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Статті в журналах з теми "Paper Penetration resistance"
1
Chanyshev, A. I., and O. E. Belousova. "Medium resistance to rigid tool penetration." Interexpo GEO-Siberia 2, no. 4 (May 18, 2022): 3–12. http://dx.doi.org/10.33764/2618-981x-2022-2-4-3-12.
Повний текст джерелаАнотація:
It is proposed to evaluate the effectiveness of the tool penetrating by the medium resistance to this action - the lower the resistance, the more effective the tool. The medium resistance can be determined by using rigid-type loading devices, when the immersion rate of the tool is monitored at steady loading speed. Another method is shock loading with measuring the penetration depth and the time to reach the depth. The paper provides a solution to the problem in dynamic setting that is the medium resistance to deformation is set at a given tool mass, its initial speed of immersion, known values of penetration depth and time. Comparing the resistance of the medium for differently sharpened tools, the one that delivers the minimum resistance of the medium at penetration to a given depth is selected.
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Seo, Man Seok, Hye Jung Youn, and Hak Lae Lee. "Penetration control of surface sizing starch using cationic PAM and its effect on the bending stiffness of paper." BioResources 15, no. 3 (May 29, 2020): 5489–502. http://dx.doi.org/10.15376/biores.15.3.5489-5502.
Повний текст джерелаАнотація:
Surface sizing is employed to increase the wetting resistance against liquids and to improve strength and surface properties of paper. Starch solution is the most widely used for surface sizing, and its effect is highly dependent upon how deep the starch solution penetrates into the paper structure. Better tensile strength can be obtained when starch penetrates deep into the thickness direction of paper. However, holdout of starch solution is beneficial for improving the stiffness and air or liquid resistance. This study was focused on the use of cationic polyacrylamide (PAM) as a surface sizing additive to control the penetration of starch solutions into paper, thus improving bending stiffness of paper. The effects of the ionic property, viscosity, and charge density of PAM on starch penetration and bending stiffness of surface sized papers were investigated. The penetration of starch solution was investigated with confocal laser scanning microscopy. The enthalpy changes accompanying the mixing of cationic PAMs with oxidized starch was determined using an isothermal titration calorimeter to see the molecular level interaction between PAM and starch in mixing. The addition of cationic PAM to oxidized starch solution made starch molecules stay on the paper surface rather than penetrating into the paper structure.
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Lobo, Bianca, Fernando Schnaid, Marcelo Rocha, and John Howie. "Shear strength of granular soils from the simulation of dynamic penetration tests." Journal of Geo-Engineering Sciences 2, no. 3,4 (July 17, 2015): 143–58. http://dx.doi.org/10.3233/jgs-140028.
Повний текст джерелаАнотація:
Abstract This paper presents a model for the numerical simulation of dynamic penetration tests in cohesionless soils. In the model, dynamic penetration equations are solved by finite difference analysis in the time domain to produce the discretization of the penetration system. The approach allows essential effects of the soil influence to be accounted for, including the dynamic soil resistance by viscous damping during penetration. The model performance has proved by comparisons between the static and dynamic resistance to reproduce the variation with time of measured force, velocity, displacement and energy associated with the interaction mechanism around split-spoon samplers when penetrating in the ground. A realistic representation of the dynamic penetration mechanism allows the internal friction angle of the soil to be estimated. The proposed methodology accounts for scale effects and produces values of φ′ within the same order of magnitude as those estimated from piezocone test data.
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Pang, Jing, Xiaojun Lin, Xuwun Zhang, Jiangtao Ji, and Lingxin Geng. "Modelling and analysis of penetration resistance of probes in cultivated soils." PLOS ONE 18, no. 1 (January 17, 2023): e0280525. http://dx.doi.org/10.1371/journal.pone.0280525.
