Cdng trinh Khoa hpc
PHAN TICH DONG LlTC HOC KET CAU KHUNG XU^ONG 6 TO KHACH THANH PHO
T ^ T H I THANH HUYEN VU TUAN DAT Khoa Cakhi
Tru&ng Bgi hgc Giao thong Vgn tdt
Tdm tdt: De nghiin ciru dgc tinh dgng lgc hoc kit cdu khung xuang 6 td khdch, md hinh phdn lu hiru hgn (PTHH) cua ket cdu khung xuang dugc xdy dung vd co xem xet dnh hudng cua cao su gdi dd dong ca vd hi thdng treo. Phdn tich dao dong riing dimg di linh loan cdc ldn sd rieng (gid In rieng) vd dgng dao dpng rieng (vie ta rieng) cua kil cdu khung. Tiip theo, tiin hdnh phdn tich dao dgng dieu hoa kel cdu khung xuang khi chiu kich thich lir ddng ca theo phuang ngang vd thdng dung. Tir cdc kit qud linh todn, liin hdnh cdi tiin do cung cao su gdi ds dpng ca de gidm biin dp dao dpng cda kil cdu khung xuang.
Summary: To study the dynamic response properties of semi-integral bus frame structure, the finite element model of this frame has been built with engine rubber mounts and the suspension system having taken into consideration. The modal analysis, used to calculate vibration characteristics of the structure, such as natural frequencies (eigenvalues) and mode shapes (eigenvectors), has been done, followed by the harmonic analysis of bus frame with engine excitation in both vertical and horizontal directions. Based on the analysis results, sliffhess of engine rubber mounts has been improved to reduce amplitude vibrations of the frame structure.
I. D A T V A N D E
Khung xuong d td khach la ket cdu khdng gian phiic tgp, cd kich thudc va tigng lugng Idn.
Ngoai yeu cdu ve dd ben, khung xuang cdn phai dam bao yeu cdu khi chiu tac diing tii cac ngudn kich thich dao ddng khdng gay ra hien tugng cgng hudng lam tang rung ddng va tieng dn. Vi vgy, nghien ciiu ddng luc hgc (DLH) ket cdu khung xuang d td khach la rat can thiet va cd y nghia thuc tien khi thiet kl che tao nhdm giam rung dn va ndng cao tinh tien nghi cho d td.
Md hinh PTHH khung xuong dugc xdy dung tren ca sd tham khao d td khach thanh phd TB115CT - WLFII logi 80 chd (46 chd diing va 34 chd ngdi). Bai bdo dd kit hgp hai phucmg phap: phan tich dac trung dao ddng ri6ng va phdn tich DLH ket cau khi chiu kich thich dieu hda tii dgng ca d l nghi6n ciiu dgc tinh DLH kit cdu. Trong md hinh PTHH cua khung xuang cd xem xet den anh hudng cua cao su gdi dd ddng co va he thdng tteo.
Tap chi KHOA HQC GIAO THONG VAN TAI S6 dac biet - 11/2015 123
II. U'NG DUNG PHAN MEM ANSYS THIET LAP MO HINH PTHH CHO KET CAU KHUNG XI/ONG
Tren ca sd d id khach thanh phd dugc tham khao, kit cdu khung xuang d td khach thugc loai cd khung satxi va khung xuang than xe cimg chm luc (Semi-integral bus frame). Bd qua anh hudng ciia tdn vd xe va cac ket cau cd khdi lugng nhd nhu xdp chdng rung dn va ndi thk tiang tii khdc, md hinh PTHH ket cau khung xuang (bao gdm khung satxi va khung xuang than xe) dugc chia ludi bang phdn tii SHELL63 vdi thudc linh vgt lieu Id thep 16Mn (khung satxi) va thep CT3 (khung xuang than xe). Sii dung phan tii C0MBIN14 vdi tham sd dd ciing va he s6 can de md phdng cac cao su gdi dd cum ddng co vd h$ thdng tieo, cac thdng sd kit cdu tham khao dugc cho tiong bang 1. Sir dung cac dilm nut ngoai vdi phan tii MASS21 de md phdng gdi dd nhip, gdi dd ddng ca va khdi tam cua cac cym tdng thanh, h^ thing lap tren khung xuong. Ky hi?u cac gdi dd nhip nhu hinh 1 the hi^n.
Bdng 1. Thdng sd kil c a cao su goi d e thong treo
FFL FRL RFL RRL Hinh 1. Ky higu cdc goi da nhip Phan tich ddng lire hgc ket cdu khung xuong d tiang thai xe ddy tai, khdi lugng ciia hdnh khach phan bd deu len phdn di6n tich san ddnh cho hanh khach diing (46 hanh khach ddng) va phan bd 16n dilm bdt ndi gifta ghi ngdi va san (34 ghi ngdi + 01 gh6 lai). Dieu kien bi6n tai cac gdi dd nhip: FFR, FFL, RRR va RRL khdng chi 4 bac t\r do UX, UZ, ROTX va ROTY;
FRR , FRL, RFR va RFL khdng chi 3 bac tiJ do UZ, ROTX va ROTY. Cac dilm nut dudi ciia phdn tii C0MB1N14 md phdng h6 thdng tieo dugc khdng chi 6 bac tu do.
