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| 1 | Failure mechanism and coupled static-dynamic loading theory in deep hard rock mining: A review显示文摘Rock failure phenomena,such as rockburst,slabbing(or spalling) and zonal disintegration,related to deep underground excavation of hard rocks are frequently reported and pose a great threat to deep mining.Currently,the explanation for these failure phenomena using existing dynamic or static rock mechanics theory is not straightforward.In this study,new theory and testing method for deep underground rock mass under coupled static-dynamic loading are introduced.Two types of coupled loading modes,i.e.'critical static stress + slight disturbance' and 'elastic static stress + impact disturbance',are proposed,and associated test devices are developed.Rockburst phenomena of hard rocks under coupled static-dynamic loading are successfully reproduced in the laboratory,and the rockburst mechanism and related criteria are demonstrated.The results of true triaxial unloading compression tests on granite and red sandstone indicate that the unloading can induce slabbing when the confining pressure exceeds a certain threshold,and the slabbing failure strength is lower than the shear failure strength according to the conventional Mohr-Column criterion.Numerical results indicate that the rock unloading failure response under different in situ stresses and unloading rates can be characterized by an equivalent strain energy density.In addition,we present a new microseismic source location method without premeasuring the sound wave velocity in rock mass,which can efficiently and accurately locate the rock failure in hard rock mines.Also,a new idea for deep hard rock mining using a non-explosive continuous mining method is briefly introduced. | Xibing Li Fengqiang Gong Ming Tao Longjun Dong Kun Du Chunde Ma Zilong Zhou Tubing Yin | 2017 | Journal of Rock Mechanics and Geotechnical Engineering2017，9，4： | 68 |
| 2 | Discontinuous deformation analysis based on complementary theory显示文摘The contact between blocks is treated by the open-close iteration in the conventional discontinuous deformation analysis (DDA),which needs to introduce spurious springs between two blocks in contact and to assume the normal stiffness and the tangential stiffness (the penalty factors). Unreasonable values of stiffness would result in numerical problems. To avoid the penalty factors and the open-close iteration,we reformulate the DDA as a mixed complementary problem (MiCP) and then choose the path Newton method (PNM) to solve the problem. Some examples including those originally designed by Shi are reanalyzed,which proves feasibility of the proposed procedure. | ZHENG Hong1,2 & JIANG Wei2 1 China Three Gorges University,Key Laboratory of Geological Hazards on Three Gorges Reservoir Area,Ministry of Education, Yichang 443002,China 2 State Key Laboratory of Geomechanics and Geotechnical Engineering,Institute of Rock and Soil Mechanics,Chinese Academy of Sciences,Wuhan 430071,China | 2009 | Science China(Technological Sciences)2009，52，9： | 15 |
| 3 | ASYMPTOTIC BEHAVIOUR OF EIGENVALUES FOR THE DISCONTINUOUS BOUNDARY-VALUE PROBLEM WITH FUNCTIONAL-TRANSMISSION CONDITIONS显示文摘In this study, the boundary-value problem with eigenvalue parameter generated by the differential equation with discontinuous coefficients and boundary conditions which contains not only endpoints of the considered interval, but also point of discontinuity and linear functionals is investigated. So, the problem is not pure boundary-value. The authors single out a class of linear functionals and find simple algebraic conditions on coefficients, which garantee the existence of innnit number eigenvalues. Also the asymptotic formulas for eigenvalues are found. | O.Sh.Mukhtarov Department of Mathematics, Science and Arts Faculty, Gaziosmanpasa University, Tokat, TurkeyMustafa Kandemir Department of Mathematics, Faculty of A mas y a Education, Ondokuz Mayis University, Amasya, Turkey | 2002 | Acta Mathematica Scientia2002，22，3： | 10 |
