NGHIEN CUfU-TRAODGI
PHAN TiCH SU-C B^N GIOI HAN K^T CAU TAU PHA SONG BIEN Dl/ai TAC DUNG C O A M 6 MEN U 6 N
ULTIMATE STRENGTH ANALYSIS OF RIVER-SEA SHIP HULL STRUCTURE UNDER BENDING MOMENT
Vu Van Tan, Mac Thi Nguyen, Nguyen Dinh Ciromg, Ngd Hihi Manh Trudng Dai hoc Sao Dd
TOM TAT
Ddi v&i tdu chay tuyen pha song bien (River-Sea ship), kit cdu hdm hdng thucmg duoc md rong de tdng khd ndng vdn chuyen hdng hoa, do do dnh hu&ng rdt l&n den sue ben doc cita tdu.
Trong bdi bdo ndy, nghien cuu sire ben giai han udn cua ket cdu tdu chay tuyen pha song bien, dudi tdc dung cua tdi trong udn bdng phuang phdp phdn tie him han phi tuyen. Tit ket qud nghien cuu, tinh todn duac sire ben gi&i hem cua thdn tdu vd xdy dung duac moi he giira gid tri sire ben udn gidi han vd goc xoay trong truong hop tdu vong len vd vong xudng Idm ca sa de tinh todn sire bin dm thdn tdu vd tinh todn, thiet ke kit cdu tdu.
Tir khoa: Tdu pha song bien; Phuang phdp phdn tu hint han phi tuyin; Site bin giai han, mo men udn.
For River-Sea ship, structural of hatch coaming are expanded to improve transportation, so it affect the longitudinal ultimate strength of the ship hull. In this paper, application ofnonline finite element method for ultimate strength of the River-Sea ship hull structure under bending moment
The calculation results of the ultimate strength of ship hull to build nexus between Bending moment- Rotation cuver in the sagging moment and hogging moment cases as a basis to calculate longitudinal ultimate strength and calculate, design of ship hull structures.
Keywords: Tfever-Sea iAp, nonlinefinite element method, ultimate strength, bending moment.
ISSN 0866-7056
TAP CHi CO KHi VIET NAM, Sd 3 nam 2016 www.cokhivietnam.vn
NGHIEN CUfU - TRAO eOl
1. GlCtt THiEU
Voi muc dich nang cao hidu qua bde dd hang hda ciing nhu tan dung tdi da kha nang chuyen chd cua cac ham hang, kit cau ciia tau pha sdng biln thudng cd kit eiu mieng him hang duoc md rdng, do do anh hudng rit Idn din sue ben doc than tau, dac biet la kha nang chiu udn va chm xoan thip. Trong tinh toan thilt kl tau, tmh toan siic bin dpe than tau la mpt trong nhung van dl co ban va cd y nghia vd cung quan trpng [1].
Ddi tuong lua ehpn dl phan tich, tinh tpan siic bin gidi ban trong bai bao nay la kit cau tau chay tuyen pha sdng biln cd chilu dai Ion nhat la 136.5m chiu tac dung cua tai trpng udn. Phuang phap sit dung dl phan tich, tinh
toan siic ben gidi han ciia ket cau la phan tich phan tii him han phi tuyen (nonlinear finite element method). Kit qua phan tich xac djnh duoc siic ben gidi han ciia ket cau than tau, xSy dung duoc mdi quan he giiia md men udn gidi han va gde xoay trong hai trudng hpp tau vdng ten va vdng xudng.
2. P H A N Tf C H s i r e B E N T H A N T A U D l / d l TAG DUNG CUA M O M E N U O N
2.1. Kich third^c ket cau va tinh chat vat lif u Cac kich thude chinh ciia tau phan tich, tinh toan trong nghien cuu nay dupe the hidn trong bang 1, mat cat ngang giiia tau dupe the hien tren hinh 1.
Bdng I. Cdc kich thude co bdn cita tdu:
TT 1 2 3 4 5 6 7 8
Hang myc Chieu dai toan bp
Chieu dai duong nuoc thiet ke Chieu dai hai tm
ChiSu rpng Chieu cao man thiet ke Mon nuac
Chieu rpng mieng ham hang He so day the tich
Ky hi^u L„.
