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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.
2
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.
3
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.
4
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.
5
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.
6
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.
7
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.
8
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.
9
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.
10
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.
11
Victor, OSYKA, KOMAKHA Olha, and KOMAKHA Volodymyr. "PAPER PACKAGING MATERIALS: RESISTANCE TO DESTRUCTIVE FACTORS." INTERNATIONAL SCIENTIFIC-PRACTICAL JOURNAL "COMMODITIES AND MARKETS" 39, no. 3 (September 20, 2021): 75–85. http://dx.doi.org/10.31617/tr.knute.2021(39)05.
Повний текст джерелаАнотація:
Background. The dynamics of change of the complex of barrier and strength properties of moisture-resistant waterproof and moisture-resistant grease-proof paper packaging materials under the influence of temperature, humidity and mechanical factors is considered. The results of tests of the developed samples of paper packaging materials during exposure in the chamber of heat and moisture aging are given. Materials and methods. Paper packaging materials of grades B-55 and ZhV-55 were obtained by surface treatment with compositions using polyamideaminepichlorohydrin, polyvinyl alcohol, urea and glycerin.To test for heat resistance and moisture resistance, the PPM samples were placed in a temperature-humidity aging chamber and kept for 900 days at a given temperature (–18, –1, +6, +18, + 25 °C) and relative humidity (45, 65, 85 %), periodically (every 180 days) determining the change in their mechanical strength and barrier properties. The resistance of barrier properties to the effects of repetitive mechanical loads was determined by measuring the corresponding index at the site of multiple double bends. Results. During 360 days of exposure, the test samples practically do not lose resistance to the penetration of water (B-55) and fat (ZhV-55). After this exposure period, there is an intensification of degradation processes, which is more pronounced at temperatures below 0 °C. The maximum decrease (32 %) of fat permeability was recorded at a temperature of –18 °C after 900 days of exposure, while at temperatures above 0 °C, at this exposure, it is not more than 4 %. The strength of the packaging paper at temperatures of –1 °C and –18 °C during the test period in waterproof materials decreased by 6 % and 12 %, and in greaseproof – 19 % and 29 %, respectively. The higher loss of strength of fat-impermeable PPM is due to the nature of the main component of the hydrooleophobic composition – PVA, which has a higher brittleness temperature compared to PAAEX in the hydrophobic composition. After 150 cycles of alternating freezing and defrosting of the samples, the destructive force of the greaseproof material ZhV-55 is reduced to 57.5 N, and the waterproof B-55 – to 63 N. The destructive force for 30 repeated cycles of temperature change is 70.9 N and 67.3 N, in comparison with the initial values of 72.4 and 71.8 N for waterproof (B-55) and greaseproof (ZhV-55) wrapping paper, respectively. With 50 repeated double bends, which is close to the real conditions of use of packaging paper for its intended purpose, the water permeability of the sample B-55 is reduced by 8 %, and the fat permeability of the sample ZhV-55 – by 3 %. Conclusion. The established dependences allow us to state that the main factors determining the barrier and strength properties of the developed materials are: physicochemical nature of the main components of hydrophobic and hydrooleophobic compositions, which determines the nature of their interaction with cellulose fiber; resistance of the structure of the material to the penetration of moisture and fat, as well as its ability to withstand various mechanical loads.
12
Verley, R. L. P., and T. Sotberg. "A Soil Resistance Model for Pipelines Placed on Sandy Soils." Journal of Offshore Mechanics and Arctic Engineering 116, no. 3 (August 1, 1994): 145–53. http://dx.doi.org/10.1115/1.2920143.
Повний текст джерелаАнотація:
This paper presents a pipe-soil interaction model for sand soils capable of predicting the development of pipe penetration into the soil and the associated soil resistance that may be mobilized against horizontal pipe motions. The model is based on dimensional analysis and development of appropriate empirical equations which are fitted to large-scale laboratory data from several sources. The development of penetration is described by considering the work done by the pipe on the soil. For a given penetration, the force-displacement curve is described. The model has been used to predict time histories of penetration and horizontal pipe displacement from large-scale laboratory tests where pipe sections were subjected to forces representative of those from irregular waves and currents. A good reproduction of the time development of both penetration and displacement is given over the whole range of relevant hydrodynamic and soil parameters.
13
He, Zhi Min, and Jun Zhe Liu. "Chloride Ions Penetration Resistance of New-Old Concrete." Advanced Materials Research 366 (October 2011): 518–21. http://dx.doi.org/10.4028/www.scientific.net/amr.366.518.
Повний текст джерелаАнотація:
By use of ASTM C1202, this paper studied the influence of mineral admixtures on the chloride ions penetration resistance of the new-old concrete compound system. The results indicate that the performance of new-old concrete exert significant influence on the new-old concrete compound system. The addition of mineral admixtures improve the permeability properties of new-old concrete. Adding fly ash(FA) require a relatively longer time to get its beneficial effect. When 30% weight of cement is replaced by 10% FA and 20% ground blast furnace slag(GGBFS), the inclusion of 30% mineral admixtures significantly improve the chloride ions penetration resistance properties of the new-old concrete compound system at 28 days and 180 days.
14
Šulc, Rostislav, Michal Himmel, and Jiří Němeček. "Chloride Resistance of Nanoparticle Repaired Concrete Measured by Accelerated Tests." Key Engineering Materials 760 (January 2018): 91–95. http://dx.doi.org/10.4028/www.scientific.net/kem.760.91.
Повний текст джерелаАнотація:
This paper describes results of experimental investigation of chloride ion penetration in concrete. Chloride concentration have been studied in accelerated conditions. Part of concrete samples were treated with colloidal nanosilica solution to increase their resistance to further chloride penetration. Measurement of chloride profiles was performed and compared on samples subjected to accelerated electrical migration tests lasting for a few days. The chloride ion profile in samples was determined in layers of 5 mm thickness up to a total profile thickness of 45 mm. The developed chloride concentrations reached values found after several years of exposure in natural conditions. It was found that the resistance to chloride penetration is substantially improved by nanosilica injection and the resistance to chloride penetration is increased by 60%.