| 4 | Error analysis of the semi-discrete local discontinuous Galerkin method for semiconductor device simulation models显示文摘In this paper we continue our effort in Liu-Shu (2004) and Liu-Shu (2007) for developing local discontinuous Galerkin (LDG) finite element methods to discretize moment models in semiconductor device simulations. We consider drift-diffusion (DD) and high-field (HF) models of one-dimensional devices, which involve not only first derivative convection terms but also second derivative diffusion terms, as well as a coupled Poisson potential equation. Error estimates are obtained for both models with smooth solutions. The main technical difficulties in the analysis include the treatment of the inter-element jump terms which arise from the discontinuous nature of the numerical method, the nonlinearity, and the coupling of the models. A simulation is also performed to validate the analysis. | LIU YunXian 1, & SHU Chi-Wang 2 1 School of Mathematics, Shandong University, Jinan 250100, China 2 Division of Applied Mathematics, Brown University, Providence, RI 02912, USA | 2010 | Science China Mathematics2010，53，12： | 8 |
| 5 | On developing data-driven turbulence model for DG solution of RANS显示文摘High-order Discontinuous Galerkin(DG) methods have been receiving more and more attentions in the area of Computational Fluid Dynamics(CFD) because of their high-accuracy property. However, it is still a challenge to obtain converged solution rapidly when solving the Reynolds Averaged Navier–Stokes(RANS) equations since the turbulence models significantly increase the nonlinearity of discretization system. The overall goal of this research is to develop an Artificial Neural Networks(ANNs) model with low complexity acting as an algebraic turbulence model to estimate the turbulence eddy viscosity for RANS. The ANN turbulence model is off-line trained using the training data generated by the widely used Spalart–Allmaras(SA) turbulence model before the Optimal Brain Surgeon(OBS) is employed to determine the relevancy of input features.Using the selected relevant features, a fully connected ANN model is constructed. The performance of the developed ANN model is numerically tested in the framework of DG for RANS, where the‘‘DG+ANN' method provides robust and steady convergence compared to the ‘‘DG+SA' method. The results demonstrate the promising potential to develop a general turbulence model based on artificial intelligence in the future given the training data covering a large rang of flow conditions. | Liang SUN Wei AN Xuejun LIU Hongqiang LYU | 2019 | Chinese Journal of Aeronautics2019，32，8： | 7 |
| 6 | Numerical simulations of deformation and movement of blocks within North China in response to 1976 Tangshan earthquake显示文摘Using methods of discontinuous deformation analysis and finite element (DDA+FEM), this paper simulates dynamic processes of the Tangshan earthquake of 1976, which occurred in the northern North China where its internal blocks apparently interacted. Studies focus upon both the movement and deformation of the blocks, in particular, the Ordos block, and variations of stress states on the boundary faults. The Tangshan earthquake was composed of three events: slipping motions of NNE-striking major fault, NE-striking fault near the northeastern end of the NNE-striking fault, and NW-striking fault on the southeastern side of the NNE-striking fault. Compared with previous studies, our model yields a result that is more agreeable with the configuration of aftershock distributions. A number of data are presented, such as the principle stress field during the earthquake, contours of the maximum shear stress, the strike-slip deformation between blocks near the earthquake focus, time-dependent variations of slips of earthquake-triggered faulting, the maximum slip distance, and stress drops. These results are in accord with the earthquake source mechanism, basic parameters from earthquake wave study, macro-isoseismic line, observed horizontal displacement vectors, etc. The Tangshan earthquake exerted different influences on the adjacent blocks and boundary faults between them, thus resulting in differential movement and deformation. The Ordos block seems to have experienced the small-scale counterclockwise rotation and deformation, but its northeast part, bounded on the east by the Taihangshan and on the north by the Yanshan and Yinshan belts, underwent relatively stronger deformation. The Tangshan earthquake also changed the stress state of boundary faults of the North China, leading to an increase in shear stress and a decrease in normal stress in the NW-trending Zhangjiakou-Penglai fault through Tangshan City and the northern border faults of the Ordos block, and therefore raises the potential risk of earthquake occurrence. This result is supported by the facts that a series of Ms≥ 6 earthquakes took place at the northern margin of the Ordos block after the Tangshan earthquake. | BAI Wuming (白武明) LIN Banghui (林邦慧) CHEN Zu'an (陈祖安) | 2003 | Science China Earth Sciences2003，46，z2： | 5 |
