摘要:

AbstractThe finite element method generates solutions to partial differential equations by minimizing a strain energy based functional. Strain energy based techniques for adaptive mesh refinements are not always effective, however. The adaptive refinement technique proposed in this paper uses strain energy but also incorporates advantages from theh‐ andp‐ finite element methods, the multigrid method and a Delaunay based mesh generation method. The refinement technique converged rapidly and was numerically efficient when applied to determining stress concentrations around the circular hole of a thick plate under tens

ISSN:0029-5981    

DOI:10.1002/nme.1620360602

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractTo perform non‐linear structural analysis including large displacements and rotations requires evaluation of the non‐linear equilibrium equations. A quadratically converging, fixed‐point iteration scheme, referred to as the work‐increment‐control solution method, is presented to iteratively evaluate the non‐linear algebraic equations. The work‐increment‐control method is superior, in many respects, to other published solu

ISSN:0029-5981    

DOI:10.1002/nme.1620360603

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractSingularity conditions that arise during structural optimization can seriously degrade the performance of the optimizer. The singularities are intrinsic to the formulation of the structural optimization problem and are not associated with the method of analysis. Certain conditions that give rise to singularities in linear elastic structures have been identified in earlier papers, along with a proposition to alleviate the consequences of their presence.1‐3These singularities were global in nature, encompassing the entire structure. Further examination revealed more complex sets of conditions in which singularities occur. Some of these singularities are local in nature, being associated with only a segment of the structure. Moreover, the likelihood that one of these local singularities may arise during an optimization procedure can be much greater than that of the global singularity identified earlier. This paper provides examples of these additional forms of singularities. It gives a framework in which these singularities can be recognized. In particular, the singularities can be identified by examination of the stress‐displacement relations along with the compatibility conditions and/or the displacement‐stress relations derived in the integrated force method of structural analysis. Methods for the elimination of the effects of these singularities are suggested and numerical illustrations are

ISSN:0029-5981    

DOI:10.1002/nme.1620360604

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractA parallel partitioning scheme based on physical‐co‐ordinate variables is presented to systematically eliminate system constraint forces and yield the equations of motion of multibody dynamics systems in terms of their independent co‐ordinates. Key features of the present scheme include an explicit determination of the independent co‐ordinates, a parallel construction of the null space matrix of the constraint Jacobian matrix, an easy incorporation of the previously developed two‐stage staggered solution procedure and a Schur complement based parallel preconditioned conjugate gradient numerical

ISSN:0029-5981    

DOI:10.1002/nme.1620360605

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractThis paper investigates the transient wave scattering by a crack by means of the Boundary Integral Equation Method (BIEM). The author has developed a new formulation to solve the BIE for the Crack Opening Displacement (COD). The resolution is done directly in the time domain. The solution is represented by means of a retarded double layer potential, and the resulting BIE, with the COD as unknown, has a hypersingular kernel. The corresponding difficulty is overcome by using a variational method. We present the application of this method to an antiplane crack, describe the approximate problem and finally give some numerical results.

ISSN:0029-5981    

DOI:10.1002/nme.1620360606

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractMany forward gradient schemes have been proposed for the time‐integration of the stiff constitutive equations of rate sensitive solids. It is shown here that one of these methods can be interpreted as a hybrid ordinary differential equation integrator which combines explicit and semi‐implicit Runge‐Kutta methods. This observation permits development of higher order schemes, illustrated here by one of second order. An embedded first order estimate provides a reliable step‐size control. The method is applied to an overstress model and to an internal variable model, and is used in a finite element analysis of hydrostatic bulging of shee

ISSN:0029-5981    

DOI:10.1002/nme.1620360607

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractThe paper presents the results of investigations conducted to evaluate the added mass to represent fluid‐structure interaction effects in vibration/dynamic analysis of floating bodies such as ship hulls. While the structural plating is idealized by 9‐noded plate/shell finite elements, the fluid domain is modelled by 20‐noded/21‐noded 3‐D finite elements in the investigations conducted. A new 8‐noded element has been developed to model the interface between the structure and the fluid. An efficient computational methodology has been used for computation of added mass. The finite element models are validated by comparing the results with those given by analytical solution for a submerged sphere. The efficacy of the finite element model is demonstrated through convergence of the results obtained for a floating barge problem. A better convergence rate and distribution of added mass in three orthogonal directions have be

ISSN:0029-5981    

DOI:10.1002/nme.1620360608

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractThe study of an axially‐loaded damped Timoshenko beam on a viscoelastic foundation is presented. The effects of the axial force, viscoelastic foundation and all the various damping components to a Timoshenko beam are considered in the formulation. The dynamic stiffness matrix is established and intensively discussed for applications. Free vibrations and the overall dampings are solved accordingly. Examples and discussions are also include

ISSN:0029-5981    

DOI:10.1002/nme.1620360609

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractA low storage, computationally efficient algorithm for the solution of the compressible Euler equations on unstructured tetrahedral meshes is developed. The algorithm takes the form of a centred scheme with the explicit addition of a high accuracy artificial viscosity and the solution is advanced to steady state by means of a multi‐stage time stepping method. The side based data structure which is employed enables a clear connection to be established between the proposed algorithm and upwind cell vertex schemes for unstructured meshes. The computational efficiency of the procedure is improved by incorporating an unstructured multigrid acceleration procedure. A number of flows of practical interest are analysed to demonstrate the numerical performance of the proposed approac

ISSN:0029-5981    

DOI:10.1002/nme.1620360610

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractConsideration is given to the prediction of the geometrically non‐linear elastic response of rectangular composite laminates with simply supported ends when subjected to uniform end shortening in their plane. At the loaded ends lateral in‐plane expansion is either allowed freely or is prevented completely. Material properties of the laminates are quite general, encompassing anisotropy and full coupling between in‐plane and out‐of‐plane behaviour. First‐order shear deformation plate theory is used as the mathematical model of laminate behaviour and the non‐linearity is introduced in the strain‐displacement equations in the manner of the von Karman assumptions. The finite strip method is used as the main numerical analysis procedure and subsidiary use is made of the finite element method. Close comparison of results generated using the two methods is demonstrated in applications ranging from isotropic plates to unsymmetric anisotropic laminates. Further comparison with the results of an earlier‐developed finite strip method, wherein properties are based on the use of classical plate theory, shows the effect of through‐thickness shearing action in d

ISSN:0029-5981    

DOI:10.1002/nme.1620360611

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY