Engineering Computations: International Journal for Computer-Aided Engineering and Software

Muttin, F.; Chenot, J. L.

doi: 10.1108/02644409510799442pmid: N/A

A twogrid iterative method for 3D linear elasticity problems,discretized using quadratic tetrahedral elements is proposed. Theconjugategradient method is used as smoother. As compared to theconjugategradient alone, it is shown, via numerical examples, that themethod is much more efficient on the basis of computing time and memoryallocation. The convergence property of the method is sensitive to theregularity of the problem.

Draztic, P.; Tassin, R.; Ravalard, Y.

doi: 10.1108/02644409510799451pmid: N/A

Rigid multibody modelling is used to study the crashrelatedglobal behaviour of transport vehicles. These models are made up rigidbodies, joints and springs. Distinct kinematic models have been developed inorder to analytically determine the resistance to collapse ofthinwalled structures of simple geometry subjected to compression orbending loading. The modeller must position these different elements but hasno information on their numbers and their locations. For this reason, amodelling aiding tool, based on the elastic buckling analysis, has beendeveloped. This method is used to resolve a problem of an Sframe undergoing a collision against a rigid block to estimate itsvalidity.

Sander, R.; Pittman, J.F.T.

doi: 10.1108/02644409510799460pmid: N/A

A tailored graphical user interface GUI for finite elementanalysis, fully integrated into Microsoft Windows 3.1, has been developed.The current application is the simulation of flat sheet extrusion ofthermoplastics, but many of the features would be common to a wide range offinite element analyses. Microsofts CC ProfessionalDevelopment System 7.0, including the Software Development Kit 3.1SDK, has been used as the programming tool for the GUI. Theinterface is based on the Common User Access Advanced Interface Design Guide,which is part of the IBM Systems Application Architecture Library, and TheWindows Interface An Application Design Guide, which is part of theSDK. A memory handling technique is proposed to break the imposed 64 KB datasegmentation. Connected finite element calculation routines are written inFortran and compiled by the Salford FTN77x86 32bit compiler. Theprotected mode interface of the Fortran compiler allows direct access by theGUI, and allows the computation to run as a 32bit backgroundapplication, without memory limitations, in the multitasking environment.Finite element routines are supported by pre andpostprocessors comprising mesh generation, postprocessing forderived results, and graphical displays. A convenient contouring algorithmis proposed to generate contoured plots of nodal quantities in the form ofisolines or isofields.

Rikards, R.; Chate, A.; Korjakin, A.

doi: 10.1108/02644409510799479pmid: N/A

The present investigation is concerned with the utilisation of thefinite element technique for predicting the natural frequencies and the modaldamping factor also called the loss factor of anisotropicfibrereinforced composite laminated plates. The simple definition ofthe modal damping factor is defined as the ratio of the strain energydissipated per radian of vibration, in the mode of interest, to the totalstrain energy of the entire laminate at maximum displacement during the samecycle. Results for the vibration and damping analysis of multilayeredplates obtained by the present methods are compared with the results obtainedby other authors and with the results of experiments.

Padra, C.; Vnere, M.J.

doi: 10.1108/02644409510799488pmid: N/A

In this work an adaptive scheme to solve diffusion problems, usinglinear and quadratic triangles, is presented. The densification algorithm,based on the subdivision of the selected elements, and the error estimatorused are described first. We pay special attention to the behaviour of theestimator. It has two contributions the residual term and thefluxjump term. Babuska and coworkers have shown that forbilinear quadrilterals, the first term is negligible, but for biquadratic, itis the dominant term. We show evidence suggesting that these results cannotbe extended to triangular elements when the problem has a singular solution.We found, in this case, that if the fluxjump term is neglected, theexpected rate of convergence cannot be obtained. Finally, some remarks aboutthe whole adaptive process are discussed.

Sori, J.; Smojver, I.

doi: 10.1108/02644409510799433pmid: N/A

A linear and geometrically nonlinear computation of a laminatedcomposite torispherical shell subjected to internal pressure was performed byusing the layered finite element whose formulation is based on degenerationprinciple. Geometric nonlinearity in terms of large deformations withtotal Lagrangian formulation was taken into account. The effect of thelamination schemes on geometric nonlinear behaviour and stressresultant distributions was analysed. The fibre directions have not a greatinfluence on the shape of the loaddisplacement curves. In contrast to the hoop stress resultant distribution, the moment distribution is significantly influenced by the lamination schemes. The influence of the lamination schemes on bending moments is greater in nonlinear than in linear computations. Likewise, the effect of the fibre orientation is greater on the hoop than on the meridional moment distribution. In unsymmetric laminated shells the values of the hoop moments exceed those of the meridional moments which is a considerable difference from metallic isotropic shells.