bluuebunny/crossref_metadata_2025_split huggingface dataset:
An efficient algorithm to generate maximum entropy distributions
Authors: Basu P. C. , Templeman A. B. 
Published: August 2005

AbstractThe paper describes an algorithm for generating maximum entropy distributions for probabilistic data. The central moments of the data form constraint equations developed from Jaynes' formalism, which are solved by mathematical programming. Criteria are presented for selecting starting points and scaling parameters, upon which the accuracy and efficiency of the algorithm depends. Results are given of tests in which maximum entropy distributions are generated from the moment information of numerous analytical distributions. They show that four moments are generally required to produce good agreement and that maximum entropy distributions can represent most data populations very well. The notation used in the paper is defined in Appendix I.
A model of binary alloy solidification
Authors: Wilson D. G. , Solomon A. D. , Alexiades V. 
Published: August 2005

AbstractA linear model for the solidification of a dilute binary alloy is presented. In this model the solidus and liquidus curves are linear. As a consequence internal energy depends linearly upon temperature and concentration. The formulation is a generalization of the well‐known enthalpy method to treat a phase change problem involving coupled heat and mass transfer. Both analytic and numerical formulations are given. Results from the latter are presented and compared with an explicit solution of Rubinstein for a Stefan‐like problem posed in a semi‐infinite slab. Some remarks on the behaviour of the explicit solution are given.
An interpolation method for an irregular net of nodes
Authors: Liszka Tadeusz 
Published: August 2005

AbstractA local interpolation method for an irregular mesh of nodal points is proposed. The method is based on a Taylor expansion of the unknown function combined with the minimization of errors. Some numerical tests as well as a computer program are presented. Applicability and stability of the method are shown. By the appropirate definition of weighting coefficients, this method may be viewed as an interpolation or approximation in the sense of minimum deviation from given values. Applications in finite element and finite difference methods are shown.
Numerical evaluation of the quarter‐point crack tip element
Authors: Saouma Victor E. , Schwemmer David 
Published: August 2005

AbstractThis paper attempts to answer two commonly raised questions during the preparation of a finite element mesh, for the linear elastic fracture analysis of cracked structure: how to set up the finite element mesh around the crack tip, and what level of accuracy is to be expected from such a modelling.Two test problems, with known analytical expressions for their stress intensity factors, are analysed by the finite element method using the isoparametric quadratic singular element. The modified parameters were the order of integration, aspect ratio, number of elements surrounding the crack tip, use of transition elements, the singular element length over the total crack length, the symmetry of the mesh around the crack tip. Based on these analyses, a data base is created and various plots produced. The results are interpreted, the accuracy evaluated and recommendations drawn.Contrary to previous reports, it is found that the computed stress intensity factor (SIF) remains within engineering accuracy (10 per cent) throughout a large range of l/a (singular element length over crack length) for problems with a uniform non‐singular stress distribution ahead of the crack tip (i.e. double edge notch), and l/a should be less than 0·1 for problems with a non‐singular stress gradient (i.e three‐point bend). Also, it is found that the best results are achieved by using at least four singular elements around the crack tip, with their internal angles around 45 degrees, and a reduced (2 × 2) numerical integration.
Structural design sensitivity analysis with general boundary conditions: Static problem
Authors: Hsieh C. C. , Arora J. S. 
Published: August 2005

AbstractThis paper presents and analyses methods for design sensitivity analysis of static response for structural systems when general boundary conditions are used during the analysis phase. The design sensitivity analysis methods where the boundary conditions are used to reduce the equilibrium equation have been presented earlier. In such procedures, the reduced stiffness matrix is non‐singular. This fact is used to show differentiability of the displacement vector. When reduction procedures are not used, the global structural stiffness matrix may be singular. In such a case, differentiability of the displacement vector may be questionable. However, it is shown that the displacement vector is still differentiable. Several forms of the structural design sensitivity equations are presented. Although these equations are derived with Lagrange multiplier treatment of general boundary conditions, it is shown that they are applicable with any treatment of general boundary conditions. For example, they can also be used with co‐ordinate reduction schemes. Therefore, design sensitivity analysis can be carried out with any existing finite element analysis computer code. Moreover, the procedures presented can be used to calculate sensitivity of a force of constraint can that is desired. The formulations are kept quite general such that design dependent boundary conditions can be routinely treated. An example is used to illustrate the procedures.
Rational approach for assumed stress finite elements
Authors: Pian T. H. H. , Sumihara K. 
Published: August 2005

