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  • 1
    Electronic Resource
    Electronic Resource
    Numerical Modelling and Assessment of Excavation Damaged Zone around the Underground Excavations: A Case Study (2006)
    s.l. ; Stafa-Zurich, Switzerland
    Key engineering materials Vol. 324-325 (Nov. 2006), p. 77-80 
    Details
    ISSN: 1013-9826
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: This paper presents a study on the quantification of the degree of damage from themicroseismic event data, for assessment of excavation damaged zone of anisotropic rock inJinchuan mine and presents numerical simulation and prediction on the deformation and failureof the rock masses surrounding laneway under rock mass properties and excavating conditions.Following an introduction to the engineering geology and mechanical properties of the rockmass in the Jinchuan mine areas, this paper reveals the features of the measured in situ stressesand puts emphasis on an analysis of the mechanism of underground opening and damageinduced by the underground mining. Stress and AE redistribution induced by excavation ofunderground engineering results in the unloading zone in parts of surrounding rock masses. Amicromechanics-based model has been proposed for brittle rock material undergoingirreversible changes of their microscopic structures due to microcrack growth. A systematicalnumerical modeling analysis method was completed. Based on numerical modelling, a series ofpredicting curves for rock mass response and deformation are obtained, which provides thebasis of guiding the design and construction of anisotropic rock cave in Jinchuan mine. The useof the in situ stress field results in enhanced modeling of the stress concentrations and potentialfailures at the mines has also been reviewed. Knowledge of the prevailing rock stress field at themines is a critical component for such modeling which has led to improved rock mechanicsunderstanding and operations at Jinchuan mines
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/01/52/transtech_doi~10.4028%252Fwww.scientific.net%252FKEM.324-325.77.pdf
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  • 2
    Electronic Resource
    Electronic Resource
    Numerical Study on Cracking Process of Masonry Structure (2005)
    s.l. ; Stafa-Zurich, Switzerland
    Advanced materials research Vol. 9 (Sept. 2005), p. 117-126 
    Details
    ISSN: 1662-8985
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Masonry structure is heterogeneous and has been widely used in building andconstruction engineering. The study on cracking pattern of masonry structure is significant to engineering design. Many previous investigations on the failure process of masonry structure are usually based on the homogenization technique by selecting a typical unit of masonry to serve as a representative volume. This kind of numerical analysis neglects the mesoscopic heterogeneous structure, which cannot capture the full cracking process of masonry structures. The cracking process of masonry structure is dominantly affected by its heterogeneous internal structures. In this paper, a mesoscopic mechanical model of masonry material is developed to simulate the behavior of masonry structure. Considering the heterogeneity of masonry material, based on the damage mechanics and elastic-brittle theory, the new developed Material Failure Process Analysis (MFPA2D) system was put forward to simulate the cracking process of masonry structure, which was considered as a two-phase composite of block and mortar phases. The crack propagation processes simulated with this model shows good agreement with those of experimental observations. The numerical results show that numerical analysis clearly reflect the modification, transference and their interaction of the stress field and damage evolution process which are difficult to achieve by physical experiments. It provides a new method to research the forecast theory of failure and seismicity of masonry. It has been found that the fracture of masonry observed at the macroscopic level is predominantly caused by tensile damage at the mesoscopic level
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/01/41/transtech_doi~10.4028%252Fwww.scientific.net%252FAMR.9.117.pdf
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  • 3
    Electronic Resource
    Electronic Resource
    Blast Performance and Its Assessment on Excavation Damaged Zone of Anisotropic Rock (2006)
    s.l. ; Stafa-Zurich, Switzerland
    Key engineering materials Vol. 324-325 (Nov. 2006), p. 1205-1208 
    Details
    ISSN: 1013-9826
