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Numerical Methods (numerical + methods)
Kinds of Numerical Methods Selected AbstractsTeaching differential equations in different environments: A first approachCOMPUTER APPLICATIONS IN ENGINEERING EDUCATION, Issue 3 2010Filipa Carneiro Abstract The use of specific softwares was the basis for a new approach for teaching ordinary and partial differential equations, in the field of heat transfer and fluid mechanics. The main objective was to enhance learning effectiveness of Numerical Methods in the post-graduate course of Polymers Engineering at the University of Minho. This degree takes place into two different environments: at the university campus and at the industrial field. Different commercial codes were used, namely EXCEL, MATLAB, and FLUENT, as well as two tools developed in house at University of Minho: CoNum and a graphics application PDE v.1. Lectures were based on videoconferencing and other web utilities. The teaching methodology presented and discussed in this article was well received and accepted by the post-graduate students, motivating teachers to improve their teaching/learning strategies. © 2009 Wiley Periodicals, Inc. Comput Appl Eng Educ 18: 555,562, 2010; View this article online at wileyonlinelibrary.com; DOI 10.1002/cae.20231 [source] Holistic but customized resources for a course in numerical methodsCOMPUTER APPLICATIONS IN ENGINEERING EDUCATION, Issue 4 2003Autar Kaw Abstract Prototype web based resources have been developed for an undergraduate course in Numerical Methods. The web modules are holistic, that is they include pre-requisite information, real-life applications, presentations and notes, simulations, and self-assessment. The student interest and learning are maximized by providing customization of content based on a student's engineering major and computational system of choice. © 2004 Wiley Periodicals, Inc. Comput Appl Eng Educ 11: 203,210, 2003; Published online in Wiley InterScience ( www.interscience.wiley.com); DOI 10.1002/cae.10053 [source] Numerical Methods to Simulate and Visualize Detailed Crane ActivitiesCOMPUTER-AIDED CIVIL AND INFRASTRUCTURE ENGINEERING, Issue 3 2009Shih-Chung Kang One major consideration for virtual construction is the simulation of the operation of construction equipment for a construction project. This research specifically focuses on developing a mathematical model to support the simulation and visualization of cranes, the most critical equipment in terms of project controls. This model is composed of two submodels,a kinematics model and a dynamic model. The kinematics model is to present the crane components controlled by the operators. The dynamic model is to present the dynamic behavior in suspended system (including the cable and rigging object), which cannot be controlled directly by the operators. To verify the feasibility of these methods, a computer program that simulates and visualizes detailed crane activities was developed. This program supports the real-time visualization of crane activities with high degree of reality accuracy and also, enables the detailed simulation of long-term construction projects. [source] Book Review: Numerical Methods for Scientists and Engineers.CRYSTAL RESEARCH AND TECHNOLOGY, Issue 12 2002By H. M. Antia No abstract is available for this article. [source] The journal Communications in Numerical Methods in Engineering with Biomedical Applications becomes the International Journal for Numerical Methods in Biomedical Engineering (IJNMBE) from 1st January 2010INTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS, Issue 16 2009Perumal Nithiarasu Editor Abstract Communications in Numerical Methods in Engineering, founded by Roland W. Lewis in 1985, will change its title to the ,International Journal for Numerical Methods in Biomedical Engineering' and has a revised Aims and Scope. Copyright © 2009 John Wiley & Sons, Ltd. [source] The journal Communications in Numerical Methods in Engineering with Biomedical Applications becomes the International Journal for Numerical Methods in Biomedical Engineering (IJNMBE) from 1st January 2010INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING, Issue 11 2009Perumal Nithiarasu Editor Abstract Communications in Numerical Methods in Engineering, founded by Roland W. Lewis in 1985, will change its title to the ,International Journal for Numerical Methods in Biomedical Engineering' and has a revised Aims and Scope. Copyright © 2009 John Wiley & Sons, Ltd. [source] Call for Papers: Special Issue on ,Flow in collapsible tube or over compliant surface for biomedical applications' Communications in Numerical Methods in Engineering (CNM)INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING, Issue 4 2008Article first published online: 7 FEB 200 No abstract is available for this article. [source] Call for Papers: Special Issue on ,Recent Advances in Computational Techniques for Biomedical Imaging' Communications in Numerical Methods in Engineering (CNM)INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING, Issue 2 2008Prof. Guo-Wei Wei Submitting Editor Guest Editor No abstract is available for this article. [source] Instationary aeroelastic computation of yacht sailsINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 8 2001Heinrich Schoop