| 7 | The interaction between membrane structure and wind based on the discontinuous boundary element显示文摘Small disturbance potential theory is widely used in solving aerodynamic problems with low Mach numbers, and it plays an important role in engineering design. Concerning structure wind engineering, the body of the structure is in a low velocity wind field, with a low viscosity of air and thin boundary layer, therefore, the tiny shear stress caused by the boundary layer can be ignored, only wind pressure being considered. In this paper, based on small disturbance potential theory, the fluid-structure interaction between the wind and membrane structure is analyzed by joint utilization of the boundary element method (BEM) and finite element method (FEM) through a loose-coupling procedure. However, the boundary of flow field to be calculated is not fully smooth, corners and edges still exist, so the discontinuous boundary element is introduced. Furthermore, because a large scale boundary element equation set with a nonsymmetrical coefficient matrix must be solved, this paper imports a preconditioning GMRES (the generalized minimum residual) iterative algorithm, which takes full advantage of the boundary element method. Several calculation examples have verified the correctness and soundness of the treatments mentioned above. | LI Ya &YE JiHong Key Laboratory of R.C. & P.C. Structures of Ministry of Education, Southeast University, Nanjing 210096, China | 2010 | Science China(Technological Sciences)2010，53，2： | 5 |
| 8 | On the Navier-Stokes Equations for Exothermically Reacting Compressible Fluids显示文摘Abstract We analyze mathematical models governing planar flow of chemical reaction from unburnt gasesto burnt gases in certain physical regimes in which diffusive effects such as viscosity and heat conduction aresignificant. These models can be then formulated as the Navier-Stokes equations for exothermically reactingcompressible fluids. We first establish the existence and dynamic behavior, including stability, regularity, andlarge-time behavior, of global discontinuous solutions of large oscillation to the Navier-Stokes equations withconstant adiabatic exponent γ and specific heat C_v. Our approach for the existence and regularity is to combinethe difference approximation techniques with the energy methods, total variation estimates, and weak conver-gence argumeots to deal with large jump discontinuities; and for large-time behavior is an a posteriori argumentdirectly from the weak form of the equations. The approach and ideas we develop here can be applied to solvinga more complicated model where | David Hoff Konstantina Trivisa | 2002 | Acta Mathematicae Applicatae Sinica2002，18，1： | 5 |
| 9 | Numerical simulation of dynamic process ofthe Tangshan earthquake显示文摘IntrodnotionItisveryimportanttostudytheruptureprocessofewthquakefaultsforeathquakeengineering,earthquakeforecastingandreducingearthquakedisaster.Inversemethodandnumericalmethodareoftenusedtoinvestigatetheprobleminseismology.Theinversemethodisonthebas... | 蔡永恩 何涛 王仁 | 1999 | Acta Seismologica Sinica(English Edition)1999，12，5： | 4 |
| 10 | GLOBAL SHOCK SOLUTIONS TO A CLASS OF PISTON PROBLEMS FOR THE SYSTEM OF ONE DIMENSIONAL ISENTROPIC FLOW显示文摘The autors apply the result obtained in [1] to consider a class of discontinuous piston problems for the system of one dimensional isentropic flow and prove that this problem admits a unique global classical discontinuous solution only containing one shock. | 李大潜 赵彦淳 | 1991 | Chinese Annals of Mathematics,Series B1991，12，4： | 4 |
