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Communications in Numerical Methods in Engineering最新文献

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Influence of initial geometric imperfections on the stability of thick cylindrical shells under internal pressure 初始几何缺陷对内压下厚圆柱壳稳定性的影响
Communications in Numerical Methods in Engineering Pub Date : 2006-09-19 DOI: 10.1002/CNM.916
S.R.X. Lopes, P. Gonçalves, D. Pamplona
{"title":"Influence of initial geometric imperfections on the stability of thick cylindrical shells under internal pressure","authors":"S.R.X. Lopes, P. Gonçalves, D. Pamplona","doi":"10.1002/CNM.916","DOIUrl":"https://doi.org/10.1002/CNM.916","url":null,"abstract":"This paper investigates numerically and experimentally the influence of initial geometric imperfections on the critical loads of initially stretched thick hyperelastic cylindrical shells under increasing uniform internal pressure. Imperfections in shells can have a global or local character. First, two types of local imperfections are considered: (1) a local axially symmetric imperfection in the form of a ring and (2) a small rectangular imperfection. The influence of the imperfection thickness, position and size are analysed in detail. Results show that the critical load decreases as the imperfections increase in size or thickness and as they move from the boundaries to the centre of the shell. The influence of multiple local imperfections is also studied in the present paper. Finally, the influence of global imperfections is considered with the imperfections described as a variation of the shell curvature in the axial direction. The results show that thick hyperelastic shells may be sensitive to local and global imperfections. In all cases the experimental results are in good agreement with the numerical ones, corroborating the conclusions.","PeriodicalId":51245,"journal":{"name":"Communications in Numerical Methods in Engineering","volume":"23 1","pages":"577-597"},"PeriodicalIF":0.0,"publicationDate":"2006-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/CNM.916","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"51600646","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 7
Modelling of metal–mold interface resistance in the A356 Aluminium alloy casting process A356铝合金铸造过程中金属-模具界面电阻的建模
Communications in Numerical Methods in Engineering Pub Date : 2006-09-07 DOI: 10.1002/CNM.903
S. Mirbagheri
{"title":"Modelling of metal–mold interface resistance in the A356 Aluminium alloy casting process","authors":"S. Mirbagheri","doi":"10.1002/CNM.903","DOIUrl":"https://doi.org/10.1002/CNM.903","url":null,"abstract":"In this study, a computational model has been developed for determination of metallostatic pressure on the heat transfer coefficient, resistance of metal–mold interface and solidification time for solving of heat transfer equations. The simulation of interface resistance is based on the zero thickness element (ZTE), using the finite element method (FEM). The solid boundary conditions, including contact resistance have been modified by pressure gradient in each ZTE. The pressure gradient has been imposed by an experimental function, which obtained based on experimental data. In order to verify the computational results, an A356 Aluminium alloy has been poured into a permanent mold and temperature of interface was measured by data acquisition system. The comparison between the experimental and the simulation results during solidification process shows a good agreement that confirms the accuracy of the model in order to simulate the effect of interface resistance on the solidification time. Copyright © 2006 John Wiley & Sons, Ltd.","PeriodicalId":51245,"journal":{"name":"Communications in Numerical Methods in Engineering","volume":"23 1","pages":"295-312"},"PeriodicalIF":0.0,"publicationDate":"2006-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/CNM.903","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"51600219","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 12
Optimization of material distribution in functionally graded structures with stress constraints 考虑应力约束的功能梯度结构材料分布优化
Communications in Numerical Methods in Engineering Pub Date : 2006-09-07 DOI: 10.1002/CNM.910
F. V. Stump, E. C. Silva, G. Paulino
{"title":"Optimization of material distribution in functionally graded structures with stress constraints","authors":"F. V. Stump, E. C. Silva, G. Paulino","doi":"10.1002/CNM.910","DOIUrl":"https://doi.org/10.1002/CNM.910","url":null,"abstract":"This work describes a topology optimization framework to design the material distribution of functionally graded structures considering mechanical stress constraints. The problem of interest consists in minimizing the volumetric density of a material phase subjected to a global stress constraint. Due to the existence of microstructure, the micro-level stress is considered, which is computed by means of a mechanical concentration factor using a p-norm of the Von Mises stress criterium (applied to the micro-level stress). Because a 0–1 (void–solid) material distribution is not being sought, the singularity phenomenon of stress constraint does not occur as long as the material at any point of the medium does not vanish and it varies smoothly between material 1 and material 2. To design a smoothly graded material distribution, a material model based on a non-linear interpolation of the Hashin–Strikhman upper and lower bounds is considered. Consistently with the framework adopted here in, the so-called ‘continuous approximation of material distribution’ approach is employed, which considers a continuous distribution of the design variable inside the finite element. As examples, the designs of functionally graded disks subjected to centrifugal body force are presented. The method generates smooth material distributions, which are able to satisfy the stress constraint. Copyright © 2006 John Wiley & Sons, Ltd.","PeriodicalId":51245,"journal":{"name":"Communications in Numerical Methods in Engineering","volume":"23 1","pages":"535-551"},"PeriodicalIF":0.0,"publicationDate":"2006-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/CNM.910","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"51600625","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 37