Повний текст джерелаАнотація:
At present, the measurement of tillage depth is mainly based on manual measurement, but the manual raking method results in low measurement accuracy and high labor intensity. Due to the complexity of soil, theoretical research on tillage depth is relatively scarce. In order to provide a new research direction and research idea for soil stratification, topsoil was taken as the research object of this paper. The correlation between penetration resistance and penetration depth of a probe in a cultivated soil was studied, and a mathematical model was established. There is a certain similarity between the process of spherical cavity expansion and the process of probe penetration, so we introduced the theory of spherical cavity expansion into the modeling of penetration resistance of the cultivated soil. In this paper, the spherical cavity expansion theory of unsaturated soil was used as the basis for solving the penetration resistance. And the unified strength criterion was employed as a yield condition of the soil to set a stress solution and a displacement solutionin into of the probe penetrating into the elasto-plastic zone of the cultivated soil to determine the model of expansion force. We have carried out indoor tests to revise the expansion force model. Firstly, according to the range of soil density and water content in the field, the soil densities were classified into 1.1×103kg/m3, 1.2×103kg/m3 and 1.3×103kg/m3, and the water contents were divided into 10%, 15% and 20%. In addition, the orthogonal tests were performed at different levels. The soil was put into the barrel, and the probe was inserted into the soil in the barrel at the speed of 8mm/s to determine the test values of the change of the probe penetration resistance with depth. Finally, the expansion force model was fitted with the results of the indoor test, and coefficient B was introduced to express the influence degree of density and water content on the resistance. Coefficient B was substituted into the expansion force model to obtain the penetration resistance model of the cultivated soil. Through the goodness of fit analysis of the penetration resistance model, the results show that the overall average goodness of fit of the penetration resistance modelat was up to 0.871 at different water contents and densities, which was a good fit and could present novel insights into the study relating to soil stratification theory.
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Proskuryakov, Evgeny, Mikhail Sorokin, and Aleksandr Poshekhonov. "PROBLEMS OF PENETRATION OF AN UNDEFORMABLE DRUMMER INTO AN OBSTACLE." Interexpo GEO-Siberia 9 (2019): 106–15. http://dx.doi.org/10.33764/2618-981x-2019-9-106-115.
Повний текст джерелаАнотація:
This paper presents engineering models for the penetration of undeformable drummers into obstacles: wood, concrete, steel and water. As undeformable drummers used: special sniper rifle bullet VSS, concrete artillery shell caliber of 152 mm, the warhead of a concrete-piercing unguided aviation missile S-8BM caliber of 80 mm, armor-piercing shell of 30 mm caliber, bullet of a submarine special APS submachine gun with a caliber of 5,66 mm, bullet of submachine gun special two-mediums ADS with a caliber of 5,45 mm. It is assumed that the resistance force of medium can be represented as the sum of three forces: dynamic drag forces proportional to the square of penetration rate, the velocity of the medium in proportion to the penetration rate and the strength of the static resistance of the medium, which is independent of the penetration rate. Penetration calculations of typical drummers were performed that are in satisfactory agreement with empirical formulas. The listed models are necessary for solving military-applied tasks of penetrating ammunition into obstacles.
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Zhou, Feng, Chengxin Du, Zhonghua Du, Guangfa Gao, Chun Cheng, and Xiaodong Wang. "Penetration Gain Study of a Tungsten-Fiber/Zr-Based Metallic Glass Matrix Composite." Crystals 12, no. 2 (February 18, 2022): 284. http://dx.doi.org/10.3390/cryst12020284.
Повний текст джерелаАнотація:
A tungsten fiber/Zr-based bulk metallic glass matrix composite (Wf/Zr-MG) is a potential penetrator material. To compare and analyze the penetration behavior of Wf/Zr-MG and a tungsten heavy alloy (WHA), a penetration experiment into the 30CrMnMo homogeneous armor target plate (RHA) is conducted in the present paper, by using a 37 mm smooth bore artillery with an impact velocity of 1550 ± 40 m/s. Unlike the penetrator made of WHA, the self-sharpening phenomenon was observed in the nose of the Wf/Zr-MG rod. The experimental results indicate that the penetration ability of Wf/Zr-MG rod is approximately 10% higher than that of the WHA rod when the impact velocity is 1550 ± 40 m/s. The combined findings on the microscopic morphology, composition, hardness distribution around the crater, and the macroscopic structure of the penetrator residual show that under this impact velocity, the Wf/Zr-MG material shows amorphous gasification. The Wfs outside the rod shows bending and backflow, resulting in the maintenance of the self-sharpening nose of the penetrator during the penetration process. Moreover, the hardness peak around the crater formed by the Wf/Zr-MG rod is lower, and the penetration crater is straighter, indicating that the Wf/Zr-MG rod has a stronger slag removal ability, lower penetration resistance, and higher penetration efficiency. It is an ideal penetrator material.
