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Auswahl der wissenschaftlichen Literatur zum Thema „Lateral resistance coefficient“
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Zeitschriftenartikel zum Thema "Lateral resistance coefficient"
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Yin, Ya Jun, Xue Wen Xie und Yong Mei Qian. „The Research of Horizontal Resistance Coefficient of Pile Lateral Soil in Horizontal Loads“. Applied Mechanics and Materials 501-504 (Januar 2014): 228–33. http://dx.doi.org/10.4028/www.scientific.net/amm.501-504.228.
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By finite element method and on the basis of measured data of horizontal static test of pile foundation, the article analyzed horizontal lateral resistance of pile lateral soil under the interaction of piles and soil and horizontal resistance coefficient of foundation soil. The results prove that weighting horizontal resistance coefficient ( m) of foundation soil and the displacement of pile top changed in the reduce of hyperbolic. Meanwhile, it indicates that the constraints of pile top can enhance pile horizontal resistance obviously.
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Griffiths, Terry, David J. White, Scott Draper, Adam Leighton, Liang Cheng, Hongwei An und Antonino Fogliani. „Lateral resistance of “rigid” pipelines and cables on rocky seabeds“. Canadian Geotechnical Journal 56, Nr. 6 (Juni 2019): 823–39. http://dx.doi.org/10.1139/cgj-2018-0208.
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Accurate assessment of lateral resistance is critical to ensure the on-bottom stability and integrity of subsea pipelines and cables in the oil–gas and marine renewable energy industries. However, on rocky seabeds recommended practices provide limited recommendations on pipe–seabed interaction, suggesting only a single value for the friction coefficient of 0.6. This paper reports on a programme of physical experiments and theoretical modelling investigating the lateral resistance of pipes on rocky seabeds. It is shown that the peak and mean effective friction can significantly exceed the interface (or Coulomb) friction coefficient when the pipe diameter (D) is similar to the median rock diameter (dn50). Only when the pipe diameter becomes large compared to the rock size does the mean effective friction approach the interface friction. The effective friction coefficient was found to vary with variability in rock size and shape, as well as the length of pipe relative to median rock diameter. Each of these findings is reproduced well using the theoretical model. Collectively, the results demonstrate that the effective lateral friction coefficient may be higher than 0.6 for mean friction, and significantly higher for peak friction. This implies that inaccuracy may exist in current design, which may be rectified using the theoretical model.
3
Kong, L. G., und L. M. Zhang. „Experimental study of interaction and coupling effects in pile groups subjected to torsion“. Canadian Geotechnical Journal 45, Nr. 7 (Juli 2008): 1006–17. http://dx.doi.org/10.1139/t08-038.
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Piles in a pile group subjected to torsion simultaneously mobilize lateral and torsional resistances. Hence, complicated pile–soil–pile interaction effects and load deformation coupling effects occur in the pile group. In this study, a series of centrifuge model tests were carried out to investigate these effects in three-diameter spaced 1 × 2, 2 × 2, and 3 × 3 pile groups subjected to torsion in both loose and dense sands. The test results showed that the effect of horizontal movement of a pile on lateral behaviors of its adjacent piles is significant in 3 × 3 pile groups and such effect varies with group configuration and pile position. The p-multiplier concept can be used to quantify the effect and values for the p-multiplier are suggested. The effect of lateral movement of a pile on the torsional resistances of its adjacent piles and the effect of torsional movement of a pile on the lateral resistances of its adjacent piles were found to be minor in these tests. For an individual pile in a pile group subjected to torsion, the mobilized lateral resistance was found to substantially increase the torsional resistance of the pile. Such a coupling effect is quantified by a coupling coefficient, β, which describes the contribution of subgrade reaction to the increase of torsional shear resistance.
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Skvortsov, K. D., und A. I. Osokin. „Optimization of the formulaof the design resistance of soil“. Вестник гражданских инженеров 17, Nr. 5 (2020): 117–22. http://dx.doi.org/10.23968/1999-5571-2020-17-5-117-122.