15
McCallum, Adrian. "Cone penetration testing (CPT) in Antarctic firn: an introduction to interpretation." Journal of Glaciology 60, no. 219 (2014): 83–93. http://dx.doi.org/10.3189/2014jog12j214.
Повний текст джерелаАнотація:
AbstractCommercial cone penetration testing (CPT) equipment was adapted to allow penetrative testing in hard polar firn to depths of 10 m. The apparatus is hydraulically driven, rate-controllable and able to penetrate firn with a resistance of 10 MPa. It can be mounted on many types of typical polar vehicles, requiring connection to only hydraulics and 12 V electricity. Data recorded include both cone tip resistance and sleeve friction, a parameter not previously examined through such testing. This paper describes the development and calibration of the equipment and examines factors including snow density, penetration rate and cone size and shape that are shown to affect CPT interpretation. CPT can be used efficiently in polar environments to potentially provide estimates of physical parameters in hard firn to substantial depth.
16
Šulc, Rostislav, Michal Himmel, and Jiří Němeček. "CHLORIDE RESISTANCE OF NANO-PARTICLE REPAIRED CONCRETE." Acta Polytechnica CTU Proceedings 22 (July 25, 2019): 107–12. http://dx.doi.org/10.14311/app.2019.22.0107.
Повний текст джерелаАнотація:
This paper describes the results of the experimentally modeled chloride ion penetration into different quality concrete structures with fully developed carbonation. Parts of concrete samples were further treated, to increase the resistance of concrete to chloride ion penetration, with a colloidal solution of Nano-silica or solution of Sodium Methyl Siliconate. Measurement of chloride profiles was performed on samples subjected to free diffusion of Cl− ions and on samples subjected to accelerated tests. The chloride ion profile in the samples was determined in layers of 5mm thickness up to a total of 45 mm.
17
Grujicic, Mica, S. Ramaswami, Jennifer Snipes, Vasudeva Avuthu, Chian-Fong Yen, and Bryan Cheeseman. "Application of the materials-by-design approach to armor-grade polymer-matrix composites for enhancement of ballistic-penetration resistance." International Journal of Structural Integrity 7, no. 1 (February 1, 2016): 142–74. http://dx.doi.org/10.1108/ijsi-02-2015-0005.
Повний текст джерелаАнотація:
Purpose – Fiber-reinforced armor-grade polymer-matrix composite materials with a superior penetration resistance are traditionally developed using legacy knowledge and trial-and-error empiricism. This approach is generally quite costly and time-consuming and, hence, new (faster and more economical) approaches are needed for the development of high-performance armor-grade composite materials. One of these new approaches is the so-called materials-by-design approach. Within this approach, extensive use is made of the computer-aided engineering (CAE) analyses and of the empirically/theoretically established functional relationships between an armor-grade composite-protected structure, the properties of the composite materials, material microstructure (as characterized at different length-scales) and the material/structure synthesis and fabrication processes. The paper aims to discuss these issues. Design/methodology/approach – In the present work, a first step is made toward applying the materials-by-design approach to the development of the armor-grade composite materials and protective structures with superior ballistic-penetration resistance. Specifically, CAE analyses are utilized to establish functional relationships between the attributes/properties of the composite material and the penetration resistance of the associated protective structure, and to identify the combination of these properties which maximize the penetration resistance. In a follow-up paper, the materials-by-design approach will be extended to answer the questions such as what microstructural features the material must possess in order for the penetration resistance to be maximized and how such materials should be synthesized/processed. Findings – The results obtained show that proper adjustment of the material properties results in significant improvements in the protective structure penetration resistance. Originality/value – To the authors’ knowledge, the present work is the first reported attempt to apply the materials-by-design approach to armor-grade composite materials in order to help improve their ballistic-penetration resistance.
18
Yan, Xiao Peng, Nian Mei Zhang, Wei Min Liang, Yong Gang Zhao, and Gui Tong Yang. "Mechanical Behaviours of Open-Cell and Closed-Cell Aluminium Foams against Spherical-Nosed Projectile Penetration." Applied Mechanics and Materials 29-32 (August 2010): 321–25. http://dx.doi.org/10.4028/www.scientific.net/amm.29-32.321.
Повний текст джерелаАнотація:
In this paper, the mechanical behaviours of open-cell and closed-cell aluminium foams against spherical-nosed projectile penetration are studied theoretically. An analytical model based on dynamic cavity expansion theory and previous experiment data is presented. The analytical equations are derived for the penetration resistance and the final penetration depth during the whole penetrating process. The effects of the mass density of target material, the geometry and initial velocity of the projectiles on the final penetration depth are investigated in detail. It is shown that the final penetration depth mostly lie on the density of aluminium foams and the kinetic energy of projectile. When the density of target is smaller, the final penetration depth of projectile in the closed-cell aluminium foams target is obviously smaller than that in the open-cell aluminium foams target. Meanwhile, with the increase of density of target and the decrease of initial impact velocity, the difference of the capacity of absorbing energy between open-cell and closed-cell aluminium foams targets becomes gradually narrow.
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Li, Yun Feng, Xiao Peng Fan, Lei Wen Gao, and Ying Tao Li. "Penetration Resistance to Chloride Ions of Silica Fume Concrete." Applied Mechanics and Materials 584-586 (July 2014): 1519–22. http://dx.doi.org/10.4028/www.scientific.net/amm.584-586.1519.
