Cdng trinh Khoa hgc
TINH TOAN DO C I T N G CHIU X O A N
VA DO BEN KET CAU KHUNG XlfONG 6 TO KHACH
VU THAN D A T Bg mdn Ca khi O id Khoa Ca khi
Trudng Dgi hgc Giao thong Van tdi
Tdm tUt: Bdi bdn irng dung phdn mem ANSYS thiit Idp md hinh phdn tir hiru hgn cho kei cdu khung xuong d td khdch (loai khung satxi vd khung xuong thdn xecimg chju luc). Ket qua tinh todn kit cdu d cdc trirdng hop ldi trgng cho thdy. Dd cung chiu xodn vd dd bin ciia kei cdu khung salxi vd khung xuong thdn xeddm bdo yiu cdu: Biin dang cua khung kinh vd cua lin xudng ndm trong gidi hgn cho phep. O trirdng hap quay vdng ngdt, khung xuang than xe cd hi sd du trir ben k < 1.5. sau khi cdi lien kit cdu dd ddp icng dugc yiu cdu do bin vdi k = 1.67.
Tit khoa: Khung xuong d Id khdch; Md hinh phdn tu hihi hgn. Do cirng chiu xodn: Dd bin.
Summary: In this paper, the finite element model of semi-iniegral bus framestructure, including chassis frame and body frame, was built by using ANSYS .sofhvare The static analysis of bus frame structure was carried outwith different operation conditions. The analysis re.sults show that- Torisional stiffness of semi-integral bus frame is reasonable in design: Strength requirement of cha,ssis frame structure is met. And the deformations of^indow glass frame and up - down side doorsis under allowance limit. With quick turning condition, the safety factor of body frame is not enough-(k < 1.5). After improvements of structure, strength requirement of body frame is met with (k^^ I 67)
Keywords: Semi-integral bus frame: Finite element model, Torisional stiffness; Strength.
I. D A T V A N D E
D e ddp u n g nhu cdu vdn tai hanh khach cdng c d n g ngay c a n g tdng, c a c d a n vj sdn xudt lap rap d td trong n u d e d a sdn xudt ldp rap nhieu chiing loai xe khdch vdi hinh thirc d d n g mdi khung x u o n g , than v d v a ndi thdt tren c a s d xe satxi nhdp khau. Ciing v d i ket c a u khung satxi, thi ket cau khung x u o n g thdn xe ciJng la ket cau chiu tai chinh, cd yeu cdu ve do ben, dg cirng cao va chiem ty trgng lgn trong gia thanh sdn pham. Vi vdy, viec nghien ciru thiet ke, c h e tgo ciing nhu danh gia chat l u g n g k h u n g satxi vd khung x u a n g thdn d td khdch ludn la van de d u g c cdc don vj san xudt lap rdp d td khach trong n u d e quan tdm,
Xudt phat tir vdn d l tren. bai bdo irng d u n g phdn m e m A N S Y S thiet lap m d hinh phdn t u hCru han ( P T H H ) cho k i t cau khung x u o n g d td khach thdnh phd logi 80 chd (34 c h o ngdi va 46 chd dung) san xudt tgi Viet N a m . K i t qua tinh toan d cac c h e d o tai trgng diing d l danh gia do cirng chju xodn, d o b i n vd b i i n dang ciia k i t cdu khung x u a n g , tir d d cd nhimg cai t i l n thich hgp de ddm bdo yeu cdu.
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II. MO HINH PTHH KET CAU KHUNG XUONG
Tren ca sd d td khdch thdnh phd dugc tham khao, kit cdu khung xuang d td khdch thudc logi cd khung satxi vd khung xuang than xe ciing chiu luc (Semi-integral bus frame). Chgn phdn
tir SHELL63 dl chia ludi PTHH cho ^ , e « ^ k^
md hinh ket cau khung xuang d td
khdch. Thugc tinh vgt Ii6u cua khung K S S ^ - s S ^ ^ ^ ^ ^ ^ i ^ . - . ^ . satxi tuomg ung thep hgp kim thudng
16Mn vd khung xuong thdn xetuang img thep CT3. De thudn Igi cho viec gdn tai trgng vd dilu kien bien khi tinh toan, sii dung cdc diem nut ngodi IN (Interface nodes) vdi phan tu MASS21 de md phdng gdi dd nhip, gdi dd ddng
ca, trgng tdm ciia cac khdi lugng (tdng ^'"'' '• ^^" ^'"^ '''^^^ '"^'' ^^" ^^""^ ^'^"S thanh, hdnh khdch ...) tdc d g n g len khung x u a n g . Md hinh P T H H ciia k i t cdu khung x u o n g , bao gdm khung satxi vd k h u n g x u a n g than xe, n h u hinh 1 t h i hien.
