摘要:

AbstractAn iterative procedure is presented for the finite element computation of unbounded electrical fields created by voltaged conductors. The procedure is based on successive evaluations of the potential on a fictitious boundary enclosing all the conductors, according to the charge lying on their surface. The convergence of the procedure to the solution of the unbounded field problem is demonstrated. Indications for the optimal placement of the fictitious boundary are provided, also taking into account the accuracy of the solution. The way in which computational efficiency can be reached is also discussed. The main advantage of this procedure lies in its simplicity of implementation in the context of a standard FE code for bounded problems, because a very limited amount of additional software is required; moreover, 2‐D and axisymmetric versions can be implemented with minor changes from a suitable 3‐D one. Examples of application are given in order to illustrate the practical use of the procedure and to validate it by comparisons with available soluti

ISSN:0029-5981    

DOI:10.1002/nme.1620372403

出版商:John Wiley&Sons, Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractThe dynamic stability of laminated composite stiffened or non‐stiffened plates and shells due to periodic in‐plane forces at boundaries is investigated in this paper. A three‐dimensional (3‐D) degenerated shell element and a 3‐D degenerated curved beam element are used to model plates/shells and stiffeners, respectively. The characteristic equations to find the natural frequencies, buckling loads and their corresponding mode shapes are obtained from the finite element equation of motion. Then, the method of Hill's infinite determinants or the method of multiple scales is applied to analyse the dynamic instability regions. Numerical results are presented to demonstrate the effects of various parameters, such as skew angle, lamination scheme, stiffened scheme, in‐plane force type and curvature of cylindrical shell, on the dynamic stability of stiffened and non‐stiffened plates and shells subjected to in‐plane pulsating force

ISSN:0029-5981    

DOI:10.1002/nme.1620372404

出版商:John Wiley&Sons, Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractThis paper discusses the use of conjugate gradient method for structural engineering analysis with multiple load cases. Specifically, we introduce a modified conjugate gradient method for the solution of a system of linear equations with multiple right‐hand sides. We show how this method can be used to improve the performance of block conjugate gradient method. Numerical results are presented to illustrate the effectiveness of the numerical schemes developed in this stud

ISSN:0029-5981    

DOI:10.1002/nme.1620372405

出版商:John Wiley&Sons, Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractThis paper presents a formulation suitable for the flutter analysis of rotating bladed assemblies. The blades are modelled using the finite element method. The aeroelastic displacements, expressed in terms of travelling wave co‐ordinates, are written as a linear combination of a number of undamped modes leading to a complex eigenvalues eigenvectors problem. The associated unsteady aerodynamic model is either two or three dimensional, leading for both cases to a consistent and flexible aeroelastic analysis method.Three numerical applications are presented which illustrate the theory and emphasize the possible effects of blade cross‐section (chord) deformation on aeroelastic damp

ISSN:0029-5981    

DOI:10.1002/nme.1620372406

出版商:John Wiley&Sons, Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractThe variable domain method for a free surface problem is considered as a weighted residual method. This considerably simplifies discretization of the problem and at the same time allows implementation of any standard discretization technique. Discretization of the problem results in a non‐linear system of equations for discrete values of a field variable and co‐ordinates of the nodes on the free boundary. Variables corresponding to a field variable are eliminated and the resulting non‐linear system is of considerable smaller size. Some new update strategies of the Jacobian together with discussion of the cost‐effectiveness and covergence rate are introduced and compared to Broyden's method. Numerical results which confirm validity of the presented discussion are given for three potential free surface problems, (i) two‐dimensional free jet impingement against an infinite wall, (ii) axisymmetric free jet impingement subjected to gravity and surface tension forces, and (iii) computation of critical flow over a weir. In case (i) comparison with known analytical results is given, while in case (iii) a good agreement with previously published results is es

ISSN:0029-5981    

DOI:10.1002/nme.1620372407

出版商:John Wiley&Sons, Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractA fixed grid method using an updated iterative implicit scheme is developed to solve one‐dimensional phase change problems. The temperature field is deduced from the resolution of the governing equations whose discretization takes into account the discontinuous variation of the temperature derivative at the phase change front. At each iteration an updated position of the moving front is found from the resolution of the energy conservation at the solid‐liquid interface. The accuracy of the proposed numerical method has been checked on three test probl

ISSN:0029-5981    

DOI:10.1002/nme.1620372408

出版商:John Wiley&Sons, Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractThe use of inconsistent displacement fields for Mindlin plate elements causes unmatched coefficients to appear in shear strain interpolations. The role of the numerical integration order in relation to these unmatched coefficients, and the existence of optimal stress points are explained through the use of the reduced minimization concept. This concept makes it possible to test whether assumed displacement fields or shear strain fields result in inconsistent strain fields which contain spurious constraints. We have included applications of reduced minimization to the conventionalC0‐continuous elements, which employ reduced integration, and to quadrilateral Mindlin plate elements of Hinton and Huang to demonstrate how these elements alleviate shear lockin

ISSN:0029-5981    

DOI:10.1002/nme.1620372409

出版商:John Wiley&Sons, Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractFrom the starting point of dynamic coupling problems in the harmonic field, such as fluid/fluid, fluid/structure, fluid/structure/fluid problems, a single procedure capable of resolving the couplage is shown when only one domain is under study. The notions of impedance transfer familiar in analytical methods in the dynamic harmonic field are introduced into numerical methods especially when transferring the structure to the fluid. The proposed work goes beyond the problems themselves and the methods currently applied io solve them (modal series, integral method, finite element method) and suggests how the ideas developed here could simplify greatly the way more complex problems might be tackled.

ISSN:0029-5981    

DOI:10.1002/nme.1620372410

出版商:John Wiley&Sons, Ltd    

年代:1994

数据来源: WILEY

ISSN:0029-5981    

DOI:10.1002/nme.1620372411

出版商:John Wiley&Sons, Ltd    

年代:1994

数据来源: WILEY

ISSN:0029-5981    

DOI:10.1002/nme.1620372412

出版商:John Wiley&Sons, Ltd    

年代:1994

数据来源: WILEY