AbstractA new method for the formulation of hybrid elements by the Hellinger‐Reissner principle is established by expanding the essential terms of the assumed stresses as complete polynomials in the natural coordinates of the element. The equilibrium conditions are imposed in a variational sense through the internal displacements which are also expanded in the natural co‐ordinates. The resulting element possesses all the ideal qualities, i.e. it is invariant, it is less sensitive to geometric distortion, it contains a minimum number of stress parameters and it provides accurate stress calculations. For the formulation of a 4‐node plane stress element, a small perturbation method is used to determine the equilibrium constraint equations. The element has been proved to be always rank sufficient.
On the computational significance of the strain space formulation of plasticity theory
Authors: Moss W. C. 
Published: August 2005

AbstractThe strain space and traditional stress space formulations of plasticity theory are compared. We show how plasticity theory has been implemented numerically to solve static and dynamic problems, and conclude that the numerical loading criteria that have been used for two decades are identical to the strain space loading criteria proposed by Naghdi and co‐workers.
An effective finite element approach for calculation of potential distribution in a multi‐dielectric cable
Authors: Sanavullah M. Y. , Dharmalingam K. 
Published: August 2005

AbstractThe radial symmetry of the cable results in circular finite elements to evaluate the potential distribution in a multi‐dielectric cable. Owing to this, a two dimensional analysis used in conjunction with triangular finite elements is reduced to one‐dimensional analysis. This method therefore suggests an alternative proposal to calculate the potential distribution in a multi‐dielectric cable with better accuracy.
An automated design scheme: Weight minimization of a single hulled ship compartment
Authors: Chowdhury M. , Caldwell J. B. 
Published: August 2005

AbstractThis paper describes the stages of development of an optimum structural design scheme. Any attempt to generate the optimum scantlings of a structure of even moderate complexity usually poses nonlinear programming problems for which there exist no universally accepted solution method. The structure considered here is a complete compartment of a single‐hulled ship acted upon by multiple load cases. The elastic responses under four different load types are obtained by a quasi finite element analysis routine developed specifically for this purpose. Sequential linear programming (SLP) with appropriate artifices to achieve rapid convergence has been successfully employed as an optimization routine to minimize the object function, which in this case was the total weight of the major structural members. The test problem has 490 basic degrees‐of‐freedom, 21 free design variables and more than 100 mixed constraints, the majority of which are nonlinear implicit stress functions. The method is then applied to a number of cases representative of small warship designs. Suggestions for future extensions and general conclusions are included at the end of the paper.
Optimal shape remodelling of linearly elastic plates using finite element methods
Authors: Na Moon‐Soo , Kikuchi Noboru , Taylor John E. 
Published: August 2005

AbstractThe optimality conditions for the optimal shape remodelling of linearly elastic plates are obtained by introducing the total variation of a function defined on a variable domain, although the variation of a function has been taken on a fixed domain in most literature on calculus of variations. Using these optimality conditions, a solution scheme involving an iterative algorithm is proposed, together with several numerical examples.
Finite plane strain deformations of nonlinear viscoelastic rubber‐covered rolls
Authors: Bapat C. N. , Batra R. C. 
Published: August 2005

AbstractFinite deformations of a nonlinear viscoelastic rubber layer bonded to a uniformly rotating rigid cylinder and indented by another rigid cylinder are studied by the finite element method. The problem formulation includes both material and geometric nonlinearities. The effect of the change in the thickness of the layer, its speed of rotation and its material properties on the pressure distribution at the contact surface, and other aspects of the deformation of the layer, are studied.
A hybrid algorithm for reducing matrix bandwidth
Authors: Armstrong Bruce A. 
Published: August 2005

AbstractA hybrid algorithm for reducing the bandwidth of symmetric matrices is described in terms of a finite element grid. The new algorithm produces significantly lower bandwidths than either the commonly‐used Gibbs–Poole‐Stockmeyer (GPS) or Cuthill–McKee (CM) algorithms, with run times comparable to the original CM algorithm. The new hybrid algorithm uses the GPS algorithm as a preprocessor to provide a good initial node numbering for the author's node‐shuffling algorithm, which accounts for variable degrees‐of‐freedom per node (DOF/node). The hybrid algorithm was tested on the 30 benchmark problems that were compiled by Everstine, and on 10 supplemental problems with variable DOF/node. Bandwidths and CPU times are presented for all problems.
A refined finite element model for the analysis of elastic–plastic frames
Authors: Corradi Leone , Poggi Carlo 
Published: August 2005

