Academic literature on the topic 'Nodal integration technique'
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Journal articles on the topic "Nodal integration technique"
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MJIDILA, Ahmed, Salah Eddine JALAL, Lahbib BOUSSHINE, and Zakaria EL LASKAOUI. "Nodal Integration Technique in Meshless Method." IOSR Journal of Mechanical and Civil Engineering 11, no. 1 (2014): 18–26. http://dx.doi.org/10.9790/1684-11141826.
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FENG, HUI, XIANGYANG CUI, and GUANGYAO LI. "STATIC AND DYNAMIC ANALYSIS OF TIMOSHENKO BEAM USING NODAL INTEGRATION TECHNIQUE." International Journal of Applied Mechanics 04, no. 04 (2012): 1250045. http://dx.doi.org/10.1142/s1758825112500457.
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In this paper, a nodal integration method (NIM) is presented to deal with the static and dynamic problems of Timoshenko beam. In the present method, linear-shape functions are employed to approximate the displacement field, and smoothing domains based on the nodes are further formed for computing the stiffness matrix. Through a smoothing operation, the shear locking is effectively avoided and the computation gets much simpler. For static problems, the upper bounds for a set of benchmark examples are obtained by nodal integration. For dynamic problems, while keeping the shear stiffness matrix the same as NIM, integration based on elements is adopted to construct the bending stiffness matrix to improve the stability and diminish singular modes caused by pure nodal integration. Results computed in this way prove to be much better than pure nodal integration method for free vibration and forced vibration problems. Numerical examples indicate that very accurate results can be obtained when a reasonable number of nodes is used. Both computational efficiency and accuracy are achieved by above formulations.
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Greco, Francesco, Domenico Umbrello, Serena Di Renzo, Luigino Filice, I. Alfaro, and E. Cueto. "Application of the Nodal Integrated Finite Element Method to Cutting: a Preliminary Comparison with the “Traditional” FEM Approach." Advanced Materials Research 223 (April 2011): 172–81. http://dx.doi.org/10.4028/www.scientific.net/amr.223.172.
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FEM implicit formulation shows specific limitations in processes such as cutting, where large deformation results in a heavy mesh distortion. Powerful rezoning-remeshing algorithms strongly reduce the effects of such a limitation but the computational times are significantly increased and additional errors are introduced. Nodal Integration is a recently introduced technique that allows finite element method to provide more reliable results when mesh becomes distorted in traditional FEMs. Furthermore, volumetric locking phenomenon seems to be avoided by using this integration technique instead of other methods, such as the coupled formulations. In this paper, a comparison between a “classical” FEM simulation and the Nodal Integration one is carried out taking into account a simple orthogonal cutting process.
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Liu, G. R., G. Y. Zhang, Y. Y. Wang, Z. H. Zhong, G. Y. Li, and X. Han. "A nodal integration technique for meshfree radial point interpolation method (NI-RPIM)." International Journal of Solids and Structures 44, no. 11-12 (2007): 3840–60. http://dx.doi.org/10.1016/j.ijsolstr.2006.10.025.
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Patel, Bhavana S. S., Babu K. S. Narayan, and Katta Venkataramana. "Strategy for refinement of nodal densities and integration cells in EFG technique." Structural Engineering and Mechanics 59, no. 5 (2016): 901–20. http://dx.doi.org/10.12989/sem.2016.59.5.901.
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Canales, Diego, Adrien Leygue, Francisco Chinesta, et al. "Efficient Updated-Lagrangian Simulations in Forming Processes." Key Engineering Materials 651-653 (July 2015): 1294–300. http://dx.doi.org/10.4028/www.scientific.net/kem.651-653.1294.
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A new efficient updated-Lagrangian strategy for numerical simulations of material forming processes is presented in this work. The basic ingredients are the in-plane-out-of-plane PGD-based decomposition and the use of a robust numerical integration technique (the Stabilized Conforming Nodal Integration). This strategy is of general purpose, although it is especially well suited for plateshape geometries. This paper is devoted to show the feasibility of the technique through some simple numerical examples.