III. TINH TOAN KET CAU KHUNG XUONG
Tinh todn k i t cdu k h u n g x u a n g bao gdm tinh todn dd c u n g chiu xodn, tinh b i n vd b i i n dgng cua ket cau khi xe day tdi. Bd qua anh h u d n g ciia tdn vd xe va cac ket cau cd khdi lugng nhd n h u go Idt sdn, xdp c h d n g rung dn va ndi thdt trang tri khdc. T i n h d o cimg chju xoan vd do ben ket cdu khung x u a n g d trgng thdi xe ddy tdi, khdi l u a n g ciia hanh khach phdn-bd d i u len phan di^n tich sdn ddnh cho hanh khdch dimg (46 hanh khach dirng) vd phdn bd 16n d i l m bdt ndi giua ghe ngdi va sdn (34 nghe ngdi + 01 nghe Idi). Ung suat t u a n g d u o n g ( c , j ) d u g c tinh theo ly thuyet b i n thii' IV [1] vdi h^ sd d u trO
Xx(7V.fTvUB;
1JfE*S- ben: k =a^|, /a„|,„j,^
gidi hgn chdy
^i6Mn =345f,j/mni-
= 1.5^2.0 (o,„)la ciia vat lieu.
o^''=240N/mm').
A^hnmgxumg^tveftoi^to^ T ~ l * B^ihimg salid & khung xuan^ cOng r^^' Biin dgng dudng cheo ciia cdc khung
kinh vd cira ten xudng phdi nhd ban 3 mm de khdng Idm vd kinh hodc ket cua [2,3].
Tinh do cung chju xoan cua khung xuang - MUX: Dg cirng cua khung xuong khi chju xodn [1,4]:
K = 0 J „ M
^(N.m/dd) (1) Hmh 2. Dd cirng chiu xodn cua mdi sd loai khung xtrang d id khdch
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Trong dd: G - md dun ddn hdi trugt; Jp - md men quan tinh khi xodn ciia mat cdt ddi vdi tdm xodn; M^ - md men xodn gay ra tren kit cdu; 9 - gdc xodn ty ddi tren chilu dai. Do cirng chiu xoan ciia mdt sd logi khung xuong d td theo chilu ddi ca sd L dugc tham khao nhu dd thi hinh 1 [3]. K\ hieu cac gdi da nhip vdi 3 ky tu: ky tu ddu tien chi vj tri cdu trudc (F) va cdu sau (R); ky tu thu hai chi vj tri gdi trudc (F) va gdi sau (R); ky tu thir ba chi gdi ben phdi (R) va gdi ben trdi (L). Dieu kien bien cho cac gdi dd nhip nhu sau: FRR. FRL. RRR va RRL d trgng thai tu do; RFR vd RFL bi ngdm cung; FFR va FFL xodn thudn chilu kim ddng hd theo true OX (ROTX) la 1 do.
Tinh todn d che do tdi trong tmh - BEUY. Khung xtrang chiu tai trgng tTnh theo phuang thang dimg khi xe day tai. Dieu kien bien tgi cdc gdi dd nhip (ky hieu dich chuyen theo cac trucla U va quay quanh cac true la ROT): FFR, FFL, RRR vd RRL khdng che 5 bac tu do UX.
UY, UZ, ROTX, ROTY; FRR, FRURFR va RFL khdng chi 4 bdc tu do UY, UZ, ROTX, ROTY
Tinh toan d che do xodn nguy hiem - MUXN: Khi xe ddy tdi, mdt banh xe ben trai cau trudc khdng tiep xuc vdi mat dudng, tgi cdc gdi dd nhip cdu trudc ben trdi chiu luc tdc dung ciia 1/2 khdi lugng phdn khdng dugc treo cdu trudc. Dieu kien bien tgi cdc gdi dd nhip: FFR, RRR va RRL khdng chi 5 bdc tu do UX. UY, UZ, ROTX, ROTY; FRR, RFR va RFL khdng chi 4 bdc tu do UY, UZ, ROTX, ROTY; FFL vd FRL tu do.
