Artykuły w czasopismach: „Triaxial”

1

Serna Moreno, María del Carmen, Sergio Horta Muñoz i Alberto Ruiz Gracia. "Design of Triaxial Tests with Polymer Matrix Composites". Polymers 14, nr 4 (21.02.2022): 837. http://dx.doi.org/10.3390/polym14040837.

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Multiaxial testing in composites may generate failure modes which are more representative of what occurs in a real structure submitted to complex loading conditions. However, some of its main handicaps include the need for special facilities, the correct design of the experiments, and the challenging interpretation of the results. The framework of this research is based on a triaxial testing machine with six actuators which is able to apply simultaneous and synchronized axial loads in the three space directions. Then, the aim was to design from a numerical point of view a triaxial experiment adapted to this equipment. The methodology proposed could allow for an adequate characterization of the triaxial response of a polymer-based composite with apparent isotropic behaviour in the testing directions. The finite element method (FEM) is applied in order to define the geometry of the triaxial specimen. The design pursues to achieve homogeneous stress and strain states in the triaxially loaded region, which should be accessible for direct measurement of the strains. Moreover, a fixing system is proposed for experimentally reproducing the desired boundary conditions imposed on the numerical simulations. The procedure to determine the full strain tensor in the triaxially loaded region is described analytically and with the help of FEM virtual testing. The hydrostatic component and the deviatoric part of the strain tensor are proposed for estimating the susceptibility of the polymer-based composite to fail due to the triaxial strain state imposed. Then, the loading scenarios that cause higher values of the deviatoric components in the triaxially loaded region are considered to be more prone to damage the region of interest. Nevertheless, the experimental failure is expected to be produced in the arms of the specimen which are uniaxially loaded, since in all of the loading cases the simulations show higher levels of stress concentration out of the triaxially loaded region. Thus, although the triaxial strength could not be accurately determined by the proposed tests, they can be utilized for observing the triaxial response before failure.

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Shahin, G., i R. C. Hurley. "HP-TACO: A high-pressure triaxial compression apparatus for in situ x-ray measurements in geomaterials". Review of Scientific Instruments 93, nr 11 (1.11.2022): 113907. http://dx.doi.org/10.1063/5.0102931.

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Triaxial compression experiments are commonly used to characterize the elastic and inelastic behavior of geomaterials. In situ measurements of grain kinematics, particle breakage, stresses, and other microscopic phenomena have seldom been made during such experiments, particularly at high pressures relevant to many geologic and man-made processes, limiting our fundamental understanding. To address this issue, we developed a new triaxial compression device called HP-TACO (High-Pressure TriAxial COmpression Apparatus). HP-TACO is a miniaturized, conventional triaxial compression apparatus permitting confining pressures up to 50 MPa and deviatoric straining of materials, while also allowing in situ x-ray measurements of grain-scale kinematics and stresses. Here, we present the design of and first results from HP-TACO during its use in laboratory and synchrotron settings to study grain-scale kinematics and stresses in triaxially compressed sands subjected to 15 and 30 MPa confining pressures. The data highlight the unique capabilities of HP-TACO for studying the high-pressure mechanics of sands, providing new insight into micromechanical processes occurring during geologic and man-made processes.

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Zhang, Shi Yin. "The Studying Fabrication and Application of the Multifunctional Frozen Triaxial Test Apparatus". Applied Mechanics and Materials 353-356 (sierpień 2013): 388–91. http://dx.doi.org/10.4028/www.scientific.net/amm.353-356.388.

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The frozen soil triaxial test apparatus is the basic equipment to study the mechanics property of the frozen soil. According to the norm of frozen soil test and the construction character of the present mine, the high-performance frozen soil triaxial test apparatus is made which could be used for many type tests, such as the static triaxial shear test, the dynamic triaxial test, the triaxial creep test, the routine triaxial strain route test, the routine triaxial proportion coordination test, the routine triaxial recycle load test, the routine triaxial concretion test and so on. The apparatus can realize the high surround pressure. During the test progress, the test parameter can be set up and the test date can be collected by the computer. The frozen soil triaxial test apparatus is a new type triaxial test apparatus.

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Stone, B. M., I. J. Jordaan, J. Xiao i S. J. Jones. "Experiments on the damage process in ice under compressive states of stress". Journal of Glaciology 43, nr 143 (1997): 11–25. http://dx.doi.org/10.3189/s002214300000277x.

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AbstractDuring ice-structure interaction, ice will fail in a brittle manner dominated by two processes. The first corresponds to the formation of macrocracks and the consequent spalling-off of large ice pieces. The second includes an intense shear-damage process in zones, termed critical zones, where high pressures are transmitted to the structure. The shear-damage process results in microstructural changes including microcrack formation and recrystallization. A range of tests on laboratory-prepared granular ice have been conducted to determine the fundamental behaviour of ice under various stress states and stress history, particularly as it relates to changes in microstructure. The test series was designed to study three aspects: the intrinsic creep properties of intact, undamaged ice; the enhancement of creep and changes in microstructure due to damage; and the effects of different stress paths. Tests on intact ice with triaxial confining pressures and low deviatoric stresses, aimed at defining the intrinsic creep response in the absence of microcracking, showed that an accelerated creep rate occurred at relatively low deviatoric stresses. Hence, a minimum Creep rate occurred under these conditions. Recrystallization to a smaller grain-size and void formation were observed. Ice damaged uniaxially and triaxially prior to testing showed enhancement of creep under both uniaxial and triaxial loading conditions Creep rates in triaxially damaged ice were found to be non-linear with high deviatoric stresses, corresponding to a power-law dependence of creep rate. Uniaxially damaged specimens contained microcracks parallel to the stressed direction which tended to close under triaxial confinement. Damage under triaxial conditions at low confining pressures produced small recrystallized grains near zones of microcracking. At high confining pressures, a fine-grained recrystallized structure with no apparent cracking was observed uniformly across the specimen. The recrystallization process contributes significantly to the enhanced creep rates found in damaged specimens.

