experiences tangential, radial, and axial (helical gears only) force components that induce bending, compressive, and shear stresses at the root area of the gear tooth. Accurate estimation of the effective bending stress at the gear root is a challenge. Lewis was the first person who attempted estimating the root bending stress of spur gears with some reasonable accuracy. Various gear standards and codes in use today are modifications and improvements of the Lewis model. Objective: This research aims at revising the Lewis model by making adjustments for dynamic loads, shear stresses, axial bending stress for helical gears, and stress concentration factor that is independent on the moment arm of tangential or axial force component. Methods: An analytical approach is used in formulating a modified formula for the root bending stress in cylindrical gears starting with the original Lewis model. Intermediate expressions are developed in the process and works from many previous authors are reviewed and summarized. The new model developed is used to estimate the root bending stress in four example gearsets of 0o to 41.41o helix angle and the results are compared with those of AGMA (American Gear Manufacturers Association) formula. Results: Analysis from the examples shows that neglecting the radial compressive stress over-estimated the root bending stress by 5.27% on average. When shear stresses are ignored, the root bending stress is under-estimated by 7.49% on average. It is important, therefore, to account for both compressive and shear stresses in cylindrical gear root bending stress. When the root bending stress estimates from the revised Lewis model were compared with AGMA results, deviations in the range of -4.86% to 26.61% were observed. The stress estimates from the revised Lewis formulae were mostly higher than those of AGMA. Conclusion: The new root bending stress model uses stress concentration factors (normal and shear) that are independent of the point of load application on the gear tooth. This decoupling of stress concentration factor from the load moment arm distinguishes the new model from AGMA formula and brings bending stress analysis in gear design in line with classical bending stress analysis of straight and curved beams. The model can be used for both normal contact ratio and high contact ratio cylindrical gears.
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CHRISTIANSEN, Tanya J., and Kiril DATCHEV. "Resolvent estimates on asymptotically cylindrical manifolds and on the half line." Annales scientifiques de l'École Normale Supérieure 54, no. 4 (2021): 1051–88. http://dx.doi.org/10.24033/asens.2477.

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Nguyen, Huy The. "Convexity and cylindrical estimates for mean curvature flow in the sphere." Transactions of the American Mathematical Society 367, no. 7 (March 4, 2015): 4517–36. http://dx.doi.org/10.1090/s0002-9947-2015-05927-3.

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Dissertations / Theses on the topic "Cylindrical estimates"

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Meas, Len. "Estimations de dispersion et de Strichartz dans un domaine cylindrique convexe." Thesis, Université Côte d'Azur (ComUE), 2017. http://www.theses.fr/2017AZUR4038/document.

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Dans ce travail, nous allons établir des estimations de dispersion et des applications aux inégalités de Strichartz pour les solutions de l’équation des ondes dans un domaine cylindrique convexe Ω ⊂ R³ à bord C∞, ∂Ω ≠ ∅. Les estimations de dispersion sont classiquement utilisées pour prouver les estimations de Strichartz. Dans un domaine Ω général, des estimations de Strichartz ont été démontrées par Blair, Smith, Sogge [6,7]. Des estimations optimales ont été prouvées dans [29] lorsque Ω est strictement convexe. Le cas des domaines cylindriques que nous considérons ici généralise les resultats de [29] dans le cas où la courbure positive dépend de l'angle d'incidence et s'annule dans certaines directions
In this work, we establish local in time dispersive estimates and its application to Strichartz estimates for solutions of the model case Dirichlet wave equation inside cylindrical convex domains Ω ⊂ R³ with smooth boundary ∂Ω ≠ ∅. Let us recall that dispersive estimates are key ingredients to prove Strichartz estimates. Strichartz estimates for waves inside an arbitrary domain Ω have been proved by Blair, Smith, Sogge [6,7]. Optimal estimates in strictly convex domains have been obtained in [29]. Our case of cylindrical domains is an extension of the result of [29] in the case where the nonnegative curvature radius depends on the incident angle and vanishes in some directions
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Shao, Shuanglin. "Restriction estimates for paraboloids and cones in the cylindrically symmetric case." Diss., Restricted to subscribing institutions, 2008. http://proquest.umi.com/pqdweb?did=1692645511&sid=1&Fmt=2&clientId=1564&RQT=309&VName=PQD.