I.., L„
B D d b
c^
Kich thude 136.5M
133m 130m 25.6m 8.7m 6.3m 20.4m
0.85
^
1 1 1 1 1 1 1 1 1 1 1
f^^
LL
Hinh 1. Mgt cdt ngang giiia tdu
ISSN 0866 - 7056
T^P CHI CO KHi VI|T NAM, S6 3 nam 2016 www.cokhivietnam.vn
NGHIEN CUfU - TRAO D 6 I
Tau CO ket cau day doi, khoang each suon thirc la 700mm, khoang each cac nep doc day la 650mm. Vat lieu dong tau dupe sir dung hai loai vSt lieu, cac k8t cku chiu luc chinh nhu ton day, ton man, ton boong, suon khoe, cac ket cau mieng ham hang.,,Su dung thep c6 dp ben cao CO gioi han ben ag^355Mpa, cac he thong ket cau con lai sir dung thep c6 gioi han ben Og^235 Mpa.
2.2. Mo hinh phSn tit hihi han
Bai bao dimg chucfng trinh phan tu huu han FEM Abaqus de phan tich, tinh toan. De dap ling dupe yeu cau dp chinh xac ciia ket qua phan tich va dam bao thoi gian tinh toan, viec nghien cim chia luoi mo hinh de lua ehpn kich thuoc luoi thich hop cho mo hinh tinh anh huong rat Ion den d6 chinh xac cua phep tinh ciing nhu Cling nhu thai gian tinh toan. Trong bai bao nay, phan ttr tam S4R trong phan mem FEA Abaqus duac su dung de mo hinh hoa cac phan tu [2], [3]. Qua qua trinh phan tich tinh toan, kich thuoc mat luoi cua mo hinh duac lua chgn la khoang each giua hai khoang sucrn duac thiet lap 3 dan vi phan fix hinh 2. Gia thilt vat lieu co tinh dan hoi tuyet doi. De dam bao dp chinh xac cua mo hinh tinh, ta thiSt lap mo hinh 1/2 + 1 + 1/2 [4]
( F r 5 5 - F r l 4 7 ) h i n h 3 .
Hinh 3: Md hinh phdn tu hihi han 2.3. Tai trong va di^u kien bien
D I thi^t lap dieu kien bien cua mo hinh, ta thiSt lap hai nut chinh gpi la hai chu dpng diem tren hai mat tren doan ket thiic ciia mo hinh. Hai ehu dpng diSm nay co rang bu6c chuyen vi voi tat ca cac mit tren mat do hinh 3. Chuyen vi cua tat ca cae mit tren m6i canh duac xac dinh bang chuyen vi ciia chu dong diem [5]. Dieu kien bien cy the trong trudng hpfp nay duac thiet lap nhu sau:
Hinh 2: Chia luoi mo hinh
Chu dpng diem ben trai han che chuyen dpng tinh tien theo phuang X, Y, Z va han ch§
chuyen dpng quay theo true X, Z. Chu dpng diSm ben phai han che chuyen dpng tinh tiln theo hai phuang Y, Z va han che chuyen dpng quay theo true X, Z.
Tai trpng tac dung len kit eiu than tau thue te bao gom, cac thanh phan tai trpng: Tai trpng do ap luc thuy tinh, ap luc thiiy dpng, tai trpng gio, tai trpng hang hoa.. .Trong nghien ciiu nay, tai trpng dh phan tich la tai trpng tong thi - mo men uon doc than tau.
Trong qua trinh phan tieh, hai chii dpng diem gia tri mo men uon dupe gia tang voi gia tri nhu nhau va tang dan gia tri mo men u6n ngoai luc cho din khi kit c4u bi pha huy.