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The assumptions made in the derivation of the formula for the design soil resistance are considered. It is shown that in the conditions of the plane problem, taking into account the coefficient of lateral soil pressure leads to lower values of the initial critical load and, consequently, to a decrease in the design resistance. The equation of limiting equilibrium is implemented in the MathCad software package, which makes it possible to obtain isolines of deviation angles at any depth from the applied uniformly distributed load. To determine the initial critical load, a formula is given that takes into account the coefficient of lateral soil pressure K0. In the final part of the article, the solution to the problem is given according to the formula of N. P. Puzyrevsky and according to the formula derived by the author, taking into account K0, the difference in the isolines of the deflection angles is presented, and an analysis of a similar problem in the Plaxis 2D software package is carried out.
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Hosseini, Ahmad, und Morteza Esmaeili. „Effect of different contact surfaces between concrete sleeper and ballast on mobilized lateral resistance against impact loads“. Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit 231, Nr. 6 (07.03.2016): 678–89. http://dx.doi.org/10.1177/0954409716636924.
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The amount of ballast particles surrounding a railway track significantly influences its resistance in all directions. As time goes by, with the development of high-speed trains, more attention has been paid to this issue owing to the increase in dynamic effects of rolling stock on track loading. The focus of the present study is on the investigation of the interaction between different surfaces (base, crib, and shoulder) of concrete sleeper and their adjacent ballast layer along with the related parameters under lateral impact loading condition. In this regard, by utilizing a pendulum loading test device, a number of lateral impact tests were conducted on an instrumented concrete sleeper in laboratory. On the basis of experimental results, the average contribution of base, crib, and shoulder zones in the total dynamic lateral resistance of sleeper was calculated as 48%, 23%, and 29%, respectively. Furthermore, in the lateral impact force domain of 13–28 kN, the sleeper–ballast dynamic friction coefficient at base and crib zones varied in the ranges 0.8–1.5 and 0.5–0.6. Moreover, a maximum impact factor of 2.5 was obtained for analysis and design purposes. It should be stated that the trend of laboratory results confirmed the common static friction coefficient of 0.8.
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Li, Feng, Shen Li, Guan Nan Wu und Dong Wang. „Experimental Investigation on Four Types of Steel Plate Shear Walls“. Applied Mechanics and Materials 166-169 (Mai 2012): 657–63. http://dx.doi.org/10.4028/www.scientific.net/amm.166-169.657.
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The overall seismic performance of steel plate shear walls, including unstiffened SPSW, cross-stiffened SPSW, and SPSW with opening, SPSW with slits and holes, under low cyclic loading were tested. Contrastive analyze their hysteretic curve, loading capacity, lateral stiffness, ductility and energy dissipation coefficient. Results indicate that the unstiffened SPSW seem to be with high resistance lateral stiffness and carrying capacity; however its hysteretic curve show pinch effect obviously. When cross-stiffener was set on unstiffened SPSW, the resistance lateral stiffness and loading capacity can be significantly improved. However, the pinch effect of hysteretic curve does not distinctly change. The resistance lateral stiffness and loading capacity of SPSW with holes and slits is lower, however hysteretic curve is full. In addition, the energy dissipation capacity and the phenomenon which the thin steel plate shear wall shows the zero stiffness even negative stiffness at the point of zero displacement under cyclic loading are dramatically improved.
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Shobolova, Т. А., S. V. Obolensky und Yu А. Kabalnov. „RADIATION RESISTANT BIPOLAR SOI TRANSISTORS“. Electronic engineering Series 2 Semiconductor devices 258, Nr. 3 (2020): 34–42. http://dx.doi.org/10.36845/2073-8250-2020-258-3-34-42.
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In this paper the new design of lateral bipolar transistors is presented, made on the basis of the charge carrier transport modeling. New design provides high level of base current transmission coefficient and enhanced radiation resistance. The manufacturing technology of the lateral bipolar transistors is compatible with a submicron SOI CMOS technology and can be of vital importance when developing RF analogue-to-digital microcircuits for ionizing radiation resistant satellite-navigation equipment.
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Yang, Yi Bo, Zhao Qiong Lai, Li Tao Ai, Wen Ying Guo, Hong Jian Huang und Heng Chang Wang. „Experimental Research on the Evaluation Method of the Resistance to Chloride Ion Penetration of Autoclaved PHC Pile“. Key Engineering Materials 629-630 (Oktober 2014): 587–92. http://dx.doi.org/10.4028/www.scientific.net/kem.629-630.587.