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Langford, Mat. "Motion of hypersurfaces by curvature." Phd thesis, 2014. http://hdl.handle.net/1885/14119.

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It is well-known that solutions of such flows necessarily suffer finite time singularities. On the other hand, under various natural conditions, singularities are characterised by a curvature blow-up. Our first main area of study concerns the asymptotic behaviour of the curvature at a singularity. We first prove a quantitative convexity estimate for positive solutions (that is, solutions moving with inward normal speed everywhere positive) under one of the following additional assumptions: either the evolving hypersurfaces are of dimension two, or the flow speed is a convex function of the curvature. Roughly speaking, the convexity estimate states that, for positive solutions, the normalised Weingarten curvature operator is asymptotically non-negative at a singularity. We then prove a family of cylindrical estimates for flows by convex speed functions. Roughly speaking, these estimates state that, for $(m+1)$-positive solutions (that is, solutions with $(m+1)$-positive Weing! arten curvature), the Weingarten curvature is asymptotically $m$-cylindrical at a singularity unless it becomes $m$-positive. The convexity and cylindrical estimates yield a detailed description of the possible singularities which may form under surface flows and flows by convex speeds. Moreover, they are uniform across the class of solutions with given dimension, flow speed, and initial volume, diameter and curvature hull, which should make them useful for applications such as the development of flows with surgeries. Our second main area of study concerns the development, in the fully non-linear setting, of the recently discovered {\it non-collapsing} phenomena for the mean curvature flow; namely, we prove that embedded solutions of flows by concave speeds are {\it interior non-collapsing}, whilst embedded solutions of flows by convex or inverse-concave speeds are {\it exterior non-collapsing}. The non-collapsing results complement the above curvature estimates by ruling out certain types of asymptotic behaviour which the curvature estimates do not. (This is mainly due to the non-local nature of the non-collapsing estimates.) As a particular application, we show how non-collapsing gives rise to a particularly efficient proof of the Andrews--Huisken theorem on the convergence of convex hypersurfaces to {\it round points} under such flows.
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Tseng, Chien-hao, and 曾健豪. "Application of the Inverse Method to Estimate the Heat Transfer Coefficient on a Cylindrical Fin with Experimental Temperature Data." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/42529698184405067693.

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碩士
國立成功大學
機械工程學系碩博士班
96
The study applies the Laplace transform method and the finite-difference method in conjunction with the least-squares scheme, the square spline and temperature measurements to estimate the heat transfer coefficient on the cylindrical surface at different inclined angle. The study assumed the heat transfer coefficient on this cylinder is non-uniform. Thus the whole cylinder is divided into several sub-intervals. Later, a series of continuous square polynomial function in space and a linear function in time are introduced to estimate the distribution of the unknown cylindrical surface condition. The results of experiment show that average heat transfer coefficient on cylindrical surface decreases with inclined angle in natural convection. A comparison of the average heat transfer coefficient between the present estimates and previous results is made in order to evidence the dependability and accuracy of the present inverse scheme.
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Books on the topic "Cylindrical estimates"

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International, ASTM, ed. Standard practice for estimate of the heat gain or loss and the surface temperatures of insulated flat, cylindrical, and spherical systems by use of computer programs. West Conshohocken, PA: ASTM, 2004.

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Book chapters on the topic "Cylindrical estimates"

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Ritoré, Manuel, and Carlo Sinestrari. "Cylindrical and gradient estimates." In Mean Curvature Flow and Isoperimetric Inequalities, 32–35. Basel: Birkhäuser Basel, 2010. http://dx.doi.org/10.1007/978-3-0346-0213-6_10.

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Hummel, Emilie, Claudio Pacchierotti, Valérie Gouranton, Ronan Gaugne, Theophane Nicolas, and Anatole Lécuyer. "Haptic Rattle: Multi-modal Rendering of Virtual Objects Inside a Hollow Container." In Haptics: Science, Technology, Applications, 189–97. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-031-06249-0_22.