Повний текст джерелаАнотація:
The penetration resistance to chloride ions of concrete is one of the important factors affecting the durability of concrete structures. The penetration resistance to chloride ions of concrete is measured with the increasing substitution amount of silica fume in this paper. For the low water-binder ratio of 0.28, 0.30 and 0.32, compared with the reference concrete, with the increase of age, the penetration resistance to chloride ions of concrete can be enhanced with the increasing substitution amount of silica fume, but the increased range is smaller. The penetration resistance of chloride ions of concrete is not necessarily improved by gradually decreasing the water-binder ratio. Considering the substitution amount of silica fume, water-binder ratio and concrete age, the best mix proportions are that the substitution amount of silica fume is 9% or 12% when the water-binder ratio is 0.28 and the substitution amount of silica fume is 12% when the water-binder ratio is 0.30.
20
Salgado, Rodrigo, and Monica Prezzi. "Penetration Rate Effects on Cone Resistance: Insights From Calibration Chamber and Field Testing." Soils and Rocks 37, no. 3 (September 1, 2014): 233–42. http://dx.doi.org/10.28927/sr.373233.
Повний текст джерелаАнотація:
Cone penetration in mixed or intermediate soils (soils containing mixtures of sand, silt and clay) is neither fully drained nor fully undrained at the standard cone penetration rate of 20 mm/s. Considerable research, mainly relying on centrifuge tests, has been undertaken to quantify the effects of penetration rate (and thus partial drainage) on cone resistance. In this paper, the effects of penetration rate on cone resistance in saturated clayey soils were investigated by performing field tests and miniature cone penetration tests in a calibration chamber. The field tests were performed at sites especially selected to span the range of drainage conditions from fully drained to fully undrained. The calibration chamber tests, using both conical and flat-tip penetrometers, were performed at different penetration rates in two specimens prepared by mixing kaolin clay and sand with different mixing ratios and one-dimensionally consolidateding the mixtures. A correlation between cone resistance and drainage conditions is established based on the cone penetration test results. The transitions from no drainage to partial drainage and from partial drainage to full drainage are defined as a function of penetration rate normalized with respect to the penetrometer diameter and the coefficient of consolidation.
21
Huang, He, Duo Zhang, and Lirong Cheng. "Modelling and Simulation on Penetration into Stone Concrete." Advances in Materials Science and Engineering 2021 (August 2, 2021): 1–14. http://dx.doi.org/10.1155/2021/2288821.
Повний текст джерелаАнотація:
Penetration into stone concrete is an important research area of concrete penetration, and related experiments and simulation tests have been carried out. However, complete theories have not been formed yet. This paper develops a differential facet resistance model for penetration into stone concrete target. Firstly, the plastic damage model is used to analyze the penetration of concrete target, and the reliability of the numerical model is verified by comparing with the classical experimental results. Besides, the numerical model of stone concrete is established based on 3D Voronoi diagram according to the random characteristics of the shape and spatial distribution of stones in concrete. Then, simulation tests are carried out with the validated numerical model, a differential facet resistance model suitable for the penetration of stone concrete target is then proposed referring to the resistance formula of Forrestal and Rosenberg. At last, a method for fast calculation of penetration into stone concrete is introduced.
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Cui, Jie, Xin Chen, Ali Tian, Renchuan Ye, Yanxi Qiao, and Dongqin Miu. "Investigation of the penetration resistance of monolithic and double-layered steel plates." International Journal of Modern Physics B 33, no. 01n03 (January 30, 2019): 1940005. http://dx.doi.org/10.1142/s0217979219400058.
Повний текст джерелаАнотація:
To analyze the influence of penetration resistance for different steel plate configurations, different steel plates impacted by various projectiles were studied using the LS-DYNA code. The calculation results obtained using the LS-DYNA code and prior experimental results reported in the literature agree well with the damaged image of projectiles penetrating steel plates and the initial residual velocity curve of the projectile. The Q235 steel constitutive model is modified based on the Johnson–Cook model. It can be concluded that the LS-DYNA code analysis is reliable when compared with the experimental results. We then used the LS-DYNA code to conduct an extensive study into the penetration resistance of monolithic, contact-type double-layered and gap-type double-layered targets with the same surface density, impacted by different projectiles. The failure mode of the steel plate, initial residual velocity, ballistic limit velocity, energy absorption and plastic deformation of the monolithic and double-layered plates were studied. The results in this paper can provide guidance for the design and application of structural protection using steel plates.
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Wang, Teng, Xiao Mei Wan, Qi Yu, Zhong Tao Sun, and Xiao Han. "Investigation on Electrical Resistance of Chloride Penetration of Alkali Activated Slag Concrete." Materials Science Forum 1036 (June 29, 2021): 378–85. http://dx.doi.org/10.4028/www.scientific.net/msf.1036.378.
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Alternating-current method for measuring chloride penetration resistance of concrete, test method for coulomb electric flux and rapid chloride migration coefficient (RCM) were applied to evaluate the resistance of chloride penetration in alkali-activated slag concrete in this paper. At the same time, the applicability of the above three electrical parameters test methods to the alkali slag concrete was discussed. The results show that NaOH activated slag concrete behaves higher resistance to chloride penetration than water glass activated slag concrete. Blend of fly ash increases the porosity of alkali-activated slag concrete and weakens the resistance of chloride penetration. Correlation coefficient between chloride migration coefficient and AC electrical resistivity is 0.99. There are good correlations among the evaluation results of three electrical parameters test methods, and all of them behave sound applicability to alkali-activated slag concrete.
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Xu, Xu, Fu You Zhang, and Ming Gu. "A Soil Stratifying Method Based on Piezocone Penetration Test." Applied Mechanics and Materials 353-356 (August 2013): 1031–34. http://dx.doi.org/10.4028/www.scientific.net/amm.353-356.1031.
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This paper introduces the empirical method of classifying soil layers with CPTU. Pore pressure dissipation test was taken in a certain soft clay field, according to the characteristics of penetration curve and the value of static point resistance, frictional resistance, friction-resistance ratio, soil horizon was divided. According to the characteristics of the pore pressure dissipation test curve of different depth, weak interlayers was further surveyed.
