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Tuyin tiip cdng trinh Hdi nghi Cffhgc todn qudc Ky niem 30 ndm Vien Cff hoc vd 30 ndm Tgp chi Cff hoc Hd Ndi, ngdy 8-9/4/2009
Mot so ling dung cua phan mem ANSYS trong tinh toan,
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thiet ke co' khi 6' Viet Nam
Vu Lam Dong, Nguyen Dinh Kien F/e77 Ca hoc,Email: vldongicb.iinech. ac. vn Do Quoc Qnang'
Vien Cdng nghi, Bg Cdng thuong. Email: [email protected]
Tom tat. Bdi bdo trinh bay mot sd irng dung ciia phdn mim tinh todn ANSYS trong viic phdn tich kit cdu vd chi tiit ca khi nhdm phuc vu cho qud trilih thiit ke vd che tgo mdy d Viet Nam. Sic dung phdn mim ANSYS da xdc dinh tnedng icng sudt, biin dgng cho mdt sd kit cdu Irong ITnh vice thiit ki vd chi tgo mdy trong ngdnh cdng nghiep xdy dung. Kit qud tinh todn Id ca sd di tdi leii hda viic thiit ke vd chi tgo mdy.
i.Mo-aau
Trong nhu'ng nam gan day viec tiep can va ap dung tinh toan vai cae chuong trinh tinh toan chuyen dung tra nen de dang ban do sir phat trien va canh tranh cua cac cong ty phan mem.
Trong so nhieu phan mem tinh toan thuang mai khac nhau, phan mem ANSYS, phat trien tren CO so phuong phap phan tu huu ban (PTHH), duoc nhieu eo' so va cae ky su su dung nhu mpt cong cu huu hieu trong phan tich eae bai toan ky thuat thuoc nhieu ITnh vuc khac nhau, dae biet trong phan tich ket cau, dong chay, dan nhiet, dien, dien tu...
Tai Viet Nam, viec thiet ke, che tao may moc thiet bi trong thai gian qua duoe tien hanh tren CO' so cac mau co san hay dira vao cac ino hinh trong cae tai lieu chuyen nganh, chu yeu tu Nga va cac nuac thuoc khoi Dong Au. Dae trung cua cac mau va mo hinh nay la do ben eao, doi khi qua muc can thiet va vi the it co tinh kinh te. Mat khac, trong thai gian gan day de co dupe cac ban ve thiet ke theo dang nay, chung ta phai tra cae ehi phi hop ly ehu khong phai tu do sir dung hoac ehi tra vai mpt gia "hu'u nghj" nhu trude day. De phat trien cong nghe, eae nha thiet ke phai tu sang tao ra cac mo hinh may moc va thiet bj mai, dap ung duge cac yeu eau thuc tien dat ra. Cac van de nay doi hoi cac nha che tao, eae ky su thiet ke phai phan tich ung xu, tinh toan kha nang chju lire cua thiet bj nham bao dam do ben va tinh toi uu cua mo hinh du dinh che tao.
2. Ph3n mim ANSYS
Mac dD ANSYS tuong doi quen voi nhieu nguai sir dung trong nuoc nhung nham giup nguoi' su dung eo dupe cac kien tbi're co ban, viec gioi thieu mpt so dac trung chinh eua phan mem nay la can thiet. Mue nay tom luac mpt so diem chinh cua chuong trinh phan tich phan tu huu ban ANSYS.
Chuang trinh ANSYS do cong ty ANSYS Inc. (My) phat trien dira tren nen tang eua phuong phap phan tu huu ban (PTHH) nham mo phong ung xii' cua mpt he vat ly khi chiu tac dpng eiia cac dang tai trong khac nhau.
24 Vu Ldm Ddng, Nguyin Dinh Kiin, Dd Quoc Quang
Chuong trinh ANSYS dupe sii dung rpng rai trong mpt s6 ITnh virc ky thuat nhu ket eau, chit long, nhiet, dien, dien tu, am hpc... ANSYS co nhi6u mo dun khac nhau nhu:
ANSYS/Mechanieal, ANSYS/ Structural, ANSYS/Multiphycis v.v. Hinh 1 minh hpa man hinh giao dien cua ANSYS.