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AbstractThe sense of touch plays a strong role in the perception of the properties and characteristics of hollow objects. The action of shaking a hollow container to get an insight of its content is a natural and common interaction. In this paper, we present a multi-modal rendering approach for the simulation of virtual moving objects inside a hollow container, based on the combination of haptic and audio cues generated by voice-coils actuators and high-fidelity headphones, respectively. We conducted a user study. Thirty participants were asked to interact with a target cylindrical hollow object and estimate the number of moving objects inside, relying on haptic feedback only, audio feedback only, or a combination of both. Results indicate that the combination of various senses is important in the perception of the content of a container.
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Akin, J. E. "Cylindrical analysis problems." In Finite Element Analysis with Error Estimators, 215–30. Elsevier, 2005. http://dx.doi.org/10.1016/b978-075066722-7/50039-4.

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"M-Components Mathematical Modeling for Deciduous Tree Ignition." In Advances in Environmental Engineering and Green Technologies, 105–17. IGI Global, 2021. http://dx.doi.org/10.4018/978-1-7998-7250-4.ch008.

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Based on a one-dimensional two-layer physical and mathematical model of ignition of a deciduous tree (birch), the influence of the m-components of a cloud-to-ground lightning discharge is estimated. The problem is solved in a cylindrical coordinate system. Typical cloud-to-ground lightning discharges are considered. An assessment of the influence of m-components was carried out for a typical range of changes in their characteristics. Surface temperature of tree trunk and heat flux to this surface are obtained during simulation.
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Serao, Paola, and Gino Bella. "Heat Capacity and Internal Thermal Resistance Measurements in Lithium-ion." In ATHENA Research Book, Volume 1, 249–54. University of Maribor Press, 2022. http://dx.doi.org/10.18690/um.3.2022.17.

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The heat capacity and the internal thermal resistance of lithiumion batteries are two important parameters for the thermal modelling of cells. These parameters are not generally available from manufactures or stated on cell datasheets. Particularly, measurements of the specific heat capacity of the cell would require disassembly of the cell and the use of an expensive calorimeter. This work describes a simple method for the measurement of both the heat capacity and the internal resistance of a cell. The method only requires an electrical characterization of the cell from which a good estimate of the thermal parameters is obtained. The method has been verified on a cylindrical lithium-ion cell. Experimental data are in excellent agreement to those obtained by conventional method of specific heat capacity measurements, thus validating the proposed setup for the thermal modelling of lithium-ion cells.
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Natarajan, Elango, Muhammad Rusydi Muhammad Razif, AAM Faudzi, and Palanikumar K. "Evaluation of a Suitable Material for Soft Actuator Through Experiments and FE Simulations." In Research Anthology on Cross-Disciplinary Designs and Applications of Automation, 339–53. IGI Global, 2022. http://dx.doi.org/10.4018/978-1-6684-3694-3.ch018.

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Soft actuators are generally built to achieve extension, contraction, curling, or bending motions needed for robotic or medical applications. It is prepared with a cylindrical tube, braided with fibers that restrict the radial motion and produce the extension, contraction, or bending. The actuation is achieved through the input of compressed air with a different pressure. The stiffness of the materials controls the magnitude of the actuation. In the present study, Silastic-P1 silicone RTV and multi-wall carbon nanotubes (MWCNT) with reinforced silicone are considered for the evaluation. The dumbbell samples are prepared from both materials as per ASTM D412-06a (ISO 37) standard and their corresponding tensile strength, elongation at break, and tensile modulus are measured. The Ogden nonlinear material constants of respective materials are estimated and used further in the finite element analysis of extension, contraction, and bending soft actuators. It is observed that silicone RTV is better in high strain and fast response, whereas, silicone/MWCNT is better at achieving high actuation.
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Djelosevic, Mirko, and Goran Tepic. "Simulation Model of Fragmentation Risk." In Simulation Modeling. IntechOpen, 2022. http://dx.doi.org/10.5772/intechopen.98955.

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In this chapter, a simulation model for fragmentation risk assessment due to a cylindrical tank explosion is presented. The proposed fragmentation methodology is based on the application of Monte Carlo simulation and probabilistic mass method. The probabilities of generating fragments during the explosion of the tank were estimated regardless of the available accident data. Aleatoric and epistemic uncertainty due to tank fragmentation has been identified. Generating only one fragment is accompanied by aleatoric uncertainty. The maximum fragmentation probability corresponds to the generation of two fragments with a total mass between 1200 kg and 2400 kg and is 17%. The fragment shape was assessed on the basis of these data and fracture lines. Fragmentation mechanics has shown that kinematic parameters are accompanied by epistemic uncertainty. The range of the fragments in the explosion of the tank has a Weibull distribution with an average value of 638 m. It is not justified to assume the initial launch angle with a uniform distribution, since its direction is defined by the shape of the fragment. The presented methodology is generally applicable to fragmentation problems in the process industry.
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Wu, Haijun, and Weikang Jiang. "A Mapping Relationship-Based near-Field Acoustic Holography." In Holography - Recent Advances and Applications [Working Title]. IntechOpen, 2022. http://dx.doi.org/10.5772/intechopen.108318.