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Horst, Vernon D., Hetal D. Patel, and Stan C. Hewlett. "Robotic Transhiatal Esophagectomy in a Community Hospital: Evolution of Technique." American Surgeon 82, no. 8 (2016): 730–32. http://dx.doi.org/10.1177/000313481608200832.
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Esophageal cancer is an uncommon but highly lethal disease. Surgical resection is the gold standard of treatment for early-stage disease. Traditional surgical approach entailed significant convalescence, hospital stay, and morbidity and mortality. Transhiatal esophagectomy (THE) involves blind dissection of the esophagus with minimal mediastinal lymphadenectomy. Integration of robotic surgery is an alternate platform for minimally invasive approach while maintaining safety and following oncologic principles. We review our technique for minimally invasive THE using robotic technology, demonstrating the safety and efficacy of robotic technology surgery. We present a retrospective review of a single surgeon's data of patients treated with robotic-assisted THE, with a chart review to evaluate pathology, adequacy of surgical resection, nodal harvest, and perioperative course. Robotic THE (rTHE) shows promise as a valid option for esophageal resection, including premalignant and advanced stages of cancer. Adequate transhiatal mediastinal nodal resection can be performed with the robot.
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Sun, Tingting, Peng Wang, Guanjun Zhang, and Yingbin Chai. "A Modified Radial Point Interpolation Method (M-RPIM) for Free Vibration Analysis of Two-Dimensional Solids." Mathematics 10, no. 16 (2022): 2889. http://dx.doi.org/10.3390/math10162889.
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The classical radial point interpolation method (RPIM) is a powerful meshfree numerical technique for engineering computation. In the original RPIM, the moving support domain for the quadrature point is usually employed for the field function approximation, but the local supports of the nodal shape functions are always not in alignment with the integration cells constructed for numerical integration. This misalignment can result in additional numerical integration error and lead to a loss in computation accuracy. In this work, a modified RPIM (M-RPIM) is proposed to address this issue. In the present M-RPIM, the misalignment between the constructed integration cells and the nodal shape function supports is successfully overcome by using a fixed support domain that can be easily constructed by the geometrical center of the integration cell. Several numerical examples of free vibration analysis are conducted to evaluate the abilities of the present M-RPIM and it is found that the computation accuracy of the original RPIM can be markedly improved by the present M-RPIM.
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Zhou, J. X., J. B. Wen, H. Y. Zhang, and L. Zhang. "A nodal integration and post-processing technique based on Voronoi diagram for Galerkin meshless methods." Computer Methods in Applied Mechanics and Engineering 192, no. 35-36 (2003): 3831–43. http://dx.doi.org/10.1016/s0045-7825(03)00376-1.
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CUI, X. Y., S. LIN, and G. Y. LI. "NODAL INTEGRATION THIN PLATE FORMULATION USING LINEAR INTERPOLATION AND TRIANGULAR CELLS." International Journal of Computational Methods 08, no. 04 (2011): 813–24. http://dx.doi.org/10.1142/s0219876211002848.
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This paper presents a thin plate formulation with nodal integration for bending analysis using three-node triangular cells and linear interpolation functions. The formulation was based on the classic thin plate theory, in which only deflection field was required and dealt with as the field variables. They were assumed to be piecewisely linear and expressed using a set of three-node triangular cells. Based on each node, the integration domain has been further derived, where the curvature in the domain was computed using a gradient smoothing technique (GST). As a result, the curvature in each integration domain is a constant whereby the deflection is compatible in the whole problem domain. The generalized smoothed Galerkin weak form is then used to create the discretized system equations where the system stiffness is obtained using simple summation operation. The essential rotational boundary conditions are imposed in the process of constructing the curvature field in conjunction with imposing the translational boundary conditions in the same way as undertaken in the standard FEM. A number of numerical examples were studied using the present formulation, including both static and free vibration analyses. The numerical results were compared with the reference ones together with those shown in the state-of-art literatures published. Very good accuracy has been achieved using the present method.