Abstract Effective schemes exist to calculate aerodynamic forces for thin bodies and structural dynamics of flexible membranes. The fluid dynamic of thin wings in a irrotational flow leads to the lifting surface theory. Neglecting the inertia of the membrane the structural dynamics are solved by the non-linear (FEM). But the interaction of flexible membranes and an irrotational flow causes problems due to the different nature of the mathematical equations. On the one hand, there is a partial differential equation for the structural dynamics and on the other hand, there is a singular integral equation for the aerodynamics. The numerical discretization scheme has to fit these different types of equation. Our work introduces a new interaction scheme to couple the singular integral equation of the lifting surface theory with the non-linear FEM of the membrane static. The fundamental examinations, showed by Schoop et al. (International Journal for Numerical Methods in Engineering 1998; 41: 217,219), are applied to realistic sail geometries and the aerodynamics is extended to instationary flow conditions. Copyright © 2001 John Wiley & Sons, Ltd. [source] Second-order Galerkin-Lagrange method for the Navier-Stokes equations (retracted article),NUMERICAL METHODS FOR PARTIAL DIFFERENTIAL EQUATIONS, Issue 6 2005Mohamed Bensaada Abstract It has come to the attention of the editors and publisher that an article published in Numerical Methods and Partial Differential Equations, "Second-order Galerkin-Lagrange method for the Navier-Stokes equations," by Mohamed Bensaada, Driss Esselaoui, and Pierre Saramito, Numer Methods Partial Differential Eq 21(6) (2005), 1099,1121 included large portions that were copied from the following paper without proper citation: "Convergence and nonlinear stability of the Lagrange-Galerkin method for the Navier-Stokes equations," Endre Suli, Numerische Mathematik, Vol. 53, No. 4, pp. 459,486 (July, 1988). We have retracted the paper and apologize to Dr. Suli Numer Methods Partial Differential Eq (2007)23(1)211. [source] Models for the estimation of a ,no effect concentration'ENVIRONMETRICS, Issue 1 2002Ana M. Pires Abstract The use of a no effect concentration (NEC), instead of the commonly used no observed effect concentration (NOEC), has been advocated recently. In this article models and methods for the estimation of an NEC are proposed and it is shown that the NEC overcomes many of the objections to the NOEC. The NEC is included as a threshold parameter in a non-linear model. Numerical methods are then used for point estimation and several techniques are proposed for interval estimation (based on bootstrap, profile likelihood and asymptotic normality). The adequacy of these methods is empirically confirmed by the results of a simulation study. The profile likelihood based interval has emerged as the best method. Finally the methodology is illustrated with data obtained from a 21 day Daphnia magna reproduction test with a reference substance, 3,4-dichloroaniline (3,4-DCA), and with a real effluent. Copyright © 2002 John Wiley & Sons, Ltd. [source] Numerical methods for large-eddy simulation in general co-ordinatesINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 1 2004Gefeng Tang Abstract Large scale unsteady motions in many practical engineering flows play a very important role and it is very unlikely that these unsteady flow features can be captured within the framework of Reynolds averaged Navier,Stokes approach. Large-eddy simulation (LES) has become, arguably, the only practical numerical tool for predicting those flows more accurately since it is still not realistic to apply DNS to practical engineering flows with the current and near future available computing power. Numerical methods for the LES of turbulent flows in complex geometry have been developed and applied to predict practical engineering flows successfully. The method is based on body-fitted curvilinear co-ordinates with the contravariant velocity components of the general Navier,Stokes equations discretized on a staggered orthogonal mesh. For incompressible flow simulations the main source of computational expense is due to the solution of a Poisson equation for pressure. This is especially true for flows in complex geometry. A multigrid 3D pressure solver is developed to speed up the solution. In addition, the Poisson equation for pressure takes a simpler form with no cross-derivatives when orthogonal mesh is used and hence resulting in increased convergence rate and producing more accurate solutions. Copyright © 2004 John Wiley & Sons, Ltd. [source] Performance of finite volume solutions to the shallow water equations with shock-capturing schemesINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 10 2002K. S. Erduran Abstract Numerical methods have become well established as tools for solving problems in hydraulic engineering. In recent years the finite volume method (FVM) with shock capturing capabilities has come to the fore because of its suitability for modelling a variety of types of flow; subcritical and supercritical; steady and unsteady; continuous and discontinuous and its ability to handle complex topography easily. This paper is an assessment and comparison of the performance of finite volume solutions to the shallow water equations