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Lovichová, Romana, Michal Mára, and Jindřich Fornůsek. "Effect of Placement Method on Projectile Impact Resistance of UHPFRC." Key Engineering Materials 722 (December 2016): 316–21. http://dx.doi.org/10.4028/www.scientific.net/kem.722.316.
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This paper presents the results of an experimental investigation of the impact resistance of UHPFRC slabs. The influence of horizontal and vertical casting of thin slabs against penetration by a projectile is described. The resistance of penetration by a projectile was investigated using projectile with lead core. The results indicate different penetration depths and crater diameters in the target specimens for both kind of casting. Which points on a different arrangement of fibers for horizontal and vertical casting slabs. However, the protective ability is guaranteed in both placement method. Based on the present findings the slabs from ultra-high performance fiber-reinforced concrete casted vertically appear to be most efficient in protection against projectile impact.
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Krasinski, Adam. "The Analysis of Soil Resistance During Screw Displacement Pile Installation." Studia Geotechnica et Mechanica 36, no. 3 (February 28, 2015): 49–56. http://dx.doi.org/10.2478/sgem-2014-0026.
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Abstract The application of screw displacement piles (SDP) is still increasing due to their high efficiency and many advantages. However, one technological problem is a serious disadvantage of those piles. It relates to the generation of very high soil resistance during screw auger penetration, especially when piles are installed in non-cohesive soils. In many situations this problem causes difficulties in creating piles of designed length and diameter. It is necessary to find a proper method for prediction of soil resistance during screw pile installation. The analysis of screw resistances based on model and field tests is presented in the paper. The investigations were carried out as part of research project, financed by the Polish Ministry of Science and Higher Education. As a result of tests and analyses the empirical method for prediction of rotation resistance (torque) during screw auger penetration in non-cohesive subsoil based on CPT is proposed.
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Burg, Patrik, Pavel Zemánek, Jan Turan, and Pavol Findura. "The penetration resistance as a soil degradation indicator in the viticulture." Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis 60, no. 8 (2012): 29–36. http://dx.doi.org/10.11118/actaun201260080029.
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This paper deals with monitoring of changes in soil compaction at two experimental sites (Lednice and Valtice) in the alleyway of vineyards. The experimental measurements were carried out during the period 2009–2011. Penetration resistance of the soil was measured using the penetrometer (type PN 10) to a depth up to 520 mm. The measurements were carried out alternatively in variants with grassed and cultivated alleyways of vineyards. The samples were performed in the wheeltracks and in the middle of an alleyway. The control samples were performed between the plants in the row. The results show that the penetration resistance reaches lower values on the grassed alleyway. At both variants is obvious increase of the penetration resistance above the critical value already in a depth of 0.2 m. From the annual comparison of the penetration resistance it is clear the higher increase in the third year.
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Zhang, Shuang, Hai Jun Wu, Zheng Jun Tan, and Feng Lei Huang. "Theoretical Analysis of Dynamic Spherical Cavity Expansion in Reinforced Concretes." Key Engineering Materials 715 (September 2016): 222–27. http://dx.doi.org/10.4028/www.scientific.net/kem.715.222.
Повний текст джерелаАнотація:
This paper aims to establish a model that considers the penetration resistance caused by the constraint effects of steel reinforcements on concrete. Firstly, based on the experiment phenomena that reinforcements increase the toughness and tensile strength of concretes, the fitting relational expression between toughness of reinforced concrete and ratio of reinforcement was used to improve the Griffith yield criterion for reinforced concrete. Then, the dynamic spherical cavity expansion analysis was developed using the improved Griffith yield criterion as constitutive model and the dilation equation as equation of state, and the response regions were consisted of six distinct zones: cavity, compaction zone, dilation zone, radially cracked zone, elastic zone and undisturbed zone. This dynamic analysis considered the compression and dilation of concretes at the same time and was applicable to the penetration problem of reinforced concrete target. At last, based on the theoretical model of this paper, the experiments of projectiles with different weights penetrating into reinforced concrete targets with different reinforcement ratios were calculated using penetration analysis method of rigid projectiles. The comparison results showed that the theoretical analysis model of this paper can be used to predict the depth of penetration and other physical parameters such as velocity and deceleration with certain rationality.
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Vojtisek, J., E. Bystrianska, O. Koutny, J. Kratochvil, and M. Drdlova. "Determination of ballistic resistance of cementitious composites." IOP Conference Series: Materials Science and Engineering 1205, no. 1 (November 1, 2021): 012013. http://dx.doi.org/10.1088/1757-899x/1205/1/012013.
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Abstract The paper describes the possibility of using the DOP test, standardly used to evaluate the ballistic resistance of ceramics, to determine the ballistic resistance of cement composites. DOP - Depth of penetration test - is based on measurement of residual penetration of projectile in witness system after the sample perforation; this parameter is used to determine differential efficiency factor (DEF), characterizing the ballistic resistance of the particular material. To verify the method for non-ceramic materials, four variants of cementitious composites with compressive strengths in the range of 30–150 MPa have been tested. The obtained results confirm the method’s suitability for determining the ballistic resistance of cement composites in terms of ease of implementation, sensitivity, and accuracy of the obtained results for both composites of common strengths and high-performance variants. The paper also discusses some aspects of the relationship between the mechanical parameters of cement composites under static loading and their ballistic resistance.
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Barrett, John W., and Luke J. Prendergast. "Empirical Shaft Resistance of Driven Piles Penetrating Weak Rock." Rock Mechanics and Rock Engineering 53, no. 12 (August 20, 2020): 5531–43. http://dx.doi.org/10.1007/s00603-020-02228-7.
