ISSN:
1432-0924
Source:
Springer Online Journal Archives 1860-2000
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Abstract This paper describes the method for automatic remeshing of the distorted hexahedral finite elements and its application in metal forming processes. It first generates a regular mesh inside the bounding box that circumscribes the given volume to be meshed. Secondly extra elements of the regular mesh that lie outside the volume are removed from the regular mesh. Then, the geometric features of the old mesh (i.e. sharp edges and corners nodes) are determined by established criteria and corresponding features of the new mesh are traced down to guarantee geometric consistency between the two meshes. After that, a Boundary Element Layer (BEL) is constructed to form new hex mesh. By classification of all surface nodes of the regular mesh into face nodes, edge nodes and corner nodes and by the corresponding treatment to different types of surface nodes, the resulted new mesh gives much-improved hex elements that best suit local geometry. Finally a smoothing process is done to reposition the edge nodes, face nodes and internal nodes sequentially before the new mesh is exported for use in continued calculation. The density of the new mesh can be controlled to be adaptive to strain gradient during smoothing. The presented scheme is mainly metal forming oriented, therefore some supporting techniques related to mesh re-generation – variables transformation and quality evaluation of mesh – are also presented. However, the method can be equally applied to other fields after modification if the geometric information is adequately provided by other means. One example – the block upsetting – is illustrated along with the description to make the algorithm easier to be understood and another two application examples related to metal forming – the indenting process by spherical punch and square shaped backward extrusion – are given at the end. The qualities of both the old mesh and the new one are evaluated quantitatively by degenerate labels and qualitatively by exposure of internal mesh patterns. The on-face as well as internal distributions of the effective strain before and after remeshing are also compared. The effectiveness of the proposed techniques has been confirmed by these examples.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s004660050458
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