Tinh todn d chi do phanh gap - BRUX: Khi xe ddy tai d trang thai di thang. phanh gdp vdi gia tdc phanh cue dai theo hudng UX la jp^a^ = 0.7 g (g Id gia tdc trgng trudng) [4, 5]. Khung xuong chiu them luc qudn tinh khi phanh ciia cdc khdi lugng ddt tgi khdi tdm (trong tam ciia cac khdi lugng tong thanh, he thdng. ngudi) vd ngugc chieu vdi gia tdc phanh. Dieu kien bien tgi cac gdi nhip tirong tu trudng hgp BEUY.
Tinh todn d che do quay vdng ngdt - TRUZ: Khi xe day tdi vd d trgng thai quay vdng nggt.
ngodi tdi trgng do cdc khdi lugng tdc dung theo phuong thdng dimg. khung xuong cdn chiu Igc qudn tinh ly tdm theo phuang ngang ciia cdc khdi luong ddt tai khdi tam. Cdn cu mgt sd kit qua nghien cim [4, 5], chgn gia tdc ly tam ju = 0.4g, dieu kien bien tgi cdc gdi nhip nhu trudng hgp BEUY.
IV. KET QUA TINH TOAN Of CAC CHE DO TAI TRONG
Ket qud tinh do cirng chiu xoan cua khung xuong - MUX: Ket qud tinh toan do cirng chiu xoan vdi chieu ddt ca sd L = 6.0 m, md men xoan do tai hai gdi nhip RFR va RFL bi ngdm cirng
|M,| =3480.4N.m. dd cimg chju xodn K^ = 209E+4 N.m/dd. So vdi dd thi tren hinh 2, do ciing chju xodn ciia ket cdu khung xuong la dam bao yeu cau.
Kit qua tinh todn a cdc chi do lai trgng BEUY. MUXS, BRUX vd TRUZ: Gia tri ung sudt tuong duang vd biin dgng ldn nhat tren ket cdu khung satxi va khung xuong than xe cung nhu he sd dg tru' bin tuong irng cho trong bdng I. Khung satxi d che dg ldi trgng MUXN cd irng sudt
9 6 Tgp chi KHOA HOC GIAO THONG V^N TAI So 50 - 02/2016
tuong tuang ldn nhdta^'^^„ =201.27N / mm", he sd du trti- ben k"',";' =1.71. dam bao dilu kien ben. Ddi vdi khung xuong than xe, d che do tai trgng TRUZ cdoj'j.^^,^^ = 166.52N/mm',he sd du triJ ben k''^^^ = | .44 < | .5 |a khdng dam bao dieu kien ben theo yeu cdu.
c. BRUX d. TRUZ Hmh 3. Trgng thdi irng sudt cua kit cdu khung xuang 0 cdc chi do tdi trong
Che do tai trong BEUY MUXN BRUX TRUZ
Bang 1, Ket qua tmh hen va bien da Khung satxi
^ i d ' - ™ v ( ^ / m m ^ ) 83.59 201 27
130.81 106 63
k"™
4.13 1 71 2 64 3 24
Ig kai cdu khung xuang dcac cl Khung xiro'ng thSn ''u-L-CN/mm')
129.88 137.84 138.21 166.52
e do Idi Irong xe
kl"
1.85 1.74 1.74 1.44
V j t h KHI KH2 KH3 KH4 KH5 KH6
Bdng 2 Bien dang dirdng cl IMUXN
Bu«Tig cheo 1 0.235 -0.017 -0.022 -0.035 -0.035 1.064
Diro'ng cheo 2 -0.311 0.003 0.01 0.057 0.004 -1.096
eo cua cdc khung kinh vd cua ten xuong (mm) T R U Z
D u o n g cheo 1 -0.441 0.074 -0.024 -0.048 -0.085 0,621
Duirng cheo 2 0.349 -0.089 0.021 0.047 0.065 -0.665 Chpn cliS dp tai trpng MUXN va TRUZ de l<hap sat bi6n dang duong cheo ciia lihung kinh chSn gio trtrcrc (KHI), lihung Icinh hju (KH2), l<hung cira len va xufing (KH3 va KH4), l<hung liinh sucm thit nhit va thit tu ben trai (KH5 va KH6) nhu' cho trong bang 2. Bi6n dang ditong cheo Icrn nhit tai lihung Itinh thir 4 suan ben trai|u^^J = 1.096min <3nim, nhu vay dam bao biSn
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dgng cua kit cdu khung xuong khdng lam vo kinh hodc ket ciia len xudng.