ISSN 0866 - 7056
TAP CHi CO KHi VIET NAM, S6 3 nam 2016 www.cokhivietnam.vn
NGHIEN C U U - IKAUUUI
2.4. K@t qua tinh toan
De tinh toan sue ben giai han cua ket cau than tau dual tac dung ciia mo men uon (sagging, hogging), trong nghien cuu nay nhom tac gia dung phan mem phan tich phan tir huu ban, Abaqus. Gia tri mo men uon dat len hai chii dpng diem duac gia tang cho den khi ket cau than tau dat den gia tri giai han. Gia tri mo men uon tac dung len hai chu dpng diem duac gia tang nhung gia tri nhu nhau.
Ket qua tinh toan sue ben gidi han cua than tau dupe the hien bang duang eong moi quan he giiJa goe xoay - Mo men uon ngoai luc tren hinh 4.
Qua duang cong m6i quan he giiia goc xoay - Mo men uon trong tmong hop tau vong xuong (sagging), mo men uon gidi han M3-1.320xlO'^Nmm; Trong trudng hap tau vong len (hogging), mo men uon gidi ban M^^ - 1.446xl0'^mm.
So sanh dudng cong the hien moi quan he giiia goc xoay va mo men uon trong hai trudng hpp cho th4y trong trudng hap tau vong xuong, kit cku nhanh dat din trang thai gidi han han so vdi trudng hpp tau vong len.
Trong trudng hop tau vong xuong, khi dat din trang thai siic ben gidi han, ket cau boong, khu vuc mieng ham hang bi pha buy trudc (hinh 5).
Thdng thudng, trong trudng hpp chiu udn, khi kit c4u boong dat din trang thai gidi han, kha nang chiu tai cua ket cau than tau giam manh. Do true trung hda gan phia day tau nen kit cku boong thudng dat den trang thai gidi han va bi pha buy trudc ket eau day (hinh 5).
a. Hogging Hinh 4: Do thi quan he md men uon - Goc xoay
b. Hogging
Hinh 5: Truong itng sudt giai hgn trong truong hgp
ISSN 0866 - 7056
TAP CHI CO KHI V I £ T NAM, So 3 nam 2016 www.cokhivietnam.vn
NGHIEN CUfU - TRAO D O I
3. K E T LUAN
Trong bai bao nay, tie gia da tinh toan, phan tich siie bdn gidi han ciia ket cau tau hang khd chay mydn pha sdng bidn dudi tac dung ciia md men udn bSng phuang phap phan tii hiiu han phi taySn. Tinh toan phan tich dupe trang thai gidi han cua kSt eiu than tau, xay dung dupe mdi quan he giiia md men udn va gde quay khi chiu udn thuan tuy.
Kdt qua nghien eiiu siic bdn gidi han cua kdt cku than tau cd y nghia quan trpng trong thiet kd kdt cau than tau, lam co sd cho vide thidt kd kdt cSu tau dam bao dp ben, dp ciing va dp dn dinh ttong qua ninh lam viec. Ben canh dd, kdt qua nghien ciiu eung lam co sd dd nghien ciiu sue ben gidi han eua than tau dudi tac dung cua tai trong phiic tap. •
Ngay nhan bai: 15/02/2016 Ngay phan bien: 17/3/2016
Tai U^u tham khao:
[1]. Nguyin Diic An, H6 Quang Long; So tay ky thuat ddng tdu thiiy tap 2, NXB. Khoa hgc va Ky thuat, 1982.
[2]. Abaqus analysis user's manual.
[3]. Jeom Kee Paik, Bong Ju Kim. Methods for ultimate limit state assessment of ships and ship-shaped offshore structures'. Part 111 hull girders. Ocean Engineering, 2008,35: 281-286.
[4]. lACS. Common Structure Rules for Bulk Carriers, 20i2.
[5]. Shi Gui-jie, Wang De-yu (2012). Residual ultimate strength of open box girders with cracked damage Ocean Engineering,43: 90-101.
[5]. Jeom Park (2006), 18^ International ship and offshore structures congress, Rostock, Geimany.
ISSN 0866 - 7056
TAP CHl CO KHi V I B T NAM, Sd 3 nam 2016 www.cokIiivietnara.vn