with the Riemann solvers; the Osher, HLL, HLLC, flux difference splitting (Roe) and flux vector splitting. In this paper implementation of the FVM including the Riemann solvers, slope limiters and methods used for achieving second order accuracy are described explicitly step by step. The performance of the numerical methods has been investigated by applying them to a number of examples from the literature, providing both comparison of the schemes with each other and with published results. The assessment of each method is based on five criteria; ease of implementation, accuracy, applicability, numerical stability and simulation time. Finally, results, discussion, conclusions and recommendations for further work are presented. Copyright © 2002 John Wiley & Sons, Ltd. [source] Influence of wick characteristics on heat pipe performanceINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 7 2006Misheck G. Mwaba Abstract The performance of a heat pipe depends on several factors, one of which is the nature of the wick structure. Optimization of heat pipe performance requires wick structures that can provide high capillary pressure, and yet still offer low resistance to fluid flow. The current level of technology being developed in our laboratory makes it possible to engineer desired wick structures both micro- and macroscopically, especially tailored to optimize heat pipe performance. In order to assist the fabrication of unique wick structure, the influence of wick structure characteristics on heat pipe performance is numerically investigated in this work. Numerical methods are an effective tool to significantly reduce the number of experimental trials. Comparisons are made between performances of heat pipe with different wick structures; coarse pore sizes, fine pore sizes and a composite comprised of coarse and fine pore sizes. Results indicate superior performance, with a factor of up to 2, for heat pipe with composite structure combining coarse/fine wick. Validation of the simulation result presented using experimental data is being carried out. Copyright © 2005 John Wiley & Sons, Ltd. [source] The reform of palaeontology and the rise of biogeography , 25 years after ,ontogeny, phylogeny, paleontology and the biogenetic law' (Nelson, 1978)JOURNAL OF BIOGEOGRAPHY, Issue 5 2004David M. Williams Abstract Aim, To document the historical development of cladistics and the roles palaeontology and biogeography played in establishing coherent concepts of phylogenetic relationships focusing on some aspects of the contributions of Gareth Nelson. Conclusions, Nelson's reformulation of the threefold parallelism provides a rationale for investigating phylogeny, replacing the central role palaeontology once played with biogeography, adding a spatial dimension to the concept of phylogeny. This approach to phylogeny replaces the old ,transformationist' view with the cladistic view, the latter dependent on discovering relationships among taxa. Numerical phylogenetic methods are inherently ,transformationist' and have replaced stratigraphy as the key to phylogenetic relationships. Numerical methods in systematics and biogeography are inherently transformational and suffer the same problems as the old palaeontology. [source] Numerical methods for palindromic eigenvalue problems: Computing the anti-triangular Schur formNUMERICAL LINEAR ALGEBRA WITH APPLICATIONS, Issue 1 2009D. Steven Mackey Abstract We present structure-preserving numerical methods for the eigenvalue problem of complex palindromic pencils. Such problems arise in control theory, as well as from palindromic linearizations of higher degree palindromic matrix polynomials. A key ingredient of these methods is the development of an appropriate condensed form,the anti-triangular Schur form. Ill-conditioned problems with eigenvalues near the unit circle, in particular near ±1, are discussed. We show how a combination of unstructured methods followed by a structured refinement can be used to solve such problems accurately. Copyright © 2008 John Wiley & Sons, Ltd. [source] On the numerical solution of hyperbolic PDEs with variable space operatorNUMERICAL METHODS FOR PARTIAL DIFFERENTIAL EQUATIONS, Issue 5 2009Allaberen Ashyralyev Abstract The first and second order of accuracy in time and second order of accuracy in the space variables difference schemes for the numerical solution of the initial-boundary value problem for the multidimensional hyperbolic equation with dependent coefficients are considered. Stability estimates for the solution of these difference schemes and for the first and second order difference derivatives are obtained. Numerical methods are proposed for solving the one-dimensional hyperbolic partial differential equation. © 2008 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 2009 [source] Numerical methods for fourth-order nonlinear elliptic boundary value problemsNUMERICAL METHODS FOR PARTIAL DIFFERENTIAL EQUATIONS, Issue 4 2001C. V. Pao Abstract The aim of this article is to present several computational algorithms for numerical solutions of a nonlinear finite difference system that represents a finite difference approximation of a class of fourth-order elliptic boundary value problems. The numerical algorithms are based on the method of upper and lower solutions and its associated