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Stone, B. M., I. J. Jordaan, J. Xiao i S. J. Jones. "Experiments on the damage process in ice under compressive states of stress". Journal of Glaciology 43, nr 143 (1997): 11–25. http://dx.doi.org/10.1017/s002214300000277x.

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AbstractDuring ice-structure interaction, ice will fail in a brittle manner dominated by two processes. The first corresponds to the formation of macrocracks and the consequent spalling-off of large ice pieces. The second includes an intense shear-damage process in zones, termed critical zones, where high pressures are transmitted to the structure. The shear-damage process results in microstructural changes including microcrack formation and recrystallization. A range of tests on laboratory-prepared granular ice have been conducted to determine the fundamental behaviour of ice under various stress states and stress history, particularly as it relates to changes in microstructure. The test series was designed to study three aspects: the intrinsic creep properties of intact, undamaged ice; the enhancement of creep and changes in microstructure due to damage; and the effects of different stress paths. Tests on intact ice with triaxial confining pressures and low deviatoric stresses, aimed at defining the intrinsic creep response in the absence of microcracking, showed that an accelerated creep rate occurred at relatively low deviatoric stresses. Hence, a minimum Creep rate occurred under these conditions. Recrystallization to a smaller grain-size and void formation were observed. Ice damaged uniaxially and triaxially prior to testing showed enhancement of creep under both uniaxial and triaxial loading conditions Creep rates in triaxially damaged ice were found to be non-linear with high deviatoric stresses, corresponding to a power-law dependence of creep rate. Uniaxially damaged specimens contained microcracks parallel to the stressed direction which tended to close under triaxial confinement. Damage under triaxial conditions at low confining pressures produced small recrystallized grains near zones of microcracking. At high confining pressures, a fine-grained recrystallized structure with no apparent cracking was observed uniformly across the specimen. The recrystallization process contributes significantly to the enhanced creep rates found in damaged specimens.

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Hauschild, K., R. Wadsworth, R. M. Clark, I. M. Hibbert, P. Fallon, A. O. Macchiavelli, D. B. Fossan i in. "Triaxial bands inCe133". Physical Review C 54, nr 2 (1.08.1996): 613–19. http://dx.doi.org/10.1103/physrevc.54.613.

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Andreghetto, Dionatas, Lucas Festugato, Gustavo Miguel i Andressa Silva. "Automated true triaxial apparatus development for soil mechanics investigation". Soils and Rocks 45, nr 2 (19.04.2022): 1–10. http://dx.doi.org/10.28927/sr.2022.077321.

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Soil mechanical fully understanding requires considering a three dimensional approach, including soil response under the second principal stress and its potential anisotropy. In order to achieve such soil mechanical understanding, a true triaxial apparatus might be used. Therefore, in the present research an automated true triaxial apparatus was developed comprising its cubical cell, data acquisition and stress control systems. The manufactured apparatus was validated by means a laboratory test campaign where true triaxial test responses were compared to standard drained triaxial tests. True triaxial and standard drained triaxial tests were carried out on both naturally and artificially cemented soils. Results were gathered and compared. A soil mechanical compatibility was observed when test results of the newest true triaxial equipment were compared to test results obtained from a well validated standard triaxial apparatus. Thereby, the present paper reports an affordable successful true triaxial apparatus development demonstrating its efficiency for regular soil mechanical tests. Finally, a full stress rosette was established for a uniform fine sand where some small anisotropy was detected.

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8

Yang, Sheng-Qi. "Strength and deformation behavior of red sandstone under multi-stage triaxial compression". Canadian Geotechnical Journal 49, nr 6 (czerwiec 2012): 694–709. http://dx.doi.org/10.1139/t2012-035.

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Based on multi-stage triaxial experimental results of red sandstone with circumferential deformation control, the influence of confining pressure on strength and deformation behavior of red sandstone under multi-stage triaxial compression is investigated. The results show that the confining pressure has an obvious effect on the deformation parameters of red sandstone under multi-stage triaxial compression. A multi-stage triaxial compression experiment with only one specimen can be used to confirm the peak strength of rock under different confining pressures. Under single-stage and multi-stage triaxial compression, the peak strength behavior of red sandstone agrees better with the nonlinear Hoek–Brown criterion than the linear Mohr–Coulomb criterion. However, the difference between single-stage and multi-stage triaxial strength changes with different post-peak deformation values, and the reason for the difference, is discussed. To predict single-stage triaxial strength using the obtained multi-stage triaxial strength with only one specimen, a new method is put forward to revise multi-stage triaxial strength of red sandstone, which testifies to being reasonable. The concluding remarks are very useful and significant for deep geotechnical and underground structural engineering.

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Hossain, Sayeed, Chris Truman, David Smith i Mark Daymond. "OS12W0072 Creating highly triaxial stresses in stainless steel". Abstracts of ATEM : International Conference on Advanced Technology in Experimental Mechanics : Asian Conference on Experimental Mechanics 2003.2 (2003): _OS12W0072. http://dx.doi.org/10.1299/jsmeatem.2003.2._os12w0072.

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Li, Rong Jian, Xi An Li, Gao Feng Che, Wen Zheng i Wen Jun Chen. "A Simple and Practicable Approach on Implementing for the Reduced Triaxial Extension by the Conventional Triaxial Apparatus". Advanced Materials Research 250-253 (maj 2011): 2089–92. http://dx.doi.org/10.4028/www.scientific.net/amr.250-253.2089.

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Stress path is one of the very important factors of soil strength. It is significant to study the strength and reveal the importance of the impact of sand in different stress path conditions. Firstly, an ameliorating approach on implementing for the reduced triaxial extension by the conventional triaxial apparatus was discussed. Then, In order to study shear behaviors of the eolian sand under different stress path, two monotonic shearing tests with the conventional triaxial compression and the reduced triaxial extension stress path were performed and analyzed. The test results not only indicate that the amelioration on conventional triaxial apparatus is simple, practicable and inexpensive, but also reveal the difference of strength’s parameter between the reduced triaxial extension and conventional triaxial compression stress path. In sum, the stress path has important effect on the strength of the eolian sand.

