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近年來節能減碳意識興起，國際間車廠紛紛投入車體輕量化之研究，使用先進高強度鋼板進行車體成形逐漸成為趨勢。然而，強度高之鋼板易產生側壁外開、側壁捲曲及扭曲等成形缺陷，本研究針對側壁捲曲，藉由控制壓料力之方式進行改善。
首先以基礎U形帽狀引伸載具為模型，推導壓料力與側壁捲曲之基本關係，而在學界現有之文獻與業界加工技術手冊中，對於高張力鋼板引伸成形時可採用之最大壓料力並無可參考之經驗公式，故本研究建立590級至1180級鋼板之引伸成形單位面積最大壓料力表，可供日後開發之參考。
針對一般固定式壓料力之缺點，可以變壓料力作為改善，本研究針對四種基本變壓料力應用於引伸成形時之機制深入探討，比較改善回彈之效果，並歸納其適用時機。本研究提出另一種可改善板材側壁捲曲之模面段差法，並將其改善結效果與變壓料力進行比較。
最後以實際汽車結構件-車側門檻件為例，比較使用傳統二道次彎曲成形與變壓料力引伸成形之模擬結果，得知使用階梯式變壓料力引伸成形，改善車側門檻件之側壁捲曲情形較彎曲工法佳；與固定式壓料力相比，亦能降低減薄率。同時，由於引伸成形所需道次較彎曲成形少，故能節省開發成本，符合廠商之目標。
關鍵字：先進高強度鋼板、側壁捲曲、壓料力、有限元素法分析
Due to the goal of reducing
emission of CO2, lightweight design of automobiles has become a
major goal for vehicle manufacturers in recent years. It results
in the tendency towards the study of sheet metal forming using
advanced high strength steels (AHSS). This research aims at
reducing of sidewall curl effect after the sheet metal forming
process of AHSS via blank holder force.
Taking U-hat drawing as an example, this thesis investigates the
basic relation between blank holder force and sidewall curl. So
far, there is no reference of maximum blank holder force for
AHSS in sheet metal forming handbook. The results of this study
provide maximum blank holder force of U-hat drawing with AHSS
DP590、DP780、DP980 and DP1180 for the future mold design.
In order to eliminate drawbacks by using constant blank holder
force, variable blank holder force is proposed. This thesis aims
at researching the mechanism of four basic variable blank holder
force curve based on CAE simulations. Then the effects of using
each variable blank holder force on sidewall curl are compared.
Another method of reducing sidewall curl effect is using step
mold. The CAE simulation results of stamping with step mold are
compared with stamping using variable blank holder force.
Side sill is a common automobiles structure. The traditional way
of forming side sill is bending with two operation processes.
The simulation results of forming side sill using drawing with
variable blank holder force are presented. With the use of
variable blank holder force, bending operation process can be
replaced by drawing with variable blank holder force.
Keywords: advanced high
strength steel, sidewall curl, blank holder force, finite
element analysis.
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