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A mapping relationship-based near-field acoustic holography (MRS-based NAH) is a kind of innovative NAH by exploring the mapping relationship between modes on surfaces of the boundary and hologram. Thus, reconstruction is converted to obtain the coefficients of participant modes on holograms. The MRS-based NAH supplies an analytical method to determine the number of adopted fundamental solution (FS) as well as a technique to approximate a specific degree of mode on patches by a set of locally orthogonal patterns explored for three widely used holograms, such as planar, cylindrical, and spherical holograms. The NAH framework provides a new insight to the reconstruction procedure based on the FS in spherical coordinates. Reconstruction accuracy based on two types of errors, the truncation errors due to the limited number of participant modes and the inevitable measurement errors caused by uncertainties in the experiment, are available in the NAH. An approach is developed to estimate the lower and upper bounds of the relative error. It supplies a tool to predict the error for a reconstruction under the condition that the truncation error ratio and the signal-to-noise ratio are given. The condition number of the inverse operator is investigated to measure the sensitivity of the reconstruction to the input errors.
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Wani, Robert Serafino. "Parasites and Worms." In Tutorial Topics in Infection for the Combined Infection Training Programme. Oxford University Press, 2019. http://dx.doi.org/10.1093/oso/9780198801740.003.0010.

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A parasite is an organism that lives on or in a host and gets its food from or at the expense of its host. Worms or helminths either live as parasites or free of a host in aquatic and terrestrial environments. Parasites and worms are found worldwide but mainly in the tropics. It is estimated that 20% of immigrants from endemic countries may have helminthic infections at their arrival to the UK. These people could be asymptomatic, but tend to present with unexplained symptoms, especially gastrointestinal in nature or eosinophilia. Travellers to endemic countries tend to be newly infected and have greater immune response and pronounced eosinophilia in some but not all parasitic infections. Parasites that can cause disease in humans fall under three classes: protozoa, helminths, and Ectoparasites Protozoa are microscopic, one- celled organisms that can be free living or parasitic in nature. Transmission of protozoa that live in a human’s intestine to another human typically occurs through a faeco-oral route (for example, contaminated food or water, or person- to-person contact). Protozoa that live in the blood or tissue of humans are transmitted to other humans by an arthropod vector (for example, through the bite of a mosquito or sand fly). Helminths are large, multicellular organisms that are generally visible to the naked eye in their adult stages. Like protozoa, helminths can be either free living or parasitic. There are three main groups of helminths that parasitize humans: cestodes, trematodes, and nematodes. These are flat worms that comprise Echinococcus species: intestinal tapeworms and neurocysticercosis (Taenia solium) These are leaf- shaped, and they vary in length from a few millimetres to 8 cm. They include: ■ Liver fluke: Clonorchis sinensis, Fasciola hepatica ■ Intestinal fluke: Fasciola buski, Heterophyes heterophyes, ■ Lung fluke: Paragonimus westernmani ■ Blood flukes: Schistosoma species These are cylindrical in structure. Blood- sucking arthropods such as mosquitoes are considered as ectoparasites because they depend on blood meal for their survival. Narrowly speaking, ectoparasites include organisms like ticks, fleas, lice, and mites (scabies) that attach or burrow into the skin and remain there for relatively long periods of time (e.g. weeks to months).
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Conference papers on the topic "Cylindrical estimates"

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Haynie, Waddy, Mark Hilburger, Massimiliano Bogge, Marco Maspoli, and Benedikt Kriegesmann. "Validation of Lower-Bound Estimates for Compression-Loaded Cylindrical Shells." In 53rd AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference
20th AIAA/ASME/AHS Adaptive Structures Conference
14th AIAA. Reston, Virigina: American Institute of Aeronautics and Astronautics, 2012. http://dx.doi.org/10.2514/6.2012-1689.

