摘要:

AbstractThe paper presents a family of methods with postintegration, for numerical integration of non‐linear dynamic equations of motion of discrete systems. Both explicit and implicit algorithms of these methods are conditionally stable, but can give solutions of accuracy of a few orders higher than the known methods with preintegration, corresponding to them. A general analysis of stability and accuracy of single‐step methods is carried out. The postintegration methods have been tested on a single‐degree‐of‐freedom non‐li

ISSN:0029-5981    

DOI:10.1002/nme.1620330502

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractThe energy release rateGfor 2‐D rubbery material problems with non‐conservative crack surface tractions is calculated by a modified version of virtual crack extension method with finite element solutions. The formulation is demonstrated to be ‘patch‐independent’ and therefore a complicated finite element model around the crack tip is not

ISSN:0029-5981    

DOI:10.1002/nme.1620330503

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractThe purpose of the present paper is the development of a numerical method for the evaluation of the Stress Intensity Factor in mode II at the tips of closed cracks subjected to compressive normal stresses and monotonically increasing shear stresses. A hybrid Boundary Element Technique, originally developed for the analysis of open cracks, has been suitably modified. The Stress Intensity Factor is evaluated directly on the basis of the displacement discontinuities computed at the crack tip element, by taking into account the development of frictional resistance on the crack surfaces. A limited number (10‐15) of displacement discontinuity elements is found to be sufficient for an accurate evaluation of the Stress Intensity Factor. Some basic aspects of the mechanical behaviour of closed cracks are also investigated on the basis of the proposed metho

ISSN:0029-5981    

DOI:10.1002/nme.1620330504

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractWe investigate the Generalized Midpoint Rule for the time integration of elastoplastic constitutive equations for pressure‐independent yield criteria. The incremental equations are divided into one scalar hydrostatic pressure/dilation rate equation, and a stress deviator/strain rate deviator tensorial equation, the solution of which reduces to one single scalar equation in the plastic multiplier. The existence and uniqueness of an incremental solution is discussed. The pressure/deviator decomposition is the basis for reduced integration of the pressure term in the Principle of Virtual Work, in order to avoid locking and spurious pressure oscillations. It is also shown that an optimal choice of the parameter of the Midpoint Rule can be computed by reference to the analytical solution of the equations assuming no work hardening. A benchmark test shows that this choice allows increased time steps. This formulation is applied to two classical problems: bulging of a tube under internal pressure and tension test on a notched specimen, and a comparison with the analytical solution is performed. Finally, the hypothesis which sustains these formulations of elastoplasticity (constant strain rate during an increment) is discussed with reference to elastic unloading and residual stress computatio

ISSN:0029-5981    

DOI:10.1002/nme.1620330505

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractA simple and efficient triangular finite element is introduced for plate bending applications. The element is a three‐node triangular one with three basic degrees of freedom per node and two internal rotation degrees of freedom, using selective reduced integration. Numerical examples indicate that, despite its simplicity, the element is not only competitively accurate, but also useful as a thick‐thin triangular plate bending element. It is also pointed out that this element using selective reduced integration is in fact a mixed elem

ISSN:0029-5981    

DOI:10.1002/nme.1620330506

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractThis paper presents a method for creating a Delaunay triangulation connected to a set of specified points. The theoretical aspect is recalled for an arbitrary dimension and the method is discussed in order to derive a practical approach, valid for dimensions 2 and 3, which is simple, robust and well adapted to computation. Convex polyhedral and arbitrary polyhedral situations are introduced.

ISSN:0029-5981    

DOI:10.1002/nme.1620330507

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractThe implementation of an explicit transient program for the three‐dimensional non‐linear finite element analysis of shells on a massively parallel SIMD computer, the CONNECTION Machine, is described. Particular emphasis is placed on interprocessor communication using router and NEWS schemes. A hybrid communication scheme, where NEWS is used within structured subdomains and the router is used to exchange nodal forces between subdomains, is examined. It is shown that the ‘mesh‐structure index’ of most large meshes is sufficient to make hybrid schemes effective and this is verified by computer runs. Some benchmark non‐linear calculations with 8K to 32K elements are als

ISSN:0029-5981    

DOI:10.1002/nme.1620330508

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractAn exact expression is derived for the general finite‐part integralover aninclined ellipticaldomainΩ.rdenotes the distance of a point in Ω to the singular point\documentclass{article}\pagestyle{empty}\begin{document}$\left({x,y} \right).f = x_{^0 }^i y_0^j \sqrt {Z\left({x_{0,} y_0 }\right)}$\end{document}is a general function of the Cartesian co‐ordinates x0,y0. The boundary of the region Ω represents the equation Z(x0, y0)=O. These integrals appear during the numerical solution of plane crack problems in three‐dimensional elasticity where they are the dominant part of a hypersingular integral equation. The availability of exact expressions for the integrals with arbitrary integersiandjwill increase the accuracy of the numerical results and, simultaneously, lead to quicker numerical results.The considered finite‐part integral can be expressed in closed form as function of complete elliptical integrals or Gauss hypergeometric functions, respectively.Formuias for special cases and somei,jvalues and their numerical verification are given in Appendices

ISSN:0029-5981    

DOI:10.1002/nme.1620330509

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractThe chief advantage claimed for nine‐noded shell elements is that they can pass constant curvature patch tests with bilinear element geometry while eight‐noded shell elements cannot. It is shown that a simple modification of the shape functions of an eight‐noded element can make this advantage disappear. Test results confirm this result and show that the performance of a modified eight‐noded element is similar to that of recently reported nine‐noded

ISSN:0029-5981    

DOI:10.1002/nme.1620330510

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractA refined model is presented for the linear transient dynamic and damping analysis of laminated anisotropic composite plates. Experimental measurements of specific damping capacity of unidirectional composite beams are used to predict the specific damping capacity of laminated composite plates in various modes of vibration. A finite element idealization is adopted, and the quadratic Lagrangian element is used together with selective/reduced integration. A viscous damping approximation is then employed to calculate the damped transient response of laminated plates. The effects of transverse shear deformation, symmetry condition, boundary conditions, anisotropy, aspect ratio, fibre orientation and the lamination scheme on specific damping capacity and damped transient response are investigated. Realistic examples illustrate the importance of these parameters. The present results agree very closely with experimental results available in the literature and can serve as a benchmark for future comparison by other investigators.

ISSN:0029-5981    

DOI:10.1002/nme.1620330511

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY