采用ABAQUS針對航空某型材件的拉彎分析
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xmlns="http://www.w3.org/TR/REC-html40">
style='line-height:240%;font-family:宋體;mso-ascii-font-family:
"Times New Roman";mso-hansi-font-family:"Times New Roman"'>采用
style='mso-bookmark:_Toc118715832'>ABAQUS
style='line-height:240%;font-family:宋體;mso-ascii-font-family:
"Times New Roman";mso-hansi-font-family:"Times New Roman"'>針對航空某型材件的拉彎分析
style='mso-bookmark:_Toc118715832'>
style='font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>美國ABAQUS
style='font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>軟件公司北京代表處 梁明剛
style='font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>前言:型材拉彎工藝廣泛應用于航空航天、汽車、機械設備、建筑等行業(yè),隨著高新技術越來越多應用于這些工業(yè),設計工程師對于計算機仿真技術的要求也與時俱進。
lang=EN-US>ABAQUS以其卓越的非線性問題的處理能力為廣大工業(yè)客戶所認可,本文以航空工業(yè)中某型材拉彎產品為例,介紹了
lang=EN-US>ABAQUS對應的分析流程,對工程中提出的四種加工方案逐一進行分析,結合回彈的結果對它們進行比較,最后提出改進方案。經實踐檢驗,仿真分析的結果跟實際結果達到高度一致,為設計工程師提供了可信的參考數據。
一、模型描述
style='font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>首先將造型設計工程師提供的型材產品目標形狀的幾何模型導入到ABAQUS/CAE
style='font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>中,如圖1所示。
src="http://www.caenet.cn/picture/abaqus0307/image002.jpg" alt="converted PNM file" v:shapes="_x0000_i1025">
style='font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>圖1 型材產品目標形狀
style='font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>考慮到型材幾何形狀的對稱性,我們針對1/2
style='font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>模型的拉彎過程進行分析,圖2所示為實際模型的一半,考慮到型材壁厚與其表面長寬之間的比例關系,我們進一步將模型簡化為殼結構,圖3為根據該模型的尺寸生成的模具模型及其有限元網格模型,圖4為裝配模型及其有限元模型。
src="http://www.caenet.cn/picture/abaqus0307/image004.jpg" alt="converted PNM file" v:shapes="_x0000_i1026">
style='font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>圖2 產品模型的二分之一
src="http://www.caenet.cn/picture/abaqus0307/image006.jpg" alt="converted PNM file" v:shapes="_x0000_i1027">
src="http://www.caenet.cn/picture/abaqus0307/image008.jpg" alt="converted PNM file" v:shapes="_x0000_i1028">
style='font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>圖3 剛體模具的幾何模型(左)和有限元網格模型(右)
src="http://www.caenet.cn/picture/abaqus0307/image010.jpg" alt="converted PNM file" v:shapes="_x0000_i1029">
src="http://www.caenet.cn/picture/abaqus0307/image012.jpg" alt="converted PNM file" v:shapes="_x0000_i1030">
圖4 裝配體的幾何模型(左)和有限元網格模型(右)
二、分析方案
style='font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>根據實際加工過程的特點,并針對此類型材拉彎問題,我們采用ABAQUS
style='font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>的隱式算法模塊ABAQUS/Standard
style='font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>進行成形分析。考慮到實際成形時的影響因素,我們按照下面四類分析過程分別進行模擬,最后分別以回彈量、型材厚度變化量、局部型材的變形量作為考查標準,為實際加工過程提供必要的數據作為參考。
style='font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>分析過程的分類如下:
1、
直接進行型材拉彎,然后考察其回彈量;
2、
首先對型材做一個整體拉伸,然后再進行型材拉彎,最后進行回彈分析;
3、
第一步進行型材拉彎,然后對彎曲得型材做一個整體拉伸,最后進行回彈分析;
4、
首先對型材做一個整體拉伸,然后再進行型材拉彎,接著對彎曲得型材做一個整體拉伸,最后進行回彈分析;
三、分析結果
style='font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>針對以上提出的四種方案的具體流程,我們分別生成相應的分析模型進行計算。下面總結了這四種分析方案得到的
lang=EN-US>Mises應力、等效塑性應變、型材壁板厚度和最終成形之后的回彈量的對比結果。
lang=EN-US>
style='font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>由圖5可以得到:對于方案2
style='font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>和方案4最大
lang=EN-US>Mises應力的大小均為:127.9MPa
style='font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>,方案1和方案
lang=EN-US>3最大Mises
style='font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>應力的大小均為:149.2MPa
style='font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>。四個方案共同之處是Mises
style='font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>應力的分布表現一致,即應力集中區(qū)域都是在型材的彎曲部分,尤其豎筋與板的交界處;不同之處在于方案
lang=EN-US>2和方案4
style='font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>的Mises應力分布更均勻,而方案
lang=EN-US>1和方案3
style='font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>的Mises應力分布集中。
v:shapes="_x0000_s1033 _x0000_s1029 _x0000_s1030 _x0000_s1031">
lang=EN-US>
src="http://www.caenet.cn/picture/abaqus0307/image015.jpg" alt="converted PNM file" v:shapes="_x0000_i1031">
style='font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>圖5 Mises
style='font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>應力分布云圖