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The usage of autoclaved PHC pile in chloride environment becomes common, so how to evaluate the resistance to chloride ion penetration of autoclaved PHC pile becomes urgent. This article Compare the resistance to chloride ion penetration of pile and pile concrete specimens based the Rapid Chloride Migration Synthesis Method and RCM. The results show that the Rapid Chloride Migration Synthesis Method is not suitable for pile, RCPT and RCM are suitable for pile; the resistance to chloride ion penetration of the pile inner and outer lateral concrete has a rather large different, so the sample must distinguish the direction when testing. Steel bar has little influence on the resistance to chloride ion penetration of autoclaved PHC pile, and the resistance to chloride ion penetration of pile outer lateral concrete is similar with pile concrete specimen, using pile concrete specimen to test the resistance to chloride ion penetration of autoclaved PHC pile is suitable. The chloride diffusion coefficient values have a good relationship with the electricity value, using the electricity value of square pile concrete specimen as commonly quality control way are suggested. The resistance to chloride ion penetration of pile can test the outer lateral concrete of pile or pile head, using the electricity value as daily quality control method and basis for project acceptance, and using RCM method as life assessment and basis for project acceptance.
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Luo, Guanwen, Leming Cheng, Liyao Li, Junfeng Wang, Xiaoguo Jiang und Weiguo Zhang. „Effect of Connection Resistance between Cyclones and Backpass on Furnace Solids Suspension Density Profile and Circulation Rates in CFB“. Energies 14, Nr. 19 (27.09.2021): 6162. http://dx.doi.org/10.3390/en14196162.
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The connection section between cyclones and backpass is an important configuration in multi-cyclone circulating fluidized bed boilers (CFB). In this work, the resistance coefficient of different connection modes, and connection resistance distribution from each cyclone outlet to backpass (connection branch) in one mode are defined and calculated, in order to investigate their effects on furnace solids suspension density distribution and circulation rates. Three connection modes with different overall resistance coefficients were tested experimentally and analyzed by a 1.5-dimensional model in a four-cyclone scaling CFB apparatus. Both experimental and theoretical results show that, with larger overall resistance of a connection, there are more solids suspended in the furnace bottom and fewer in the top section. The investigation of the C-type connection has revealed that when the branch resistance of the connection decreases from branch No. 1–4, the solids suspension density and circulation rate from corresponding solids recycle loops (No. 1–4) increase. Moreover, the non-uniformity of connection branch resistance distribution will lead to uneven lateral solids suspension density distribution and circulation rates allocation. This effect is enhanced by growing superficial velocity.
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Yeo, Na Eun, Doo-In Kim und Myung Yung Jeong. „Compressive and Shear Resistances of Confined Water Droplet in Sliding Motion Against Hydrophobic Counterpart“. Science of Advanced Materials 12, Nr. 4 (01.04.2020): 589–93. http://dx.doi.org/10.1166/sam.2020.3671.
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The compressive and shear resistances of the water droplet confined between the hydrophobic surfaces were investigated to evaluate the effect of the micro-scale surface pattern on the repulsive capillary force and friction of droplet. The hydrophobic surfaces covered with square pillar structures in the hexagonal array were prepared and the repulsive normal load and friction coefficient of the droplet were characterized. The force measurements in the vertical and lateral directions on the droplet confined between the prepared hydrophobic surfaces revealed that the compressive resistance to the vertical motion which is identical with the repulsive capillary force increases with deformation when the deformed droplet is horizontally symmetric. On the other hand, the friction coefficient of the squeezed droplet is inversely proportional to the repulsive capillary force. It was found that the reduced pressure acting on the solid–liquid interface results in the abnormal reduction in friction coefficient. In addition, the critical hydraulic pressure analysis confirmed that the partially wetted Cassie-Baxter (CB) state is maintained during sliding motion.
Dissertationen zum Thema "Lateral resistance coefficient"
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Iyalla, Ibiyekariwaripiribo. „Computational fluid dynamics modelling of pipeline on-bottom stability“. Thesis, Robert Gordon University, 2017. http://hdl.handle.net/10059/2721.