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Hinh 1. Man hinh giao dien cua ANSYS 3. Mot so bai toan thuc te va mo hinh va ket qua tinh toan
Mue nay trinh bay mpt s6 bai toan trong thue t l can phan tich, tinh toan truang iing suit, bilt dang nham kiem chung dp bin cung nhu toi uu boa kit eSu nhim dam bao tinh kinh t l eiia san pham thiet ke va che tao.
3.1 Thiet bj thdo da sdn pham theo nguyen ly chdn khong
Hinh 2 minh boa thiet bj thao do san pham t4in lop gpn song PVA xi mang do Vien Cong nghe - Bp Cong thuang thiit kl chi tao, hien dugc ISp dat tai Cong ty C6 phan TSm Igp Tan Thuan Cuong, Hai Duong. Dac diem cua may la sir dung nguyen ly chan khong de nham tao ra ap luc can thiet de thao da eae tam lap ggn song sau qua trinh bao duong tii khuon thep hoac chuyen tam lac uot tu bang tai hinh nhSin tao song eho san pham
Toan bg he thong bao gom may hiit chan khong di chuyin theo chieu ngang voi hanh trinh ngang la lOOOinm, len xuong voi hanh trinh 400inni va he kit cau khung dung da may va cac ehi tiet khac nhu minh hpa tren hinh 2. May dupe dilu khiln bang dpng ca dien, khii lugng tong the cua thiet bi ap len khung la 2500kg.
Mdt so img dung cita phan mim ANSYS trong tinh todn, thiit ki co khi a Viet Nam 25
Hinh 2. Thiet bi tao hinh san pham tam Igp ggn song khong amiang
Khung da may dugc tao tu cac dam ehu' 1350x150. Chieu dai cua eae dam ngang va dp eao cac cot duoe cho tren hinh 3.
Hinh 3. Kieh thuoc dam va so' do chat tai tTnh
Trong vi du nay iing xu cua ket cau va cac da trung co' hpc eiia khung chiu tai dupe phan tich. Trong truang hgp toe dp di chuyen eiia may hiit nho, bai toan eo the xem nhu la tua tTnh va chiing dua ve mo hinh tinh toan he khung khong gian. Vi may hiit va he khung dugc gan voi nhau qua cac con Ian, vi the tai trpng tac dpng len khung sinh ra tu trpng lugng cua may moc va cac chi tiet khac co the dua ve tai trpng tap trung theo phuong thang diing, dat tai 4 diem tiep xiic giUa cae con lan vai cac dam ngang. Vat lieu cho thep hinh 1300x150 eo mo dun dan hoi E
= 200.000N/inm2 va he so Poatxong v = 0.3.
Ket cau dugc mo hinh boa dudi dang khung khong gian 3D. Tren thue te do toe do chuyen dpng cua cac thiet bj chan khong la chain nen bai toan co the xem la tua tTnh va vi the phan tich tTnh dupe xem la dii eho bai toan tren. Mot so khai bao eu the cho bai toan nhu sau:
26 Vii Ldm Ddng, Nguyin Dinh Kien, Dd Qudc Quang
- Hgn chi chuyin vi: Ngam ciing tai eae mit: 1, 2, 3, 4 nhu mo ta tren hinh 4.
- Tdi trgng: Trudng hgp tai tira tTnh luc tac dung len khung chu ylu la trgng lugng ban than eiia eae bp phan thiet bi dugc quy dii thanh eae lire tap trung tai vi tri eon lan tren ray vdi gia tri FY = 5000N, CO ehilu hudng xuIng dudi.