V. CAI TIEN KET CAU KHUNG XU'ONG 6 TO KHACH
O che do tai trgng TRUZ, ket cdu khung xuong thdn xe Id khdng dam bdo dilu kien ben,
^^mm = 1 -44 < 1.5. Ung suat tuong duong Idn nhdt ndm tgi cdc cgt chdng mang san ben trai phia dudi xe (thep hinh Y40x40x2 mm, vat lieu CT3, a^'j^'n,,, =166.52N/mm"). Dk dam bao dilu kien ben, bdi bao chgn phuong an tang chieu day cac cgt chdng tir 2 mm len 3 mm, van giQa nguyen vat lieu che tgo Id thep CT3. Sau khi cai tiln kit cdu, tiln hdnh tinh toan vdi che do tai trgng TRUZ, gia tri irng sudt tuong duong ldn nhata^j''.^^^, = 144.02N / mm\tuang irng he sd du tr& bin kj^^^" = 1.67 > 1.5 ddm bao dilu kien bin theo yeu cdu.
VI. KET LUAN
Tir ket qua tinh toan do cumg chiu xodn, do ben vd bien dgng ket cdu khung xuong d td khach thdnh phd d cac chi dg tdi trgng khac nhau, bai bao cd nhung ket ludn chinh nhu sau:
Khung xuong xe khach thanh phd cd dg cung chiu xodn phii hgp dang ket cdu khung satxi vd khung xuong thdn xe cung chiu luc (Semi-Integral Bus Body);
Dg ben ciia khung satxi dam bdo yeu cdu vdi he sd du tru- ben nhd nhdt d chi do tdi trong MUXN Id k2'=1-71;
Bien dgng dudng cheo cua cac khung kinh va cira len xudng nhd hon 3 mm, ddm bdo khdng Idm vd kinh hodc k?t cdnh cira;
Ci chi dg tai trgng TRUZ, khung xuong thdn xe cd h? sd dg trir bin nhd hem 1.5. Sau khi cdi tien kit cdu, h^ sd du trir bin la k^^^^ = 1.67, dam bao dilu kien bin theo yeu cdu.
Ngdy nhan bai ldn dSu: 24/9/2015 Ngay nhan bai sua: 27/11/2015 Ngay ch^p nhan dang bai: 30/10/2015 Tai llfu tham khao
[1]. Le Quang Minh, Nguyin Vdn Vuong. Sire bin vat lieu-Tap 1 & II. Nha xudt ban Giao due, 2004.
[2], Bui Vinh Phuc. Nghien cdu anh hudng cua chi do khai thdc den dp ben va dp cimg cua khung xucmg 6 to khach chi tgo tgi Viet Nam. Dgi hpc Giao thong Van tai. Ludn van Thac sT Ky thuat, 2001 [3]. He H. J. Study on Analytical Method and Structural Optimization of Semi-Integral Bus Body.
China; Jilin University, Thesis of Master Degree, 2010.
[4]. iVei N B. The Finite Element of Analysis of Integrated Coach Body Based on ANSYS. China:
Changan University, Thesis of Master Degree, 2011
[5]. Li Ch. B. Finite Element Modeling and Analysis of Static and Dynamic Characteistics for Coach- Body Frame. China: Hefei University ofTechnology, Thesis of Master Degree, 2010*
Phan bien: PGS. TS. NguySn Van Bang; TS. Nguyin Thanh Cong.
98 Tap chi KHOA H O C GIAO THONG V ^ N TAI S6 50 - 02/2016"