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Subsea pipelines are subjected to wave and steady current loads which cause pipeline stability problems. Current knowledge and understanding on the pipeline on-bottom stability is based on the research programmes from the 1980’s such as the Pipeline Stability Design Project (PIPESTAB) and American Gas Association (AGA) in Joint Industry Project. These projects have mainly provided information regarding hydrodynamic loads on pipeline and soil resistance in isolation. In reality, the pipeline stability problem is much more complex involving hydrodynamic loadings, pipeline response, soil resistance, embedment and pipe-soil-fluid interaction. In this thesis Computational Fluid Dynamics (CFD) modelling is used to investigate and establish the interrelationship between fluid (hydrodynamics), pipe (subsea pipeline), and soil (seabed). The effect of soil types, soil resistance, soil porosity and soil unit weight on embedment was examined. The overall pipeline stability alongside pipeline diameter and weight and hydrodynamic effect on both soil (resulting in scouring) and pipeline was also investigated. The use of CFD provided a better understanding of the complex physical processes of fluid-pipe-soil interaction. The results show that the magnitude of passive resistance is on the average eight times that of lateral resistance. Thus passive resistance is of greater significance for subsea pipeline stability design hence the reason why Coulomb’s friction theory is considered as conservative for stability design analysis, as it ignores passive resistance and underestimates lateral resistance. Previous works (such as that carried out by Lyons and DNV) concluded that soil resistance should be determined by considering Coulomb’s friction based on lateral resistance and passive resistance due to pipeline embedment, but the significance of passive resistance in pipeline stability and its variation in sand and clay soils have not be established as shown in this thesis. The results for soil porosity show that increase in pipeline stability with increasing porosity is due to increased soil liquefaction which increases soil resistance. The pipe-soil interaction model by Wagner et al. established the effect of soil porosity on lateral soil resistance but did not attribute it to soil liquefaction. Results showed that the effect of pipeline diameter and weight vary with soil type; for sand, pipeline diameter showed a greater influence on embedment with a 110% increase in embedment (considering combined effect of diameter and weight) and a 65% decrease in embedment when normalised with diameter. While pipeline weight showed a greater influence on embedment in clay with a 410% increase. The work of Gao et al. did not completely establish the combined effect of pipeline diameter and weight and soil type on stability. Results also show that pipeline instability is due to a combination of pipeline displacement due to vortex shedding and scouring effect with increasing velocity. As scoring progresses, maximum embedment is reached at the point of highest velocity. The conclusion of this thesis is that designing for optimum subsea pipeline stability without adopting an overly conservative approach requires taking into consideration the following; combined effect of hydrodynamics of fluid flow on soil type and properties, and the pipeline, and the resultant scour effect leading to pipeline embedment. These results were validated against previous experimental and analytical work of Gao et al, Brennodden et al and Griffiths.
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Sýs, Tomáš. „Komplexní analýza funkce distribučního systému typu U“. Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2021. http://www.nusl.cz/ntk/nusl-443219.
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Fluid flow maldistribution plays a key role in equipment used in process and energy industries, although its evaluation is often underestimated or fully neglected. Uneven flow distribution may cause thermal or mechanical load on the tube bundle, and in extreme scenarios, it can also have an adverse effect on the process efficiency. This thesis aims to find the optimal computational tools for flow distribution prediction suitable for the initial stage of the equipment design process and to identify suitable settings of these tools for their subsequent industrial deployment. The results of simplified analytical models, detailed numerical simulations, and experimental measurements were compared for the dividing header and the U-type distribution system. It was found that the results provided by simplified mathematical models, the solution of which is also significantly less time-consuming compared to detailed CFD simulations, best correspond to the measured experimental values in all modeled configurations. For arrangements with higher lateral resistance coefficient, both computational approaches provide approximately equally accurate results. However, for arrangements with lower lateral resistance coefficient, the deviation of the results obtained by CFD calculations from the experimental data is significantly larger.
Buchteile zum Thema "Lateral resistance coefficient"
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Memon, Qurban A. „Authentication and Error Resilience in Images Transmitted through Open Environment“. In Handbook of Research on Security Considerations in Cloud Computing, 102–26. IGI Global, 2015. http://dx.doi.org/10.4018/978-1-4666-8387-7.ch006.