Dissertations / Theses on the topic "Nodal integration technique"
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Jia, Yabo. "Numerical simulation of steady states associated with thermomechanical processes." Thesis, Lyon, 2020. http://www.theses.fr/2020LYSEE007.
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De nombreux procédés de fabrication thermomécanique comme le laminage, le soudage ou encore l’usinage mettent en jeu soit des sollicitations mobiles par rapport à la matière fixe, soit de la matière mobile par rapport à des sollicitations fixes. Dans tous les cas, après un régime transitoire en général assez court, les champs thermiques, métallurgiques et mécaniques associés à ces procédés atteignent un état stationnaire. La recherche de ces états stationnaires à l’aide de la méthode des éléments finis classique nécessite de mettre en œuvre des modèles complexes et couteux où les sollicitations se déplacent par rapport à la matière (ou l’inverse). La recherche directe des états stationnaires a fait l’objet de nombreux travaux de recherche ces trente dernières années. Des méthodes sont aujourd’hui disponibles et pour certaines sont proposées dans des codes de calcul du commerce. Ainsi, une option de calcul dite repère mobile proposée par différents auteurs est disponible dans le logiciel SYSWELD. Cette méthode permet de calculer les états thermique, métallurgique et mécanique stationnaires associés à un procédé de soudage, en résolvant un problème de diffusion-convection en thermique et en intégrant, en mécanique, les équations constitutives du comportement du matériau le long des lignes de courant. Si cette méthode a été utilisée avec succès dans de nombreuses applications, elle présente néanmoins quelques limitations. Ainsi le maillage doit être structuré et la convergence des calculs est en général assez lente. Nous proposons dans cette thèse de résoudre le problème mécanique dans un repère lié aux sollicitations, en nous appuyant sur une méthode de calcul par éléments finis reposant sur l’intégration nodale et la technique SCNI (Stabilized Conforming Numerical Integration). Cette méthode permet l’utilisation de maillages en tétraèdres (ou triangles en 2D) sans rencontrer de problème de verrouillage volumique résultant de l’incompressibilité plastique associée au critère de plasticité de von Mises. Plutôt que de rechercher directement l’état stationnaire, l’idée générale est ici de construire l’état stationnaire à partir d’une analyse transitoire en faisant entrer pas à pas la matière par l’amont et en la faisant sortir par l’aval d’un maillage fixe par rapport aux sollicitations et de taille limitée. L’état stationnaire n’est donc atteint qu’au bout d’un certain temps d’analyse. Après une introduction générale (Chapitre 1) et un état de l’art sur les méthodes existantes (Chapitre 2), nous présentons une approche de simulation du mouvement de matière dans le cadre de la méthode des éléments finis classique sur un problème de soudage (Chapitre 3). Nous y proposons également des conditions aux limites thermiques pertinentes pour calculer directement la distribution de températures en régime stationnaire. La méthode des éléments finis reposant sur l’intégration nodale est ensuite décrite au Chapitre 4. Les avantages et inconvénients de la méthode sont discutés. La méthode est validée sur une application en grandes déformations élastoplastiques, un problème de flexion et une simulation thermomécanique de soudage. La méthode des éléments finis reposant sur l’intégration nodale est alors développée pour prendre en compte un mouvement de matière (Chapitre 5). Trois types de mouvement sont considérés : en translation, circulaire et en hélice. Différentes méthodes de transport de champ sont abordées et discutées ainsi que le couplage thermomécanique. Des perspectives à ce travail sont proposées au Chapitre 6. Les perspectives envisagées visent d’une part à améliorer la méthode proposée et d’autre part, à développer la méthode pour simuler d’autres procédés. Une première application de la méthode à la simulation de la coupe orthogonale y est présentée<br>In the numerous thermomechanical manufacturing processes such as rolling, welding, or even machining involve either moving loads with respect to the fixed material or moving material with respect to fixed loads. In all cases, after a transient regime which is generally quite short, the thermal, metallurgical, and mechanical fields associated with these processes reach a steady state. The search for these stationary states using the classical finite element method requires the implementation of