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Li, Yu Lei, Jin Jun Tang, Xiao Yu Jin, Qun Wang, and Zheng Ren. "Numerical Simulation of Multi-Angle Incidence Aluminum Composite Targets with 7.62mm Piercing Armor." Applied Mechanics and Materials 602-605 (August 2014): 562–65. http://dx.doi.org/10.4028/www.scientific.net/amm.602-605.562.
Повний текст джерелаАнотація:
To calculate the multi-angle penetration, this paper established a 3D finite element model of aluminum alloy plates and 7.62mm armor-piercing by using LS-DYNA software and the Johnson-Cook material model. The process of bullet penetrating 20mm thickness target with different angles of incidence was carried out. The impact of combinations on composite targets resistance projectile penetrating ability was analyzed. Simulation results show that,ballistic of composite targets can be between two aluminum target plate, clearly different combinations of composite targets for resistance to different angles of incidence between projectile penetrating relationship.
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Zheng, Jingbin, Shaoqing Zhang, Dong Wang, and Jun Jiang. "Optimization for the Assessment of Spudcan Peak Resistance in Clay–Sand–Clay Deposits." Journal of Marine Science and Engineering 9, no. 7 (June 24, 2021): 689. http://dx.doi.org/10.3390/jmse9070689.
Повний текст джерелаАнотація:
Clay–sand–clay deposits are commonly encountered in the offshore field. For spudcan installation in this soil stratigraphy, the potential for punch-through exists, with the peak penetration resistance formed within the interbedded sand layer. Therefore, a careful assessment of the penetration resistance profile has to be performed. Based on the recently proposed failure-stress-dependent model, this paper presents a modified predictive model for estimating the peak resistance. The modified model incorporates the bearing capacity depth factor and the protruded soil plug in the bottom clay layer into the formulation. It is proven that the modified predictive model provides improved deterministic estimations for the peak resistances measured in centrifuge tests. Based on the modified predictive model, a parameter optimization technique is utilized to optimize the prediction of peak resistance using penetration resistances observed beforehand. A detailed application procedure is proposed and applied to the centrifuge tests accumulated from existing publications, with further improvement on the predictions demonstrated. The proposed parameter optimization procedure combined with the modified predictive model provides an approach to perform real-time optimization for assessing spudcan peak resistance in clay–sand–clay deposits.
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Wei, Hong Yun, Yu Guo Wei, Xiu Li Zhang, Wei Feng Zhou, and Yuan Yuan Li. "Study on Influences of Slag Powder and Fly Ash on Concrete Penetration Performance." Applied Mechanics and Materials 357-360 (August 2013): 570–77. http://dx.doi.org/10.4028/www.scientific.net/amm.357-360.570.
Повний текст джерелаАнотація:
The resistance to chloride ion penetration of the concrete added with slag powder and fly ash is studied in this paper. The tests show that: adding slag powder and fly ash to concrete can improve the concrete’s resistance to chloride ion penetration; if only adding slag powder, the larger the adding content and the longer the test age, the better the concrete’s resistance to chloride ion penetration; if only adding fly ash, the longer the test age, the better the concrete’s resistance to chloride ion penetration; at the age of 28, 56 days, if the fly ash adding content is 30%, the concrete’s resistance to chloride ion penetration is optimal, while at the age of 84 days, if the fly ash adding content is 40%, the concrete’s resistance to chloride ion penetration is optimal; if adding both slag power and fly ash, the larger the adding content and the longer the test age, the better the concrete’s resistance to chloride ion penetration; if the test age and adding content remain constant, for the concrete’s resistance to chloride ion penetration, it is the best when adding both slag power and fly ash, it is good when adding only slag power, and it is poor when adding only fly ash; for the influences of the test age on the concrete’s resistance to chloride ion penetration, it is maximum when adding only fly ash, it is moderate when adding both slag powder and fly ash, and it is minimum when adding only slag power; and the larger the adding content, the greater the influences of the test age on the concrete’s resistance to chloride ion penetration.