monotone iterations. Three linear monotone iterative schemes are given, and each iterative scheme yields two sequences, which converge monotonically from above and below, respectively, to a maximal solution and a minimal solution of the finite difference system. This monotone convergence property leads to upper and lower bounds of the solution in each iteration as well as an existence-comparison theorem for the finite difference system. Sufficient conditions for the uniqueness of the solution and some techniques for the construction of upper and lower solutions are obtained, and numerical results for a two-point boundary-value problem with known analytical solution are given. © 2001 John Wiley & Sons, Inc. Numer Methods Partial Differential Eq 17:347,368, 2001 [source] Numerical valuation of options under Kou's modelPROCEEDINGS IN APPLIED MATHEMATICS & MECHANICS, Issue 1 2007Jari ToivanenArticle first published online: 6 AUG 200 Numerical methods are developed for pricing European and American options under Kou's jump-diffusion model which assumes the price of the underlying asset to behave like a geometrical Brownian motion with a drift and jumps whose size is log-double-exponentially distributed. The price of a European option is given by a partial integro-differential equation (PIDE) while American options lead to a linear complementarity problem (LCP) with the same operator. Spatial differential operators are discretized using finite differences on nonuniform grids and time stepping is performed using the implicit Rannacher scheme. For the evaluation of the integral term easy to implement recursion formulas are derived which have optimal computational cost. When pricing European options the resulting dense linear systems are solved using a stationary iteration. Also for pricing American options similar iterations can be employed. A numerical experiment demonstrates that the described method is very efficient as accurate option prices can be computed in a few milliseconds on a PC. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Reliability Model for Polyimide,Metal Interconnect Shorts in GaAs ASICsQUALITY AND RELIABILITY ENGINEERING INTERNATIONAL, Issue 8 2004N. Strifas Abstract A physical reliability model has been developed to calculate the time to failure of polyimide,metal multilevel interconnected GaAs components due to the shorts between interconnect metallizations through a polyimide interlayer. The failure mechanism for the shorts between neighboring metals through the polyimide is described as a stress-assisted diffusion process along a polyimide microcrack due to the combination of process defect and high thermal stress concentration. The finite element method has been used to determine the temperature increase during operation and the resulting thermal stress due to the difference in coefficients of thermal expansion (CTEs) of the materials used in the multilevel metallization GaAs module of devices. Numerical methods have been used to solve the partial differential diffusion equations with stress gradients in order to obtain the time to failure of the devices. The time to failure for the shorts between metal level 4 and metal 2 at 123 °C operating temperature was calculated to be 20 h for the conditions analyzed. The activation energy for the failure of the shorts between two level metals was calculated to be 0.48 eV. Copyright © 2004 John Wiley & Sons, Ltd. [source] CFD Sinflow Library: A framework to develop engineering educational codes in CFD and thermal sciencesCOMPUTER APPLICATIONS IN ENGINEERING EDUCATION, Issue 1 2004Romeu André Pieritz Abstract This work introduces the educational code development library "CFD Sinflow Library" specialized in 2D numerical methods in computational fluid dynamics (CFD) and termal science. This library is for research, educational, and engineering purposes like an open and platform independent architecture. The library was developed with C++ standard programming language using an object-oriented approach allowing educators and graduation/undergraduation students to access the numerical methods in a simplified way. The numerical capabilities and results quality are evaluated, where comparisons are made with benchmark and analytical solutions. © 2004 Wiley Periodicals, Inc. Comput Appl Eng Educ 12: 31,43, 2004; Published online in Wiley InterScience (www.interscience.wiley.com); DOI 10.1002/cae.10056 [source] Holistic but customized resources for a course in numerical methodsCOMPUTER APPLICATIONS IN ENGINEERING EDUCATION, Issue 4 2003Autar Kaw Abstract Prototype web based resources have been developed for an undergraduate course in Numerical Methods. The web modules are holistic, that is they include pre-requisite information, real-life applications, presentations and notes, simulations, and self-assessment. The student interest and learning are maximized by providing customization of content based on a student's engineering major and computational system of choice. © 2004 Wiley Periodicals, Inc. Comput Appl Eng Educ 11: 203,210, 2003; Published online in Wiley InterScience ( www.interscience.wiley.com); DOI 10.1002/cae.10053 [source] STRANDS: Interactive Simulation of Thin Solids using Cosserat ModelsCOMPUTER GRAPHICS FORUM, Issue 3 2002Dinesh K. Pai Strandsare thin elastic solids that