Numerical simulation of transient water infiltration in heterogeneous soils combining central schemes and mixed finite elements 中心方案与混合有限元相结合的非均质土壤瞬态水入渗数值模拟
Communications in Numerical Methods in Engineering Pub Date : 2006-09-07 DOI: 10.1002/CNM.905
J. Aquino, A. Francisco, F. Pereira, H. P. A. Souto, F. Furtado
{"title":"Numerical simulation of transient water infiltration in heterogeneous soils combining central schemes and mixed finite elements","authors":"J. Aquino, A. Francisco, F. Pereira, H. P. A. Souto, F. Furtado","doi":"10.1002/CNM.905","DOIUrl":"https://doi.org/10.1002/CNM.905","url":null,"abstract":"We present a new numerical scheme for the approximation of solutions of transient water infiltration problems in heterogeneous soils. The two-phase (water and air) flow problem is governed by a pressure-velocity equation coupled to a saturation equation. The numerical scheme combines a non-oscillatory, second-order, conservative central finite differencing scheme for the saturation equation with mixed finite elements for the pressure-velocity equation. An operator splitting technique allows for the use of distinct time steps for the solution of the equations of the governing system. One and two-dimensional numerical experiments show that the proposed scheme is able to capture accurately and efficiently sharp fronts in two-phase water-air problem. The simulations were carried out taking into account the effects of gravity and capillary diffusion forces.","PeriodicalId":51245,"journal":{"name":"Communications in Numerical Methods in Engineering","volume":"23 1","pages":"491-505"},"PeriodicalIF":0.0,"publicationDate":"2006-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/CNM.905","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"51600230","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 11
A fully implicit finite difference scheme for velocity and temperature coupled solutions of polymer melt flow 聚合物熔体流动速度和温度耦合解的全隐式有限差分格式
Communications in Numerical Methods in Engineering Pub Date : 2006-08-14 DOI: 10.1002/CNM.902
M. Vaz, P. Zdanski
{"title":"A fully implicit finite difference scheme for velocity and temperature coupled solutions of polymer melt flow","authors":"M. Vaz, P. Zdanski","doi":"10.1002/CNM.902","DOIUrl":"https://doi.org/10.1002/CNM.902","url":null,"abstract":"This work presents a fully implicit finite difference scheme aimed at simulation of polymer melt flow in channels and mould cavities. This class of problems is characterized by strong material non-linearity and coupling of momentum, heat and mass transfer. The computational approach is based on the generalized Newtonian model and utilizes central discretization for both diffusive and convective terms, collocated meshes and artificial dissipation control to handle spurious pressure modes. The formulation accounts for the full interaction between the thermal effects caused by viscous heating and the momentum diffusion effects dictated by a shear rate and temperature-dependent constitutive model. Solutions for plane channels and asymmetric sudden expansion illustrate application to polymer melt flow. Copyright © 2006 John Wiley & Sons, Ltd.","PeriodicalId":51245,"journal":{"name":"Communications in Numerical Methods in Engineering","volume":"23 1","pages":"285-294"},"PeriodicalIF":0.0,"publicationDate":"2006-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/CNM.902","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"51600213","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 26
The GDC method as an orthogonal arc‐length method GDC法为正交弧长法
Communications in Numerical Methods in Engineering Pub Date : 2006-08-14 DOI: 10.1002/CNM.899
E. Cardoso, J. Fonseca
{"title":"The GDC method as an orthogonal arc‐length method","authors":"E. Cardoso, J. Fonseca","doi":"10.1002/CNM.899","DOIUrl":"https://doi.org/10.1002/CNM.899","url":null,"abstract":"The method of generalized displacements (GDC) is a path-following algorithm for non-linear mechanics, capable to overcome both limit and snap-back points. It was proposed as a consistent alternative to most existing techniques, such as the arc-length family of algorithms. Although it is a reliable algorithm, it has not been as widely used as the arc-length methods, possibly because it has been seen as belonging to a different category. This paper shows that the GDC method can be seen as an orthogonal arc-length method, with an interesting constraint equation which leads to its appealing features. Copyright © 2006 John Wiley & Sons, Ltd.","PeriodicalId":51245,"journal":{"name":"Communications in Numerical Methods in Engineering","volume":"23 1","pages":"263-271"},"PeriodicalIF":0.0,"publicationDate":"2006-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/CNM.899","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"51600149","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 17
Parallel computation of arbitrarily shaped waveguide modes using BI‐RME and Lanczos methods 用BI - RME和Lanczos方法并行计算任意形状波导模式
Communications in Numerical Methods in Engineering Pub Date : 2006-08-14 DOI: 10.1002/CNM.901
A. Vidal, A. Vidal, V. Boria, V. García