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Nowadays data compression and authentication are believed to be vital to image transmission through heterogeneous infrastructure or storage at a centralized place. Though compression and authentication have independently grown to be matured technologies, but currently integration of these technologies is understood to be a key factor in handling tampering in images transmitted through unsecure channels like cloud. In this chapter, an error-resistant approach is investigated to add to low cost image authentication scheme to increase visual quality as well as improve author and user satisfaction. The image authentication includes content based digital signature that is watermarked and later diffused in the whole image before JPEG2000 coding. To tackle manipulations in the image, edge information of the image is examined to offset manipulations in the image transmission through noisy or open and unsecure channels. The edge image is sent along with JPEG2000 coded image to determine corrupted coefficients. The simulation results are conducted on test images for different values of bit error rate to judge confidence in error concealment within the received images.
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Memon, Qurban A. „Authentication and Error Resilience in Images Transmitted through Open Environment“. In Medical Imaging, 1651–76. IGI Global, 2017. http://dx.doi.org/10.4018/978-1-5225-0571-6.ch069.
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Nowadays data compression and authentication are believed to be vital to image transmission through heterogeneous infrastructure or storage at a centralized place. Though compression and authentication have independently grown to be matured technologies, but currently integration of these technologies is understood to be a key factor in handling tampering in images transmitted through unsecure channels like cloud. In this chapter, an error-resistant approach is investigated to add to low cost image authentication scheme to increase visual quality as well as improve author and user satisfaction. The image authentication includes content based digital signature that is watermarked and later diffused in the whole image before JPEG2000 coding. To tackle manipulations in the image, edge information of the image is examined to offset manipulations in the image transmission through noisy or open and unsecure channels. The edge image is sent along with JPEG2000 coded image to determine corrupted coefficients. The simulation results are conducted on test images for different values of bit error rate to judge confidence in error concealment within the received images.
Konferenzberichte zum Thema "Lateral resistance coefficient"
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Yang, Zhixun, Jun Yan, Liang Zhang, Dongyan Shi und Qingzhen Lu. „Research on Lateral Buckling Mechanism of Tensile Armor Wires in Unbonded Flexible Pipe“. In ASME 2020 39th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/omae2020-18204.
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Abstract The buckling behavior and critical value are analyzed to explain the mechanism of the lateral buckling. Moreover, a 3D numerical model of four tensile armor wires with symmetrical arrangement is established with the interaction between armor wires and inner structure. The lateral buckling is discussed through a relationship between critical value and axial displacement. Then the sensitivity of critical value on friction coefficient is figured out. The results show that the lateral buckling resistance of tensile armor wires performs better with the friction coefficient in the range of 0.25 to 0.3. Finally, this research provides mechanical support for the lateral buckling resistance design of the unbonded flexible pipe.
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Gergel, John T., Vishali M. Vasudevan und Matthew H. Hebdon. „Railroad Tie Lateral Resistance on Open-Deck Plate Girder Bridges“. In 2020 Joint Rail Conference. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/jrc2020-8053.
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Abstract On open-deck railroad bridges, the crossties (sleepers) are directly supported by the bridge superstructure and anchored with deck tie fasteners such as hook bolts. These fasteners provide lateral resistance for the bridge ties, and in railroad bridge design, their spacing is controlled by the required lateral resistance of the ties. Currently there are no provisions to assist in the calculation of lateral resistance provided by railroad ties on open-deck bridges, and as a result there are no specific requirements for the spacing of deck tie fasteners. This has led to different design practices specific to each railroad, and inconsistent fastener spacing in existing railroad bridges. A research plan was conducted to experimentally quantify the lateral resistance of timber crossties on open-deck plate girder bridges using different wood species and types of fasteners. Experimental tests were conducted on four different species of timber crossties (Beech, Sycamore, Southern Pine, and Oak) with three different types of fasteners (square body hook bolt, forged hook bolt, and Quick-Set Anchors). A structural test setup simulated one half of an open-deck bridge with a smooth-top steel plate girder, and hydraulic actuators to apply both vertical and horizontal load to a railroad tie specimen. The three main contributions to lateral resistance on open-deck bridges were identified as friction resistance between tie and girder due to vertical load from a truck axle, resistance from the fastener, and resistance from dapped ties bearing against the girder flange. Initial testing conducted at Virginia Tech isolated each component of lateral resistance to determine the friction coefficient between tie and girder as well as resistance from just the fastener itself. Results indicate that friction resistance varies based on the magnitude of vertical truck axle load, species of wood, and quantity of creosote preservative on the tie, while fastener resistance varies based on type of fastener and displacement of the tie. With the experimental results, a preliminary equation for calculating the overall resistance of open-deck timber crossties is developed, which allows for a recommendation of fastener spacing based on the type of fastener, wood species, and anticipated lateral loads on the structure.