are visually well approximated as smooth curves, and yet possess essential physical behaviors characteristic of solid objects such as twisting. Common examples in computer graphics include: sutures, catheters, and tendons in surgical simulation; hairs, ropes, and vegetation in animation. Physical models based on spring meshes or 3D finite elements for such thin solids are either inaccurate or inefficient for interactive simulation. In this paper we show that models based on the Cosserat theory of elastic rods are very well suited for interactive simulation of these objects. The physical model reduces to a system of spatial ordinary differential equations that can be solved efficiently for typical boundary conditions. The model handles the important geometric non-linearity due to large changes in shape. We introduce Cosserat-type physical models, describe efficient numerical methods for interactive simulation of these models, and implementation results. [source] An experimental investigation of water level effects on the dynamic behaviour of a large arch damEARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 8 2001Jean Proulx Abstract The need for full-scale dynamic tests, which are recognized as the most reliable method to evaluate a structure's vibration properties, is increasing as new analysis techniques are developed that take into account the complex interaction phenomenons that occur in dam,reservoir,foundation systems. They are extremely useful to obtain reliable data for the calibration of newly developed numerical methods. The Earthquake Engineering and Structural Dynamics Research Center (CRGP) at the University of Sherbrooke has been developing and applying dynamic testing methods for large structures in the past 10 years. This paper presents the experimental evaluation of the effects of the varying water level on the dynamic response of the 180 m Emosson arch dam in Switzerland. Repeated forced-vibration tests were carried out on the dam during four different periods of the reservoir's filling cycle during a one-year span. Acceleration and hydrodynamic pressure frequency responses were obtained at several locations while the dam was subjected to horizontal harmonic loading. The variation of the resonant frequencies as a function of the reservoir level is investigated. A summary of the ongoing numerical correlation phase with a three-dimensional finite element model for the dam,reservoir,foundation system is also presented. Copyright © 2001 John Wiley & Sons, Ltd. [source] EVOLUTION OF NICHE WIDTH AND ADAPTIVE DIVERSIFICATIONEVOLUTION, Issue 12 2004Martin Ackermann Abstract Theoretical models suggest that resource competition can lead to the adaptive splitting of consumer populations into diverging lineages, that is, to adaptive diversification. In general, diversification is likely if consumers use only a narrow range of resources and thus have a small niche width. Here we use analytical and numerical methods to study the consequences for diversification if the niche width itself evolves. We found that the evolutionary outcome depends on the inherent costs or benefits of widening the niche. If widening the niche did not have costs in terms of overall resource uptake, then the consumer evolved a niche that was wide enough for disruptive selection on the niche position to vanish; adaptive diversification was no longer observed. However, if widening the niche was costly, then the niche widths remained relatively narrow, allowing for adaptive diversification in niche position. Adaptive diversification and speciation resulting from competition for a broadly distributed resource is thus likely if the niche width is fixed and relatively narrow or free to evolve but subject to costs. These results refine the conditions for adaptive diversification due to competition and formulate them in a way that might be more amenable for experimental investigations. [source] FEM-Simulation of Real and Artificial Microstructures of Mo-Si-B Alloys for Elastic Properties and Comparison with Analytical Methods,ADVANCED ENGINEERING MATERIALS, Issue 10 2007G. Biragoni Various three phase microstructures of Mo-Si-B alloys were simulated in tensile loading conditions using a 2D finite element method to predict the elastic properties of the composite material. Voronoi structures with the same areal fraction of phases as the real microstructures have been generated and simulated similarly. Also, with these Voronoi structures a variation of grain or phase sizes, respectively, was carried out for different compositions in order to study on the elastic properties of the composite. Finally, a comparison was made over the whole temperature range between the above numerical methods, classical analytical approaches and experimentally determined values for Young's modulus E, shear modulus G and Poisson's ratio ,. [source] Online expert systems for fault diagnosis in technical processesEXPERT SYSTEMS, Issue 2 2008Chrissanthi Angeli Abstract: It is generally accepted that there has been an increasing interest in online fault detection and diagnosis techniques for technical processes during the last few years. These techniques come from the artificial intelligence field or are classical numerical methods in combination with artificial intelligence methods. This paper