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AbstractIn this paper, an empirical relationship between the Unconfined Compressive Strength (UCS) of intact rock and the unit shaft resistance of piles penetrating rock is investigated. A growing number of civil engineering projects are utilizing steel piles driven into rock where a significant portion of the pile capacity is derived from the shaft resistance. Despite the growing number of projects utilizing the technology, little to no guidance is offered in the literature as to how the shaft resistance is to be calculated for such piles. A database has been created for driven piles that penetrate bedrock. The database consists of 42 pile load tests of which a majority are steel H-piles. The friction fatigue model is applied to seven of the pile load tests for which sufficient UCS data exists in order to develop an empirical relation. The focus of this paper is on case histories that include driven pipe piles with at least 2 m penetration into rock.
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de Backer, Hans, Amelie Outtier, and Philippe van Bogaert. "Weld Penetration in Orthotropic Steel Bridges." Advanced Materials Research 711 (June 2013): 279–84. http://dx.doi.org/10.4028/www.scientific.net/amr.711.279.
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This paper reports the results of experimental research concerning the connection between the deck plate and the web of the longitudinal stiffeners in an orthotropic plated bridge deck on a microscopic scale. An important number of test specimens of a weld are studied with the help of a video microscope, to detect the efficiency of the root of the weld. The second part of the paper is concerned with parametric analysis of the lack of weld penetration by using accurate finite element modeling. The results demonstrate that the weld quality often required cannot always be assured, which surely has important consequence on the stresses in the weld and the fatigue resistance.
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Kotrocz, Krisztian, and György Kerényi. "Analysation of the Effect of the Contact Properties on Soil’s Penetration Resistance in Discrete Element Simulations." Acta Technica Jaurinensis 12, no. 2 (April 26, 2019): 148–60. http://dx.doi.org/10.14513/actatechjaur.v12.n2.500.
Повний текст джерелаАнотація:
Cone penetration in-situ tests are commonly used to measure the cone index of the soils. This measurement process can be modelled very well with Discrete Element Method (DEM) if the parameters of the correct contact model are defined properly. In this paper the Hertz-Mindlin with bonding contact model are used and the effect of the properties of this contact model on soil’s penetration resistance is investigated. Our aim was to determine those contact parameters which play important role in the penetration process, thus are necessary to take into account while calibrating the discrete element soil model to the results of real penetration tests.
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Basyir, Abdul, Erna Shevilia Agustian, and Adhistia Amelia. "A REVIEW OF PENETRATION TUNGSTEN BASED PROJECTILE ON DEPTH OF PENETRATION AT ARMOR OF CERAMIC BASED." Jurnal Pertahanan: Media Informasi ttg Kajian & Strategi Pertahanan yang Mengedepankan Identity, Nasionalism & Integrity 6, no. 3 (December 31, 2020): 286. http://dx.doi.org/10.33172/jp.v6i3.890.
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<p>Nowadays, tungsten-based material is used for the core of projectile, while ceramic-based is used for the main material of armor. Tungsten-based material is chosen because it has density and hardness superior to steel based-material. Meanwhile, the ceramic-based can enhance mobility and resistance penetration of armor. Penetration of projectile on target generates an impact velocity parameter. This velocity has resulted when the projectile hits the target. Therefore, the value of impact velocity affects the quantity of depth of penetration (DoP) result. This paper reviews some papers regarding the penetration of tungsten-based projectile on ceramic-based armor. Furthermore, the content of these papers is reviewed by the narrative review method, and the impact velocity and DoP are the main data to analyze. Through this paper, impact velocity has a linear correlation with the DoP, the big of impact velocity produced bigger of DoP, and vice versa. Based on the data in this review, for the same impact velocity, material, and (almost) dimension of a projectile, SiC has better penetration resistance than B4C, TiB2, and Al2O3. Furthermore, the parameter of projectile dimension, projectile material type, target design, and material composition of the target also affects the DoP result.</p>
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Feng, Wang, Jiang Yaqiong, Ma Yurong, Li Dan, and Zhou Wei. "Engineering Approximate Analysis Method of Rod Projectile Penetrating Concrete Target." E3S Web of Conferences 283 (2021): 01014. http://dx.doi.org/10.1051/e3sconf/202128301014.
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The penetration process of rod projectile into concrete target is very complex, and the theoretical analysis is very difficult. In this paper, by using the engineering approximation method, through some reasonable simplification of the rod projectile penetration model, the analytical formulas of the penetration resistance, penetration depth and other important physical quantities are established. Through the calculation of penetration depth, when the sliding friction coefficient is 0.1, the results are in good agreement with the experimental results. The results show that the higher the projectile density and the sharper the shape of the warhead, the stronger the penetration ability.
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Yan, Yong Dong, Jiang Hong Mao, and Chun Hua Lu. "Experimental Research on the Durability of PVA Fibers Reinforced Concrete." Advanced Materials Research 446-449 (January 2012): 703–7. http://dx.doi.org/10.4028/www.scientific.net/amr.446-449.703.
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In order to investigate the effects of polyvinyl alcohol (PVA) fibers on the performance of concrete, such as strength, crack resistance, permeability and chloride penetration properties, experimental research were carried out in this paper . Three types of fiber reinforced concretes with 0, 0.5%, 1.0% volume fractions were designed with the same water to cement ratio of 0.43. Flat band method was used to evaluate the cracking resistance, while AutoCLAM and ASTM C1202 were adopted to measure the permeability of concrete. The experimental results showed that the workability and the compression strength decreased as PVA adding volume increasing. However, the tension and the bending strengths increased for PVA fiber concrete. The number of cracks induced by the shrinkage of concrete was reduced by adding more PVA fibers. The permeability and chloride penetration ascended as PVA volume increasing. However, all the parameters with regards to strength, crack resistance, permeability and chloride penetration for fiber reinforced concrete were more reasonable than those for the specimens without PVA fiber. In additional, a very good correlation between the permeability and the electric flux was found in this paper, that means both AutoCLAM and ASTM C1202 could be used for concrete penetration test.