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Khasanov, A. R. "A Dynamic expansion of a cylindrical cavity in a compressible elastic-plastic medium. The Analysis of medium resistance to dynamic penetration of a sharp-nosed impactor." PNRPU Mechanics Bulletin, no. 1 (December 15, 2020): 126–37. http://dx.doi.org/10.15593/perm.mech/2020.1.10.
Повний текст джерелаАнотація:
This paper presents the solution of the problem related to the dynamic cylindrical cavity expansion in a compressible elastic-plastic medium. Finite strains, nonlinear compressibility and dependence of the yield stress versus pressure are taken into account in the problem formulation. The study targets at developing a new engineering model on the penetration of a sharp-nosed impactor in the range of middle impact velocities based on the problem analysis results of the cylindrical cavity expansion in a half-space (cylindrical cavity expansion approximation). Based on the analytical approach a model is obtained that determines the resistance of the medium to dynamic cavity expansion. The main parameters of the model depend on the mechanical properties of the medium. For these dependences we proposed approximating relations based on manipulation of the mechanical properties of a number of materials (some alloys and soils). To derive the dynamic penetration model the A.Ya. Sagomonyan assumption of the radial expansion of the hole is used. It is assumed that particles of the medium material move in a radial direction from the surface of the impactor penetrating into the shield. Such assumption can be applied for the class of impactors in the form of slender sharp-nosed bodies of revolution. Based on the assumptions we obtained a model of the medium resistance to the dynamic penetration of a slender sharp-nosed body of revolution. The new model, in addition to the "standard" strength and inertial components, contains the "attached mass", which changes during the penetration process. The experimental validation of the new penetration model using a series of experimental studies on the penetration of various forms of impactors into aluminum alloys is considered. The influence of the “attached mass” and inertial forces of the medium resistance to the penetration is estimated. The conditions of applicability of the new model are obtained: the penetration model is applicable for estimation of the resistance of a compressible medium to penetration of a thin sharp-nosed body of revolution at impact velocities of 200-800 m/s.
Частини книг з теми "Paper Penetration resistance"
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Ahmad, Mahmood, Xiaowei Tang, Feezan Ahmad, Marijana Hadzima-Nyarko, Ahsan Nawaz, and Asim Farooq. "Elucidation of Seismic Soil Liquefaction Significant Factors." In Earthquakes - From Tectonics to Buildings. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.97278.
Повний текст джерелаАнотація:
The paper develops a framework to analyze the interactions among seismic soil liquefaction significant factors using the interpretive structural model (ISM) approach based on cone penetration test. To identify the contextual relationships among the significant factors, systematic literature review approach was used bearing in mind the selection principle. Since multiple factors influence seismic soil liquefaction, determining all factors in soil liquefaction would be extremely difficult, as even a few seismic soil liquefaction factors are not easy to deal with. This study highlighted two main characteristics of seismic soil liquefaction factors. First, the seismic soil liquefaction factors–peak ground acceleration F2 (amax), equivalent clean sand penetration resistance F5 (qc1Ncs), and thickness of soil layer F11 (Ts) influenced soil liquefaction directly and were located at level 2 (top level) in the ISM model, meaning they require additional seismic soil liquefaction factors except thickness of soil layer F11 (Ts) to collaboratively impact on soil liquefaction potential. The multilevel hierarchy reveals that depth of soil deposit F10 (Ds) is formed the base of ISM hierarchy. Secondly, Matrice d’impacts croisés multiplication appliqués à un classement (MICMAC) analysis has been employed for evaluating these identified factors in accordance with driving power and dependence power. Factors with a higher driving power should be given special consideration. Autonomous soil liquefaction factors have no reliance on other soil liquefaction factors and interfere less. In order to identify the significant factors that affect seismic soil liquefaction susceptibility, the model built in this study clearly illustrates the complex relationships between factors and demonstrates the direct and indirect relationships.