AbstractA finite element model for the elastic–plastic analysis of plane frames is proposed. The formulation is based on the independent modelling of the displacement and plastic strain fields; the latter is modelled both over the cross‐section and along the element length as function of a finite number of parameters, which are considered as an extra set of independent variables, in addition to nodal displacements. Stress redistribution is allowed for over the cross‐section, but not over the element length, where the distribution of stress resultants (axial forces and bending moments) is imposed consistently with the assumed displacement model; stress redistribution in terms of stress resultants becomes possible only because of the finite number of redundancies introduced when assembling. It is shown that the model can be formulated in such a way that not only compatibility and elasticity, but also equilibrium (in the sense of beam theory), are fully complied with and only the plastic portion of the constitutive relationship is approximately fulfilled, even if, in principle, to any desired level of accuracy. The model produces accurate results, including a detailed representation of the spreading of plastic zones, with a fairly limited number of elements.
A finite element method for contact problems related to fracture mechanics
Authors: Yagawa G. , Hirayama H. 
Published: August 2005

AbstractA finite element method for contact problems in crack mechanics is developed on the basis of the penalty function method. The method is successfully applied to three important problems in fracture mechanics: a crack propagated from a pin hole, a two‐point supported specimen with an edge crack loaded by a stamp, and a thick plate with a through‐wall crack under bending force.
A total lagrangian formulation for the geometrically nonlinear analysis of structures using finite elements. Part I. Two‐dimensional problems: Shell and plate structures
Authors: Oliver J. , On̄ate E. 
Published: August 2005

AbstractA total Lagrangian finite element formulation for the geometrically nonlinear analysis (large displacement/large rotations) of shells is presented. Explicit expressions of all relevant finite element matrices are obtained by means of the definition of a local co‐ordinate system, based on the shell principal curvature directions, for the evaluation of strains and stresses. A series of examples of nonlinear analysis of shell and plate structures is given.
The post‐processing approach in the finite element method—Part 3: A posteriori error estimates and adaptive mesh selection
Authors: Babuška I. , Miller A. 
Published: August 2005

AbstractThis paper is the final in a series of three in which we have discussed a finite element post‐processing technique. Here we shall deal with the questions of adaptive mesh selection and a posteriori error estimation. Some numerical examples computed by the FEARS program will be used to illustrate the approaches taken.
Thin turbomachinery blade design using a finite‐volume method
Authors: Soulis Johannes V. 
Published: August 2005

AbstractA numerical method is presented for the design of thin turbomachinery blades with specified whirl velocities across the blade span. The numerical scheme involves iteration between the directs solution of a finite‐volume method developed earlier on by Soulis1 and a design solution.The finite‐volume method, which is a combination of finite elements and finite differences, solves the three‐dimensional, inviscid, steady arid potential flow through turbomachinery blade rows in the incompressible, compressible and transonic flow range. In the design step, the whirl velocity distribution is specified across the blade span (Dirichlet boundary condition). The design procedure yields a new set of co‐ordinates for the blade geometry which are used in the next iteration of the direct solution. However, in the present analysis only thin turbomachinery blades are designed, although a fully three‐dimensional numerical method is used (the whirl velocity components of the flow field are averaged over the blade suction and pressure surface).The numerical method has been used to design free‐vortex thin turbomachinery blades. Results show that the new numerical procedure is a comparatively economic and reliable method for designing thin turbomachinery blades. It may form the baseline for complete three‐dimensional turbomachinery blade designs.
An improved three‐noded triangular element for plate bending
Authors: Fricker A. J. 
Published: August 2005

AbstractA new three‐noded triangular element for plate bending is described. The element is based on an earlier stress‐smoothed triangular element due to Razzaque,1 but extra internal ‘bubble’ functions are included to make it more flexible. The accuracy of the new element is compared with that of a number of other high‐performance triangular elements. It is concluded that the present element and that due to Hansen, Bergan and Syvertsen2 are the two most accurate triangular thin plate elements currently available. The extra lines of FORTRAN required to convert Razzaque's shape function subroutine to that for the new element are given, thus making the new element easy to implement in any general‐purpose finite element program.
Analysis of some fully‐discrete algorithms for the one‐dimensional heat equation
Authors: Hughes Thomas J. R. , Tezduyar Tayfun E. 
Published: August 2005

AbstractA fully discrete stability and accuracy analysis of some algorithms for the one‐dimensional heat equation is presented. Results illustrate that 2‐pass explicit schemes which simultaneously employ lumped and coupled capacity matrices are capable of improved performance over the standard 1‐pass explicit scheme.
Discretization of the expliclt enthalpy method for planar phase change
Authors: Tacke Karl‐Hermann 
Published: August 2005

AbstractA procedure to discretize explicit enthalpy formulations for one‐dimensional planar phase change problems is derived, which removes numerical oscillations in temperature and phase front position. The technique is based on an enthalpy balance for the control volume containing the phase front in combination with linearized temperature profiles near the phase front. A continuous casting solidification problem and a problem with known analytical solution are applied to demonstrate the effect of the scheme.
Nonlinear static and dynamic analysis of circular plates and shallow spherical shells using the collocation method
Authors: Nath Y. , Dumir P. C. , Bhatiaf R. S. 
Published: August 2005