complex and expensive models where the loads move with respect to the material (or vice versa). The steady-state simulation in one increment has been the subject of much researches over the past thirty years. Methods are now available and some are integrated into calculation codes commercial. Thus, a so-called Moving Reference Frame method proposed by various authors is available in the SYSWELD software. This method makes it possible to calculate the steady-state of thermal, metallurgical, and mechanical states associated with a welding process, by solving a thermal diffusion-convection problem in thermal-metallurgy and by integrating, in mechanics, the constitutive equations of the material along the streamline. Moreover, this method has been used successfully in many applications, it nevertheless has some limitations. Thus the mesh must be structured and the convergence of computations is generally quite slow. In this thesis, we propose to solve the mechanical problem in a frame linked to the solicitations, by relying on a finite element calculation method based on nodal integration and the SCNI (Stabilized Conforming Numerical Integration) technique. This method allows the use of tetrahedron meshes (or 2D triangles) without encountering a locking problem resulting from the plastic incompressibility associated with the von Mises plasticity criterion. Rather than directly calculating the steady-state, the general idea here is to construct the steady-state from a transient analysis by bringing material step by step upstream and by making it exit downstream of a fixed mesh related to the solicitations and of the limited mesh size. The steady-state is therefore only achieved after certain steps of analysis. Apart from a general introduction (Chapter 1) and a state of the art on the existing methods (Chapter 2), we present an approach of simulation of the movement of material within the framework of the classical finite element method on a welding problem (Chapter 3). We also provide relevant thermal boundary conditions for directly calculating the steady-state of temperature distribution. The finite element method based on the nodal integration technique is then described in Chapter 4. The advantages and disadvantages of the method are discussed. The nodal-integration-based finite element is validated by comparing its simulation results with classical finite element methods in large elastoplastic strains, a bending problem, and a thermomechanical simulation of welding. The nodal-integration-based finite element is then developed and applied to simulate material motion (Chapter 5). Three types of movement are considered: translational, circular, and helical. Different methods of field transport are approached and discussed as well as thermomechanical coupling. Perspectives for this work are presented in Chapter 6. The envisaged perspectives aim, on the one hand, to improve the proposed method and on the other hand, to develop the method to simulate other processes. A first application of the material motion method to the simulation of the orthogonal cut is presented there
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Strohm, Christian. "Circuit Simulation Including Full-Wave Maxwell's Equations." Doctoral thesis, Humboldt-Universität zu Berlin, 2021. http://dx.doi.org/10.18452/22544.
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Diese Arbeit widmet sich der Simulation von elektrischen/elektronischen Schaltungen welche um elektromagnetische Bauelemente erweitert werden. Im Fokus stehen unterschiedliche Kopplungen der Schaltungsgleichungen, modelliert mit der modifizierten Knotenanalyse, und den elektromagnetischen Bauelementen mit deren verfeinerten Modell basierend auf den vollen Maxwell-Gleichungen in der Lorenz-geeichten A-V Formulierung welche durch Finite-Integrations-Technik räumlich diskretisiert werden. Eine numerische Analyse erweitert die topologischen Kriterien für den Index der resultierenden differential-algebraischen Gleichungen, wie sie bereits in anderen Arbeiten mit ähnlichen Feld/Schaltkreis-Kopplungen hergeleitet wurden. Für die Simulation werden sowohl ein monolithischer Ansatz als auch Waveform-Relaxationsmethoden untersucht. Im Mittelpunkt stehen dabei Zeitintegration, Skalierungsmethoden, strukturelle Eigenschaften und ein hybride Ansatz zur Lösung der zugrundeliegenden linearen Gleichungssysteme welcher den Einsatz spezialisierter Löser für die jeweiligen Teilsysteme erlaubt. Da die vollen Maxwell-Gleichungen zusätzliche Ableitungen in der Kopplungsstruktur verursachen, sind bisher existierende Konvergenzaussagen für die Waveform-Relaxation von gekoppelten differential-algebraischen Gleichungen nicht anwendbar und motivieren eine neue Konvergenzanalyse. Auf dieser Analyse aufbauend werden hinreichende topologische Kriterien entwickelt, welche eine Konvergenz von Gauß-Seidel- und Jacobi-artigen Waveform-Relaxationen für die gekoppelten Systeme garantieren. Schließlich werden numerische Benchmarks zur Verfügung gestellt, um die eingeführten Methoden und Theoreme dieser Abhandlung zu unterstützen.