{"title":"Parallel computation of arbitrarily shaped waveguide modes using BI‐RME and Lanczos methods","authors":"A. Vidal, A. Vidal, V. Boria, V. García","doi":"10.1002/CNM.901","DOIUrl":"https://doi.org/10.1002/CNM.901","url":null,"abstract":"This paper is devoted to the parallelization of a new method for solving large, structured eigenvalue problems, which appear in the electromagnetic modal analysis of arbitrarily shaped waveguides, typically present in many modern passive devices. This new method, based on the boundary integral-resonant mode expansion (BI-RME) technique and in the Lanczos method (for solution of the eigenvalue problem), was recently proposed by the authors, showing important advantages in terms of CPU time and memory over previously used solutions. As it will be fully described in this paper, the parallel version of such a new method allows further important savings in the overall CPU computation time. Comparative benchmarks and scalability issues related to the implemented parallel algorithm are discussed. Copyright © 2006 John Wiley & Sons, Ltd.","PeriodicalId":51245,"journal":{"name":"Communications in Numerical Methods in Engineering","volume":"23 1","pages":"273-284"},"PeriodicalIF":0.0,"publicationDate":"2006-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/CNM.901","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"51600206","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 3
On the resolution of transverse stresses in solid-shells with a multi-layer formulation 基于多层公式的固体壳层横向应力解析
Communications in Numerical Methods in Engineering Pub Date : 2006-08-14 DOI: 10.1002/CNM.908
Mark Fiolka, A. Matzenmiller
{"title":"On the resolution of transverse stresses in solid-shells with a multi-layer formulation","authors":"Mark Fiolka, A. Matzenmiller","doi":"10.1002/CNM.908","DOIUrl":"https://doi.org/10.1002/CNM.908","url":null,"abstract":"A locking free solid-shell element, based on a surface orientated shell formulation, is used for a single-layer approach as well as for a multi-layer analysis. Locking is removed by a combination of the assumed strain and enhanced assumed strain methods. The suggested incompatible strain field enables the element to pass the patchtest for plates with a minimum of enhancement parameters. It is tested at various benchmark examples for the resolution of the transverse shear and normal stresses in thin-walled structures. Copyright © 2006 John Wiley & Sons, Ltd.","PeriodicalId":51245,"journal":{"name":"Communications in Numerical Methods in Engineering","volume":"23 1","pages":"313-326"},"PeriodicalIF":0.0,"publicationDate":"2006-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/CNM.908","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"51600250","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 16
Stabilized velocity post‐processings for Darcy flow in heterogeneous porous media 非均质多孔介质中达西流的稳定速度后处理
Communications in Numerical Methods in Engineering Pub Date : 2006-08-14 DOI: 10.1002/CNM.904
M. R. Correa, A. Loula
{"title":"Stabilized velocity post‐processings for Darcy flow in heterogeneous porous media","authors":"M. R. Correa, A. Loula","doi":"10.1002/CNM.904","DOIUrl":"https://doi.org/10.1002/CNM.904","url":null,"abstract":"Stable and accurate finite element methods are presented for Darcy flow in heterogeneous porous media with an interface of discontinuity of the hydraulic conductivity tensor, Accurate velocity fields are computed through global or local post-processing formulations that use previous approximations of the hydraulic potential. Stability is provided by combining Galerkin and least squares (GLS) residuals of the governing equations with an additional stabilization on the interface that incorporates the discontinuity on the tangential component of the velocity field in a strong sense. Numerical analysis is outlined and numerical results are presented to illustrate the good performance of the proposed methods, Convergence studies for a heterogeneous and anisotropic porous medium confirm the same rates of convergence predicted for homogeneous problem with smooth solutions, for both global and local post-processings.","PeriodicalId":51245,"journal":{"name":"Communications in Numerical Methods in Engineering","volume":"23 1","pages":"461-489"},"PeriodicalIF":0.0,"publicationDate":"2006-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/CNM.904","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"51600225","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 27
Solution of non-linear dispersive wave problems using a moving finite element method 用移动有限元法求解非线性色散波问题
Communications in Numerical Methods in Engineering Pub Date : 2006-08-14 DOI: 10.1002/CNM.897
A. Wacher, D. Givoli
{"title":"Solution of non-linear dispersive wave problems using a moving finite element method","authors":"A. Wacher, D. Givoli","doi":"10.1002/CNM.897","DOIUrl":"https://doi.org/10.1002/CNM.897","url":null,"abstract":"The solution of the fully non-linear time-dependent two-dimensional shallow water equations is considered. Dispersive effects due to the Coriolis forces are taken into account. Such effects are of major importance in geophysical fluid dynamics applications. The recently proposed string gradient weighted moving finite element method is extended for this class of problems. This method simultaneously determines, at each time step, the solution of the governing partial differential equations and an optimal location of the finite element nodes. It has previously been applied to non-dispersive wave problems; here its performance under the demanding conditions of large Coriolis forces, inducing large mesh and field rotation, is studied. Optimal rates of convergence are obtained. Results for some example problems of water hump release are presented. Non-linear and linearized solutions are compared.","PeriodicalId":51245,"journal":{"name":"Communications in Numerical Methods in Engineering","volume":"23 1","pages":"253-262"},"PeriodicalIF":0.0,"publicationDate":"2006-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/CNM.897","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"51600406","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 2
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