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Keswick, P. R., and M. P. Norton. "Coupling Loss Factors and Coupling Damping for Flanged Cylindrical Shells." In ASME 1991 Design Technical Conferences. American Society of Mechanical Engineers, 1991. http://dx.doi.org/10.1115/detc1991-0293.

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Abstract This paper reports on an investigation into an experimental and theoretical evaluation of coupling loss factors and the experimental evaluation of coupling damping for statistical energy analysis of flanged cylindrical shells. It includes the following. 1. An evaluation of the power injection method and the steady state energy method for determining the coupling loss factors of conservative and non-conservatively coupled cylindrical shells. The investigation also establishes if it is necessary to use post processing or additional damping to the subsystems to obtain meaningful loss and coupling loss factors from the power injection method. 2. Establishment of a procedure for measuring coupling damping using the in-situ loss factors measured from the power injection method for non-conservatively coupled systems. The coupling damping estimates are measured for the same non-conservatively coupled cylindrical shell as used for the coupling loss factor experiments. 3. Usage of an elastic wave propagation analysis to obtain theoretical estimates of the coupling loss factors for cylindrical shells connected by a solid flange joint using the Fliigge stress equations for cylindrical shells. The flange joint arrangement is modelled as a ring connecting the two shell halves, where the Love equations are used to develop the in-plane and out-of-plane ring forces and moment. The coupling loss factor is calculated from the power transmitted across the joint and from the stored energy on the incident side.
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Jagodnik, John J., and Sinan Mu¨ftu¨. "A Cylindrical Contact Model for Two-Dimensional Multiasperity Profiles." In STLE/ASME 2003 International Joint Tribology Conference. ASMEDC, 2003. http://dx.doi.org/10.1115/2003-trib-0269.

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In practice, multi-asperity contact problems are often solved as two dimensional (2D) plane problems rather than true three dimensional (3D) problems. This is accomplished by assuming that each peak on a 2D scanned profile is the pinnacle of a half sphere. Hertz contact equations are then used to solve for the radius of contact and pressure profile. In reality, the local maximum in the plane may not be the maximum in the unmeasured depth direction, creating inherent errors in the contact model. This error is shown to be significant in contact problems when estimating the area of contact and total contact force over a single asperity. The pressure corrected Sternberg-Turteltaub model is introduced, in which a cylinder is used to model a sphere in a plane. This model is shown to improve the contact area and total force estimates for a range contact parameters.
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Muratori, Matteo, Ning Ma, Marcello Canova, and Yann Guezennec. "A Model Order Reduction Method for the Temperature Estimation in a Cylindrical Li-Ion Battery Cell." In ASME 2010 Dynamic Systems and Control Conference. ASMEDC, 2010. http://dx.doi.org/10.1115/dscc2010-4200.

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The thermal characterization of Li-ion batteries for EVs, HEVs and PHEVs is a topic of great relevance, especially for the evaluation of the battery pack state of health (SoH) during vehicle operations and for battery life estimation. This work proposes a reduced-order model that estimates the thermal dynamics of a cylindrical Li-ion battery cell, with respect to time-varying current demands. Unlike most “black-box” dynamic models, based on system identification techniques, the proposed approach relies on the definition of a boundary-value problem for heat conduction, in the form of a linear partial differential equation. The problem is then converted into a low-order linear model by applying model-order reduction method in the frequency domain. The resulting model predicts the temperature dynamics at the center and at the external surface in relation with the rate of heat generation and the coolant temperature. In this paper, the model is applied to estimate the internal temperature of a cylindrical cell during a discharging transient. The model uses electrical data acquired from experimental tests and is validated by comparison with experimental data and 3D FEM thermal simulation.
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Clayton, Alan M. "A Simplified Method to Determine Initial Estimates of Peak Strains in Composite Explosive Containment Vessels." In ASME 2013 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/pvp2013-97068.

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Explosive containment vessels made of a fiber-matrix composite require specialized finite element programs to estimate their strains. However for centrally loaded cylindrical vessels the stresses for any general lay up of the fibers in the vessel at the shortest offset of the explosive to the vessel can be assessed by simple analytical methods and these can be used to make initial assessments of the required material and thickness. The results of this simplified method are compared with experimental data on open ended composite tubes carried out by RFNC-VNIIF for Sandia National Laboratories and calculations on these performed by O’Toole et al at the University of Nevada [1].
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Taniguchi, Tomoyo, and Daisuke Okui. "A Case Study of Evaluation of Tank Rock Motion With Simplified Analysis Procedure." In ASME 2014 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/pvp2014-28635.