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Qi, Wenjie, Bowen Liu, Tian Liang, Jian Chen, Deyong Chen i Junbo Wang. "MEMS-Based Integrated Triaxial Electrochemical Seismometer". Micromachines 12, nr 10 (26.09.2021): 1156. http://dx.doi.org/10.3390/mi12101156.

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This paper presents a micro-electromechanical systems (MEMS)-based integrated triaxial electrochemical seismometer, which can detect three-dimensional vibration. By integrating three axes, the integrated triaxial electrochemical seismometer is characterized by small volume and high symmetry. The numerical simulation results inferred that the integrated triaxial electrochemical seismometer had excellent independence among three axes. Based on the experimental results, the integrated triaxial electrochemical seismometer had the advantage of small axial crosstalk and could detect vibration in arbitrary directions. Furthermore, compared with the uniaxial electrochemical seismometer, the integrated triaxial electrochemical seismometer had similar sensitivity curves ranging from 0.01 to 100 Hz. In terms of random ground motion response, high consistencies between the developed integrated triaxial electrochemical seismometer and the uniaxial electrochemical seismometer could be easily observed, which indicated that the developed integrated triaxial electrochemical seismometer produced comparable noise levels to those of the uniaxial electrochemical seismometer. These results validated the performance of the integrated triaxial electrochemical seismometer, which has a good prospect in the field of deep geophysical exploration and submarine seismic monitoring.

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Rao, Yunfei, Chen Zhang, Zhe Li, Qianqian Li, Honghua Zhang i Wei Li. "Flexural behavior analysis of composites with triaxial woven fabric as reinforcement". Journal of Engineered Fibers and Fabrics 16 (styczeń 2021): 155892502110323. http://dx.doi.org/10.1177/15589250211032324.

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The triaxial woven fabric is known for their light weight and isotropy of mechanical properties. However, researches that using it as reinforcement to form different structural composites were rarely mentioned. Here, we found that the effect of the triaxial woven fabric can be almost equivalent to the unidirectional fabric in flexural strength (99.18%) when it was added as a reinforcing material into the unidirectional fabric composites even though the weight of triaxial woven fabric has only a third of unidirectional fabric. Moreover, the effects and mechanisms are quite different when changing the position of the triaxial woven fabric in the composites. The damage modes of composites when triaxial woven fabric in different stacking sequences were summarized and the resin blocks model from triaxial woven fabric composites was presented in this paper.

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Ning, T., S. Y. An, X. X. Li, X. R. Yu i Y. Zhang. "Triaxial models description of the low-lying properties in 192Os". International Journal of Modern Physics E 25, nr 10 (październik 2016): 1650083. http://dx.doi.org/10.1142/s021830131650083x.

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Several typical triaxial models have been parallel addressed and applied to describe the energy values and [Formula: see text] transitional rates in the ground band and the [Formula: see text] band for [Formula: see text]Os. It is shown that the different triaxial model presents different triaxial dynamics but each of them can only succeed to explain part of the spectral properties of this nucleus, which indicates that the triaxial shape of [Formula: see text]Os may be more complicated than that reflected by an ideal triaxial model. In addition, the staggering signature in experiments hints that [Formula: see text]-rigid triaxiality should be more or less involved in [Formula: see text]Os.

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Sakane, Masao, Hiroki Kobayashi, Ryohei Ohki i Takamoto Itoh. "Creep Void Formation and Rupture Lifetime in Multiaxial Stress States". Key Engineering Materials 795 (marzec 2019): 159–64. http://dx.doi.org/10.4028/www.scientific.net/kem.795.159.

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This paper discusses creep void formation and rupture lifetimes in multiaxial stress states for a SUS 304 stainless steel at elevated temperatures. Biaxial and triaxial tension creep tests were performed using a cruciform and a cubic specimen, respectively. These two types of the specimens were designed to achieve uniform equi-biaxial and equi-triaxial stress distributions by a finite element analysis in the gage parts. Void formation at grain boundaries was observed by intermitting biaxial creep tests and by interrupting triaxial creep tests. Creep rupture lifetimes were also obtained in biaxial and triaxial creep tests. Biaxial stresses increase the void formation but give a little influence on a creep rupture lifetime in the correlation with von Mises equivalent stress. Triaxial stresses also increase the void formation and drastically reduce a creep rupture lifetime in the correlation with von Mises equivalent stress. Evident void formation in an equi-triaxial stress condition demonstrates that von Mises equivalent stress is not a suitable measure to evaluate creep damage development in multiaxial stress states. A new equivalent stress is proposed to evaluate creep rupture lifetimes in biaxial and triaxial stress states.

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Scheeper, Patrick, Jens Ole Gulløv i Lars Munch Kofoed. "A piezoelectric triaxial accelerometer". Journal of Micromechanics and Microengineering 6, nr 1 (1.03.1996): 131–33. http://dx.doi.org/10.1088/0960-1317/6/1/032.

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Sarantites, D. G., D. R. LaFosse, M. Devlin, F. Lerma, V. Q. Wood, J. X. Saladin, D. F. Winchell i in. "Triaxial superdeformed bands in86Zr". Physical Review C 57, nr 1 (1.01.1998): R1—R5. http://dx.doi.org/10.1103/physrevc.57.r1.

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Poon, M. Y., i David Merritt. "Triaxial Black Hole Nuclei". Astrophysical Journal 568, nr 2 (1.04.2002): L89—L92. http://dx.doi.org/10.1086/340395.

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Domscheit, J., S. Törmänen, B. Aengenvoort, H. Hübel, R. A. Bark, M. Bergström, A. Bracco i in. "Triaxial superdeformation in 163Lu". Nuclear Physics A 660, nr 4 (grudzień 1999): 381–92. http://dx.doi.org/10.1016/s0375-9474(99)00392-9.

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Lewandowska, Urszula, Wojciech Zajaczkowski, Stefano Corra, Junki Tanabe, Ruediger Borrmann, Edmondo M. Benetti, Sebastian Stappert i in. "A triaxial supramolecular weave". Nature Chemistry 9, nr 11 (24.07.2017): 1068–72. http://dx.doi.org/10.1038/nchem.2823.