<br>This work is devoted to the simulation of electrical/electronic circuits incorporating electromagnetic devices. The focus is on different couplings of the circuit equations, modeled with the modified nodal analysis, and the electromagnetic devices with their refined model based on full-wave Maxwell's equations in Lorenz gauged A-V formulation which are spatially discretized by the finite integration technique. A numerical analysis extends the topological criteria for the index of the resulting differential-algebraic equations, as already derived in other works with similar field/circuit couplings. For the simulation, both a monolithic approach and waveform relaxation methods are investigated. The focus is on time integration, scaling methods, structural properties and a hybrid approach to solve the underlying linear systems of equations with the use of specialized solvers for the respective subsystems. Since the full-Maxwell approach causes additional derivatives in the coupling structure, previously existing convergence statements for the waveform relaxation of coupled differential-algebraic equations are not applicable and motivate a new convergence analysis. Based on this analysis, sufficient topological criteria are developed which guarantee convergence of Gauss-Seidel and Jacobi type waveform relaxation schemes for introduced coupled systems. Finally, numerical benchmarks are provided to support the introduced methods and theorems of this treatise.
Book chapters on the topic "Nodal integration technique"
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Gander, Martin J., and Niteen Kumar. "A New Nodal Integration Method for Helmholtz Problems Based on Domain Decomposition Techniques." In Lecture Notes in Computational Science and Engineering. Springer Nature Switzerland, 2024. http://dx.doi.org/10.1007/978-3-031-50769-4_23.
Full textConference papers on the topic "Nodal integration technique"
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Nagpure, Mrunali, Ganesh Wakte, and Mukesh Kumar. "Advanced Nodal Pricing and Optimization Techniques for Integrating Renewable Energy in Electricity Markets." In 2025 International Conference on Computational, Communication and Information Technology (ICCCIT). IEEE, 2025. https://doi.org/10.1109/icccit62592.2025.10927868.
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Nallathambi, Ashok Kumar, Eckehard Specht, and Albrecht Bertram. "Finite Element Technique for Phase-Change Heat Conduction Problem." In ASME 2009 Heat Transfer Summer Conference collocated with the InterPACK09 and 3rd Energy Sustainability Conferences. ASMEDC, 2009. http://dx.doi.org/10.1115/ht2009-88106.
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Liquid-solid phase transition is accompanied by a latent heat release, both in isothermal and non-isothermal phase transformations. The latent heat and the discontinuous phase change function increase the difficulty of obtaining a solution for the Fourier heat conduction equation. Celentano et al. [Int. J. Numer. Meth. Eng. 37(20), 1994] proposed a temperature-based finite element model for solving multidimensional transient heat conduction involving phase change. The present work addresses the computational aspects of the Celentano et al. model. The importance of a line search algorithm for improving the convergence of the Newton-Raphson iterations are explained in detail. While performing the iterations in this kind of fixed domain methods, the phase front moves back and forth fictitiously. The introduced phase change matrix handles the latent effect efficiently. The phase fractions are evaluated at the integration points instead of the nodal points. Several numerical examples are presented and the benefits and difficulties of the solution technique are elaborately discussed.
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Wang, Kunpeng, Hongchun Wu, Liangzhi Cao, and Changhui Wang. "Analytic Basis Function Expansion Nodal Method for Neutron Diffusion Equations in Triangular Geometry." In 18th International Conference on Nuclear Engineering. ASMEDC, 2010. http://dx.doi.org/10.1115/icone18-29518.
