2009-08-012024-05-18https://scholars.lib.ntu.edu.tw/handle/123456789/701210摘要：用自行撰寫描述晶格變形機制之聚晶體模型，搭配有限元素分析套裝軟體針對尺寸效應進行有系統之研究，期藉由開發之分析工具適切掌握因尺寸效應對於某些場域造成之影響。藉由已知文獻之實驗結果與本計畫執行之數值模擬結果進行相對應定性與定量之比較，確認成果之合宜性。進一步將聚晶體模型應用於精微深引伸成形模擬，檢視工件厚度，衝床圓角半徑，衝頭直徑與工件厚度比例等參數對於引伸力量歷程，引伸成品高度變化，失效模式與發生位置等之影響，並與實驗量測進行比對與解釋。本計畫亦嘗試模擬精微衝孔成形製程，考慮尺寸效應於材料性質之影響，結合實驗量測數據以獲取模擬所需參數，針對衝頭幾何形狀，模具間隙，尺寸，夾持力量，衝孔尺寸，形狀，及排列特徵等於成形品質之影響進行檢視。<br> Abstract: A Taylor-like micromechanical crystalline model, implemented into the finite element analysis commercial software, is developed to investigate behaviors of metal materials with fcc structures in the present study. Three-dimensional grain shapes, sizes, and orientations are re-constructed by utilizing a serious of the experiments and an image processing technique as well. The so-called size effects of thin sheets on fundamental material properties are demonstrated based on the polycrystalline model. Results would be validated by measurements in the current literatures. Simulations of the micro deep drawing operations are used to examine effects of some potential critical parameters, such as sheet thickness, round radius of die, and a ratio of punch radius to sheet thickness, on the drawing force history, drawing height variations, failure sites, etc. The polycrystalline model is also incorporated into the simulation of the precision micro punching operations here. A finite element analysis is carried out to explore effects of various parameters such as the punch geometry, clearance between dies and the punch, binder force, and the size and shape of punching holes on the tool fatigue life, punch force, and forming dimensional precision. Numerical results are further compared with the corresponding experimental measurements.聚晶體模型精微深引伸成形精微衝孔成形有限元素分析polycrystalline modelmicro deep drawingmicro punchingfinite element analysis