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Fedorova, E. A. "Mechanical triaxial compression machines". Journal of Mining Science 44, nr 4 (lipiec 2008): 421–28. http://dx.doi.org/10.1007/s10913-008-0047-5.

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Goricki, A., i E. Pimentel. "Triaxial Tests on Cataclasites". Rock Mechanics and Rock Engineering 48, nr 5 (15.11.2014): 2167–71. http://dx.doi.org/10.1007/s00603-014-0668-8.

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TANIGUCHI, YASUTAKA. "TRIAXIAL SUPERDEFORMATION OF 40Ar". Modern Physics Letters A 25, nr 21n23 (30.07.2010): 1915–18. http://dx.doi.org/10.1142/s0217732310000630.

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Superdeformed (SD) states in 40 Ar have been studied using the deformed-basis antisymmetrized molecular dynamics and the generator coordinate method (GCM). GCM basis wave functions were obtained by the energy variation with a constraint on the quadrupole deformation parameter β, while other quantities such as triaxiality γ were optimized by the energy variation. An SD band is obtained just above the ground state band. The SD band involves a Kπ = 2+ side band due to the triaxiality. The calculated quadrupole electric transition strengths of the SD band reproduce well the experimental values. Triaxiality is significantly important to understand low-lying states.

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Sanders, Jason L., i N. Wyn Evans. "Self-consistent triaxial models". Monthly Notices of the Royal Astronomical Society 454, nr 1 (18.09.2015): 307–22. http://dx.doi.org/10.1093/mnras/stv1898.

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Merritt, David, i Tema Fridman. "Triaxial Galaxies with Cusps". Astrophysical Journal 460 (marzec 1996): 136. http://dx.doi.org/10.1086/176957.

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Waalkens, Holger, Jan Wiersig i Holger R. Dullin. "Triaxial Ellipsoidal Quantum Billiards". Annals of Physics 276, nr 1 (sierpień 1999): 64–110. http://dx.doi.org/10.1006/aphy.1999.5936.

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Lywood, D. W., D. J. Adams, A. van Eyken i J. M. Macpherson. "Small, triaxial force plate". Medical and Biological Engineering and Computing 25, nr 6 (listopad 1987): 698–701. http://dx.doi.org/10.1007/bf02447343.

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Rossato, Gianni, i Paolo Simonini. "Stress–strain behaviour of sands in triaxial and direct simple shear tests". Canadian Geotechnical Journal 28, nr 2 (1.04.1991): 276–81. http://dx.doi.org/10.1139/t91-033.

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The behaviour of a natural sand in triaxial compression and direct simple shear tests was compared by means of dimensionless analysis of parameters controlling the evolution of stresses and strains. The secant triaxial compression and direct simple shear moduli were interpreted in a dimensionless form. A criterion based on the equivalence between major principal strain in the two tests was considered to compare the results. Key words: sand, stress–strain behaviour, triaxial test, direct simple shear test, shear modulus, triaxial compression modulus.

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Ren, Xinbo, Xinhai Zhao, Chao Zheng, Libin Song, Ji Liu i Zhiyuan Si. "Research on the Mechanical Properties and Stretch Forming Simulation of Triaxial Geogrid with Different Pre-Punched Hole Diameters". Polymers 14, nr 13 (27.06.2022): 2594. http://dx.doi.org/10.3390/polym14132594.

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In this paper, the tensile behavior of industrial polypropylene triaxial geogrid with different pre-punched hole diameters was studied by experiment and numerical analysis. The industrial polypropylene sheets with different diameters of circular holes were stretched at elevated temperature and then the tensile properties of triaxial geogrids at room temperature were evaluated. It was found that the pre-punched hole diameter of triaxial geogrid had a very close relationship with the mechanical properties. With the increase of the pre-punched hole diameter, the tensile strength of triaxial geogrid shows a trend of first increasing and then decreasing. Combined with numerical simulation, the optimal pre-punched hole diameter can be accurately obtained, and the distribution law of the width, thickness, stress, and strain of triaxial geogrid can be obtained. Under the condition of a stretching ratio of 3 and node spacing of 3 mm, it was found that the mechanical properties of industrial polypropylene triaxial geogrid was the best when the pre-punched hole diameter was 2.6 mm.

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Nam, Myung Jin, David Pardo i Carlos Torres-Verdín. "Simulation of triaxial induction measurements in dipping, invaded, and anisotropic formations using a Fourier series expansion in a nonorthogonal system of coordinates and a self-adaptive hp finite-element method". GEOPHYSICS 75, nr 3 (maj 2010): F83—F95. http://dx.doi.org/10.1190/1.3431041.

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Borehole triaxial induction instruments were designed to diagnose and measure rock electrical conductivity parallel and perpendicular to the bedding plane. Experience has shown that the interpretation of triaxial induction measurements often requires numerical modeling for a proper diagnosis of rock electrical conductivity anisotropy in the presence of geometric effects such as dipping wells, layer boundaries, and invasion. We introduce a new algorithm to simulate triaxial induction measurements that combines a Fourier series expansion in a nonorthogonal system of coordinates with a 2D goal-oriented, self-adaptive, high-order [Formula: see text] finite-element method. This procedure enables the accurate and reliable simulation of triaxial induction measurements across reservoir rock formations with extreme contrasts of electrical conductivity while reducing the 3D computational complexity associated with deviated wells. Numerical results indicate that borehole dip effects on triaxial induction measurements are larger than on standard coaxial induction measurements. The sensitivity of triaxial induction measurements to transversely isotropic rock formations decreases with increasing dip angle.

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Cui, Feng-kun, Huai-shuai Shang, Tie-jun Zhao, Guo-xi Fan i Guo-sheng Ren. "Mechanical and Failure Criteria of Air-Entrained Concrete under Triaxial Compression Load after Rapid Freeze-Thaw Cycles". Advances in Materials Science and Engineering 2017 (2017): 1–8. http://dx.doi.org/10.1155/2017/6786270.