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Paniagua, P., J. Fonseca, A. S. Gylland, and S. Nordal. "Microstructural study of deformation zones during cone penetration in silt at variable penetration rates." Canadian Geotechnical Journal 52, no. 12 (December 2015): 2088–98. http://dx.doi.org/10.1139/cgj-2014-0498.
Повний текст джерелаАнотація:
During conventional cone penetration testing in silt, the soil will normally be partially drained. If the penetration rate varies, time for drainage is altered and therefore the measured cone resistance and pore pressure will change. This paper studies the change in soil microstructure around the probe during cone penetration carried out at different penetration rates to investigate the failure mechanism and the processes controlling drainage in silt. Backscattered electron images of polished thin sections prepared from frozen samples at the end of penetration were used. Making use of advanced image-processing techniques, the statistical distribution of particle orientations and the local porosity were investigated for zones around the cone tip and shaft. The spatial distribution of the measured microscale parameters in the region near the probe indicates that the soil deformation during a piezometric cone penetration test (CPTU) in silt leads to the formation of both contractive and dilative zones. The macro response of the material, presented by the pore pressure and cone penetration resistance measured during the test, results from the competition between these zones during penetration, which is shown to be dependent on the penetration rate.
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Ding, Yang, Tong-Lin Yang, Hui Liu, Zhen Han, Shuang-Xi Zhou, Zhong-Ping Wang, An-Ming She, Yong-Qi Wei, and Jing-Liang Dong. "Experimental Study and Simulation Calculation of the Chloride Resistance of Concrete under Multiple Factors." Applied Sciences 11, no. 12 (June 8, 2021): 5322. http://dx.doi.org/10.3390/app11125322.
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Cement is widely used in marine concrete, and its resistance to chloride ion corrosion has been widely considered. In this paper, based on a laboratory test, the influence of different hydrostatic pressures, coarse aggregate contents and w/c ratios on the chloride resistance performance is analyzed. Based on COMSOL finite element software, a two-dimensional cementitious materials model is established, and the simulation results are compared with the experimental results. The results show that the penetration depth of chloride ions in cement increases with the increase of the w/c ratio. Under the hydrostatic pressure of 0 MPa, when the w/c ratio is 0.35, the penetration depth of chloride ions is 7.4 mm, and the simulation result is 8.0 mm. When the w/c ratio is 0.45, the penetration depth of chloride ions is 9.3 mm, and the simulation result is 9.9 mm. When the w/c ratio is 0.55, the penetration depth of chloride ions is 12.9 mm, and the simulation result is 12.1 mm. Under different hydrostatic pressures, the penetration depth of chloride ions obviously changes, and with the increase in hydrostatic pressure, the penetration depth of chloride ions deepens. Under the w/c ratio of 0.35, when the hydrostatic pressure is 0.5 MPa, the penetration depth of chloride ions is 11.3 mm, and the simulation result is 12.1 mm. When the hydrostatic pressure is 1.0 MPa, the penetration depth of chloride ions is 16.2 mm, and the simulation result is 17.5 mm.
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Tho, Kee Kiat, Chun Fai Leung, Yean Khow Chow, and Andrew Clennel Palmer. "Deep cavity flow mechanism of pipe penetration in clay." Canadian Geotechnical Journal 49, no. 1 (January 2012): 59–69. http://dx.doi.org/10.1139/t11-088.
Повний текст джерелаАнотація:
The evolution of penetration resistance as a function of penetration depth of a pipe into a cohesive seabed is of practical importance, particularly in the areas of pipeline on-bottom stability assessment and T-bar penetrometer data interpretation. In the past, this subject was addressed primarily in a discontinuous manner by separating the penetration response into two broad regimes of shallow and deep penetrations followed by deriving plasticity solutions assuming a simplified “wished-in-place” configuration. In this manner, the effects of evolving seabed topology and the progressive transition from a shallow failure mechanism to a deep failure mechanism are neglected. This paper aims to provide greater insights into the transition zone, which is especially important for the interpretation of T-bar test data at shallow depths. In this study, the penetration response of a smooth pipe over a wide range of normalized clay strengths is numerically simulated. A deep cavity flow mechanism where the bearing capacity factor is 12% less than the conventional full-flow mechanism is identified and found to be operative up to a depth of 10 pipe diameters under a certain combination of material properties. An analysis method is proposed to predict the load–penetration response for a given set of clay strengths and pipe diameters.
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Harada, Kenji, Rolando P. Orense, Kenji Ishihara, and Jun Mukai. "Lateral stress effects on liquefaction resistance correlations." Bulletin of the New Zealand Society for Earthquake Engineering 43, no. 1 (March 31, 2010): 13–23. http://dx.doi.org/10.5459/bnzsee.43.1.13-23.
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When the sand compaction pile (SCP) method is implemented to improve loose deposits of sandy soils, its effect is evaluated generally in terms of increase in density, which is beneficial for reducing the liquefaction potential of the deposits during earthquakes. An additional advantage can be expected to occur due to concurrent increase in lateral stress. When the resistance to liquefaction is evaluated on the basis of SPT N-value or CPT qc-value, the increased resistance to penetration due to the sand compaction has been interpreted conventionally as being associated mainly with the increase in density. Therefore, in order to properly evaluate the effectiveness of ground improvement in compacted soils, it is necessary to quantify the effect of lateral stresses on the penetration resistance and liquefaction strength. In this paper, based on the results of SPT and CPT performed in a chamber box in the laboratory, the relationships between penetration resistance, liquefaction resistance and relative density were re-examined and the influence of lateral stress, expressed in terms of KC, was investigated. Although the results indicated that generally the resistance to liquefaction increases with increasing KC–value, little difference was noted when the density of the deposit was high. Based on the results, recommended charts incorporating the effect of KC were proposed.
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Liu, Xin, Mao Liu, Bin Wu, Jingjing Liu, Wencheng Tang, and Bin Yan. "Effect of the Maxillary Sinus on Tooth Movement during Orthodontics Based on Biomechanical Responses of Periodontal Ligaments." Applied Sciences 12, no. 10 (May 15, 2022): 4990. http://dx.doi.org/10.3390/app12104990.
