摘要:

AbstractThe computer algebra system MATHEMATICA is applied to the iterative solution of systems of linear algebraic equations where the matrix of the coefficients depends on a parameter. The solution is found in a Taylor‐Maclaurin series form with respect to this parameter at an appropriate point and, therefore, the system can be solved only once and for all even if the parameter varies. All three popular iterative methods, that is, the Gauss–Jacobi, the Gauss–Seidel and the successive overrelaxation method are used in particular applications. The complete MATHEMATICA procedure for the last of these methods is also presented. Two elementary applications to structural mechanics are also made and further possibilities are disc

ISSN:0748-8025    

DOI:10.1002/cnm.1630080702

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractRecirculating flow around a backward‐facing step is calculated by large eddy simulation (LES). The reattachment length is found to bexR/H= 8 for a Smagorinsky constant of C =0.15, andxR/H= 9 for C =0.10. In the recirculating region, three eddy structures can be observed in the instantaneous streamline distributions, and the location of the reattachment point varies according to the size of these eddies. The stream‐wise turbulence intensities at the start of the recirculating region around the step are considerably reduced by LES in comparison with the values predicted by thek– ϵ model, but they have somewhat higher values than those of thek– ϵ model as it approaches the reattachm

ISSN:0748-8025    

DOI:10.1002/cnm.1630080703

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractA methodology has been developed to hierarchically model discontinuous fields by means of the s‐version of the finite‐element method. This is achieved by overlaying portions of the finite‐element mesh where discontinuities need to be embedded with a finite‐element mesh which is discontinuous across the crack faces (containing unconstrained double nodes along the discontinuity). By this technique crack propagation can be simulated by advancing the crack front in the superimposed mesh only, keeping the base mesh fixed and unaware of the crack existence. The hierarchical structure of the method ensures computational efficiency, especially in linear systems. Numerical experiments for mode I and mixed‐mode problems are presented to validate the present fo

ISSN:0748-8025    

DOI:10.1002/cnm.1630080704

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractA short pressurized tube with a fabric end cap is placed concentrically within a longer, larger tube with a contaminated, turbulent flow. The effects of external velocity and internal pressure on the infiltration of contaminant into the pressurized tube are studied. The SIMPLER finite‐difference method, together with the two equation model of turbulence, is used to model the flo

ISSN:0748-8025    

DOI:10.1002/cnm.1630080705

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractA new technique of multi‐level substructuring based on a regular mesh is presented. The technique takes advantage of the physical symmetry and repetitivity generated by the regular mesh. A special node‐numbering/addressing system is developed to exploit the symmetry which results in the stiffness matrices not only being symmetrical about the leading diagonal, but a regular pattern emerging with respect to the other diagonal. The same pattern exists for their inverses. A new condensation scheme is used to take full advantage of the regular patterns. As a result, only about a quarter of the stiffness matrices and their inverses need to be processed, as compared to half when using the conventional method.Based on the technique, a two‐dimensional finite‐element analysis program FEMSUB has been implemented in the University's VAX network. Through a number of numerical tests, it is discovered that the new technique can result in savings of both core storage and computing time. The savings become more significant when the scale of a problem increases. The investigation indicates that the core storage requirement decreases when using substructures of higher levels. However, for computational efficiency, both the level of substructuring and the number of repeated substructures have an effect. Thus, a dimensionless parameterR(number of substructures used/maximum number of substructures) has been introduced to correlate the effect of the technique on computational eff

ISSN:0748-8025    

DOI:10.1002/cnm.1630080706

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractProcedures are derived in this paper for defining fully stressed statically indeterminate trusses under a single loading condition for the particular case where redundant supporting members are added to a determinate truss. If the orientations of the redundant members are prescribed, their length can be computed easily from the fully stressed conditions. The cross‐sectional areas of truss in fully stressed configuration (FSC) are not unique. The minimum weight FSC can be determined with use of linear programming. Several examples are included to illustrate the general formulatio

ISSN:0748-8025    

DOI:10.1002/cnm.1630080707

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

ISSN:0748-8025    

DOI:10.1002/cnm.1630080708

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

ISSN:0748-8025    

DOI:10.1002/cnm.1630080701

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY