| 摘要: | 薄殼CAD模型通常可以分為內部和外部區域，在這些區域上駐留各種結構和功能特徵。薄殼CAD模型上各種類型的面的識別是特徵識別中的關鍵步驟，可用於自動生成更好類型的網格。本文的實質是提出一種分離薄殼零件上的麵類型（包括內，輔助和外面）的方法。首先，根據模具的打開方向，將薄殼零件分為兩種類型的區域：可觀察區域和不可觀察區域，分別稱為內表面和外表面。其次，在輔助面臉識別中，然後將內部面臉分為幾種類型，包括：過渡，牆，下一層牆，基礎，山脊和內部突出面，其中前五種類型稱為輔助面臉。最後，在外表面識別中，外表面分為以下麵類型：法蘭，殼體，地面和外拉擠面。此外，薄殼CAD模型分為凹殼和非凹殼兩種類型，以方便開發面臉識別算法。本文對內外分割，輔助人臉識別和外面臉識別算法進行了詳細描述。此外，測試了現實的薄殼CAD模型，以證明該方法的可行性。認識到這些類型的面後，可以開發出可以生成更好類型的實體網格的合適的網格劃分算法，以用於薄殼CAD模型的網格劃分。;A thin-shell CAD model can typically be divided into inner and outer regions, on which various structural and functional features are resided. The recognition of various types of faces on a thin-shell CAD model is an essential step in feature recognition that can be used for automatic generation of better type of meshes. The essence of this paper is to propose a method for detaching face types, including inner, auxiliary and outer faces, on thin-shell parts. Firstly, a thin-shell part is split into two types of regions: observable and unobservable, based on the mold opening direction, called inner and outer faces, respectively. Secondly in auxiliary faces recognition, the inner faces are then divided into several types, including: transition, wall, next-layer wall, base, ridge and inner protrusion faces, where the first five types are termed auxiliary faces. Finally, in outer faces recognition, the outer faces are divided into the following face types: flange, shell, ground and outer protrusion faces. Also, the thin-shell CAD models are divided into two types: concave-shell and non-concave shell cases, for facilitating the development of outer-faces recognition algorithm. A detailed description of the algorithms for inner-and-outer faces splitting, auxiliary faces recognition, and outer faces recognition is provided in this thesis. Also, realistic thin-shell CAD models are tested to demonstrate the feasibility of the proposed method. With these types of faces recognized, appropriate meshing algorithms that can yield a better type of solid meshes could be developed for the meshing of thin-shell CAD models. |