- Kit qud tinh todn:
Chuong trinh eho phep ehiing ta dua ra nhung kit qua theo y mudn nhu chuyen vj, iing suit,...theo tung true toa dp hay toan bp kit eau tdng the. Sau day la 1 sd kit qua thu dupe sau khi giai bai toan:
• Chuyin vi cue dai ciia kit cku theo true y la l,356inm. Cau binh bien dang cua khung dupe minh hoa tren hinh 5.
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Hinh 4. Cae rang buoe eiia khung l-linb 5. Cau hinh bien dang eua khung
• Cae gia trj cue tri eiia momen thu nhan duge tu phan tich tTnh la:
Mmin = -6.480.000Ninin; Mmax = 5.480.OOONmin. Bieu do mdmen cua khung nhan dugc tu tinh toan dupe cho tren hinh 6.
• U'ng suat doc true: Cac gia tri ciia iing suat cue tri la Sinin = -1.247N/min2; Smax = 0.740E-12N/mm2. Bieu do phan bo iing suat eiia khung dugc minh hpa tren hinh 7.
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Hinh 6. Bieu do mo men trong ket cau Hinh 7. Phan bd cua iing suSt
Mdt so img dung ciiaphdn mim ANSYS trong tinh todn, thiit ki co khi a Viet Nam 27
Nhgn xet: Cac kit qua phan tich trinh bay tren eho thay bien dang ciia khung, dae biet chuyen vj cue dai la rat nhd so vdi khau dp 7500mm. Dilu nay eho thay chung ta cd thi giam bdt kich thude eiia cac dam chu' I. Tuy nhien, can nhan manh rang, de dam bao cho may boat ddng chinh xac, khung da may can thue su dn dinh. Vi the, phuong an thay doi ket cau khung cin duac trao doi ky vdi cac chuyen gia thiet ke eua Vien Cdng nghe. Cac ket qua nhan dugc tu phan tich phan tii huu ban bang ANSYS trong bai bao phu hgp vdi ket qua tinh toan thd sii dung chuong trinh COSMOS2000 do Vien Cdng nghe tbiic hien. Uu diem chinh ciia viec sii dung ANSYS la eae ket qua sd nhan dugc chi tiet hon, dae biet biie tranh su phan bd eiia trudng iing suat, biin dang chi tiet va day dd hon.
3.2 Thiit bj ndng hg sdn pham bdng xi lanh thuy lire
Thiet bi nang ha san pham la mpt phan trong chuoi day chuyen tu dpng eua nha may san suit tam Igp khong sir dung sgi amiang do Vien Cdng nghe thiet ke va che tao. Tren thue te thiet bj la mpt ban nang ha dudi tae ddng ciia 1 xi lanh thuy lire, cho phep ban nang di chuyen theo hudng len xudng vdi siie nang tdi da la 4 tan. Hinh 8 minh hpa thiet bi nang ha.
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Hinh 8. Thiet bi nang ha san pham sii dung xi lanh thiiy lire
Ddi vdi nhung ket eau phiic tap, chuong trinh ANSYS eo mdt tien ich ANSYS Connection Products cho phep ket ndi vdi nhung chuong trinh CAD khac nhu AutoCAD, Solid Works, AutoDesk Inventor...nham giup ngudi thiet ke giam thieu dupe cdng doan xay dung md hinh phiic tap. Chang ban, sii dung chuong trinh Inventor ta cd the md phdng thiet bj nang ha nhu tren hinh 9.
Theo nhu tinh toan thiet ket ban nang chiu dupe tai trpng 4 tan, phan bo theo ehu vi cua khung thi lue phan bd tae dung vao khoang q = 6.5N/mm. Vi vay coi nhu tai trpng dat vao ket eau ed dang lire phan bd tren dam.
- Hgn che chuyin vi: Thiet bi chiu ngam ciing tai cac diem: 1, 2, 3, 4 va ban ebe chuyen vj thang cac dudng L l , L2, L3, L4, L5, L6, L7 va L8 theo chieu true y. Cae rang budc va tai trpng nhan duoc tir khai bao tren ANSYS duoe minh hoa tren hinh 10.