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: The 290 level cave is situated in Nanfen Surface Mine, Liaoning, China. Nanfen surfacemine is one of the biggest iron ore in Benxi Iron Company. The base line of the pit bottom hasreached 346m level in Nanfen surface mine. The importance of in situ assessment of stability of the290 level cave for next mining design and construction has been met. Investigation at the NanfenSurface Mine has shown that damage exists around 290 level cave and that the damage developsfrom the energy imparted to the rock by the excavation method and by redistribution of the in situstress field around the 290 level cave. Subsequent near-by excavations, removal of loose materialfrom the existing cave and pore pressure changes will all influence the development and extent ofrock damage, as does the rock type and its fabric. Based on the engineering characters and rockmechanics, the main characteristics of stress induced brittle failure of the site are introduced.Various evaluation and measures are sought to stabilize the over-stressed rock mass. The inducedanisotropic damage process was modeled. The major results from numerical analysis of the cavernare presented and validated by direct comparison with actual monitoring data. Next, an optimizationstudy was conducted with the experimentally validated and adjusted mathematical model, measuredwith a recorder within such a cave. And the stability of the 290 level cave in Nanfen Surface Minewas analysis. As a result, the model is expected to be a useful tool for simulation, design, andoptimization of pasteurization tunnels. A suitable support measure was proposed and taken
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/01/52/transtech_doi~10.4028%252Fwww.scientific.net%252FKEM.324-325.1205.pdf
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  • 4
    Electronic Resource
    Electronic Resource
    Micromechanical Analysis of Excavation Damaged Zone in Anisotropic Rock Mass (2006)
    s.l. ; Stafa-Zurich, Switzerland
    Key engineering materials Vol. 324-325 (Nov. 2006), p. 81-84 
    Details
    ISSN: 1013-9826
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Rock is a heterogeneous and anisotropic compound material, containing many shearsurfaces, cracks, weak surfaces and faults. Damage and failure in a rock mass can occur throughsliding along persistent discontinuities, or fractures. A new micromechanical approach tomodeling the mechanical behavior of excavation damaged or disturbed zone (EDZ) ofanisotropic rock is presented based on knowledge of the inhomogeneity of rock. In thisnumerical model, damage is analyzed as a direct consequence of microcracks growth. A studyof the effect of elastic and failure anisotropy plus inhomogeneity on the undergroundexcavations reveals that the modes of failure can be significantly influenced by the rockstructure on the small and large scales. Fractures that develop progressively aroundunderground excavations can be simulated using a numerical code called RFPA (RealisticFailure Process Analysis). This code incorporates the microscopic inhomogeneity in Young’smodulus and strength characteristic of rock. In the numerical models of a rock mass, values ofYoung’s modulus and rock strength are realized according to a Weibull distribution in whichthe distribution parameters represent the level of inhomogeneity of the medium. Anothernotable feature of this code is that no a priori assumptions need to be made about where andhow fracture and failure will occur – cracking can occur spontaneously and can exhibit a varietyof mechanisms when certain local stress conditions are met. These unique features have madeRFPA capable of simulating the whole fracturing process of initiation, propagation andcoalescence of fractures around excavations under a variety of loading conditions. The resultsof the simulations show that the code can be used not only to produce fracturing patterns similarto those reported in previous studies, but also to predict fracturing patterns under a variety ofloading conditions. The numerical model was able to reproduce the associated complex stresspatterns and the microseismic emission distribution for a variety of rock structural conditions
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/01/52/transtech_doi~10.4028%252Fwww.scientific.net%252FKEM.324-325.81.pdf
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  • 5
    Electronic Resource
    Electronic Resource
    The Plane Problem Solution of Piezoelectric Material with a Line Crack (2008)
    s.l. ; Stafa-Zurich, Switzerland
    Advanced materials research Vol. 33-37 (Mar. 2008), p. 533-538 
    Details
    ISSN: 1662-8985
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: A two-dimensional electromechanical analysis is performed on a transversely isotropicpiezoelectric material containing a line crack of length 2a, which is subjected to uniform distributedforces with intensity q along the crack faces and uniform electric displacement fields at infinity.Based on the impermeable electric boundary conditions, the closed complex form expression for theelectromechanical fields are deduced in the vicinity of the crack. Taking PZT-4 ceramic intoconsideration, electromechanical fields under different loads are illustrated through several examples.It can be seen that electromechanical fields show 1/2 order singularity at the crack tip, and thepiezoelectric effect can’t be negelected
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/01/40/transtech_doi~10.4028%252Fwww.scientific.net%252FAMR.33-37.533.pdf