| 11 | Evaluation of mountain slope stability considering the impact of geological interfaces using discrete fractures model显示文摘The stability of rock slope is often controlled by the existing discontinuous surfaces, such as discrete fractures, which are ubiquitously distributing in a geological medium. In contrast with the traditional approaches used in soil slope with a continuous assumption, the simulation methods of jointed rock slope are different from that of in soil slope. This paper presents a study on jointed rock slope stability using the proposed discontinuous approach, which considers the effects of discrete fractures. Comparing with traditional methods to model fractures in an implicit way, the presented approach provides a method to simulate fractures in an explicit way, where grids between rock matrix and fractures are independent. To complete geometric components generation and mesh partition for the model, the corresponding algorithms were devised. To evaluate the stability state of rock slope quantitatively, the strength reduction method was integrated into our analysis framework. A benchmark example was used to verify the validation of the approach. A jointed rock slope, which contains natural fractures, was selected as a case study and was simulated regarding the workflow of our framework. It was set up in the light of the geological condition of the site. Slope stability was evaluated under different loading conditions with various fracture patterns. Numerical results show that fractures have significant contributions to slope stability, and different fracture patterns would lead to different shapes of the slip surface. The devised method has the ability to calculate a non-circular slip surface, which is different from a circular slip surface obtained by classical methods. | WANG Lu-yu CHEN Wei-zhong TAN Xu-yan TAN Xian-jun YUAN Jing-qiang LIU Qi | 2019 | Journal of Mountain Science2019，16，9： | 3 |
| 12 | A priori error analysis of a discontinuous Galerkin approximation for a kind of compressible miscible displacement problems显示文摘A kind of compressible miscible displacement problems which include molecular diffusion and dispersion in porous media are investigated.A symmetric interior penalty discontinuous Galerkin (SIPG) method is applied to the coupled system of flow and transport.Using the induction hypotheses instead of the cut-off operator and the interpolation projection properties,a priori hp error estimates are presented.The error bounds in L2(H1) norm for concentration and in L∞(L2) norm for velocity are optimal in h and suboptimal in p with a loss of power 1/2. | YANG JiMing1,& CHEN YanPing2 1College of Science,Hunan Institute of Engineering,Xiangtan 411104,China 2School of Mathematical Sciences,South China Normal University,Guangzhou 510631,China | 2010 | Science China Mathematics2010，53，10： | 3 |
| 13 | Mantle flow beneath the Asian continent and its force to the crust显示文摘The mantle unsteady flows, which are in an incompressible and isoviscous spherical shell, are investigated by using algorithms of the parallel Lagrange multiplier dissonant decomposition method (LMDDM) and the parallel Lagrange multiplier discontinuous deformation analyses (LMDDA) in this paper. Some physical fields about mantle flows such as velocity, pressure, temperature, stress and the force to the crust of the Asian continent are calculated on a parallel computer. | 孙荀英 张怀 梁国平 | 2002 | Acta Seismologica Sinica(English Edition)2002，15，3： | 3 |
| 14 | NUMERICAL SIMULATION OF DISCONTINUOUS FLOW IN CIRCULAR CONDUITS显示文摘NUMERICAL SIMULATION OF DISCONTINUOUS FLOW IN CIRCULAR CONDUITSNUMERICALSIMULATIONOFDISCONTINUOUSFLOWINCIRCULARCONDUITS￥MaoZe... | Mao Ze-Yu (Hydraulics Group, Department of hydraulic enginering, Tsinghua University, Beijing 100084, P. R. China) | 1996 | Journal of Hydrodynamics1996，8，3： | 3 |
| 15 | Monotone Iterative Methodfor Nonlinear Discontinuous ParabolicDifferential Equations显示文摘In this paper, the existence of solutions for discontinuous nonlinear parabolic differential IBVP is proved by using a more generalized monotone iterative method. Moreover, the convergence of this method is discussed. | Zou Qingsong Tian Yan Let Jingan(College of Mathematical Sciences, Wuhan University, Wuhan 430072, China) | 1998 | Wuhan University Journal of Natural Sciences1998，3，4： | 2 |
| 16 | SUPERCONVERGENCE OF DISCONTINUOUS GALERKIN METHOD FOR NONSTATIONARY HYPERBOLIC EQUATION显示文摘AbstractFor the first order nonstationary hyperbolic equation taking the piecewise linear discontinuous Galerkin solver, we prove that under the uniform rectangular partition, such a discontinuous solver, after postprossesing, can have two and half approximative order which is half order higher than the optimal estimate by Lesaint and Raviart under the rectangular partition. | Chen, Y Lin, JF Lin, Q | 2002 | Journal of Computational Mathematics2002，20，4： | 2 |
