ISSN:0748-8025    

DOI:10.1002/cnm.1630060102

出版商:John Wiley&Sons, Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractThe response of offshore structures subjected to wave loading is generally dominated by pseudo‐static behaviour which is not efficiently expressed in truncated modal co‐ordinates. In this paper, a new and efficient method has been developed to reduce modal truncation error in the numerical evaluation of transfer functions for the wave response of offshore structures. The solution is based on a transformation to a reduced system of generalized Ritz co‐ordinates using load‐dependent transformation vectors generated by a subspace iteration type of scheme from specified distributions of the dynamic loads. Numerical applications on a simple gravity platform model were used to establish systematic comparisons between the performance of the mode‐displacement, the mode‐acceleration and load‐dependent solutions using various numbers of transform

ISSN:0748-8025    

DOI:10.1002/cnm.1630060103

出版商:John Wiley&Sons, Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractTwo apparently different time‐domain boundary‐element formulations for plane‐stress/plane‐strain elastodynamic problems exist in the literature. The present paper shows why one of the formulations, which is valid for a particular type of interpolation function, forms part of the other, which can be used with any interpolation function. The main differences presented in the past between the two existing time‐domain boundary‐element methods were based on an incorrect expression of the tractions in the complete plane due to the rectangular impulse load. Results obtained in the past which were presented to evaluate the differences between the two formulations are shown to be incorrect. A compact expression for the fundamental solution integrated along a time step when the time interpolation functions of all the boundary variables are assumed to be piecewise constant is presented. This integral gives the same tractions as those corresponding to a rectangular i

ISSN:0748-8025    

DOI:10.1002/cnm.1630060104

出版商:John Wiley&Sons, Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractIn this work three implicit methods are considered for the solution of the constant‐coefficient diffusion‐convection equation. Two of these methods are seen to be first and second‐order accurate in time and to be L‐stable or L0‐stable, depending on the relation between the convection and diffusion parameters and the step size. The third one is seen to be third‐order accurate in time and is also L‐stable (L0‐stable). However, some oscillations may appear in the solution. To avoid these oscillations some restriction

ISSN:0748-8025    

DOI:10.1002/cnm.1630060105

出版商:John Wiley&Sons, Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractA variational inequality principle which is suitable for various constitutive laws of elasto‐plasticity is given in this paper. Then the variational inequality is reduced to a linear complementary problem by using incremental theory and the finite‐element meth

ISSN:0748-8025    

DOI:10.1002/cnm.1630060106

出版商:John Wiley&Sons, Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractA new superconvergent projection formula for determining vorticity boundary data in the stream‐function‐vorticity method is construc

ISSN:0748-8025    

DOI:10.1002/cnm.1630060107

出版商:John Wiley&Sons, Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractIn the direct boundary element method (DBEM) of analysis, much of the numerical computation involves the integrations along a boundary. The integration is usually performed by quadrature, and in recent pevious papers by the authors1,2it has been shown that integration can in general be carried out analytically, with the results of the integration presented as algebraic functions, and programmed accordingly. These results have, to this time, been presented for straight boundaries, with application to thinplate bending analysis only.For an arbitrary shaped curved element, the derivation of closed‐form expressions for boundary integrations is not possible. A semi‐analytical‐numerical procedure, based on representing the boundary as piecewise straight is developed in this paper. In this procedure, the boundary shape is considered dependent of the approximation of the boundary variables, and in the sense that each‘quadratic’ boundary element is considered geometrically to be made up of several piecewise cubic functions, the mulation might be termed‘super‐parametric’. Generally, a curved boundary does not necessarily imply need for higher‐order approximation of boundary variables, but does necessitate that the more applicated shape be accurately modelled.The integration procedure presented in this paper can be applied in other two‐d

ISSN:0748-8025    

DOI:10.1002/cnm.1630060108

出版商:John Wiley&Sons, Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractIn the application of the boundary element method (BEM) source terms give rise to domain integrals. To keep in the spirit of this method these integrals should be transformed into boundary integrals. Infortunately this is possible only in some circumstances. In this paper we develop further an idea of Vijayakumar and Cormack (1987) to obtain other cases where such transformation is possible

ISSN:0748-8025    

DOI:10.1002/cnm.1630060109

出版商:John Wiley&Sons, Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractA possible alternative to the conventional way of modelling heat generation in the solution of coupled electric and thermal fields is presented. The numerical method presented uses a resistance network analogy and results in a 7% saving in computing time. An analytical formulation presented saves a further 4%. This will be important in the solution of large problems.

ISSN:0748-8025    

DOI:10.1002/cnm.1630060110

出版商:John Wiley&Sons, Ltd    

年代:1990

数据来源: WILEY

ISSN:0748-8025    

DOI:10.1002/cnm.1630060111

出版商:John Wiley&Sons, Ltd    

年代:1990

数据来源: WILEY