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Wang, Wangning, Taotao Li, Yuqiang Jia, Jianqiang Wei, and Zhonglong Cao. "The State-of-the-Art Review on Road Harmless Utilization Technology of Phosphogypsum." In Advances in Transdisciplinary Engineering. IOS Press, 2022. http://dx.doi.org/10.3233/atde220892.
Повний текст джерелаАнотація:
The “Guiding Opinions on the Comprehensive Utilization of Bulk Solid Waste during the 14th Five-Year Plan” issued by the Ministry of Ecology and Environment in 2021 pointed out that by 2021, China’s cumulative bulk solid waste stockpiles are about 60 billion tons, and the annual new stockpiles are nearly 3 billion. At the same time, there is a problem of low solid waste utilization rate, occupying a large amount of land resources, and a large hidden danger to the ecological environment. In order to further improve the utilization of solid waste, reduce the cost of road construction, and reduce the damage and impact of solid waste accumulation on the environment. This paper analyzes phosphogypsum impaction of the incorporation of various solid wastes on asphalt penetration, softening point, ductility and other properties, as well as the impact on the high temperature stability, low temperature crack resistance and water stability of asphalt mixtures, and the summarize and evaluate the microscopic modification mechanism and other aspects. At present, there is a relatively lack of research on the reuse of some solid wastes in asphalt in China. This review can provide reference and reference for judging a variety of solid wastes as asphalt modifiers, promote the green reuse of solid wastes, and reduce the construction of asphalt pavements.
Тези доповідей конференцій з теми "Paper Penetration resistance"
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Nili Ahmadabadi, Zahra, Frédéric Laville, and Raynald Guilbault. "An Empirical Prediction Law for Quasi-Static Nail-Particle Board Penetration Resistance." In ASME 2017 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/imece2017-70218.
Повний текст джерелаАнотація:
The present study belongs to a broader investigation aiming to reduce noise emissions in nail guns. This noise reduction objective may be achieved by nail gun concept design improvements. However, modifying the tool design requires precise understanding of it dynamics. Therefore a dynamic model of the system including accurate predictions of the tribo-dynamic interactions at the wood-nail interface generating the penetration resistance forces (PRF) appears to be essential. Since different wood products possess different structural/material properties, PRF is first evaluated for various types of wood product individually. Ref. [1] develops the PRF modeling strategy and examines the nail penetration process for plywood samples. The present paper proposes an empirical model predicting PRF imposed on nails when penetrating particle board (PB) at quasi-static velocities (20–500 mm/min range). A universal testing machine (MTS) is used to drive the nails into the wood samples. Each wood sample is composed of five panels PB screwed together. The sample size is chosen to reduce the boundary influence on the penetration process and to avoid the complete perforation of the sample. To eliminate the possible acceleration influence, the penetration speed is maintained at constant amplitudes. The MTS machine measured PRF as a function of the position. The objective is to prepare a formulation predicting PRF as a function of nail position. In order to extend the prediction formula application range, the analysis reduces the studied factors to dimensionless parameters. The analysis shows that the PB fabrication process results in panels presenting three regions of different hardness modulus. As a result, at the region transitions the PRF curves show large amplitude fluctuations. This layered heterogeneity makes the development of a high precision prediction model representing various nail sizes very difficult. Nevertheless, the final model produces PRF evaluations with overall precision greater than 88% for most of the nail penetration.
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Walters, William P., and Cyril L. Williams. "The Influence of Armor Material Parameters on the Penetration by Long-Rod Projectiles." In ASME 2006 Pressure Vessels and Piping/ICPVT-11 Conference. ASMEDC, 2006. http://dx.doi.org/10.1115/pvp2006-icpvt-11-93716.