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An analytic basis function expansion nodal method for directly solving the two-group neutron diffusion equation in the triangular geometry is proposed in the present paper. In this method, the distribution of neutron flux is expanded by a set of analytic basis functions. The diffusion equation is satisfied at any point in a triangular node for each group assuming that the flux within a node is flat. No transverse integration is needed. To improve the nodal coupling relations and computation accuracy, nodes are coupled with each other fulfilling both the zero- and first-order partial neutron current moments across all the three interface of the triangle mesh at the same time. Coordinate conversion is used to transform arbitrary triangle into regular triangle in order to simplify the derivation. A new sweeping scheme is developed for the triangular mesh and the response matrix technique was used to solve the nodal diffusion equation iteratively. Based on the proposed model, the code ABFEM-T is developed. Validation of code for accuracy and efficiency are carried out by calculating both rectangular and hexagonal assembly benchmark problems. Numerical results for the series of benchmark problems show that both the multiplication factor and nodal power distribution are predicted accurately. Therefore this method can be used for solving neutron diffusion problems in complex unstructured geometry.
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Almeida, C. A. "Adaptivity and Mesh Generation in 2-D Finite Element Analysis." In ASME 1994 International Computers in Engineering Conference and Exhibition and the ASME 1994 8th Annual Database Symposium collocated with the ASME 1994 Design Technical Conferences. American Society of Mechanical Engineers, 1994. http://dx.doi.org/10.1115/cie1994-0444.
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Abstract A methodology for the automatic mesh generation of triangular and quadrilateral finite element discretizations for two-dimensional elasticity problems is proposed. The methodology is based on: i) an h-adaptive process with powerful mesh generator facilities capable of achieving meshes of specified density, ii) a general stress recovery technique developed for determining the element solutions at the nodes, and iii) an a posteriori error estimation. The h-adaptive process used is based on a complete mesh regeneration procedure which is guided by specified mesh requirements such as geometry definitions, boundary conditions, and space node functions to achieve an optimal refinement. This optimality condition is, as established by Zienkiewicz and Zhu, the mesh refinement with the least number of elements that yields a uniform strain energy norm error distribution in all elements. In the stress recovery process, the nodal values are assumed to belong to a polynomial expansion of the same complete order in the interpolation function basis used, which is valid over all elements adjoining a particular node. A least-squares fit of superconvergent sampling points existing in the path is used to obtain the recovered nodal point parameters for each element. These parameters are averaged to all elements adjoining the node of interest. The technique is simple and cost-effective, and the recovered nodal values of derivatives are superconvergent at the Gauss integration points, which are used as sampling points for quadrilateral elements. This condition is also achieved when centroid and mid-side points are used for triangular elements. The error estimation is done evaluating differences between the post-processed stress gradients and those from the finite element solutions. The energy error norm associated with stress field differences and the finite element predicted strain energy gives an effective error estimate which can be used for comparison with the process tolerance. The technique has been implemented and allows for a fully automatic numerical analysis under a specified global energy error norm. Numerical tests conducted with various planar element formulations illustrate that the proposed technique converges in fewer steps than with previous methods of adaptive mesh refinement.
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Tang, Jinsong, Linfang Qian, and Guangsong Chen. "A GFEM With Local Gradient Smoothed Approximation for 2D Solid Mechanics Problems." In ASME 2020 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/imece2020-23041.
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Abstract In this paper, a generalized finite element method (GFEM) with local gradient smoothed approximation (LGS-GFEM) using triangular meshes is proposed. The displacement field function of LGS-GFEM consists of the finite element shape function and the node displacement function. In order to obtain the nodal displacement function, the second order Taylor expansion is considered. The derivative term in Taylor expansion is obtained by using gradient smoothed technique in a smoothed domain. The displacement in smoothed operation is interpolated by polynomial basis function and radial basis function. Two kinds of integration schemes are considered, i.e. LGS-GFEM-I and LGS-GFEM-II respectively. The smoothed composite shape function of LGS-GFEM retains the ideal Kronecker property of the finite element shape function. Besides, the proposed LGS-GFEM has some other important properties such as no extra DOFs, linear independent, etc. The superiority of LGS-GFEM including high accuracy, rapid error convergence and temporal stability, is demonstrated by two representative numerical examples of static and free vibration, and compared with the classical finite element of triangular (FEM-T3) and quadrilateral (FEM-Q4) elements.