presents a survey of recent research work in online expert systems for fault detection and diagnosis in technical processes. In addition, a short reference to other recent artificial intelligence methods for online fault detection is included and the main advantages and limitations of each method are illustrated. [source] Fatigue crack growth and life prediction of a single interference fitted holed plateFATIGUE & FRACTURE OF ENGINEERING MATERIALS AND STRUCTURES, Issue 10 2010T. N. CHAKHERLOU ABSTRACT To understand the different aspects of fatigue behaviour of complex structural joints it will be much helpful if the effects of different parameters are studied separately. In this article, to study the isolated effect of interference fit on fatigue life a pined hole specimen is investigated. This specimen is a single-holed plate with an oversized pin which force fitted to the hole. The investigation was carried out both experimentally and numerically. In the experimental part, interference fitted specimens along with open hole specimens were fatigue tested to study the experimental effect of the interference fit. In the numerical part, three-dimensional finite element (FE) simulations have been performed in order to obtain the created stresses due to interference fit and subsequent applied longitudinal load at the holed plate. The stress distribution obtained from FE simulation around the hole was used to predict crack initiation life using Smith,Watson,Topper method and fatigue crack growth life using the NASGRO equation with applying the AFGROW computer code. The predicted fatigue life obtained from the numerical methods show a good agreement with the experimental fatigue life. [source] Effects of non-proportional loading paths on the orientation of fatigue crack pathFATIGUE & FRACTURE OF ENGINEERING MATERIALS AND STRUCTURES, Issue 5 2005L. REIS ABSTRACT Fatigue crack path prediction and crack arrest are very important for structural safety. In real engineering structures, there are many factors influencing the fatigue crack paths, such as the material type (microstructure), structural geometry and loading path, etc. In this paper, both experimental and numerical methods are applied to study the effects of loading path on crack orientations. Experiments were conducted on a biaxial testing machine, using specimens made of two steels: 42CrMo4 and CK45 (equivalent to AISI 1045), with six different biaxial loading paths. Fractographical analyses of the plane of the stage I crack propagation were carried out and the crack orientations were measured using optical microscopy. The multiaxial fatigue models, such as the critical plane models and also the energy-based critical plane models, were applied for predicting the orientation of the critical plane. Comparisons of the predicted orientation of the damage plane with the experimental observations show that the shear-based multiaxial fatigue models provide good predictions for stage I crack growth for the ductile materials studied in this paper. [source] Nonlinear FE-analysis of tunnel excavation , comparison of EC7 design approaches.GEOMECHANICS AND TUNNELLING, Issue 1 2010Nichtlineare FE-Analysen im Tunnelbau, Vergleich der Nachweisverfahren des EC Structural analysis; Support; Statik; Stützmittel Abstract Although Eurocode 7 does not mention tunnelling explicitly it is under discussion amongst practitioners to what extent the principles of EC7 can be applied to the design of tunnels. In EC7 three different design approaches, which differ in the application of partial factors on actions, soil strength and resistance, have been established. A characteristic feature of tunnelling is that the surrounding soil or rock represents loading and support for tunnel, similar to deep excavation problems. In addition, the highly nonlinear behaviour of shotcrete linings needs special attention and therefore care must be taken when choosing partial factors of safety. In this contribution the applicability of the different design approaches for tunnelling employing numerical methods are investigated and the differences obtained are discussed. Two examples are presented, namely a station tunnel in soil and a tunnel in rock, both constructed based on NATM principles. Obwohl Tunnelbau im Eurocode 7 nicht explizit erwähnt wird, steht zur Diskussion, ob der EC7 prinzipiell auch für die Bemessung im Tunnelbau anwendbar ist. Im EC7 sind drei Nachweisverfahren definiert, die sich in der Anwendung der Teilsicherheitsfaktoren auf Einwirkungen, Widerstände und Bodenkennwerte unterscheiden. Ein wesentlicher Aspekt im Tunnelbau ist, dass der Baugrund sowohl Einwirkung als auch Widerstand sein kann, und somit sind Parallelen zur Bemessung von Baugruben gegeben. Zusätzlich kommt hinzu, dass das mechanische Verhalten von Spritzbeton hochgradig nichtlinear ist, was bei der Wahl der Teilsicherheitsbeiwerte beachtet werden muss. In diesem Beitrag wird die Anwendbarkeit der unterschiedlichen Nachweisverfahren des EC7 für den Tunnelbau bei Anwendung numerischer Methoden untersucht und die Unterschiede in den Ergebnissen aufgezeigt. Zwei Beispiele wurden gewählt, ein Stationstunnel im Lockergestein und ein Tunnel im Fels, beide nach der Neuen Österreichischen Tunnelbauweise aufgefahren. [source] | ||||||||||||||||||||||||||||||||||||||||