1、 l :2005null07null06; l :2006null04null27null “ :S E 1 S “ (19832020);S E M S (10125208) “ .T e : (1981null), o , V ; null * (1956null), 3 ,p V , q ,p V 3 = .第24卷第4期2007年8月null 9 nullChineseJournal of Computational MechanicsVol.24,No. 4August 2007 c I | :1007null4708(2007)04null0529null04 q ! 9 Z E刘
2、玉琳1, null 龚科家2, null 郭null 威2, null 胡平* 3(1. L # H L 3 w b9 8 E 3 4 ,y E 3 w 1 p L O M , “ H w L w L 9 wL H 9 , i O | v , w Q 9 # = i p 9 v , 3 M , . 8 w E 3 by N s 3 E , M # L W 3 w b n 5 | L W , q H w L w L b. d S E | H w L , E 3 NURBS w L b “ S 1 5 :(1) 1 5 | w L , Z L b(2) 3 w L B ? V U w L by N
3、 / 3 NURBS w L b 1 d | w L b 2 F E , w L NURBS w L O b 3 O ,| w L s Y NURBS V U b 4 Cohen E 3,| NURBS w L 6 p Q ,p = max(pi), pi w L Q b “ , NURBS w L Q p Q b 5 w L O a e NURBS w L O e b 3 w L ,s L W L , _ E 3 w b_ w l w Z _ B M w L H _ 3 b : X , NURBS B t M 1 E 7,8, + Y Q U S / 4, 6 3 E _ w E 5,6,
4、V _ w NURBSV U T b 8 L CV / :L ! m H u _ n H v _ w L NURBS w L , u_ mH w L K Q p,v_ nH w L K Q q, _ w w Z E 7, V / 3M Q U S / NURBS w Sw1,Sw2,Sw3b Ni,p(u),Nj,q(v) l uavZ _ B“ H f ,P1wi,j,P2wi,j,P3wi,j s Y 3 w Q U S / F e bSw1 = nullnui= 0 nullm+ q-2j= 0Ni,p(u)Nj,q(v)P1wi, j (2)T u_ w L _ Z E 3 NURBS
5、 w , O T1u,T1v, v_ Q p w e H | Q q,nu+ 1 w u_ e bSw2 = nulln+p-2i= 0 nullmvj= 0Ni,p(u)Nj,q(v)P2wi,j (3)T v_ w L _ Z E 3 NURBS w , O T2u,T2v , u_ Q p w e H | Q p,mv+ 1 w v_ e bSw3 = nulln+p-2i= 0 nullm+q-2j= 0Ni,p(u)Nj,q(v)P3wi,j (4)T Sw3 u,v w L f w , O T2u ,T1v ,Q p w e H | u_Q p,v_ Q qb 3f w u_ v_
6、 M Q p q, O M b P M O , | w 1 w 2 O T i “ ,null null Tu = T1u T2u null null Tv = T1v T2v (5)s Y 3f w u_ v_ , 3f NURBS w V r T S!w1 = nulln!i= 0 nullm!j= 0Ni,p(u)Nj,q(v)P1!wi,jS!w2 = nulln!i= 0 nullm!j= 0Ni,p(u)Nj,q(v)P2!wi,jS!w3 = nulln!i= 0 nullm!j= 0Ni,p(u)Nj,q(v)P3!wi,j (6)N H , 3f NURBS w u_ v_
7、M Q p q, l M O Tu Tv ,n!+ 1 m!+ 1 w u_ v_ b d X , V : Z T , /M w V r T :Sw = S!w1 + S!w2 - S!w3 (7)| NURBS w V V :Sw = nulln!i= 0 nullm!j= 0Ni,p(u)Nj,q(v)Pwi,j (8)531null 第4期 刘玉琳,等:汽车覆盖件工艺补充面参数化设计方法m 5null 3 U Fig.5null The example forthe addendum surface generationT Pwi,j = P1!wi,j + P2!wi,j - P3!w
8、i, j (9)m 5 m 4 L a L 3 $ 3 U m b5null q ! 9 1 , ! 9 % ? ? q 1 o b 4 y L o ,i M 1 + 3 L , L Y V F 3 L , _ NURBS E s 3 Z E , i 7 ? M ! 9 v b “ ! 9 , . d ! 9 Z E , Y V CAE V a s , Q n H W 4 Z E H W 2 3 by N , 4 Z E V r !9 i ? 4 ! 9 ,V 7 q V / i 7 ? b I D (References):1 null 姚null 兴,陈null 军,石晓祥,等. 覆盖件拉
9、延模工艺补充面及压料面参数化设计研究J. 模具技术,2002, 4:6null9.(YAO Xing, CHEN Jun,SHI Xiaonullxiang,et al.Parametric design research of addendum and blanknullholder of drawing automobile panel J. Die Technullniques,20002,4:6null9.(inChinese)2 null 唐荣锡. CAD/CAM 技术M. 北京:北京航空航天出版社, 1994. (TANG Rongnullxi. CAD/CAM Technulln
10、ique M . Beijing: Aeronautics 2. Institute of Automobile Body andDie Engineering, Jilin University, Changchun 130022, China;3.State Key Laboratory ofStructuralAnalysisofIndustrialEquipment, DalianUniversity of Technology,Dalian116024,China)Abstract: The addendum surface design has great effects on t
11、he forming quality to automotive panel.Theconvenienceof addendum modeling and modification is an important access to improve design effinullciency. Thepaper presents themethod and process of building section curvestyledatabasewhich can bemodified by characteristicparameter and generating the addendu
12、m surfaceby binulldirection NURBS skinnullning. Applying themethod presented in this paper, theaddendum surface can be generated rapidly acnullcording to theshapeofsectioncurves, andfurthermore, can bemodifiedconveniently byalternateways.And therelevant parametricdesign modules areindependentlydeveloped in VisualC+ + . Thefeasibilinullty of thetechniqueis provedbythenumericalsimulationwhich createsaddendumsurfaceof somepractinullcalparts successfully.Keywords: automotivepanel; diefaceengineering; parametricdesign; addendum;binulldirection NURBS skinning532 计 算 力 学 学 报 null 第24卷null