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The experiment study on the air-entrained concrete of 100 mm cubes under triaxial compression with different intermediate stress ratioα2=σ2D : σ3Dwas carried out using a hydraulic-servo testing system. The influence of rapid freeze-thaw cycles and intermediate stress ratio on the triaxial compressive strengthσ3Dwas analyzed according to the experimental results, respectively. The experimental results of air-entrained concrete obtained from the study in this paper and the triaxial compression experimental results of plain concrete got through the same triaxial-testing-system were compared and analyzed. The conclusion was that the triaxial compressive strength is greater than the biaxial and uniaxial compressive strength after the same rapid freeze-thaw cycles, and the increased percentage of triaxial compressive strength over biaxial compressive strength or uniaxial compressive strength is dependent on the middle stress. The experimental data is useful for precise analysis of concrete member or concrete structure under the action complex stress state.

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Pradhan, Tej B. S., Fumio Tatsuoka, Yoshiyuki Mohri i Yasuhiko Sato. "An Automated Triaxial Testing System Using a Simple Triaxial Cell for Soils". Soils and Foundations 29, nr 1 (marzec 1989): 151–60. http://dx.doi.org/10.3208/sandf1972.29.151.

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Li, J. S. "Monotonic triaxial shear strength and cyclic triaxial properties of undisturbed soft soil". IOP Conference Series: Materials Science and Engineering 780 (10.04.2020): 042021. http://dx.doi.org/10.1088/1757-899x/780/4/042021.

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Atkinson, J. H., i D. B. Clinton. "Stress Path Tests on 100 mm Diameter Samples". Geological Society, London, Engineering Geology Special Publications 2, nr 1 (1986): 133–37. http://dx.doi.org/10.1144/gsl.1986.002.01.28.

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AbstractThe use of stress path tests is discussed in relation to geotechnical design, and a description is given of the triaxial test stress path apparatus developed at The City University.Test results are presented from a series of triaxial tests following stress paths commonly encountered in engineering design problems. These are compared with the results of conventional triaxial tests.The stress-strain behaviour and pore pressure response of soil are shown to be very much dependent on the stress path followed, and the advantages of using stress-controlled loading in triaxial tests is demonstrated.

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Černý, Miroslav, Petr Šesták i Jaroslav Pokluda. "Stress Coupling Effect on Ideal Shear Strength: Tungsten as a Case Study". Advances in Materials Science and Engineering 2016 (2016): 1–5. http://dx.doi.org/10.1155/2016/5317985.

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Mechanical response of a perfect bcc tungsten crystal to a multiaxial loading was investigated from first principles. The multiaxial stress state consisted of the shear stress and a superimposed compressive triaxial stress with various levels of differential stresses. The studied shear system was 111110. Results obtained within a relatively wide range of the compressive stresses showed that increasing hydrostatic triaxial stress (with zero differential stresses) increased the shear strength almost linearly. On the other hand, triaxial stresses with greater portion of the differential components did not have such a simple effect on the shear strength: we found a certain optimum value of the superimposed triaxial stress yielding the maximum shear strength. Any change (both increase and decrease) in the triaxial stress then reduced the ideal shear strength value.

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Iz, H., C. Shum, X. Ding i C. Dai. "Orientation of the Geometrically Best fitting Triaxial Lunar Ellipsoid with Respect to the Mean Earth/Polar Axis Reference Frame". Journal of Geodetic Science 1, nr 1 (1.03.2011): 52–58. http://dx.doi.org/10.2478/v10156-010-0007-2.

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Orientation of the Geometrically Best fitting Triaxial Lunar Ellipsoid with Respect to the Mean Earth/Polar Axis Reference FrameThis study provides new estimates for the orientation of a geometrically best fitting lunar triaxial ellipsoid with respect to the mean Earth/polar axis reference frame calculated from the footprint positions of the Chang'E-1 (CE-1), SELenological and ENgineering Explorer (SELENE) laser altimetry measurements and Unified Lunar Control Networks 2005, (ULCN 2005) station coordinates. The semi-principal axes of the triaxial ellipsoid and the coordinates of its geometric center are also calculated simultaneously. All the estimated parameters from all three data sets are found to be consistent. In particular, the RMS differences of the semi-principal axes of the triaxial ellipsoids and the locations of their geometric centers from solutions with and without modeling Euler angles (orientation of the triaxial ellipsoid) using uniformly distributed laser altimetry (LAL) footprints are 29 and 31 m respectively. The misclosures of all the solutions indicate a better fit for the triaxial ellipsoid to the footprint and station coordinates if the Euler angles are included in the models.

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Xia, Wei, Erlei Bai, Jinyu Xu i Gaojie Liu. "Experimental Study on the Strength and Deformation Characteristics of Concrete under True Triaxial Compression after Sulfate Attack". Advances in Civil Engineering 2021 (14.04.2021): 1–15. http://dx.doi.org/10.1155/2021/5548313.

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To explore the mechanical properties of concrete under true triaxial static compressive load after sulfate attack, uniaxial static compression test and true triaxial static compression test at four stress ratios were carried out on concrete specimens immersed in 15% sulfate solution for 0–120 days by the integrated true triaxial static and dynamic load testing system, and the variation of performance indicators such as the strength and deformation of concrete under the coupling action of sulfate attack and complex stress state was analyzed. The results show that the uniaxial compressive strength of concrete increases at the beginning and then decreases with the increase of sulfate attack time and reaches the peak on the 30th day, with an increase rate of 16.57%; the strength of concrete under triaxial compression increases significantly, and the maximum triaxial compressive strength is 3.18 times of uniaxial compressive strength under the combination of 0-day sulfate attack and 0.2 : 0.8 stress ratio; and the deterioration of concrete under sulfate attack is more prominent at high confining pressure, and as the sulfate attack worsens, the sensitivity of triaxial compressive strength of concrete to lateral compressive stress is reduced. In conclusion, triaxial compression can significantly enhance the ductility of concrete by playing a role in restraining the deformation and cracking of concrete after sulfate attack.

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Toyeb, Muhammad. "ANALISIS BALIK KUAT GESER TANAH TERSTABILISASI SEMEN DENGAN METODE NUMERIK". Racic : Rab Construction Research 5, nr 1 (29.06.2020): 48–57. http://dx.doi.org/10.36341/racic.v5i1.1315.