Повний текст джерелаАнотація:
The Alekseevski-Tate equations have long been used to predict the penetration, penetration velocity, rod velocity, and rod erosion of long-rod projectiles or kinetic-energy penetrators [1]. These nonlinear equations were originally solved numerically, then by the exact analytical solution of Walters and Segletes [2, 3]. However, due to the nonlinear nature of the equations, the penetration was obtained implicitly as a function of time, so that an explicit functional dependence of the penetration on material properties was not obtained. Walters and Williams [4, 5, 6] obtained the velocities, length, and penetration as an explicit function of time by employing a perturbation solution of the non-dimensional Alekseevski-Tate equations. Algebraic equations were obtained for a third-order perturbation solution which showed excellent agreement with the exact solution of the Tate equations for tungsten heavy alloy rods penetrating a semi-infinite armor plate. The current paper employs this model to rapidly assess the effect of increasing the impact velocity of the penetrator and increasing the armor material properties (density and target resistance) on penetration. This study is applicable to the design of hardened targets.
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Rochaeni, Henny, Candra Irawan, Mira Nurfitri, Poppy Sri Lestari, and Unang Rosdianan. "The Influence and The Analysis Of Alkyl Ketene Dimers (AKD) to Paper Resistance in Water Absorption and Chemical Solution Penetration." In Proceedings of the International Conference on Science and Technology (ICST 2018). Paris, France: Atlantis Press, 2018. http://dx.doi.org/10.2991/icst-18.2018.63.
Повний текст джерела
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Gao, Wen, Tom Harrup, Yuxia Hu, and David White. "Effect of a Strong Middle Layer on Spudcan Penetration." In ASME 2014 33rd International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/omae2014-23925.
Повний текст джерелаАнотація:
The rapid penetration of one or more of the foundations of a mobile jack-up rig into the seabed is an ongoing major problem in the offshore industry, with the potential to cause major damage to the structure and endangering any personnel on board. A recent example is the jack-up drilling rig Perro Negro 6 incident happened near the mouth of the Congo river in July 2013 with one of the rig’s crew of 103 reported missing and six others injured. This uncontrollable displacement is due to a form of failure known as punch through failure and commonly occurs on stratified seabed profiles. It has been reported that unexpected punch-through accidents have resulted in both rig damage and lost drilling time at a rate of 1 incident per annum with consequential costs estimated at between US$1 and US$10 million [1]. This paper presents the bearing capacity profiles and associated soil flow mechanisms of a common spudcan foundation penetrating into a three layer soft-stiff-soft clay soil through the use of large deformation finite element (LDFE) analysis. The Remeshing and Interpolation with Small Strain (RITSS) [2, 3] technique was implemented in the software package AFENA [4] to conduct the LDFE analysis. Both soil layer thickness and soil layer strength ratios were varied to study their effect on the spudcan penetration responses. The LDFE results of spudcan penetration into the soft-stiff-soft clay soils were calibrated by existing centrifuge test data. A parametric study was then conducted to study the bearing capacity responses and soil flow mechanisms during spudcan large penetrations by varying the soil layer strength ratio and relative layer thickness to the diameter of spudcan. It was found that there were three types of bearing responses during continuous penetration of spudcan: (a) when the top soft layer is relatively thin, the spudcan bearing response was similar to that of two layer soils with stiff over soft clays; (b) when the top soil layer thickness is medium, a peak resistance is observed when spudcan penetrates into the middle stiff layer followed by reduction; (c) when the soil layer is thick, the peak resistance occurs when spudcan gets into the bottom soft soil layer. The critical thickness of top soil layer is a function of soil strength ratio and middle stiff soil layer thickness. The bearing response types were also corresponding to the soil cavity formations during spudcan initial penetration.
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Xiao, Zhong, Teng Ma, Haixiao Liu, Wei Zhang, and Muhammad Akbar Rafique. "Numerical Investigate of Penetration Resistance of Bucket Foundation With Internal Cylindrical and Cruciform Skirts." In ASME 2020 39th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/omae2020-18332.