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Sun, Zhiyuan, Ping Li und Hanbing Sun. „Research of Wind Resistance and Flow Field of Container Ship“. In ASME 2019 38th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/omae2019-96798.
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Abstract In order to study the super large container ship characteristics of the wind resistance coefficient and the air flow field in the different angle of attack, wind tunnel test based on the 14000 containers ship is carried out on the state of the design draft. The wind resistance coefficient of superstructure is obtained through test. The CFD (Computational Fluid Dynamics) technology is introduced to simulate the wind resistance and yaw moment of the model. The numerical results are basically in agreement with the experimental data. The results indicates that with the increase of the wind direction angle, the longitudinal wind resistance coefficient curve shows a “sine curve” rule and exists opposite resistance extremums, whereas the lateral wind resistance coefficient curve presents a parabolic change rule. Numerical simulation method is proved has high accuracy for wind resistance prediction of container ship. The size of wind load on the ship is related to the form and size of the wake region.
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Higuchi, Tatsuya, Akimaro Kawahara, Michio Sadatomi und Hiroyuki Kudo. „Single- and Two-Phase Diversion Cross-Flows Between Triangle Tight Lattice Rod Bundle Subchannels: Data on Flow Resistance and Interfacial Friction Coefficients for the Cross-Flow“. In 14th International Conference on Nuclear Engineering. ASMEDC, 2006. http://dx.doi.org/10.1115/icone14-89215.
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Single- and two-phase diversion cross-flows arising from the pressure difference between tight lattice subchannels are our concern in this study. In order to obtain a correlation of the diversion cross-flow, we conducted adiabatic experiments using a vertical multiple-channel with two subchannels simplifying the triangle tight lattice rod bundle for air-water flows at room temperature and atmospheric pressure. In the experiments, data were obtained on the axial variations in the pressure difference between the subchannels, the ratio of flow rate in one subchannel to the whole channel, the void fraction in each subchannel for slug-churn and annular flows in two-phase flow case. These data were analyzed by use of a lateral momentum equation based on a two-fluid model to determine both the cross-flow resistance coefficient between liquid phase and channel wall and the gas-liquid interfacial friction coefficient. The resulting coefficients have been correlated in a way similar to that developed for square lattice subchannel case by Kano et al. (2002); the cross-flow resistance coefficient data can be well correlated with a ratio of the lateral velocity due to the cross-flow to the axial one irrespective of single- and two-phase flows; the interfacial friction coefficient data were well correlated with a Reynolds number, which is based on the relative velocity between gas and liquid cross-flows as the characteristic velocity.
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Yan, Shu-Ming, Fu-Ping Gao, Jing Cao, En-Yong Zhang, Guo-Hui Li und Ying-Xiang Wu. „Physical Modeling of Untrenched Pipeline Breakout From Sand-Bed in Ocean Currents“. In ASME 2010 29th International Conference on Ocean, Offshore and Arctic Engineering. ASMEDC, 2010. http://dx.doi.org/10.1115/omae2010-20183.
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The ultimate lateral soil resistance for pipe losing lateral stability on a sandy seabed under the action of ocean currents is investigated with a newly developed test facility by employing mechanical actuators to simulate hydrodynamic loads on the pipe. Two kinds of constraint conditions, i.e. anti-rolling pipe and freely-laid pipe, are taken into account, respectively. The experimental observations indicate that, the horizontal lateral soil resistance increases gradually to its maximum (ultimate) value when the additional settlement is fully developed. The buildup of the ultimate lateral soil resistance to the anti-rolling pipe benefits from not only the additional settlements but also the sand-particle collections in front of the moving pipe, especially for the anti-rolling pipes. The lateral-soil-resistance coefficient for the anti-rolling pipe is much larger than that for the freely-laid pipe. The pipe surface roughness also affects the lateral stability of anti-rolling pipes. A comparison is made between present mechanical-actuator tests and the previous water-flume tests, indicating the results of two types of tests are comparable and the local scour may reduce the pipe lateral stability in ocean currents.
