J. Altenbach, K. Naumenko and V.K. Naumenko. Analysis of rectangular thin plates and plate structures basing on the Vlasov's variational procedure. CAMES 1998 (5) 2: 115-128

The solution procedure proposed by Vlasov based on the reduction of the basic two-dimensional boundary value problems into ordinary differential equations provides a good accuracy in the case of rectangular domains with small size ratios. The paper presents an extension of this method applied to rectangular Kirchhoff's plates in connection with the iterational scheme. The results are compared with analytical solutions available for rectangular plates with simplified boundary conditions and loading. The possibilities of application of the solutions for simple plate geometry to complex plate problems (e.g. complex geometry, boundary conditions) are discussed and illustrated by numerical examples.

W. Blocki. Hydrodynamic moments due to water on ship deck. CAMES 1998 (5) 2: 129-137

An analysis of the ship stability requires computer simulations of the ship motions leading to its capsizing. The large amplitudes of roll motion of the ship are connected with phenomena of immersing of ship deck into water. These phenomena require to take into account additional moments connected with water on a deck. The paper presents a new method (1994) of calculating these additional moments. An approximate and simple calculation of the additional moments is based on the second principle of dynamics applied to an element of a water running off the deck. The additional moments applied in numerical simulations of the ship motions, change significantly the roll motion. The paper presents results obtained from computer simulations. Some of the results are compared with the results of an experiment done with the ship model.

I. Bock and J. Lovísek. On optimum design of a vibrating plate with respect to its thickness and eigen-frequencies. CAMES 1998 (5) 2: 139-150

The eigenvalue optimization problem for anisotropic plates has been dealt with. The variable thickness of a plate plays the role of a design variable. The state problem arises considering free vibrations of a plate. The demand of the lowest first eigenfrequency means the maximal first eigenvalue of the elliptic eigenvalue problem. The continuity and differentiability properties of the first eigenvalue have been examined. The existence theorem for the optimization problem has been stated and verified. The finite elements approximation has been analyzed. The shifted penalization and the method of nonsmooth optimization can be used in order to obtain numerical results.

C. Chinosi, L. Della Croce and T. Scapolla. Hierarchic finite elements for thin plates and shells. CAMES 1998 (5) 2: 151-160

We consider the numerical approximation of thin plate and shell structures. The plate model is described following the Reissner-Mindlin assumptions while the shell is described using the Naghdi formulation. It is well known that the numerical approximation with standard finite elements suffers of the so-called locking phenomenon, i.e., the numerical solution degenerates as the thickness of the structure becomes smaller. Plates exhibit shear locking and shells show both shear and membrane locking. Several techniques to avoid the numerical locking have been proposed. Here we solve the problems using a family of high order hierarchic finite elements. We present several numerical results that show the robustness of the finite elements, able to avoid in many circumstances the locking behavior.

T.W. Chiu and A.H. Berney. Absolute instabilities of a finite length vortex street with external axial velocities. CAMES 1998 (5) 2: 161-172

This paper presents a numerical algorithm for the study of the absolute instability of a vortex street with external axial velocities and finite length vortices. The aim is that this will be of relevance to the study of the flow over slender bodies at yaw. The algorithm is based on the vortex dynamics momentum equation. Special core treatments have been implemented to tackle the problem of infinite self-induced velocity. A small perturbation method is then used to formulate the eigenvalue problem.

V. Kalro and T. Tezduyar. Parallel iterative computational methods for 3D finite element flow simulations. CAMES 1998 (5) 2: 173-183

In this paper we discuss sparse matrix computational methods, and their parallel implementations, for evaluating matrix-vector products in iterative solution of coupled, nonlinear equations encountered in finite element flow simulations. Based on sparse computation schemes, we introduce globally-defined preconditioners by mixing clustered element-by-element preconditioning concept with incomplete factorization methods. These preconditioners are implemented on a CRAY T3D parallel supercomputer. In addition to being tested in a number of benchmarking studies, the sparse schemes discussed here are applied to 3D simulation of incompressible flow past a circular cylinder.

Z. Knesl, J. Vrbka and D. Vilímek. Estimation of the driving force acting on the interface edge. CAMES 1998 (5) 2: 185-192

This paper introduces a simple and approximate method of calculating the elastic driving force acting on the interface in two-phase materials. The method is based on considerations of the elastic energy connected with the change in the shape of the interface. The two phases are considered to be elastically isotropic media with different elastic constants. The procedure is developed in the framework of the finite element method and is applied to the estimation of the local driving force in the case of the edge of aa interface with a singular distribution of stress. The application of T-stress to the problem is suggested.

V. Kozák and I. Dlouhý. Local approach and FEM in brittle fracture prediction. CAMES 1998 (5) 2: 193-198

Local approach in fracture mechanics is based on the application of appropriate failure micromechanistic models to make predictions of fracture behaviour. The FEA of crack-tip and an associated post-processing routine is usually applied. Here should be noted the distinction between the cells of material, having characteristic microstructural dimensions, which constitute the cleavage process zone, and the corresponding finite elements used to represent their behaviour. Predictions of brittle fracture are based on the Beremin local approach model, where the Weibull location parameter sigma_u and shape parameter m have been calculated using FEM for Charpy type specimen. These parameters are considered to be transferable material properties, independent of temperature, specimen geometry or loading mode and can be used for prediction of the stress intensity factor K.