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Yoshida, Shoichi, Kazuyoshi Sekine, Tomohiko Tsuchida, and Katsuki Iwata. "Lagrangian Finite Element Formulation to Axisymmetric Liquid Sloshing." In ASME 2011 Pressure Vessels and Piping Conference. ASMEDC, 2011. http://dx.doi.org/10.1115/pvp2011-57450.
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The sloshing analysis of liquid storage tanks by the finite element method is basically categorized into two approaches, Lagrangian approach and Eulerian approach. In the Lagragian approach, the behavior of the fluid is expressed in terms of the displacements at nodal points. The advantage of the Lagragian method is that the computer code can be easily developed to modify an existing structural analysis code. The disadvantage is that some spurious modes are included in the vibration modes. The Lagrangian method is widely used in two- and three-dimensional problems. On the other hand, it has not been reported its applicability to the axisymmetric problem. This paper presents the applicability of the Lagragian method to the axisymmetric sloshing problem. The eigenvalue of an elemental stiffness matrix is analyzed in order to investigate the characteristics of the rotational stiffness to the compressibility of the fluid. As a result, this method is found to be difficult to apply to the axisymmetric problem if the equation of motion is directly solved using time integration. However, it gives the highly precise response solutions if the only sloshing modes are taken out and the modal analysis technique is used.
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Bao, Ji, Shenwei Zhang, and Billy Zhang. "Application of PyAnsys for Level 3 Assessment Tool Development." In 2024 15th International Pipeline Conference. American Society of Mechanical Engineers, 2024. https://doi.org/10.1115/ipc2024-133367.
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Abstract Finite Element Analysis (FEA) is a prevalent tool for the integrity assessment of pipelines in the industry and is widely acknowledged by industrial standards such as CSA Z662 and CFR 192.712. Previous research has established the capability of FEA to accurately simulate the response of pipelines under various loading scenarios, demonstrating high fidelity in processes like dent simulation and predicting the failure of corroded pipelines. The Finite Element method is a complex numerical technique that involves discretizing a continuous pipeline into small finite elements. While the accessibility of commercial FEA software tools has facilitated the application of this method, challenges and potential issues persist. Firstly, FEA simulations generate substantial amounts of data, including nodal solutions and stiffness matrices. Secondly, debugging can be intricate, necessitating a combination of experience and specialized knowledge. Thirdly, postprocessing can be time-consuming; for instance, calculating the Ductile Failure Damage Indicator (DFDI) involves integrating stress components across all time steps. Lastly, commercial FEA software typically operates as closed source, limiting customization options to the features provided by the software. This paper introduces the use of a Python-based FEA library, PyAnsys, offering a more accessible and streamlined approach to managing the extensive data generated by FEA simulations. The integration of PyAnsys with Python enhances the debugging process by providing an intuitive and user-friendly scripting interface. Python’s readability and extensive debugging tools contribute to a smoother debugging experience, reducing the dependency on specialized knowledge. Additionally, PyAnsys facilitates efficient pre-processing and post-processing by leveraging the power of Python. The open-source nature of PyAnsys enhances customization options, allowing integration with other Python libraries, such as the visualization package PyVista, making PyAnsys a versatile and powerful tool for FEA applications. Two case studies are presented in the paper to demonstrate the effectiveness of PyAnsys. The first case study utilizes PyAnsys to analyze a dented pipe in structural analysis, while the second case study involves study simulating a corroded pipeline to evaluate the load carrying capacity of a pipeline containing metal loss corrosions.
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Li, Zhen, Baoyuan Sun, Min Qian, and Jun Zhang. "Topological Optimization Design and Manufacture of Microactuator Based on the Nodal Density Method." In 2007 First International Conference on Integration and Commercialization of Micro and Nanosystems. ASMEDC, 2007. http://dx.doi.org/10.1115/mnc2007-21168.
