B-rep模型凸起特徵辨識及分解技術發展

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Title:	B-rep模型凸起特徵辨識及分解技術發展
Authors:	吳添瑜;Wu, Tien‑Yu
Contributors:	機械工程學系
Keywords:	凸起特徵辨識;凸起特徵分解;對稱凸起特徵;結構化網格;Protrusion recognition;Protrusion decomposition;Symmetric protrusion;Structured mesh
Date:	2022-07-19
Issue Date:	2022-10-04 12:11:11 (UTC+8)
Publisher:	國立中央大學
Abstract:	隨著 CAD 及 CAE 技術的迅速發展，在設計塑膠射出成型產業中，模流分析軟體的使用已經非常普遍。而模流分析前需要將欲分析的 CAD 模型網格化，提供實體網格資料給分析軟體計算，因此實體網格資料的品質優劣，會直接影響分析結果的準確性及分析時間的長短。若使用者需要較精確的分析分析結果，需要利用手動的方式，將模型進行切割並搭建結構化網格，其過程非常繁瑣且複雜。為了輔助結構化網格的搭建，本實驗室開發「特徵辨識」及「特徵分解」相關技術，辨識出薄殼元件 CAD 模型中的各種孔特徵、面屬性及凸起特徵，並藉由這些特徵資料將 CAD 模型分解為數個可以搭建結構化網格的規則區塊。本研究將接續先前開發的演算法，繼續發展凸起特徵辨識及分解技術，以提高辨識及分解完整度，並期望將此技術應用於更廣泛的 CAD 模型上。首先，為了能同時辨識出內部及外部凸起特徵，有對演算法中的資料結構進行整理，以達成此目的。接續為開發對稱凸起特徵辨識及分解技術。在辨識的部分，改善原先第一型對稱凸起特徵的演算法，並接續開發第二型及第三型對稱凸起特徵辨識。接著在分解的部分，將產生每一種對稱凸起特徵的主要特徵區塊，並建立其接合特徵區塊及中間層特徵區塊，得到完整的對稱凸起特徵分解結果。關鍵字：凸起特徵辨識，凸起特徵分解，對稱凸起特徵，結構化網格 ;With the rapid development of CAD and CAE technology, the use of mold flow analysis software has become very common in the design of the plastic injection molding industry. Before the mold flow analysis, the CAD model needs to be converted into solid meshes. Then, the solid mesh data will be employed to the solver for calculation. Therefore, the quality of the solid mesh data can affect the accuracy of the analysis results and the efficiency of the computational time. If users need more accurate analysis results, they need to manually separate a model and build structured meshes, which is a very tedious and complicated process. To assist the construction of structured meshes, our laboratory develops the technology of "feature recognition" and "feature decomposition". Thus, we can recognize hole features, face types, and protrusion features for thin shell CAD model, and decompose the CAD model into several regular blocks by which structured meshes can be built. This research will continue the previously developed algorithm, continue to develop protrusion recognition and decomposition technology to improve the recognition and decomposition integrity and expect this technology can deal with more kinds of CAD models. First, to recognize the inner and outer protrusion at the same time, the data structure in the algorithm needs to be organized to achieve this purpose. Secondly, this study is to develop the recognition and decomposition technology of symmetric protrusion. In the recognition part, this study is to improve the original algorithm of the first type of symmetric protrusion, and continue to develop the second and third types of symmetric protrusion recognition. Then in the decomposition part, the main feature blocks of each symmetric protrusions are generated, and connect feature block and the mid-layer feature blocks are established. Finally, the complete symmetric protrusion decomposition results are obtained. Keywords: Protrusion recognition, Protrusion decomposition, Symmetric protrusion, Structured mesh
Appears in Collections:	[Graduate Institute of Mechanical Engineering] Electronic Thesis & Dissertation

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