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Ji, Guomin, Lanjing Li und Muk Chen Ong. „On-Bottom Stability Analysis of Subsea Pipelines Under Combined Irregular Waves and Currents“. In ASME 2017 36th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/omae2017-61363.
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The objective of the paper is to study the effect of different parameters regarding on-bottom stability of subsea pipelines under combined irregular waves and currents. The effect of friction coefficient is first investigated. The development of lateral displacement and penetration for three different friction coefficients are compared for sandy and clayey seabed respectively when applied wave and current conditions are kept same for all the cases. The friction coefficient affects the soil resistance force and further changes the initial time when the pipeline starts to move in the lateral direction. The accumulated displacement reduces for large friction coefficient and it results in less penetration. The total effect of the increasing friction coefficient depends on the competition between the increased friction force and the reduced passive soil resistance force. The pipeline usually crosses different types of soil along the route. Hence, different combinations of soil types along the route are applied in the analysis. The soil property at middle of the pipeline is found to be important when the boundary conditions at both ends are fixed. Three analyzing procedures, namely standard 3-hour procedure, the procedure recommended by PONDUS and the procedure recommended by DNV, could be used for on-bottom stability analysis under storm conditions. The comparison of these procedures shows that the procedure recommended by PONDUS is the most appropriate for the storm conditions. The procedure recommended by DNV considers the build-up of initial penetration before the storm; and it could be applied in the analysis when the penetration is stabilized after the start -up time (20% of 3-hour).
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Chee, Jayden, Alastair Walker und David White. „Effect of Lateral Pipe-Soil Interaction on Controlled Lateral Buckling Using Pre-Deformed Pipeline“. In ASME 2018 37th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/omae2018-77154.
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A novel approach to eliminate the onset of global buckling in pipelines is investigated in the paper. The method is based on pre-deforming a pipeline continuously with a specific wavelength and amplitude prior to installation on the seabed. The response of the pipeline to applied high temperature and pressure was studied in conjunction with variations in the lateral pipe-soil interaction (PSI) — both as uniform friction along the pipe and also with locally varying friction. Pipe and seabed parameters representing a typical wet-insulated infield flow line on soft clay are used. The pre-deformed pipeline has a higher buckle initiation temperature compared to a straight pipeline due to the reduced effective axial force build-up resulting from the low axial stiffness generated by the pre-deformed lobes along the pipeline. The results from this paper show that the strains in the pre-deformed pipeline are not significantly affected by the local variability of lateral PSI but rather by the global mean PSI. At a typical lateral soil resistance, i.e. a friction coefficient of 0.5, lateral buckling occurs at a very high temperature level that is not common in the subsea operation. At a very low friction, i.e. 0.1, lateral buckling occurs at a lower operating temperature but the strain is insignificant. The longitudinal strain of the pipeline is not highly sensitive to the lateral PSI, which is a quite different response to an initially straight pipeline. Therefore, this method could prove to be a valuable tool for the subsea industry as it enables the pipeline to be installed and operated safely at very high temperatures without the need for lateral buckling design and installation of expensive structures as buckle initiators. Even if the pre-deformed pipeline buckles at a very high temperature, during cycles of heat-up and cool-down the buckle shape ‘shakes down’ by geometric rearrangement to minimize the energy, and in doing so creates a series of ‘short pipelines’ in which the longitudinal strain is self-controlled. The system is therefore shown to be very robust in the conditions investigated and not affected by one of the biggest unknowns in seabed pipeline engineering, which is the local variability in lateral PSI.
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Lin, Chun-Cheng, und Yu-Chi Hsaio. „Application of Experimental Design on Small Surface Boat for Resistance and Payload Study“. In ASME 2020 39th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/omae2020-18124.