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Shear strenght is a parameter to soils strenght analysis. Shear strenght can be obtained from laboratorium test that interpreted as stress and strain. Soil tests had done on soil stabilization of cement with mixing 5%; 10%; 15% of content. Soil tests were used by triaxial test of unconsolidated undrained (triaxial UU) with cell pressure at 50; 100; 200 kN/m2 and unconfined compression test. The test specimens were disturbed soil samples which compacted and remolded, and then carry out curing for 0; 3; 7; 14; 28 days. The laboratory test results were back analysis in Plaxis 2D by using Mohr-Coulumb and Hardening Soil model later. The Mohr-Coulumb and Hardening Soil model had deviator stress results was almost equal to the test results of triaxial UU and unconfined compression test. Especially of strain by Mohr-Coulumb model, shew the lower strain than be showed by triaxial UU test and unconfined compression test. The Hardening Soil model, provides fluctuating strain results of triaxial UU test because it is affected by the application of cell pressure (σ3) and it provides greater strain results from unconfined compression test. Keywords: Triaxial UU, Unconfined Compresssion, Stress and Strain, Plaxis 2D

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Zhou, Yan, Chuanxiao Liu i Depeng Ma. "Method Improvement and Effect Analysis of Triaxial Compression Acoustic Emission Test for Coal and Rock". Advances in Civil Engineering 2019 (1.04.2019): 1–10. http://dx.doi.org/10.1155/2019/8910362.

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In the study of the acoustic emission (AE) characteristics of rock samples or coal samples under triaxial compression conditions, most scholars carry out relevant experiments by placing the AE detector on the outer wall of the triaxial chamber of the rock mechanics test system. Owing to the continuous obstruction of AE signals by hydraulic oil in the triaxial chamber and the frequent interference of external noises, the final experimental data cannot objectively and truly reflect the essential characteristics of AE of rock or coal under triaxial compression conditions. It is difficult to scientifically guide and accurately predict precursory information of rock’s or coal’s rupture and instability. Based on this, a series of improvements and optimizations were made to the original triaxial compression AE test method, which is based on the modification of the communication interface of the rock mechanics test system, a test head which can put the AE detector into the triaxial chamber and withstands high confining pressure, in order to obtain the true, comprehensive, and reliable AE signals. It is of considerable significance to the scientific determination of the precursory characteristics of rock’s or coal’s rupture and instability.

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Sun, Yifan, i Xiang Xu. "Calibration of MEMS Triaxial Accelerometers Based on the Maximum Likelihood Estimation Method". Mathematical Problems in Engineering 2020 (21.09.2020): 1–10. http://dx.doi.org/10.1155/2020/4617365.

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As a widely used inertial device, a MEMS triaxial accelerometer has zero-bias error, nonorthogonal error, and scale-factor error due to technical defects. Raw readings without calibration might seriously affect the accuracy of inertial navigation system. Therefore, it is necessary to conduct calibration processing before using a MEMS triaxial accelerometer. This paper presents a MEMS triaxial accelerometer calibration method based on the maximum likelihood estimation method. The error of the MEMS triaxial accelerometer comes into question, and the optimal estimation function is established. The calibration parameters are obtained by the Newton iteration method, which is more efficient and accurate. Compared with the least square method, which estimates the parameters of the suboptimal estimation function established under the condition of assuming that the mean of the random noise is zero, the parameters calibrated by the maximum likelihood estimation method are more accurate and stable. Moreover, the proposed method has low computation, which is more functional. Simulation and experimental results using the consumer low-cost MEMS triaxial accelerometer are presented to support the abovementioned superiorities of the maximum likelihood estimation method. The proposed method has the potential to be applied to other triaxial inertial sensors.

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Öztekin, Ertekin. "ANN based investigations of reliabilities of the models for concrete under triaxial compression". Engineering Computations 33, nr 7 (3.10.2016): 2019–44. http://dx.doi.org/10.1108/ec-03-2015-0065.

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Purpose A lot of triaxial compressive models for different concrete types and different concrete strength classes were proposed to be used in structural analyses. The existence of so many models creates conflicts and confusions during the selection of the models. In this study, reliability analyses were carried out to prevent such conflicts and confusions and to determine the most reliable model for normal- and high-strength concrete (NSC and HSC) under combined triaxial compressions. The paper aims to discuss these issues. Design/methodology/approach An analytical model was proposed to estimate the strength of NSC and HSC under different triaxial loadings. After verifying the validity of the model by making comparisons with the models in the literature, reliabilities of all models were investigated. The Monte Carlo simulation method was used in the reliability studies. Artificial experimental data required for the Monte Carlo simulation method were generated by using artificial neural networks. Findings The validity of the proposed model was verified. Reliability indexes of triaxial compressive models were obtained for the limit states, different concrete strengths and different lateral compressions. Finally, the reliability indexes were tabulated to be able to choose the best model for NSC and HSC under different triaxial compressions. Research limitations/implications Concrete compressive strength and lateral compression were taken as variables in the model. Practical implications The reliability indexes were tabulated to be able to choose the best model for NSC and HSC under different triaxial compressions. Originality/value A new analytical model was proposed to estimate the strength of NSC and HSC under different triaxial loadings. Reliability indexes of triaxial compressive models were obtained for the limit states, different concrete strengths and different lateral compressions. Artificial experimental data were obtained by using artificial neural networks. Four different artificial neural networks were developed to generate artificial experimental data. They can also be used in the estimations of the strength of NSC and HSC under different triaxial loadings.

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Callisto, L., A. Gajo i D. Muir Wood. "Simulation of triaxial and true triaxial tests on natural and reconstituted Pisa clay". Géotechnique 52, nr 9 (listopad 2002): 649–66. http://dx.doi.org/10.1680/geot.2002.52.9.649.