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The maxillary sinus is a common anatomic limitation for orthodontic tooth movement. The effect of orthodontic forces on a particular anatomy can be studied using finite element analysis (FEA). Our study aimed to determine the effect of different tooth penetration depths into the maxillary sinus floor (MSF) on the orthodontic force system for bodily tooth movement. Using the cone-beam computed tomography of a patient with low MSF, we modeled the geometry of canine, premolar, and molar teeth with their periodontal ligaments and the alveolar bone surrounding them. The models were manually modified to simulate different root penetration depths. Thereafter, the center of resistance and stress distributions for teeth penetrating into the MS were determined using FEA. Moreover, the force systems for teeth with a low MSF to varying degree were evaluated based on the FEA results. During orthodontic tooth movement, the individual differences in the periodontal anatomy should be considered. The CR position decreases with the penetration depth, while the average hydrostatic stress in the PDL increases rapidly. In this paper, we present the correction coefficients of the orthodontic force and moment for a tooth penetrating into the MSF, which is necessary for personalized treatment planning.
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Robertson, P. K., and CE (Fear) Wride. "Evaluating cyclic liquefaction potential using the cone penetration test." Canadian Geotechnical Journal 35, no. 3 (June 1, 1998): 442–59. http://dx.doi.org/10.1139/t98-017.
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Soil liquefaction is a major concern for structures constructed with or on sandy soils. This paper describes the phenomena of soil liquefaction, reviews suitable definitions, and provides an update on methods to evaluate cyclic liquefaction using the cone penetration test (CPT). A method is described to estimate grain characteristics directly from the CPT and to incorporate this into one of the methods for evaluating resistance to cyclic loading. A worked example is also provided, illustrating how the continuous nature of the CPT can provide a good evaluation of cyclic liquefaction potential, on an overall profile basis. This paper forms part of the final submission by the authors to the proceedings of the 1996 National Center for Earthquake Engineering Research workshop on evaluation of liquefaction resistance of soils.Key words: cyclic liquefaction, sandy soils, cone penetration test
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Liu, Jing Xian, De Qiang Chang, Li Ting Miao, Ning Mao, and Xi Sun. "Experiment Investigation on Two Filter Medias for Air Filtration." Applied Mechanics and Materials 300-301 (February 2013): 1340–43. http://dx.doi.org/10.4028/www.scientific.net/amm.300-301.1340.
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As the fast development of industry, clean air quality environment are needed in more manufactory fields. Filter media is the key material for high efficiency filtration. In this paper, glass fiber filter and PTFE membrane filter are studied with filtration test. The results show that glass fiber filter has low porosity, lead to lower penetration and higher resistance than PTFE filter. Penetration of filters decrease with mass load increasing and face velocity decreasing. Resistance increase with mass loading and face velocity increasing.
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Li, Yun Feng, Yang Liu, Rong Qiang Du, and Fan Ying Kong. "Effect of Steel Slag Powder on the Durability of High Performance Concrete." Advanced Materials Research 79-82 (August 2009): 175–78. http://dx.doi.org/10.4028/www.scientific.net/amr.79-82.175.
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dvanced mineral admixtures can lead to economical high performance concrete with enhanced durability and reduced cement content. When super fine steel slag powder is mixed into concrete as active admixture, resistance to abrasion and resistance to chloride penetration are improved as well as workability and mechanical properties of the concrete. Resistance to abrasion of steel slag concrete is measured and resistance to chloride penetration is also determined by the method of NEL and ASTM C1202 in this paper. Result shows that compound mineral admixtures as partial replacement for Portland cement in mortar enhance abrasion resistance. Mixing mineral admixture is an effective means for controlling the chloride permeability. Concrete specimens prepared with compound mineral admixture with steel slag powder and blast furnace slag powder has very low permeability.
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Hossain, M. S., B. M. Lehane, Y. Hu, and Y. Gao. "Soil flow mechanisms around and between stiffeners of caissons during installation in clay." Canadian Geotechnical Journal 49, no. 4 (April 2012): 442–59. http://dx.doi.org/10.1139/t2012-008.
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Structural stiffeners placed inside caissons have created significant uncertainty regarding soil flow mechanisms, side friction, and end bearing, and consequently in the prediction of the underpressure required for installation. This paper describes centrifuge modelling of the penetration of stiffened skirts in overconsolidated clay, identifying the soil flow mechanisms around and between stiffeners and the penetration resistance. The effects of stiffener width and spacing as well as soil strength ratio are discussed. The present guidelines for predicting the point of soil backflow in the gap that forms between the stiffeners are shown to be invalid and a new expression, based on a stability factor (su/γ′B, where su and γ′ are the undrained shear strength and effective unit weight of the soil, respectively, and B is the combined width of the skirt and stiffener close to the caisson tip) is proposed. End bearing at the skirt tip and base stiffener are seen to dominate installation resistance. The normalized installation resistance stabilizes at a value of ∼17.5 at deep penetrations and is shown to be independent of whether the cavity between the stiffeners remains open or is backfilled with a soil–water mixture. This factor of 17.5 is shown to be in good agreement with reported field data and centrifuge test data and hence may be used to obtain a first-order estimate of the installation resistance of a caisson with stiffeners.
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Kosior-Kazberuk, Marta, and Walery Jezierski. "EVALUATION OF CONCRETE RESISTANCE TO CHLORIDE IONS PENETRATION BY MEANS OF ELECTRIC RESISTIVITY MONITORING." JOURNAL OF CIVIL ENGINEERING AND MANAGEMENT 11, no. 2 (June 30, 2005): 109–14. http://dx.doi.org/10.3846/13923730.2005.9636339.