style='font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>由圖6可以得到:對于方案2
style='font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>和方案4最大等效塑性應變的大小均為:
lang=EN-US>0.04734,方案
lang=EN-US>1和方案3
style='font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>最大等效塑性應變的大小均為:0.04738
style='font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>。四個方案等效塑性應變的最大值基本相等,不同之處在于方案2
style='font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>和方案4的等效塑性應變分布更均勻。
v:shapes="_x0000_s1042 _x0000_s1043 _x0000_s1044 _x0000_s1045">
lang=EN-US>
src="http://www.caenet.cn/picture/abaqus0307/image018.jpg" alt="converted PNM file" v:shapes="_x0000_i1032">
style='font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>圖6 等效塑性應變分布云圖
style='font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>由圖7可以得到:四個成形方案對于型材厚度的影響基本相等,即厚度變化最大的區(qū)域的位置和大小相同。
v:shapes="_x0000_s1046 _x0000_s1047 _x0000_s1048 _x0000_s1049">
lang=EN-US>
src="http://www.caenet.cn/picture/abaqus0307/image021.jpg" alt="converted PNM file" v:shapes="_x0000_i1033">
style='font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>圖7 壁板厚度分布云圖
style='font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>由8可以得到:對于方案2
style='font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>和方案4,最終變形位移最大為:
NumberType="1" TCSC="0" w:st="on">146.1mm
style='font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>,方案1和方案
lang=EN-US>3,變形位移最大為:
NumberType="1" TCSC="0" w:st="on">142.3mm
style='font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>。從分析步驟來看,型材位移大小表征了型材成型之后的回彈量,圖9為回彈分析之前各方案中型材的變形位移大小。
lang=EN-US>
v:shapes="_x0000_s1038 _x0000_s1039 _x0000_s1040 _x0000_s1041">
lang=EN-US>
src="http://www.caenet.cn/picture/abaqus0307/image024.jpg" alt="converted PNM file" v:shapes="_x0000_i1034">
style='font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>圖8 回彈分析之后變形位移分布云圖
v:shapes="_x0000_s1050 _x0000_s1051 _x0000_s1052 _x0000_s1053">
lang=EN-US>
src="http://www.caenet.cn/picture/abaqus0307/image027.jpg" alt="converted PNM file" v:shapes="_x0000_i1035">
style='font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>圖9 回彈分析之前變形位移分布云圖
style='font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>圖9與圖8相減后得到,方案1
style='font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>的回彈大小為
TCSC="0" w:st="on">3.3mm
style='font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>,方案3的回彈大小為
TCSC="0" w:st="on">6.5mm
style='font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>,方案4的回彈大小為
TCSC="0" w:st="on">2.8mm
style='font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>。
四、總結
style='font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>從表一可以看出,方案二和方案四的成形過程對于成形效果來說具有變形相對均勻、應力集中不大、回彈量較小等特點,尤其方案四,優(yōu)勢更為突出,因此更應作為實際加工流程來考慮。
style='font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>表一:四種方案計算結果對比
|
Mises應力 |
等效塑性應變 |
壁板厚度 |
回彈量(U2) |
方案一 |
分布相對集中,最大值為149.2MPa. |
分布相對集中,最大值為0.04738. |
厚度變化為:
|
|
方案二 |
分布相對均勻,最大值為127.9MPa. |
分布相對均勻,最大值為0.04734. |
厚度變化為:
|
|
方案三 |
分布相對集中,最大值為149.2MPa. |
分布相對集中,最大值為0.04738. |
厚度變化為:
|
|
方案四 |
分布相對均勻,最大值為127.9MPa. |
分布相對均勻,最大值為0.04734. |
厚度變化為:
|
|
五、方案改進
style='font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>我們從方案四出發(fā),通過修正模具的形狀來達到影響最終成形的回彈量的目的。
style='font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>第一步,考慮到方案四的回彈量為
w:st="on">2.8mm,我們直接修正模具的圓弧部分,將其半徑減小
TCSC="0" w:st="on">2.8mm
style='font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>,圖10是重新計算得到的最終位移分布云圖。
src="http://www.caenet.cn/picture/abaqus0307/image029.jpg" alt="converted PNM file" v:shapes="_x0000_i1036">
style='font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>圖10 初步修正模具后得到的型材變形位移云圖
style='font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>最終的位移大小為
w:st="on">148.6mm,與方案四中最終期望的位移(
NumberType="1" TCSC="0" w:st="on">148.9mm
style='font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>)相差
NumberType="1" TCSC="0" w:st="on">148.9mm
style='font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>處,跟目標形狀一致。
src="http://www.caenet.cn/picture/abaqus0307/image031.jpg" alt="converted PNM file" v:shapes="_x0000_i1037">
style='font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>圖11 最終修正模具得到的型材變形位移云圖
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