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In order to improve the situation that the design of microactuator is mostly based on the intuition and experience of researchers, the method of continuum topology optimization using the nodal density is introduced to the conceptual design of microactuator. This new method can ensure C0 continuity of density field in a fixed design domain. The ratio of mutual energy to strain energy of the mechanism is regarded as the objective function, where, the mutual energy and strain energy describe the kinematic function and structural function of microactuator respectively. The final configuration of microactuator is decided on the guide of conceptual design combined with the given working conditions. The finite element method is applied to analysis the transmission ratio and clamping force of microactuator. The prototype of the microactuator is fabricated by using micro-electroforming and SU-8 photolithography techniques and the displacement of the micro actuator is measured by using the stereo vision microscopy. The experimental results show that the properties of the micro actuator can satisfy the designing demands. This topological optimization method based on nodal density plays an important role in guiding the structure design of micro actuator.
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Panta Pazos, Ruben, Marco Tullio de Vilhena, and Eliete Biasotto Hauser. "Solution and Study of the Two-Dimensional Nodal Neutron Transport Equation." In 10th International Conference on Nuclear Engineering. ASMEDC, 2002. http://dx.doi.org/10.1115/icone10-22611.
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In the last decade Vilhena and coworkers10 reported an analytical solution to the two-dimensional nodal discrete-ordinates approximations of the neutron transport equation in a convex domain. The key feature of these works was the application of the combined collocation method of the angular variable and nodal approach in the spatial variables. By nodal approach we mean the transverse integration of the SN equations. This procedure leads to a set of one-dimensional SN equations for the average angular fluxes in the variables x and y. These equations were solved by the old version of the LTSN method9, which consists in the application of the Laplace transform to the set of nodal SN equations and solution of the resulting linear system by symbolic computation. It is important to recall that this procedure allow us to increase N the order of SN up to 16. To overcome this drawback we step forward performing a spectral painstaking analysis of the nodal SN equations for N up to 16 and we begin the convergence of the SN nodal equations defining an error for the angular flux and estimating the error in terms of the truncation error of the quadrature approximations of the integral term. Furthermore, we compare numerical results of this approach with those of other techniques used to solve the two-dimensional discrete approximations of the neutron transport equation6.
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Strzelczyk, Andrzej T., and San S. Ho. "Evaluation of “Linearized” Stresses Without Linearization." In ASME 2007 Pressure Vessels and Piping Conference. ASMEDC, 2007. http://dx.doi.org/10.1115/pvp2007-26357.
Full textAbstract:
ASME Code stress assessment of pressure vessels in the power generation industry is usually done by finite element analysis using one of the two approaches. In the first, “shell-element” approach, vessels are modeled out of shell elements; primary plus bending and primary plus secondary stresses are taken directly from the finite element analysis results and the alternating stresses are based on primary plus secondary stresses prorated by respective stress concentration factors. The strength of the “shell-element” approach is its simplicity; its weakness is problematic modeling of the stress concentration and some modeling difficulties (varying wall thickness, nozzle/vessel connectivity, pressure applied to the mid-surface instead of to the inner surface.) In the second, “solid-element” approach, vessels are modeled out of solid elements; “linearized” stresses can not be taken directly from the finite element analysis results, first they must be linearized, and only then, can be compared against their allowable counterparts; the alternating stresses can be based directly on the outer/inner-surface-node-stresses, provided that the mesh of the model is fine enough to account for the stress concentration effect. The strength of the “solid-element” approach is its high accuracy; its weakness is the time consuming, sometimes ambiguous, stress linearization process. This paper proposes a modification of the “solid-element” approach, in which the time consuming linearization process is replaced by a modification of the original model. To do so, a vessel must be modeled out of quadratic 20 node solid elements; the mesh density of the model (on its surface and through thickness) must be adequate for stress concentration representation and the mesh lines in the thickness direction must be more or less normal to the surfaces. The results from this original model can be taken directly for fatigue evaluation. To obtain the “linearized” stresses the original model must be slightly modified, specifically the number of elements through thickness must be reduced to one, and the reduced integration technique is recommended. For such a modified model, the nodal stresses are equivalent to the “linearized stresses” of the original model. The equivalence is discussed on a model of a circular nozzle attached to a cylindrical vessel. The vessel loads are pressure and thermal expansion.