Computers

  2010 AUG 5 - (VerticalNews.com) -- "In this paper, a quadtree-based mesh generation method is described to create guaranteed-quality, geometry-adapted all-quadrilateral (all-quad) meshes with feature preservation for arbitrary planar domains. Given point cloud, our method generates all-quad meshes with these points as vertices and all the angles are within [45 degrees, 135 degrees]," researchers in the United States report.

  "For given planar curves, quadtree-based spatial decomposition is governed by the curvature of the boundaries and narrow regions. 2-refinement templates are chosen for local mesh refinement without creating any hanging nodes. A buffer zone is created by removing elements around the boundary. To guarantee the mesh quality, the angles facing the boundary are improved via template implementation, and two buffer layers are inserted in the buffer zone. It is proved that all the elements of the final mesh are quads with angles between 45 degrees +/- epsilon and 135 degrees +/- epsilon (epsilon <= 5 degrees) with the exception of badly shaped elements that may be required by the sharp angles in the input geometry. We also prove that the scaled Jacobians defined by two edge vectors are in the range of [sin(45 degrees-epsilon),sin90 degrees], or [0.64, 1.0]. Furthermore, sharp features and narrow regions are detected and preserved automatically. Boundary layer meshes are generated by splitting elements of the second buffer layer," wrote X.H. Liang and colleagues, Carnegie Mellon University ...read more

  2010 AUG 5 - (VerticalNews.com) -- "This article proposes a new type of discretizations for initial boundary value problems of thermodynamical systems. Based on a combination of finite elements in space and fractional step methods in time, we formulate algorithms that exactly preserve the symmetries and the laws of thermodynamics of the continuum problem," scientists writing in the journal Computer Methods in Applied Mechanics and Engineering report ...read more

  2010 AUG 5 - (VerticalNews.com) -- According to recent research published in the journal Computer Methods in Applied Mechanics and Engineering, "We study the 'classical' discrete, solid-void or black-and-white topology optimization problem, in which minimum compliance is sought, subject to constraints on the available material resource. We assume that this problem is solved using methods that relax the discreteness requirements during intermediate steps, and that the associated programming problems are solved using sequential approximate optimization (SAO) algorithms based on duality. ...read more