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    Title: 微小圓杯引伸成形分析與料片最佳化之研究
    Other Titles: Study of formability analysis in cylindrical micro cup drawing and blank optimization
    Authors: 陳世傑;Chen, Shih-chieh
    Contributors: 淡江大學機械與機電工程學系碩士班
    葉豐輝;Yeh, Fung-huei
    Keywords: 微成形;有限元素法;圓杯引伸;料片最佳化;適應性網路模糊控制理論;Micro Forming;Finite Element Method;Cylindrical Cup Drawing;Blank Optimization;ANFIS
    Date: 2006
    Issue Date: 2010-01-11 06:36:00 (UTC+8)
    Abstract: 本文係探討微小圓杯引伸成形與料片最佳化之模擬分析。為了驗證有限元素方法能有效分析微小圓杯引伸成形,本文首先模擬微小圓杯引伸凸緣,並與期刊論文之實驗比較,其結果一致。且本文亦探討間隔環大小對皺折產生的影響。其次模擬微小圓杯引伸貫穿,分析成形負荷、厚度分佈及成形杯高,藉由期刊論文之實驗比較,探討模擬分析與實驗結果之差異,並藉著模擬分析來預測實驗時模具間之摩擦係數。本文亦針對影響微小成形之重要因素(模具間摩擦係數、板材異向性及尺寸效應)作一系列之探討。在尺寸效應方面,本文將料片厚度及晶粒大小導入材料應力應變構成式,並利用適當之猜測值,以期使用單一式子就能準確預測不同料片厚度及晶粒大小之應力應變曲線,結果顯示,與單純應力應變構成式相比,導入尺寸效應因子的應力應變構成式差距皆在5%以內。本文亦探討模具Dp/t=20之極限引伸率,利用成形極限圖與對應成形狀況圖可以了解破裂的原因及趨勢,結果顯示模具Dp/t=20之極限引伸率為2.3。
    本文為改善金屬板材異向性所導致微小圓杯引伸貫穿之耳緣現象,採用真應變法(true strain method)結合權重因子與ANFIS來預測無耳緣之最佳化料片輪廓。並探討板材異向性值分佈不同所造成真應變法之適用性。結果顯示料片45度異向性值較小時,可適用於真應變法來取得最佳化的效果。料片45度異向性值較大時,必須使用權重因子來修飾料片外徑並製成資料庫,再採用適當之規屬函數來進行ANFIS最佳化,結果顯示有相當好的耳緣修正成效,本文之研究成果可提供微小成形及料片最佳化相關研究之參考
    This thesis discusses the simulation of micro cylindrical cup drawing and blank optimization. In order to prove that finite element method can effectively analyze the micro cylindrical cup drawing. The simulation of micro cylindrical flange cup drawing is firstly performed and compared with the experimental result in the journal paper. It shows that the result is the same. Besides, wrinkle dues to the improper gap of the blank holder is also discussed. Secondly, the simulation of micro cylindrical cup drawing is performed and compared with punch load, thickness distribution and cup height in the journal paper. Friction coefficient of the tools is predicted to verify the corresponding model in the experiments. This thesis also focus on the important factors of micro forming, which are friction coefficient, anisotropy of the sheet metal and size effect. In the discussion of size effect, this thesis combines the thickness and grain size into the stress-strain relation. A set of proper values is imported to predict the stress-strain curve by only one equation. The result of original stress-strain relation and stress-strain relation combines with the thickness and grain size is compared. The result shows the difference is within 5%. In the field of forming limit, this thesis uses the model that Dp/t=20 and check the limit drawing ratio (LDR) by the forming limit diagram (FLD).With the forming limit diagram, the reason and tendency of crack is realized and the result shows the limit drawing ratio is 2.3.
    In order to reduce the earing dues to anisotropy of sheet metal in the micro cylindrical cup drawing, true strain method combines weighting factor and Adaptive-Network-based Fuzzy Inference System (ANFIS) to predict the optimum blank with no earing. The distribution of the anisotropy of the sheet metal affects the applicability of true strain method. The result shows that if the anisotropic value in the 45 degree in the rolling direction is smaller, true strain method is suitable. If the anisotropic value in the 45 degree in the rolling direction is larger, weighting factor is used to modify the blank shape and sort the result into a data base as training data for ANFIS and a proper membership function is used. It shows good result of the modification. The research of this thesis can be the reference to the relative research in micro forming and blank optimization.
    Appears in Collections:[機械與機電工程學系暨研究所] 學位論文

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