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Minglibayev, M. Zh, i O. B. Baisbayeva. "TRANSLATIONAL-ROTATIONAL MOTION OF THE TRIAXIAL BODY WITH VARIABLE COMPRESSIONS IN THE PRESENCE OF REACTIVE FORCES AND MOMENTS". BULLETIN Series of Physics & Mathematical Sciences 69, nr 1 (10.03.2020): 241–46. http://dx.doi.org/10.51889/2020-1.1728-7901.42.

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In this paper we investigated the translational-rotational motion of a triaxial body of constant dynamic shape and variable mass and size in a non-stationary Newtonian central gravitational field. Differential equations of the translationalrotational motion of the triaxial non-stationary body in the relative coordinate system with the origin at the center of a non-stationary spherical body are derived. The axes of the own coordinate system of the non-stationary triaxial body are directed along the principle axes of inertia of the body and we assumed that in the course of evolution their relative orientation remains unchanged. An analytical expression for the force function of the Newtonian interaction of the triaxial body of variable mass and size with a spherical body of variable size and mass is given. In the presence of reactive forces and moments the equations of translational-rotational motion of a triaxial non-stationary body in osculating elements are obtained in the presence of reactive forces and moments.

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Xu, Weiwei, Enyue Ji, Beixiao Shi i Chenghao Chen. "A Novel Procedure to Measure Membrane Penetration of Coarse Granular Materials". Applied Sciences 12, nr 13 (23.06.2022): 6381. http://dx.doi.org/10.3390/app12136381.

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The membrane penetration effect will significantly influence the measurement of specimen volume deformation in the triaxial test. This paper presents a novel procedure for measuring and correcting the membrane penetration of rubber by using a newly developed multiscale triaxial apparatus. A series of triaxial tests on coarse granular materials was conducted with different specimen diameters, and it is found that the proportion of volume change due to membrane penetration decreases linearly with increasing specimen diameter. To reduce the margin of error induced by membrane penetration in the triaxial test, it is recommended to use specimens of larger size. Such a method can facilitate the correction and estimation of the membrane penetration effect of coarse granular materials.

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Deng, Zhiheng, Jingkai Zhou, Beiquan Chen, Xiaoyan Wen i Bing Liu. "Triaxial Compression Performance Research of Steel Slag Concrete on the Unified Strength Theory". Applied Sciences 11, nr 1 (24.12.2020): 128. http://dx.doi.org/10.3390/app11010128.

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To better explore the mechanical properties of steel slag concrete (SSC) under triaxial compression, true triaxial tests were performed on SSC with three replacement ratios (30%, 70%, 100%) by a servo-controlled setup (TAWZ-5000/3000). Through the test, failure modes, peak stress, and corresponding strain of SSC are obtained. Results show that the failure modes of SSC are plate-splitting and slant-shear. Compared with the corresponding uniaxial strength, the triaxial compressive strength of SSC is significantly improved and is influenced by the stress ratio and the replacement ratio. Finally, based on unified strength theory, the strength failure criterion formula of SSC with different replacement rates under triaxial compression is given.

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Olson, Scott M., i Benjamin B. Mattson. "Mode of shear effects on yield and liquefied strength ratios". Canadian Geotechnical Journal 45, nr 4 (kwiecień 2008): 574–87. http://dx.doi.org/10.1139/t07-114.

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A database of 386 laboratory triaxial compression, direct simple shear, rotational shear, and triaxial extension test results was collected to examine yield and liquefied strength ratio concepts used in liquefaction analysis of sloping ground. These data envelope the yield and liquefied strength ratios obtained from back-analyses of liquefaction flow failure case histories. Generally, triaxial compression exhibits the highest yield and liquefied strength ratios, triaxial extension yields the lowest ratios, and direct simple shear – rotational shear shows intermediate responses. However, mode of shear appears to have a considerably smaller effect on laboratory-measured liquefied strength ratios for specimens with a positive state parameter (i.e., difference in consolidation void ratio and steady state void ratio at the same effective stress).

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MATHUR, RAVI, i ADITI SONI. "STUDY ON THE PARTICLE SIZE DISTRIBUTION (NANO-PARTICLES) OF MINING MINERALS ON WHITENESS OF TRIAXIAL BODY". International Journal of Modern Physics: Conference Series 22 (styczeń 2013): 239–47. http://dx.doi.org/10.1142/s2010194513010180.

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White wares produced worldwide represent the foundation of much of the ceramic industry; Porcelain bodies fabricated from triaxial mixtures of clay, quartz and feldspar with different size and amounts of nano particles were investigated. Although the purity of raw materials has a strong effect on the colour of the fired bodies, the particle size of raw materials also effect the whiteness The raw material mining minerals china Clay, Feldspar, quarts were prepared of various sized nano particles contains 10.60 -20.22%, 56.84- 70.80 % and 34.87-50.76 % of 100nm respectively. The fired bodies of raw mining minerals and triaxial bodies were subjected to colour measurement. The differences in whiteness were compared and discussed. The studies so far carried out is upto 400 mesh size while the present study has included up to 100nm particle size. A statistical correlation between whiteness of feldspar and triaxial body was also carried out. The correlation between china clay and triaxial body are 0.53, 0.57 and 0.66 for china clay similarly correlation for feldspar is 0.49, 0.73 and 0.83 for triaxial body it are 0.97, 0.84 and 0.75 for A1, A2 and A3 samples. Correlation between china clay and feldspar with triaxial body are 0.79 and 0.92 respectively.

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Gao, Yanbin, Lianwu Guan i Tingjun Wang. "Triaxial Accelerometer Error Coefficients Identification with a Novel Artificial Fish Swarm Algorithm". Journal of Sensors 2015 (2015): 1–17. http://dx.doi.org/10.1155/2015/509143.