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Based on mechanical analogy between rocking motion of cylindrical tanks and that of two degree of freedom (2DOF) system, equations of motion for cylindrical tanks allowed to rock, that naturally includes effects of rocking-bulging interaction, are derived. Employing that the tank bulging motion is specified by a value of response acceleration spectrum in the absence of uplift and ordering terms, the simplified analysis for evaluating the angular acceleration of the tank rock motion, absolute maximum response acceleration of the tank bulging motion, base shear and reaction is derived. Assuming two percent of the ratio of the uplift width of the tank bottom plate to the diameter of tank, all physical quantities used for the simplified analysis are determined, tank responses are calculated and compared with corresponding responses computed by the Explicit Finite Element Analysis (EFEA). Comparison suggests that the proposed simplified analysis conservatively estimates all responses besides the angular acceleration.
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Mohan, Prashant, Jami Shah, and Joseph K. Davidson. "A Library of Feature Fitting Algorithms for GD&T Verification of Planar and Cylindrical Features." In ASME 2013 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/detc2013-12612.

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Conformation of a manufactured feature to the applied geometric tolerances is done by analyzing the point cloud that is measured on the feature. To that end, a geometric feature is fitted to the point cloud and the results are assessed to see whether the fitted features lies within the specified tolerance limits or not. Coordinate Measuring Machines (CMMs) use feature fitting algorithms that incorporate least square estimates as a basis for obtaining minimum, maximum, and zone fits. However, a comprehensive set of algorithms addressing the fitting procedure (all datums, targets) for every tolerance class is not available. Therefore, a Library of algorithms is developed to aid the process of feature fitting, and tolerance verification. This paper addresses linear, planar, circular, and cylindrical features only. This set of algorithms described conforms to the international Standards for GD&T. In order to reduce the number of points to be analyzed, and to identify the possible candidate points for linear, circular and planar features, 2D and 3D convex hulls are used. For minimum, maximum, and Chebyshev cylinders, geometric search algorithms are used. Algorithms are divided into three major categories: least square, unconstrained, and constrained fits. Primary datums require one sided unconstrained fits for their verification. Secondary datums require one sided constrained fits for their verification. For size and other tolerance verifications we require both unconstrained and constrained fits.
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Mahadev, Sthanu, and Wen S. Chan. "Closed-Form Analytical Solutions for Thin-Walled Cylindrical Composite Shell Structures Subjected to Axial and Bending Loads Under Temperature Environment." In ASME 2015 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/imece2015-52181.

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This research discourse presents the development of a holistic mathematical model that is dedicated to showcase a set of analytical expressions for predicting global stiffness (axial stiffness, bending stiffness) and a material response characterization based on ply-per-ply in-plane stress investigations relevant to open-celled multidirectional curved cylindrical shell configurations. Additionally, the analytical model is shown to present the capability to mathematically determine the location of the centroid for thin-walled, composite cylindrical shells. The resulting centroidal expression for a composite system is essentially shown to be a primary function of material properties, composite stacking sequence, fiber orientation angle and the structural geometry as opposed to metal counterparts whose centroidal point is solely governed by their geometry. Analytical stress estimates are computed for thin-walled curved cylindrical shell constructions that are subjected to typical tension and longitudinal bending type loading conditions applied at the centroid under the presence and absence of a uniformly distributed thermal loading environment. A broad parametric investigation on the in-plane ply stresses (σx,σy,τxy) are conducted via choosing three fundamental parameters namely; varying mean radius of curvature, changing laminate thickness-to-mean radius ratio and increasing laminate thickness respectively. Three preferentially tailored variabilities in ply stacking sequence are established from a [(±45° / 0°]s symmetric-balanced composite lay-up to illustrate the effects on ply stresses. An ANSYS based finite element analysis scheme is employed to numerically determine the location of centroid and further substantiate the analytically acquired centroid predictions including and excluding the effects of temperature. The centroidal point is identified and its location is progressively reported for a fully open cross-sectioned curved strip to a fully closed cylindrical composite tube configuration by examining their distribution pattern as a function of circumferential arc angle (2α). FE tool is additionally utilized to compare the analytical stiffness predictions and analyze the validity of the in-plane analytical stress estimates. Excellent agreement is achieved in comparison between analytical solutions and computationally generated FE results. The central goal of this work is to demonstrate the potential of the formulated mathematical framework in accurately predicting the key mechanical attributes that dictates the structural behavior of curved composite shell members. This analytical model is designed to serve as a robustly efficient tool towards assisting structural design engineers in quickly gaining a broad fundamental understanding on the physical characteristics and structural response of such configurations by accurately conducting simple parametric studies during preliminary design phase prior to performing complex FE analyses.
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9