28 Vii Ldm Ddng, Nguyin Dinh Kien, Dd Qudc Quang
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Hinh 9. Mo hinh thiit bj nang ha tren Hinh 10. Md hinh chiu lue va cac rang budc Autodesk Inventor
Kit qua phdn tich:
• Chuyen vj cue dai theo true y la Uy = 3.447min. Trudng ehuyin vj va c§u hinh bien dang ciia thiit bj nang ha san pham dugc minh hpa tren hinh 11.
• Mdmen : cac gia trj mdmen cue tri la Mmin = -l.lOO.OOONmm ; Mmax = 941.173Nmin. Hinh 12 minh hpa bilu do mdmen nhan dupe tir ANSYS.
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Hinh 11. Trudng chuyen vj va cau hinh bien Hinh 12. Mdmen trong ket cau dang cua thiet bj nang ha
Nhgn xet: Cac ket qua phan tich trinh bay tren nhan duge eho trirdng hgp bat Igi la khi hanh trinh ciia xi lanh nhd nhat. Cae ket qua thu dupe eho thay dupe su dn djnh ciia ket cau khi lam
\'iee. Tuy nhien de nghien eiiu ky ban nua chung ta can tinh toan cho mdt vai vj tri nang ha khac nhau de co the danh gia ky ban nua ve kha nang chju lire eiia ket cau khi lam viec.
4. Ket luan
Bai bao trinh bay mdt sd iing dung cua phin mlm ANSYS trong viec phan tich, tinh toan trirdng iing, suat bien dang cua mpt s6 thiit bj co kbi nhim trg giup cho qua trinh thiet ke va toi
Mdt so img dung cita phan mim ANSYS trong tinh todn, thiit ke ca khi a Viet Nam 29
uu hda kit cau. Mdt sd dac diem co ban ciia md dun phan tich ket eau eiia ANSYS dugc torn luge. Sii dung ANSYS da tien hanh phan tich mpt sd thiet bj eu the do Vien Cong nghe, Bd Cdng thuang thiit ke va che tao. Ket qua nhan dugc cho thay eae ket eau, may mde thiit kl co dp an toan cao, phu hgp vdi cac ket qua tinh toan so bp bang phan mem COSMOS2000 do cac ky su thiet ke thue hien. Tren co sd gia trj iing suat, bien dang nhan dupe da de nghj phuong an giam bdt thiet dien ngang ciia mpt sd chi tiet. Tuy nhien, can than trpng trong viec giam thiet dien ngang cua ket cau thiet bj thao dd san pham do eo kha nang dan tdi anh hudng ciia tai trpng ddng dan tdi sir lam viec thieu chinh xac cua thiet bi. De dua ra phuong an eu the ciia viec giam bdt thiet dien ngang ddi hdi cac phan tich tiep theo, tren co sd eau hinh mdi. Cac phan tich nhan dupe da gop phan giiip cho cac ky su thiet ke va nha che tao tin tudng vao san pham cua minh.
Tir do giup danh gia kha nang chju luc ciia ket cau mdt each chinh xac, de ed the thu dupe hieu suat Idn nhat. Tren thue te, anh hudng eua tai trpng ddng trong nhieu trirdng hgp ddng vai trd quan trpng tdi ung xir ciia ket cau, dae biet khi toe dp cua tai Idn va vl the cae ket qua nhan dupe trong nghien eiiu hien tai chi dung lai d muc dp tham khao eho cae ky su thiet ke. De eae ket qua sd ed tinh thuc te hon cac nghien cuu tiep theo theo hudng phan tich dpng can dupe thuc hien.
Tai lieu tham khao
[1] Przemieniecki, J. S. (1968), Theory of Matrix Structural Analysis, McGraw-Hill, New York.
[2] Finite Element ANSYS (1999) Theoiy and Application with ANSYS - Saeed Moaveni, Minnesota Sate University, Mankato.
[3] Vu Quoc Anh, Pham Thanh Hoan (2006). Tinh kit cdu bdng phdn mem ANSYS, Nha xuat ban xay dun".
