Abstract We developed in this paper a variational formulation of heat diffusion equation applicable to the flat shell context and cellular structures. For this purpose, we introduce the average mid‐surface temperature field, through‐the‐thickness gradient and their dual generalized fluxes. Moreover, we introduced radiative heat exchange in the same way, which leads to a non‐linear and unsymmetrical thermal discrete problem. The model performance is illustrated by several numerical examples concerning cellular structures like hollow clay bricks submitted to thermal loading. Thermo‐mechanical coupling for such structure which is well adapted to the shell‐like modelling approach, is presented in the elastic regime with the numerical results concerning temperature field and forces. Copyright © 2005 John Wiley & Sons, Ltd.

Abstract This paper deals with a coupled finite element/scaled boundary finite element method (FE/SBFEM) and its application to wave propagation problems in fluids in the time domain. This method is already well established and has proven to be an efficient technique for treating radiation problems. In its application to time domain problems, convolution integrals arise. For each time step ti, i matrix–vector multiplications have to be performed, where the involved influence matrix—due to the non‐locality in space—is fully populated. This numerical evaluation becomes a significant, time‐consuming task for long time calculations, thus decreasing the attractiveness of the method. In this paper, the application of hierarchical matrices (ℋ︁‐matrices) is to overcome this drawback. ℋ︁‐Matrices represent an octree‐based clustered low‐rank approximation of the original, fully populated matrix and allow a considerable increase in efficiency for matrix–vector products encountered, e.g. in convolution integrals. The application of ℋ︁‐matrices to this method results in an increase in efficiency without noticeable loss in accuracy. Since convolution integrals arise in various large‐scale engineering computations the application of ℋ︁‐matrix techniques might turn out to be a highly promising way to pursue. Copyright © 2005 John Wiley & Sons, Ltd.

Abstract In this study, we present a new highly accurate composite laminated hybrid‐mixed curved beam element. The present element, which is based on the Hellinger–Reissner variational principle and the first‐order shear deformation lamination theory, employs consistent stress parameters corresponding to cubic displacement polynomials with additional nodeless degrees of freedom in order to resolve the numerical difficulties due to the spurious constraints. The stress parameters are eliminated and the nodeless degrees are condensed out to obtain the (6 × 6) element stiffness matrix. Several numerical examples confirm the superior behaviour of the present hybrid‐mixed laminated curved beam element. Copyright © 2005 John Wiley & Sons, Ltd.

Abstract A caisson breakwater may experience various modes of motions under wave action. The elementary motion modes are classified into two categories, i.e. the horizontal and rotational vibration coupled motion and the horizontal slide and rotational vibration coupled motion. The motion modes of caisson will transform from one to another depending on the wave forces and the motion behaviours of a caisson. The numerical models of the two motion modes of caisson are developed, the numerical simulation procedure for joint motion process of the two modes of caisson breakwater under wave excitation is presented and tested by a physical model experiment. It is concluded that the simulation procedure is reliable and can be applied to the dynamic stability analysis of caisson breakwaters. Copyright © 2005 John Wiley & Sons, Ltd.

Abstract A vector potential for the electric induction is applied to static three‐dimensional fully coupled electromechanical problems. A Coulomb gauge condition imposed on the electric vector potential improves the convergence behaviour of nonlinear problems, and in combination with a discrete set of Dirichlet boundary conditions, it can enforce unique vector potential solutions. Based on a spectral analysis of the stiffness matrix, the Coulomb gauge is compared with other gauge conditions. A penalized version of the weak vector potential formulation with Coulomb gauge is proposed and tested on some numerical examples in electrostatics, piezoelectricity and ferroelectricity. Copyright © 2005 John Wiley & Sons, Ltd.

Abstract In this paper, we present and analyse some local and parallel covolume algorithms for second‐order elliptic problems. We first prove some local a priori error estimates for covolume method. With these results, we shall apply the two‐grid strategy to covolume approximation to give two novel covolume algorithms, and show that the convergence rates of these algorithms are optimal in piecewise H1‐norm. Numerical results confirming the theory are also provided. Copyright © 2005 John Wiley & Sons, Ltd.

Abstract This paper presents a numerical method for determination of reworking or scraping defective items in a finite production rate model with backlogging permitted. In most practical manufacturing settings, due to process deterioration or other factors, generation of defective items is inevitable. The defective items can either be repaired or be discarded. In the finite production model we studied, the defective rate is assumed to be a random variable and the rework process can start immediately when regular production ends. The optimal lot sizes and the expected annual inventory costs for the cases of production systems with the rework process and without the rework process are compared and analysed. A set of numerical equations are developed to assist in determining on whether or not it is beneficial to rework defective items. A numerical example is provided to demonstrate their practical usages. Copyright © 2005 John Wiley & Sons, Ltd.

Abstract Runoff regulation of hydropower station is always an important point and difficult issue for researchers and engineers, and different methods have been advanced for obtaining simple and accurate results, but they do not often do good work. In this paper a new approach is presented to regulate runoff of hydropower station that through iterative equation for turbine discharge and construct numerical computation for runoff regulation of hydropower station. A case shows that the solution is simple, accurate and easy to use in practice. Copyright © 2005 John Wiley & Sons, Ltd.

This work presents a back-tracking procedure for the optimization of meshes. It can be applied to all ill-shaped elements in a mesh in order to improve quality in mesh optimization. Basically, the original mesh is reconstructed in regions around the ill-shaped elements by means of a set of deletion and reconstruction operations based on visibility tests. The back-tracking procedure fixes problems related to the quality of generated meshes in general and can be applied in two or three dimensions. The procedure works by deleting elements ranked below a predefined shape quality measure. It is important to mention that, although the presented procedure was devised for advancing-front algorithms, it can also be used in meshes generated by different approaches, such as Delaunay and others, requiring no modification. The proposed procedure is applicable to simplex elements (triangles and tetrahedra), although ideally it could be extended to other types of elements. Examples of improved meshes using the back-tracking procedure are presented, in which the quality of these meshes is assessed in order to validate the procedure proposed in this work. Copyright © 2005 John Wiley & Sons, Ltd.