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  • 6
    Electronic Resource
    Electronic Resource
    Plane Electromechanical Fields in a Piezoelectric Material Containing an Elliptical Hole (2008)
    s.l. ; Stafa-Zurich, Switzerland
    Advanced materials research Vol. 33-37 (Mar. 2008), p. 539-544 
    Details
    ISSN: 1662-8985
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: A two-dimensional electromechanical analysis is performed on a transversely isotropicpiezoelectric material containing an elliptical hole, which is subjected to uniform compressiveforces with intensity q acting on the edge of the hole and uniform electric displacement fields atinfinity. Based on the impermeable electric boundary conditions, general electromechanical fieldssolution are obtained in the form of complex potentials
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/01/40/transtech_doi~10.4028%252Fwww.scientific.net%252FAMR.33-37.539.pdf
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  • 7
    Electronic Resource
    Electronic Resource
    Investigation on the Key Technologies of Mechanical Expanding of Large Diameter LSAW Pipe (2008)
    s.l. ; Stafa-Zurich, Switzerland
    Materials science forum Vol. 575-578 (Apr. 2008), p. 472-477 
    Details
    ISSN: 1662-9752
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Long distance transmission pipeline is one of promising transportation methods developedin recent years. It is safe, economical, convenient and prompt. It is mainly used in transmitting gas,liquid, and other dispersed material. Oil and natural gas is especially suitable to be transmitted by highpressure large diameter longitudinal submerged arc welded (LSAW) pipelines. Mechanicalexpanding is one of the most important processes in the production of large diameter LSAW steelpipe for long distance transmission pipeline. Firstly, the LSAW steel pipe mechanical expanding ismodeled. Two FEM models are established to simulate the mechanical expanding process at the crosssection and longitudinal section of the LSAW steel pipe respectively. Secondly, the deformationcharacteristics of the LSAW steel pipe are simulated while mechanical expanding processes. Finally,main mechanical expanding process parameters and their influence on the quality of finished LSAWpipe are analyzed in detail according to the FEM simulation. The results presented by the analyses arevery consistent with the experiment, and can be used to direct the production of LSAW steel pipe
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/02/18/transtech_doi~10.4028%252Fwww.scientific.net%252FMSF.575-578.472.pdf
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  • 8
    Electronic Resource
    Electronic Resource
    Plane Electromechanical Fieldes in a Piezoelectric Material with a Crack (2006)
    s.l. ; Stafa-Zurich, Switzerland
    Key engineering materials Vol. 324-325 (Nov. 2006), p. 247-250 
    Details
    ISSN: 1013-9826
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: A two-dimensional electromechanical analysis is performed on a transversely isotropicpiezoelectric material containing a crack based on the impermeable electric boundary condition. Byintroducing stress function, a general solution is provided in terms of triangle series. It is shown thatthe stress and electric displacement are all of 1/2 order singularity in front of the crack tip. Inaddition, the electromechanical fields in the vicinity of the crack when subjected to uniform tensilemechanical load are obtained using boundary collocation method
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/01/52/transtech_doi~10.4028%252Fwww.scientific.net%252FKEM.324-325.247.pdf
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  • 9
    Electronic Resource
    Electronic Resource
    Ligand–receptor binding revealed by the TNF family member TALL-1 (2003)
    [s.l.] : Macmillian Magazines Ltd.
    Nature 423 (2003), S. 49-56 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] The tumour necrosis factor (TNF) ligand TALL-1 and its cognate receptors, BCMA, TACI and BAFF-R, were recently identified as members of the TNF superfamily, which are essential factors contributing to B-cell maturation. The functional, soluble fragment of TALL-1 (sTALL-1) forms a virus-like ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/nature01543
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  • 10
    Electronic Resource
    Electronic Resource
    TNF ligands (communication arising: response) Is Tall-1 a trimer or a virus-like cluster? (2004)
    [s.l.] : Nature Publishing Group
    Nature 427 (2004), S. 414-414 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Liu et al. reply Our conclusion that a 60-meric soluble-TALL-1 cluster is the functional unit of this ligand is based on several lines of evidence. We have shown that soluble TALL-1 (sTALL-1; residues 134–285) with a Flag tag, secreted from 293 cell lines, ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/427414a
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