tailieunhanh - Meshing User's Guide ANSYS phần 9

tạo ra các mô hình độc đáo topo mà không có hệ thống CAD khác tạo ra. Trong tất cả các hệ thống CAD khác, phải đối mặt với không tuần hoàn có thể có chỉ có 1 vòng lặp bên ngoài topo. Mặt khác, các mô hình trong Pro / ENGINEER có thể không định kỳ phải đối mặt với các vòng bên ngoài nhiều. | 266 Release - SAS IP Inc. All rights reserved. - Contains proprietary and confidential information of ANSYS Inc. and its subsidiaries and affiliates. Miscellaneous Tools The miscellaneous meshing tools described in the following sections include Generation of Contact Elements Renaming Mesh Control Tool Mesh Numbering Mesh Connection Generation of Contact Elements To model contact between parts in an assembly you must define specific contact conditions. One of those conditions is tolerance which controls the extent of contact between parts in an assembly. Tolerance is set as a percentage of the bounding box of the assembly. The bounding box is the smallest volume that the assembly will fit in. You can change the tolerance between -100 and 100 in the Options dialog box under the Mechanical application s Connections category. The higher the number the tighter the tolerance. A loose tolerance generally increases the number of contact faces and areas of contact between parts while a tight tolerance will decrease the number of contact faces. Each face of the part is checked against the faces of other parts in the assembly. A contact pair is generated between any faces within the tolerance. When solving the elements for the two faces that make up the pair are compared. If any of the faces are within the tolerance contact elements are generated for them. Recommendations for Defining Contact for CFD Analyses CFD users should be aware of the following recommendations By default contact detection is computed upon geometry import when Physics Preference is set to CFD. If you do not want contact detection to be computed you must change the Auto Detect Contact on Attach setting in the Mechanical application to No. This setting is available in the Options dialog box under the Mechanical application s Connections category. For CFX users it is best practice to set the Group By option to None when defining Global Contact Settings. This is true because CFX only accepts contact .