| 17 | A Rotating Pendulum Linked by an Oblique Spring显示文摘We present a novel model which comprises a rotating pendulum linked by an oblique spring pinned to its rigid support.This model provides a cylindrical dynamical system with both smooth and discontinuous regimes depending on the value of a system parameter and also the dynamics transient relying on the coupling strength between the pendulum and the linked spring.The presented system behaves with both standard(smooth)and nonstandard(discontinuous)nonlinear dynamics of equilibrium bifurcations and the periodic patterns when it is unperturbed.Complicated resonant structures of period,quasi-period and stochastic phenomena are presented for the system with unique harmonic perturbation.The chaotic behavior of the system perturbed by both viscous-damping and external excitations is also demonstrated. | 曹庆杰 韩宁 田瑞兰 | 2011 | Chinese Physics Letters2011，28，6： | 2 |
| 18 | GLOBAL EXISTENCE OF CLASSICAL SOLUTIONS TO THE TYPICAL FREE BOUNDARY PROBLEM FOR GERENAL QUASILINEAR HYPERBOLIC SYSTEMS AND ITS APPLICATIONS显示文摘In this paper the authors prove the existence and uniqueness of global classicalsolutions to the typical free boundary problem for general quasilinear hyperbolic systems.As an application,a unique global discontinuous solution only containing n shocks ont≥0 is obtained for a class of generalized Riemann problem for the quasilinear hyperbolicsystem of n conservation laws. | 李大潜 赵彦淳 | 1990 | Chinese Annals of Mathematics,Series B1990，11，1： | 2 |
| 19 | ROBUST ANALYSIS AND GLOBAL MINIMIZATION OF A CLASS OF DISCONTINUOUS FUNCTIONS (Ⅱ)显示文摘In this Paper we continue to investigate global minimization problems. An integral approach is applied to treat a global minimization problem of a discontinuous function. With the help ofthe theory of measure (Q-measure) and integration, optimality conditions of a robust function over arobust set are derived. Algorithms and their implementations for finding global minima are proposed.Numerical tests and applications show that the algorithms are effective. | 郑权 | 1990 | Acta Mathematicae Applicatae Sinica1990，6，4： | 2 |
| 20 | Method for Predicting the Fatigue Life of Geometrically Discontinuous Structures Under Combined Bending and Torsion显示文摘The fatigue damage model based on theory of damage mechanics is capable of predicting the fatigue life under multiaxial loading. Meanwhile, the application of critical plane method in the prediction of multiaxial fatigue life has made certain progress. According to the law of thermodynamics, a new damage evolution equation is developed in the present study to predict the fatigue life of geometrically discontinuous structure under tension-torsion loading based on damage mechanics and the critical plane method. The essence of this approach is tha t the st rain parame ter of the uniaxial nonlinear fatigue damage model is replaced with the equivalent strain, which consists of the releva nt parame ters of the critical plane. However, it is difficult to calculate the stress-strain status and the critical plane position of geometrically dis? continuous structure by theoretical methods because of the existence of stress concentration and the multiaxial nonproportional characteristics. Therefore, a new numerical simulation method is proposed to determine the critical plane of geometrically discontinuous structure under multiaxial loading by means of the finite element method and MATLAB software. The fatigue life of notched specimens subjected to combined bending and torsion is predicted using the proposed met hod, and the result is compared with t hose from the experimen ts and the Manson-Cfiffin law. The comparisons show that the proposed method is superior to the Manson-Coffin law and is capable of reproducing the experimental results reasonably when the geometry of the structure is complex. It completely meets the needs of engineering practice. | Jianhui Liu Xuemei Pan Yaobing Wei Youliang Wang | 2019 | Acta Mechanica Solida Sinica2019，32，3： | 2 |
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