Geometry and Structural Modeling for High-Fidelity Aircraft Conceptual Design Optimization

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/140431/1/6.2014-2041.pd

Development of the process planning for machining prismatic parts

Machining of the complicated parts of high accuracy in large quantities has been an increasing demand since sophisticated technological equipment and machinery rapidly developed. These complicated components can be machined by employing NC machine tools. TIle motion commands for NC machine tool are determined by the path of the cutter. Obtaining optimal cutter path length is vital important in reducing the machining time. Nevertheless, another factor which has also influenced over machining time is the sequence of the machining operation. Hence, this project has presented the development of the process planning for machining diaphragm valve with Y - valve body (prismatic parts) with regard an optimum machining time. An effective process planning was developed with considering two major influences over machining time which are cutter path and machining operation sequence. Tool paths planning and simulation have been done by Unigraphics CAD/CAM Software. The machining operation is assumed to be carried out by 3-axis CNC vertical milling machine and has five setups for machining completion. The process planning developed comprises of six phases. They are fcature recognition, machining operation selection, machine selection, cutting tool sclection, cutting parameters selection and finally sequencing of the machining operation. The study results revealed that the total shortest machining time was 99.81 minutcs resulted from an optimum tool path and machining sequencc. The rcsults also revealed that two types of cut paths have contributed to highcr machining timc which are zig and zig with contour cut type. Both cut types were not suggcsted for machining of the diaphragm valve with Y -valve body

An algorithm for automatic 2D quadrilateral mesh generation with line constraints

Abstract Finite element method (FEM) is a fundamental numerical analysis technique widely used in engineering applications. Although state-ofthe-art hardware has reduced the solving time, which accounts for a small portion of the overall FEM analysis time, the relative time needed to build mesh models has been increasing. In particular, mesh models that must model stiffeners, those features that are attached to the plate in a ship structure, are imposed with line constraints and other constraints such as holes. To automatically generate a 2D quadrilateral mesh with the line constraints, an extended algorithm to handle line constraints is proposed based on the constrained Delaunay triangulation and QMorph algorithm. The performance of the proposed algorithm is evaluated, and numerical results of our proposed algorithm are presented.