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Abstract: Surface subdivision gains popularity in surface design owing to its flexible applications for geometry with complicated topology and simple computational scheme, and the geometric partial differential equation (GPDE) method is an advanced technology for constructing high-quality smooth surfaces. In this paper, we composite these two ingredients to form a unified method for freeform surface design. We choose the mean curvature flow and Willmore flow as our driven GPDEs, and the finite element method coupled with a hybrid Loop and Catmull–Clark subdivision algorithm as the numerical simulation method. This research presents a novel technique to evaluate the finite element basis functions and the first attempt for constructing the GPDE subdivision surface with hybrid control meshes consisting of triangles and quadrilaterals. Numerical experiments show that the construction method is efficient and robust, yielding high-quality hybrid subdivision surfaces. [Copyright &y& Elsevier]

A finite element (FE) model for analysis of tire rolling on the drum, based on a specially developed CAD model, is presented in the paper. All the changes performed on the geometry of CAD model are automatically propagated to FE model. This makes the FE model very suitable for parametric studies, which help tire designer to quickly find the optimal values of tire design parameters. In this way the tire design process is shortened and the quality of resulting tires improved. The results of finite element analyses conducted on the model have directly been compared to experimental ones, confirming model validity. Equipment and methods used for experimental determination of braking and cornering characteristics of the tire as well as for experimental determination of friction coefficient of tire tread have been shown. The difference between experimental and numerical results was smaller after the calibration of friction coefficient had been performed and in such a way a further improvement of the existing model was achieved. [ABSTRACT FROM AUTHOR]

This paper presents a parallel algorithm to improve the quality of surface meshes representing models obtained from surface reconstruction, as well as models generated by the application of the Boolean and assembly operations to predefined primitives, such as spheres and blocks. The smooth surface approximation is generated in parallel, the faces are distributed evenly among the processors. Then, the surface mesh is divided into sections, which are refined first, and intersections for remeshing at the end. [ABSTRACT FROM PUBLISHER]

Abstract: This paper describes a numerical procedure for the blank shape design of thin metallic parts obtained by stamping. The objective is to determine the initial blank shape knowing the geometry of the desired 3D CAD part. The numerical procedure consists of two stages: At first, an estimation of the initial blank shape is given using the one step inverse approach (IA). Then, update of the blank shape is continued by iterations combining optimization algorithms and finite element analysis (FEA). The numerical procedure for the blank shape design is tested in the case of an industrial stamping process where the part is formed using a manual press without blank-holder. The proposed numerical procedure can provide very quickly the optimal blank shape in a few iterations. [Copyright &y& Elsevier]

Abstract: Beams are high aspect ratio structural members that are used extensively in civil, automotive, aerospace, and MEMS applications. In all such applications, one must typically analyze and optimize the beams through computer simulations. Standard 3D finite element analysis (FEA) of beams can be used in such simulations; it is however prone to errors, and is computationally expensive for thin structures. Therefore, a common strategy is to carry out a dimensionally reduced 1D beam analysis. Unfortunately, 1D beam analysis is hard to automate and integrate with 3D CAD. In this paper, we propose an alternate “algebraic reduction” method that combines the generality of 3D FEA, and the computational efficiency of 1D beam analysis. This is achieved via a dual-representation framework where the geometry of the beam is captured via a 3D finite element mesh, while the physics is captured via a 1D beam model. The proposed method is formally established, and supported through numerical experiments. [Copyright &y& Elsevier]

In this paper, we present a methodology of generating nonlinear microfluidic macromodels for system-level simulations of 3-D microchannels using the Galerkin-based technique. Each generated macromodel consists of a low-order model and a few basis functions. For generating the basis functions, the ensembles of snapshots of fluidic field distributions are calculated by a finite-element-method or finite-volume-method solver, and then, the proper orthogonal decomposition is employed to extract the basis functions from the ensembles. For creating the low-order model, the Galerkin condition is used to formulate a set of simple ordinary differential equations. Compared with the full-meshed simulations, the generated macromodels not only provide accurate results (i.e., about 1% error) but also give computational speedups of at least three orders of magnitude. Also, the scaling and reusability of the generated macromodels are described and discussed. Furthermore, the macromodels of complicated channels can also be created by assembling the macromodels of other simple channels. The errors between the results by the assembled macromodels and the results by the full-meshed models are less than 2%. [ABSTRACT FROM AUTHOR]

A moving rail vehicle may cause propagating waves to the surroundings potentially leading to detrimental effects for the track construction, nuisances for the surroundings and interference with delicate electronic equipment. A full computational model should be able to couple a correct simulation of the rigid body motion of the different train parts with accurate prediction of the solid wave propagation in the ground. This paper integrates the dynamics of the vehicle and the elastic soil into one monolithic system. Equations of motion for the train have been merged the system representing the FEM problem for the rest of the structure. Three models of modern high-speed locomotives were run over a solid finite element model of a rail structure. [Copyright &y& Elsevier]

This paper describes the basic items needed for design and simulation of optical integrated circuits and analysis tools for optical waveguides. Because the finite element method and beam propagation method are emphasized, the scalar wave approximation (which has been extensively used) is used in the discussion. In addition, using examples of analyses on various optical integrated circuits, the design and simulation technologies for optical integrated circuits will be introduced. [ABSTRACT FROM AUTHOR]