AbstractThe present work investigates the efficacy and applicability of interior global orthogonal point collocation method to the axisymmetric nonlinear analysis of elastic circular plates and shallow spherical shells subjected to uniformly distributed transverse load. Spacewise discretisation has been carried out using a polynomial expansion with the zeros of a Chebyshev polynomial as collocation points. Timewise integration has been carried out with Newmark k‐β scheme corresponding to average acceleration method. The static response and snap‐through buckling results, as well as, the dynamic response and dynamic buckling results under a uniformly distributed step load have been obtained and found to agree closely with the available results.
Modelling and estimation for a moving boundary problem
Authors: Okuyiga M. O. , Ray W. H. 
Published: August 2005

AbstractThe displacement of a slightly compressible liquid by another in a porous medium has been modelled. This problem, which involves a moving boundary, has been numerically solved for the one‐dimensional case by using the Galerkin method. State and parameter estimation have been carried out using the extended Kalman filter.
A curved quadrilateral element for static analysis of shells with geometric and material nonlinearities
Authors: Yang T. Y. , Saigal Sunil 
Published: August 2005

AbstractA 48 degrees‐of‐freedom quadrilateral element, including the effect of both material and geometric nonlinearities, is formulated and appropriate numerical procedures are adopted for the development of a systematic and efficient approach for the static nonlinear analysis of general shell structures. The element surface is described by a variable‐order polynomial in curvilinear co‐ordinates. The displacement functions are described by bicubic Hermitian polynomials in curvilinear co‐ordinates. Without being confined to the assumption of axisymmetry, this formulation allows for the treatment of shells with a more general shape and with a complex spread of plastic zones. In the formulation for geometric nonlinearity, the total Lagrangian approach is adopted. Only small strains and small rotations are allowed. In the formulation for plastic deformation, the concept of a layered element model is used. In the inelastic range, the material is assumed to obey the Von Mises yield criterion and the Prandtl–Reuss flow rule. A tangential stiffness formulation is combined with the modified Newton–Raphson iteration method for the solution of nonlinear problems. A systematic choice of examples ranging from fiat plates to cylindrical panels and to spherical caps is solved and compared with available solutions to evaluate the recommended formulations and procedures in terms of their accuracy and efficiency.
The elastic–plastic analysis of frames by the theorems of structural variation
Authors: Majid K. I. , Celik T. 
Published: August 2005

AbstractThe theorems of structural variation for rigidly jointed frames are extended to cover the nonlinear elastic–plastic analysis of frames to collapse. Strain hardening and other material changes are included in the analysis. It is shown that the entire load–deflection history of a frame, following the successive formation of plastic hinges up to and including collapse, is obtained from a single initial elastic analysis.The manner in which these theorems are used to insert real (or plastic) hinges to a frame is presented and details of the manual calculations involved in the elastic–plastic analysis of a portal is given to demonstrate the simplicity of the method. This is followed by a comparison of the results with those obtained experimentaly by Baker and Charlton. The versatility of the method is then demonstrated by altering the shape of a frame before its elastic–plastic analysis.
Combined convection in an annulus applied to a thermal storage problem
Authors: Zenen S. R. , Collins M. W. , Simonson J. R. 
Published: August 2005

AbstractIn a solar energy application involving thermal storage, one of the heat transfer situations is that of combined convection in vertical annuli for rather complex wall thermal boundary conditions. Predictive data of a high order of reliability are needed for incorporation within the suite of programs treating the whole problem.The program reported here treats the complete equations for combined free and forced convection in a vertical annulus. It allows for viscosity and density variation with temperature, and a variable heat flux or temperature at the walls. It was developed from a similar program for circular tubes.Comparisons are made with published data for velocity profiles and heat transfer performance. These are good, and show the step‐wise energy balance method is necessary and valid.The strategy of generation of the required data is explained, together with sample output. These data are themselves analysed computationally; the performance equations agree with original predictions typically to within ± 11 per cent, with a standard deviation of around 2 per cent.The working fluid is water with 37 per cent ethylene glycol. Upward heated and downward cooled flows give aided combined convection. For the given design, laminar flow is predicted for the Reynolds number range 1800–2200.
Modelling and state estimation for a two‐dimensional moving boundary problem
Authors: Okuyiga M. O. , Ray W. H. 
Published: August 2005

AbstractThe five‐spot waterflooding problem has been modelled as a two‐dimensional moving boundary problem with a sharp interface separating the water and oil regions. The Galerkin method was used to solve for the shape and movement of the interface, as well as for the pressures in the reservoir. Having obtained a working model, the extended Kalman filter was then used to estimate the interfacial position when using corrupted pressure measurements from a single sensor in the field.