3,585 research outputs found
Extended isogeometric boundary element method (XIBEM) for two-dimensional Helmholtz problems.
Get PDFIsogeometric analysis is a topic of considerable interest in the field of numerical analysis. The boundary element method (BEM) requires only the bounding surface of geometries to be described; this makes non-uniform rational B-splines (NURBS), which commonly describe the bounding curve or surface of geometries in CAD software, appear to be a natural tool for the approach. This isogeometric analysis BEM (IGABEM) provides accuracy benefits over conventional BEM schemes due to the analytical geometry provided by NURBS. When applied to wave problems, it has been shown that enriching BEM approximations with a partition-of-unity basis, in what has become known as the PU-BEM, allows highly accurate solutions to be obtained with a much reduced number of degrees of freedom. This paper combines these approaches and presents an extended isogeometric BEM (XIBEM) which uses partition-of-unity enriched NURBS functions; this new approach provides benefits which surpass those of both the IGABEM and the PU-BEM. Two numerical examples are given: a single scattering cylinder and a multiple-scatterer made up of two capsules and a cylinder
Interactive boundary element analysis for engineering design.
Get PDFStructural design of mechanical components is an iterative process that involves multiple stress analysis runs; this can be
time consuming and expensive. Significant improvements in the eciency of this process can be made by increasing the
level of interactivity. One approach is through real-time re-analysis of models with continuously updating geometry. Three
primary areas need to be considered to accelerate the re-solution of boundary element problems. These are re-meshing
the model, updating the boundary element system of equations and re-solution of the system.
Once the initial model has been constructed and solved, the user may apply geometric perturbations to parts of the
model. The re-meshing algorithm must accommodate these changes in geometry whilst retaining as much of the existing
mesh as possible. This allows the majority of the previous boundary element system of equations to be re-used for the
new analysis. For this problem, a GMRES solver has been shown to provide the fastest convergence rate. Further time
savings can be made by preconditioning the updated system with the LU decomposition of the original system. Using
these techniques, near real-time analysis can be achieved for 3D simulations; for 2D models such real-time performance
has already been demonstrated
The Mine Action Process
Get PDFThere are three ways to improve the mine action process to allow displaced people to return to their land sooner and with less risk of injury. Naturally, a major increase in aid funding would achieve a similar result using the existing process. Three main avenues to achieve improved outcomes with the same level of funding are as follows: Improving the technology, cost effectiveness and reliability of the mine clearance process, Applying risk management approaches to manage mine contamination problems, and Utilizing local resources and seeking alternative sources of funding more effectively
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