Sracic, Michael W., and William J. Elke. "Predicting Finite Element Submodel Boundary Conditions for Contact Models Using Richardson Extrapolation." In ASME 2019 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/detc2019-98070.

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Abstract This paper considers an efficient way to apply submodeling methods to finite element models using Richardson Extrapolation. A problem is considered where a rigid cylindrical indenter contacts an elastic half plane (RCEHP). A submodeling method is introduced where the errors of the displacements on the boundaries of the submodel are controlled by employing a best-fit Richardson Extrapolation curve. Specifically, the curve is fit to the convergence relationship of various estimates of submodel boundary displacements. The method is tested on the RCEHP problem, and the results of the model predictions for maximum contact pressure are compared to an analytical and converged global model result. The submodeling method predicted the maximum contact pressure of the RCEHP contact interface to be about 7% higher than the analytical prediction and 5% higher than the converged global model prediction. The error is likely due to the selection of the global and submodel domains, the numerical algorithm used to estimate the Richardson Extrapolation Curve Fits, and the mesh refinements used for the various models. The proposed method solved in about 42.6 minutes while the converged global model solved in 11.19 hours. Future work will aim to provide best practices to reduce error and maximize computational time savings when using the method.
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Charles, Richard, David W. Beardsmore, Huaguo Teng, and Chris T. Watson. "Load History Effects on Crack Driving Force for Cracks in Residual Stress Fields." In ASME 2008 Pressure Vessels and Piping Conference. ASMEDC, 2008. http://dx.doi.org/10.1115/pvp2008-61376.

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Fracture mechanics assessments of engineering components and structures containing defects are made by comparing an estimate of the crack driving force KJ with an effective fracture toughness KJc. The assessments must account for the combined effect of primary loads, such as internal pressure in pressurised components, and secondary stresses arising from welding and/or thermal loading. Elastic-plastic finite element analysis, or simplified methods set out in standard assessment procedures, can be used to estimate the crack driving force KJ as a function of the applied primary load on the component. The effective fracture toughness KJc should take account of the material fracture toughness and the crack tip constraint. For the assessment of defects in weld residual stress fields, it is usually assumed that the defect is inserted into the as-welded stress distribution in such a way that traction free crack surfaces are created simultaneously at all positions on the crack faces. However, it may be beneficial to take account of any relaxation in the residual stress field that might arise during proof-testing or in-service cyclic loading, and to consider a more gradual, progressive introduction of the defects. These benefits could, in principle, result in a reduction in the crack driving force. This paper describes work that has been undertaken to provide estimates of the crack driving force KJ for a fully-circumferential defect in a circumferential repair weld in a cylindrical pipe. Calculations have been carried out to establish KJ for a number of cases where different pressure overloads are applied to the uncracked pipe and different methods of crack insertion are applied. Estimates of the margin of safety on fracture toughness and pressure loading were calculated. At the outset, it was assumed that the fracture toughness of relevance for the defects is the material fracture toughness KJc* derived from strain free, high constraint fracture toughness specimens. No allowance was made for constraint effects associated with the finite geometry or initial strains in the pipe. The values of KJ were derived from values of J calculated using the JEDI post-processing code; this allows for initial inelastic strains present in the model prior to the start of the crack insertion process.
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Reports on the topic "Cylindrical estimates"

1

Warrick, Arthur, Uri Shani, Dani Or, and Muluneh Yitayew. In situ Evaluation of Unsaturated Hydraulic Properties Using Subsurface Points. United States Department of Agriculture, October 1999. http://dx.doi.org/10.32747/1999.7570566.bard.