Повний текст джерелаАнотація:
Abstract Bucket foundation has broad application prospects in marine engineering as a competitive foundation. By providing internal cylindrical and cruciform skirts inside the bucket foundation,. the performance of the bucket foundation can be improved . But penetration resistance will also increase. However, few large deformation numerical analysis is carried out to simulate the penetration process of the bucket foundation with internal skirts. In this paper, three-dimensional large deformation finite element (LDFE) models for bucket foundations with and without internal cylindrical and cruciform skirts considering strain softening effect of soft soil were established using the coupled Eulerian-Lagrangian (CEL) approach. It was found that the elevation of the soil surface inside the bucket is higher than that of initial soil surface when the penetration depth ratio is relatively small for the bucket foundation with internal cylindrical and cruciform skirts. However, with increase of the penetration depth ratio, the increased frictions on the cylindrical and cruciform skirts drive the soil inside the inner cylinder downward, and the elevation of the soil surface inside the inner cylinder is lower than that of initial soil surface. It is also lower than that of soil surface between outer and inner cylinders. The average lateral friction per unit area on each skirt decreases from outer to inner skirt. The soil flow can explain well for the evolution of the penetration resistance.
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Ma, Hongliang, Mi Zhou, Yuxia Hu, and Muhammad Shazzad Hossain. "Large Deformation FE Analyses of Cone Penetration in Single Layer Non-Homogeneous and Three-Layer Soft-Stiff-Soft Clays." In ASME 2014 33rd International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/omae2014-23709.
Повний текст джерелаАнотація:
Continuous profiles from in-situ penetrometer tests are now identified as essential for site specific soil investigation as part of designing offshore structures in deep and ultradeep waters and in highly layered seabed conditions. This paper describes the results from large deformation FE (LDFE) analysis undertaken to provide insight into the behavior of cone penetrometer penetrating through single layer non-homogeneous clays and three-layer uniform soft-stiff-soft clays. For the smooth cone penetration in non-homogeneous clays, the soil strength non-homogeneity factor was shown to have insignificant effect on the cone bearing capacity factor. However, for the rough cone, the bearing capacity factor in non-homogeneous clay was about 10∼12% lower than that in uniform clay. Bearing capacity factors for smooth and rough cones were also similar for non-homogeneous clay. For cone penetration in stratified soft-stiff-soft clays, a minimum layer thickness of 20 diameters was required to mobilise the full resistance of the stiff layer. The corresponding soil flow mechanisms are also discussed linking directly to the profile of penetration resistance.
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Xie, Qiang, Yuxia Hu, Mark Cassidy, and Alireza Salehi. "Cone Penetration Test in Stiff Over Soft Clay in Centrifuge Test." In ASME 2019 38th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/omae2019-96698.
Повний текст джерелаАнотація:
Abstract This paper describes a numerical study on soil characterization of stiff over soft clays in centrifuge test using cone penetration test (CPT), especially when the top stiff layer is thin relative to the centrifuge cone size. An extensive parametric study was conducted using large deformation finite element (LDFE) analysis, with the cone penetrating continuously from the soil surface. The LDFE model has been validated against existing physical test data with very good agreement. Since the bottom soft clay was normally thick enough to fully mobilise the ultimate cone resistance, its undrained shear strength can be interpreted by the existing approach for cone deep penetration in a uniform clay layer. Thus, the challenge was to interpret the strength of the top stiff layer, where the layer thickness was not thick enough to fully mobilise its ultimate resistance. Both top layer thickness ratios (to the cone diameter) and layer strength ratios were considered in the parametric study. Based on the results from LDFE analyses, the interpretation formula of the undrained shear strength in the top stiff layer was proposed as a set of new bearing factors. The proposed cone bearing factor was a function of the ratio of the measured peak cone resistance in the top layer to the stable/ultimate cone resistance in the bottom layer and the ratio between the top layer thickness to the cone diameter. The formula can be used directly when the top layer thickness was known based on the sample preparation. However, the layer interface can be identified based on the study here, if the top layer thickness was not certain. A design flow chart was provided for interpretations of top clay layer strength and top layer thickness based on the cone resistance profile obtained from CPT test.
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Mahmoodzadeh, Hamed, Noel Boylan, Mark Randolph, and Mark Cassidy. "The Effect of Partial Drainage on Measurements by a Piezoball Penetrometer." In ASME 2011 30th International Conference on Ocean, Offshore and Arctic Engineering. ASMEDC, 2011. http://dx.doi.org/10.1115/omae2011-50245.
