高強度鋼板沖壓成形扭曲現象分析
Other Title
An Analysis of Distortion in the Stamping of High Strength Automotive Structural Parts
Journal
鍛造
Journal Volume
22
Journal Issue
1
Start Page
23
End Page
30
ISSN
1023-750X
Date Issued
2013-03
Author(s)
周暐宬
Abstract
在高強度鋼板之沖壓成形製程中，除了傳統鋼板成形會產生之破裂、皺褶外，最主要的是必需解決回彈、側壁捲曲及扭曲等缺陷，其中又以扭曲（distortion）現象影響零件整體尺寸差異最為深遠，將降低整車裝配精度並提高焊接難度，且難以掌控其扭曲的方向與大小，為汽車工業沖壓製程中之最大難題。為了克服這些問題，國際間產學研各界均使用有限元素法進行模具設計與分析，以減少板金成形過程中之回彈量。在過去研究當中，雖然已經對有限元素模擬參數進行最佳化之收斂性分析，但對於提升預測回彈準確度仍不足。因此，本文針對描述材料受力行為之材料模型進行探討，配合參考NUMISHEET 1996年國際會議之Benchmark實驗數據進行S-rail模擬驗證，提出較適用於高強度鋼板沖壓成形扭曲現象模擬分析之材料模型。本文比對NUMISHEET S-rail實驗數據，確認以Barlat降伏準則加上考量包辛格效應之Y-U材料模型進行模擬較接近實驗值。而由U形帽狀模型進行延伸探討可知，板件造型與零件造型的影響，造成材料流動速度分佈不均，進而產生扭曲現象。
The common defects present in the stamping of conventional steel sheets are fracture and wrinkling. However, the occurrence of springback, side-wall curl and distortion makes it more difficult to be solved in the stamping of advanced high strength steels. Among these problems, distortion plays a critical role in influencing the overall size difference of parts, resulting in the difficulty in welding and assembly process of the automobile parts. In order to cope with this dilemma, the finite element analysis is employed to help the tooling design so as to reduce the springback in the sheet forming process. Although previous studies have endeavored to establish the optimum simulation parameters, the accuracy in the prediction of springback is yet to be improved. Accordingly, this thesis investigates the optimum material model that describes the material behavior best to raise the accuracy of the finite element simulations on the prediction of springback and distortion.
Subjects
高強度鋼板
沖壓成形
扭曲
有限元素法分析
材料模型
advanced high strength steel
stamping
distortion
finite element analysis
material model
Type
journal article