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The primary information for accurately predicting water and solute movement and their impact on water quality is the characterization of soil hydraulic properties. This project was designed to develop methods for rapid and reliable estimates of unsaturated hydraulic properties of the soil. Particularly, in situ methodology is put forth, based on subsurface point sources. Devices were designed to allow introduction of water in subsurface settings at constant negative heads. The ability to operate at a negative head allows a direct method of finding unsaturated soil properties and a mechanism for eliminating extremely rapid preferential flow from the slow matrix flow. The project included field, laboratory and modeling components. By coupling the measurements and the modeling together, a wider range of designs can be examined, while at the same time realistic performance is assured. The developed methodology greatly expands the possibilities for evaluating hydraulic properties in place, especially for measurements in undisturbed soil within plant rooting zones. The objectives of the project were (i) To develop methods for obtaining rapid and reliable estimates of unsaturated hydraulic properties in situ, based on water distribution from subsurface point sources. These can be operated with a constant flow or at a constant head; (ii) To develop methods for distinguishing between matrix and preferential flow using cavities/permeameters under tension; (iii) To evaluate auxiliary measurements such as soil water content or tensions near the operating cavities to improve reliability of results; and (iv: To develop numerical and analytical models for obtaining soil hydraulic properties based on measurements from buried-cavity sources and the auxiliary measurements. The project began in July 1995 and was terminated in November 1998. All of the objectives were pursued. Three new subsurface point sources were designed and tested and two old types were also used. Two of the three new designs used a nylon cloth membrane (30 mm) arranged in a cylindrical geometry and operating at a negative water pressure (tension). A separate bladder arrangement allowed inflation under a positive pressure to maintain contact between the membrane and the soil cavity. The third new design used porous stainless steel (0.5 and 5 mm) arranged in six segments, each with its own water inlet, assembled to form a cylindrical supply surface when inflated in a borehole. The "old" types included an "off-the-shelf" porous cup as well as measurements from a subsurface drip emitter in a small subsurface cavity. Reasonable measurements were made with all systems. Sustained use of the cloth membrane devices were difficult because of leaks and plugging problems. All of the devices require careful consideration to assure contact with the soil system. Steady flow was established which simplified the analysis (except for the drip emitter which used a transient analysis).
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Kamai, Tamir, Gerard Kluitenberg, and Alon Ben-Gal. Development of heat-pulse sensors for measuring fluxes of water and solutes under the root zone. United States Department of Agriculture, January 2016. http://dx.doi.org/10.32747/2016.7604288.bard.

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The objectives defined for this study were to: (1) develop a heat-pulse sensor and a heat-transfer model for leaching measurement, and (2) conduct laboratory study of the sensor and the methodology to estimate leaching flux. In this study we investigated the feasibility for estimating leachate fluxes with a newly designed heat-pulse (HP) sensor, combining water flux density (WFD) with electrical conductivity (EC) measurements in the same sensor. Whereas previous studies used the conventional heat pulse sensor for these measurements, the focus here was to estimate WFD with a robust sensor, appropriate for field settings, having thick-walled large-diameter probes that would minimize their flexing during and after installation and reduce associated errors. The HP method for measuring WFD in one dimension is based on a three-rod arrangement, aligned in the direction of the flow (vertical for leaching). A heat pulse is released from a center rod and the temperature response is monitored with upstream (US) and downstream (DS) rods. Water moving through the soil caries heat with it, causing differences in temperature response at the US and DS locations. Appropriate theory (e.g., Ren et al., 2000) is then used to determine WFD from the differences in temperature response. In this study, we have constructed sensors with large probes and developed numerical and analytical solutions for approximating the measurement. One-dimensional flow experiments were conducted with WFD ranging between 50 and 700 cm per day. A numerical model was developed to mimic the measurements, and also served for the evaluation of the analytical solution. For estimation WFD, and analytical model was developed to approximate heat transfer in this setting. The analytical solution was based on the work of Knight et al. (2012) and Knight et al. (2016), which suggests that the finite properties of the rods can be captured to a large extent by assuming them to be cylindrical perfect conductors. We found that: (1) the sensor is sensitive for measuring WFD in the investigated range, (2) the numerical model well-represents the sensor measurement, and (2) the analytical approximation could be improved by accounting for water and heat flow divergence by the large rods.
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