Повний текст джерелаАнотація:
Full-flow penetrometers such as the T-bar and ball are now widely used in offshore site investigations to measure penetration resistance and then infer the strength properties of the seabed. To provide additional data on flow properties of the soil and increase the number of parameters that can be obtained from these tests, ball penetrometers fitted with pore pressure transducers, known as piezoballs, are now being used. Depending on the soil characteristics and rate of penetration, the soil conditions during penetration may vary from undrained to fully drained. The drainage condition during penetration will influence both the measured penetration resistance and excess pore pressure response and therefore influence any parameters interpreted. This paper examines the effect of drainage condition on piezoball measurements during penetration in a muddy silt sample collected from offshore Australia. Tests were conducted in the beam centrifuge at the University of Western Australia using a miniature piezoball, with pore pressure measurement at the equator position. The effect of drainage condition was examined by conducting tests at various rates of penetration, ranging from undrained to fully drained conditions. Methods of interpreting the results of a partially drained penetration test in order to deduce the undrained penetration resistance are also discussed.
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Li, Yu Ping, Fook Hou Lee, Siang Huat Goh, Jiang Tao Yi, and Xi Ying Zhang. "Centrifuge Study of the Effects of Lattice Leg on Penetration Resistance and Bearing Behavior of Spudcan Foundations in NC Clay." In ASME 2012 31st International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/omae2012-83137.
Повний текст джерелаАнотація:
This paper reports the primary results of a centrifuge model study into the possible effects of the lattice leg on the penetration resistance and vertical bearing capacity of spudcan foundations in normally consolidated clay. Up to now, the possible effects of the lattice leg has been largely ignored in both research and design of spudcan foundation. Centrifuge experimental results show that there is an increase in penetration resistance for spudcan footing equipped with lattice leg, in comparison with spudcan footing connected to slender circular column leg as widely used by current research. Larger excess pore water pressure was generated by the spudcan penetration with lattice leg in compare with that without. Moreover, the presence of the lattice leg is shown to affect the cavity depth formed around the penetrated spudcan footing, which is simply assumed completely back flow for spudcan penetration in soft clay by SNAME (2008). It was found that the bearing capacity of spudcan foundation has been further underestimated by SNAME (2008) due to the neglecting of lattice leg effect. Taken altogether, this implies that changes in penetration resistance arising from the lattice leg may be due to the effect of the latter on the backflow pattern. Apart from highlighting the effect of the sleeve with big openings, the results also highlight the possible future use of sleeves to enhance the bearing capacity and possibly reduce the penetration of spudcan foundations in various soil deposits.
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Wilden, J., V. E. Drescher, and O. Lehmann. "Coating of Aluminum Components with Iron-Based Nanocrystalline Solidifying Materials to Improve Wear Resistance." In ITSC2010, edited by B. R. Marple, A. Agarwal, M. M. Hyland, Y. C. Lau, C. J. Li, R. S. Lima, and G. Montavon. DVS Media GmbH, 2010. http://dx.doi.org/10.31399/asm.cp.itsc2010p0358.
Повний текст джерелаАнотація:
Abstract Conventional processes of gas shielded metal arc welding (GMAW) do not offer directly the possibility for cladding heat sensitive materials such as aluminum with iron-based materials due to intermetallic Al/Fe phases form. This paper deals with the first evaluated cladding results of aluminum components with iron-based nanocrystalline solidifying materials by controlled shielded metal arc welding processes to improve wear resistance. In the present work, the design of experiments and data evaluations are systematically applied to get the first results about the dependence between controlled arc welding process parameters and the iron-based coatings of aluminum substrate. In particular, the effect of the chosen parameters such as wire feed speed, welding speed, frequency and further factors on the heat input, welding penetration, micro hardness, rate of welding penetration and width of intermetallic phases in the interface zone are investigated. Optical and scanning electron spectroscopy provide input for further statistical evaluation. The experiments were carried out using various controlled arc technologies which offer different control over the heat input to the substrates. Different power supplies were used.