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Abstract With commercialization, marine science and military applications in offshore and shallow waters is increasing, the development of the small surface vessels are getting greater, and that design targets are focus on multi-functional platforms, smart navigation and autonomous, etc. Therefore, the goals of multi-purpose small surface vessels such as the coastal patrol, offshore observation and data collection, intelligence reconnaissance, anti-mine warfare, marine shooting training targets, and so on. In currently, to achieve these missions, the length of most small surface vessels were designed less than 10 meters. Furthermore, based on these multi-propose requirements, this study will explore the configuration design of monohull and trimaran, combine the research source of the Horizontal Circulating Water Channel (HCWC), through the ship model test to acquire experimental data. In addition, to promote the study quality and experimental efficiency, we applied Taguchi design of experimental (DOE) and the variance of analysis (ANOVA) to compare the resistance and payload of various configurations ship design. In this study, we defined two control factors (such as factor-A is Longitudinal distance, factor-B is Lateral distance) and set up three-level factorial design, and planned factorial experiment based on Taguchi orthogonal array L9 (34). Also used the neural network and training metamodeling. This metamodeling was decided by relative coefficient (R) and decision coefficient (R2). According to this metamodeling, and then, applied the genetic algorithm to search the best solution such as A2B3. The results of this study showed that the resistance performance of the trimaran is better than the monohull while the volume Froude number Fr∇ > 0.95, and the optimum configuration has greater resistance performance at both higher and lower speed fields to achieve robust design. In the other hand, this paper will also discuss the feasibility and effectiveness of the installation space and multi-function performance on platform. Hence, for payload study, we also applied ANOVA to analyze these nine different configurations, and indicated a significant main effect for factor-B. However, no significant main effect for factor-A and interaction effect were found. To conclude, this study may be of importance in explaining small surface vessel design, as well as in providing ship designer with a better understanding of trade-off about speed and payload. While this study has its limitations (such as HCWC characteristic dimension), it is hoped that it could as a basis for further study in the multi-functional small surface vessel.
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Park, Keunhan, Graham L. W. Cross, Zhuomin M. Zhang und William P. King. „Heat Transfer Between a Heated Microcantilever and the Substrate“. In ASME/JSME 2007 Thermal Engineering Heat Transfer Summer Conference collocated with the ASME 2007 InterPACK Conference. ASMEDC, 2007. http://dx.doi.org/10.1115/ht2007-32536.
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This paper describes the heat transfer from a heated microcantilever to the substrate and the resultant temperature distributions. A four-point probe platinum resistive thermometer having a 140 nm lateral resolution has been fabricated on the SiO2-coated silicon substrate. The estimated temperature coefficient of resistance (TCR) of the thermometer is 0.0011 K−1, approximately one third of the bulk value. When the heated cantilever scans over the thermometer, up to 70% of the cantilever power is transferred to the substrate through the air, heating up the substrate. The maximum substrate temperature rise measured with the thermometer is around 7 K. From the force-displacement experiment, the effective contact thermal conductance was estimated to be around 40 ± 20 nW/K. The obtained results will help further understanding of thermal behavior of the heated cantilever during the scanning and its effect on the substrate.
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Liu, Wenjun, und Mehdi Asheghi. „Thermal Conduction in Ultra-Thin Pure and Doped Single Crystal Silicon Layers at High Temperatures“. In ASME 2005 Summer Heat Transfer Conference collocated with the ASME 2005 Pacific Rim Technical Conference and Exhibition on Integration and Packaging of MEMS, NEMS, and Electronic Systems. ASMEDC, 2005. http://dx.doi.org/10.1115/ht2005-72540.
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This work presents the in-plane thermal conductivity data for pure as well as boron (1.6 × 1021 /cm3), arsenic (2.3 × 1020 /cm3) and phosphorus (2.3 × 10 20/cm3) doped silicon layers of thickness 30 and 50 nm at high temperature. The steady-state Joule heating and electrical resistance thermometry is used to measure lateral thermal conductivity of suspended silicon layers. Thermal conductivity data for pure and lightly doped single crystalline silicon layers can be interpreted using thermal conductivity integral and relaxation time approximation for phonon-boundary and phonon-impurity scattering rates. No additional fitting parameters are used in this work; in contrast with previous studies that required an unusually large phonon-impurity scattering coefficient to match the predictions to the thermal conductivity data for bulk doped silicon. This paper was also originally published as part of the Proceedings of the ASME 2005 Pacific Rim Technical Conference and Exhibition on Integration and Packaging of MEMS, NEMS, and Electronic Systems.