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Artificial fish swarm algorithm (AFSA) is one of the state-of-the-art swarm intelligence techniques, which is widely utilized for optimization purposes. Triaxial accelerometer error coefficients are relatively unstable with the environmental disturbances and aging of the instrument. Therefore, identifying triaxial accelerometer error coefficients accurately and being with lower costs are of great importance to improve the overall performance of triaxial accelerometer-based strapdown inertial navigation system (SINS). In this study, a novel artificial fish swarm algorithm (NAFSA) that eliminated the demerits (lack of using artificial fishes’ previous experiences, lack of existing balance between exploration and exploitation, and high computational cost) of AFSA is introduced at first. In NAFSA, functional behaviors and overall procedure of AFSA have been improved with some parameters variations. Second, a hybrid accelerometer error coefficients identification algorithm has been proposed based on NAFSA and Monte Carlo simulation (MCS) approaches. This combination leads to maximum utilization of the involved approaches for triaxial accelerometer error coefficients identification. Furthermore, the NAFSA-identified coefficients are testified with 24-position verification experiment and triaxial accelerometer-based SINS navigation experiment. The priorities of MCS-NAFSA are compared with that of conventional calibration method and optimal AFSA. Finally, both experiments results demonstrate high efficiency of MCS-NAFSA on triaxial accelerometer error coefficients identification.

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Chen, Yuzhi, Yingjie Ning, Xudong Chen, Weihong Xuan i Xiangyi Zhu. "Experimental and Numerical Investigation on the Triaxial Compressive Behavior of Steamed Recycled Aggregate Concrete". Buildings 13, nr 2 (23.01.2023): 334. http://dx.doi.org/10.3390/buildings13020334.

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The use of recycled aggregates to produce precast concrete products is conductive to the green development of construction industrialization. This paper aimed to study the effects of curing regimes and confining pressures on the triaxial compression behavior of recycled aggregate concrete (RAC). Triaxial compression tests were carried out on RAC under different curing regimes (standard curing, 60 °C—12 h and 80 °C—9 h), and the designed confining pressures were 0 MPa, 2.5 MPa, 5 MPa, and 10 MPa. The results show that the increase of confining pressure limits the expansion of cracks, causing the failure mode to change from vertical splitting to oblique shearing, and the triaxial compressive strength is doubled at most. Compared with standard curing, steam curing significantly weakened the triaxial compressive strength of RAC, which was related to the reduction of RAC cohesion, and the cohesion of RAC steam cured at 80 °C was reduced by 30%. The triaxial compression failure of RAC closely follows the Mohr–Coulomb criterion. Based on the discrete element method and test results, an RAC triaxial compression numerical model considering the shape of the actual coarse aggregate was established, and the propagation of cracks was discussed at the mesoscopic level.

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Vakharia, Kunal, Muhammad Waqas, Hakeem J. Shakir, Felix Chin, Joelle N. Hartke, Hussain Shallwani, Jeffrey S. Beecher, Adnan H. Siddiqui i Elad I. Levy. "Versatile use of catheter systems for deployment of the Pipeline embolization device: a comparison of biaxial and triaxial catheter systems". Journal of NeuroInterventional Surgery 12, nr 6 (20.01.2020): 585–90. http://dx.doi.org/10.1136/neurintsurg-2019-015610.

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BackgroundA Pipeline embolization device (PED; Medtronic, Dublin, Ireland) can be deployed using either a biaxial or a triaxial catheter delivery system.ObjectiveTo compare the use of these two catheter delivery systems for intracranial aneurysm treatment with the PED.MethodsA retrospective study of patients undergoing PED deployment with biaxial or triaxial catheter systems between 2014 and 2016 was conducted. Experienced neurointerventionalists performed the procedures. Patients who received multiple PEDs or adjunctive coils were excluded. The two groups were compared for PED deployment time, total fluoroscopy time, patient radiation exposure, complications, and cost.ResultsEighty-two patients with 89 intracranial aneurysms were treated with one PED each. In 49 cases, PEDs were deployed using biaxial access; triaxial access was used in 33 cases. Time (min) from guide catheter run to PED deployment was significantly shorter in the biaxial group (24.0±18.7 vs 38.4±31.1, P=0.006) as was fluoroscopy time (28.8±23.0 vs 50.3±27.1, P=0.001). Peak radiation skin exposure (mGy) in the biaxial group was less than in the triaxial group (1243.7±808.2 vs 2074.6±1505.6, P=0.003). No statistically significant differences were observed in transient and permanent complication rates or modified Rankin Scale scores at 30 days. The triaxial access system cost more than the biaxial access system (average $3285 vs $1790, respectively). Occlusion rates at last follow-up (mean 6 months) were similar between the two systems (average 88.1%: biaxial, 89.2%: triaxial).ConclusionOur results indicate near-equivalent safety and effectiveness between biaxial and triaxial approaches. Some reductions in cost and procedure time were noted with the biaxial system.

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Fayek, Sara, Xiaolong Xia, Lin Li i Xiong Zhang. "Photogrammetry-Based Method to Determine the Absolute Volume of Soil Specimen during Triaxial Testing". Transportation Research Record: Journal of the Transportation Research Board 2674, nr 8 (30.06.2020): 206–18. http://dx.doi.org/10.1177/0361198120928339.

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Triaxial tests are used extensively to evaluate stress-strain behavior for both saturated and unsaturated soils. A literature review indicates that all conventional triaxial test methods measure the relative volume of soil; however, between the initial measurements and the start of the triaxial tests, there are unavoidably disturbances during installation that cause deviation of soil volume from that at the initial condition. Recently image-based methods have been developed to measure the absolute volume of soil specimens. However, these methods still have a major limitation in their inability to determine top and bottom boundaries between the soil specimen, and the top and bottom caps. This paper proposes a photogrammetry-based method to overcome this limitation by developing a mathematically rigorous technique to determine the upper and lower boundaries of soil specimens during triaxial testing. The photogrammetry technique was used to determine the orientations of the camera, and the shape and location of the acrylic cell. Multiple ray-tracings and least-square optimization techniques were also applied to obtain the coordinates of any point inside the triaxial cell, and thus back-calculate the upper and lower boundaries. With these boundaries and the side surface, a triangular surface mesh was constructed and the specimen volume was then calculated in both unconfined compression tests and triaxial tests. The calculation procedures are presented in detail with validation tests performed on a cylindrical specimen to evaluate the accuracy of the method. Results indicate that the accuracy of the proposed method is up to 0.023% in unconfined compression tests and 0.061% in triaxial tests.

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