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The chloride‐induced corrosion of reinforcing steel is the major reason for the premature deterioration and degradation of field concrete structures built in a salt‐laden environment. The results of investigation of the bituminous addition effect on Portland cement concrete resistance to chloride ions penetration are presented in this paper. Chloride penetration was simulated by subjecting samples to cyclic loading with salt solution and drying. Concrete resistivity development was monitored during 12 months. The test results have been analysed to verify the effect of addition content, the time of exposure in aggressive environment, as well as the sort of cement on chloride ion permeability of Portland cement concrete. The statistical analysis showed that bituminous addition significantly improves the concrete resistance to chloride salt solution penetration.
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Vavřiník, Tomáš, and Jan Zatloukal. "Influence of Different Mechanical Properties to the Concrete Penetration Resistance." Advanced Materials Research 982 (July 2014): 119–24. http://dx.doi.org/10.4028/www.scientific.net/amr.982.119.
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This paper describes influence of different mechanical properties to the concrete penetration resistance. The resistance is evaluated on the basis of the presented experimental program. In the experiment, non-deformable ogive-nose projectiles with diameter of 7.92 mm and mass of 8 g with impact velocity of about 700 m/s were hitting center of the specimens. Determination of the concrete penetration resistance was than based on projectile residual velocity obtained from high-speed camera record. The specimens were made from high strength concrete, steel fiber-reinforced concrete, ultra-high performance concrete and ultra-high performance fiber-reinforced concrete with different fiber content. The concrete penetration resistance was evaluated on total 32 specimens. Influence of mechanical properties, addition of coarse aggregate and steel fibers were discussed. Mechanical properties of the tested materials were investigated on total 125 specimens. Data from the measurements were used for creation of new RHT concrete models in Autodyn. In order to confirm experiment's setup and results, numerical analysis was performed in Autodyn. Results of the numerical simulations were compared to the experimental program.
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Goué, Erwan Le, Frédérique Ham-Pichavant, Stéphane Grelier, Jordan Remy, and Véronique Coma. "Functional Chitosan–Calcium Carbonate Coatings for Enhancing Water and Fungal Resistance of Paper Materials." Molecules 27, no. 24 (December 14, 2022): 8886. http://dx.doi.org/10.3390/molecules27248886.
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The objective of this study was to increase the water resistance of paper while providing fungal resistance using a bio-based coating made from chitosan. The water resistance was improved through the surface control of roughness using modified calcium carbonate particles. The higher the quantity of particles in the film-forming solution, the higher the surface hydrophobicity of the paper. The addition of particles was found to counterbalance the chitosan hydrophilicity through the control of the coatings’ penetration in the paper bulk. As a consequence, the wetting time and liquid water resistance were enhanced. The antifungal activity of the film-forming solutions and coated paper was also investigated against the growth of Chaetomium globosum, which was selected as a model strain able to contaminate paper materials. The results reveal that the antifungal activity of chitosan was improved by a possible synergic effect with the bicarbonate ions from the mineral particles.
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Robertson, P. K. "Interpretation of cone penetration tests — a unified approach." Canadian Geotechnical Journal 46, no. 11 (November 2009): 1337–55. http://dx.doi.org/10.1139/t09-065.
Повний текст джерелаАнотація:
The electric cone penetration test (CPT) has been in use for over 40 years and is growing in popularity in North America. This paper provides some recent updates on the interpretation of some key geotechnical parameters in an effort to develop a more unified approach. Extensive use is made of the normalized soil behaviour type (SBTn) chart based on normalized cone resistance (Qt) and normalized friction ratio (Fr). Updates are provided regarding the normalization process and its application to the identification of soil type. The seismic CPT has provided extensive data linking CPT net cone resistance to shear-wave velocity and soil modulus. New correlations are presented in the form of contours of key parameters on the SBTn chart. These new relationships enable a more unified interpretation of CPT results over a wide range of soils. Updates are also provided in terms of in situ state parameter, peak friction angle, and soil sensitivity. The correlations are evaluated using available laboratory and full-scale field test results. Many of the recommendations contained in this paper are focused on low to moderate risk projects where empirical interpretation tends to dominate. For projects where more advanced methods are more appropriate, the recommendations provided in this paper can be used as a screening to evaluate critical regions–zones where selective additional in situ testing and sampling maybe appropriate.
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Konečný, Petr, Petr Lehner, Pratanu Ghosh, and Quang Tran. "Variation of Diffusion Coefficient for Selected Binary and Ternary Concrete Mixtures Considering Concrete Aging Effect." Key Engineering Materials 761 (January 2018): 144–47. http://dx.doi.org/10.4028/www.scientific.net/kem.761.144.
Повний текст джерелаАнотація:
The paper deals with the variation of resistance of selected High Performance Concrete (HPC) materials against chloride ion penetration. The resistance of chloride penetration is described by means of the diffusion coefficient and it is derived from emerging non-destructive tests. It is computed from the measurements of surface electrical resistivity (see e.g. AASTHTO TP-95 specification) data. The effect of concrete aging on the diffusion coefficient is taken into account as the concrete properties are time dependent and it is significantly important for High Performance Concrete (HPC) materials.
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Holan, Jiří, and Lukáš Merenda. "The fire resistance of wood depending on material's thickness." Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis 56, no. 5 (2008): 89–96. http://dx.doi.org/10.11118/actaun200856050089.
Повний текст джерелаАнотація:
The paper presents the resisitance of wood against a pilot flame. The fire has negative effect on the wood and its properties. The fire and its high temperature cause a degradation of chemical components of wood. Hence the physical properties are changed and strength of the wood is decreased. The combustion velocity and the loss weight depend on the material's thickness. For tests have been chosen groups of samples with thickness of 5, 10, 15 and 20 mm. The result of submitted work is a time estimation of the fire penetration and an observation of weight losses coupled with visual changes observation of degraded samples. It have been established that with an action of the pilot flame the needed time to fire penetration is rising with rising material's thickness and at the same time the cumbustion velocity is decreasing.