Md hinh PTHH cua kit cau khung xuang d Id khach thanh phd nhu hinh 2.
III. PHAN TICH DAO DONG RIENG CHO KET CAU KHUNG XI/ONG
Vdi mgc dich tinh loan dgc tiimg riSng bao gdm: tdn sd rieng (Eigenvalues) va cac dgng dao ddng rieng (Eigenvectors)
Thdng s6 Do Cling cao su gdi dd:
- Theo UX, UY (cho mdi gdi) - Theo UZ (cho mdi gdi) Do Cling he thdng treo cau trudc cho mdi b6n
Dg Cling h6 thdng tieo cau sau cho mdi bSn
HS sd can giam chan cau trudc cho mdi b8n
He sd can giam chdn cdu sau cho mdi ben
Don vi
N/m
N/m N/m N.s/m N.s/m
Gia tri
3.0E6 4.0E5 2.5E5 3.4E5 4.0E3 4.5E3
Hinh 2. Mo hinh PTHH kit cdu khung xtrang
124 Tap chi KHOA HQC GIAO THONG Vi\N TAI S6 dac bift - 11/2015
Cdng trinh Khoa hpc cho ket cdu khung xuong [1]. Bai bao chgn phuang phap Block-Lanczos [2] de tmh toan cho 300 dac trung rieng vdi tdn sd tii 0Hz^300Hz, kit qua linh loan 10 dgc trung rieng ddu lien cho trong bang 2.
Hai dac tnmg rieng dau tien la dac trung dao dgng rieng cua kit cau khdng dan hdi. Can cii [3], tan sd dao dgng rieng theo phuang thdng diing phdn dugc tieo ciia d td khach < 2.5Hz. Dac tnmg rieng dau tien cd dgng dao ddng thang diing vdi tdn sd rieng la 1.62 Hz la phii hgp vdi yeu cdu. Tii dac tnmg thii 3 din thii 10 Id dgc trung dao ddng rieng ciia tdng thi kit cdu dan hdi (dac uung bgc thdp), cd tdn sd rieng tu 7.43Hz-17.23Hz. Tir dac trung thii II tiep theo diu la cd Bdng 2. Kit qud tinh todn cdc ddc trtmg rieng dang dao ddng phiic tgp cue bd cua ket cau.
Do anh hudng ciia he thdng treo va ldp xe, lan sd kich thich tii mat dudng khdng bdng phang tac ddng len khung satxi <
4Hz. Tan sd kich thich tii ddng ca phu thugc tdc do quay cua true khuyu (n), vdi ddng CO 6 xi lanh: f = 3ii/60 Hz. Khi lam viec dn dinh, ddng ca diesel cd n = 600v/ph-2300v/ph, tirong iing f = 30Hz^ll5Hz. De trdnh cgng hudng, yeu cau cdc dac tnmg bac thap cua khung xuang d td khach cd tan sd rieng tii 5Hz-20Hz [4,5]. Nhu vay, tiieo kit qua phan tich dao ddng rieng, ket cau khung xuong xe khdch thanh phd dugc thiet ke hgp Iy.
IV. PHAN TICH DQNG LlTC HQC KET CAU CHIU KICH THICH DIEU HOA
Phan tich DLH ket cau chiu kich thich dieu hda tu ddng co vdi muc dich kiem tra
tuang quan phan ling cua kit cdu trong vung tdn sd kich thich. Phuang tiinh DLH ciia md hinh PTHH:
MU-HCU + KU = F (1) Trong dd, M, C va K la ma tran khdi lugng, ma tign can va ma Iran do ciing; u la vec to
chuyen vi cua mit; F la vec ta ngoai luc. Khi F cd dang ham dieu hda viet dudi dang sd phiic:
F-(F,.«e'*)e'^ - F _ { c o s v + isim|r)e'^ -{F, +iF,)e'^ (2) Trong dd: F,^ - bien dg luc tac dung; i|/ - pha dao ddng; i - don vi phdn ao; Q - tan sd
gdc; Fl = F,^cosv - vec to luc phdn thuc; Fi ^ F^.^sim(; Id vec ta lire phan do. Tuong tu, u dugc bieu diln nhu sau:
u-(Um«e'*)e'"' - u ^ ( c o s . i . + isin<J))e'"' - ( u , +m^y' (3) TT
1 2 3 4 5 6 7 8 9
10 T S D SO
rieng (Hz) 1.62 2.25 7.43 9.24 10.29 14.47 15.03 15.95 16.79
17.23
Dang dao d^ng ri§ng Dao dpng thang diing Lac dpc
Xo ngang phan khung xuong khoang hanh khach Uon thang dung Xoan theo true dpc Uon ngang khimg xuong Xoan bac 2 theo true dpc Uon thSng dijng phan khung xuong khoang hanh khach Uon ngang bac 2 phan khung xuong khoang hanh khach Uon thang diing phan khung satxi va uon ngang phan khung xuong
Tap chi KHOA HQC GIAO THONG VAN TAI S8 d a c biet - 11/2015 125
Trongdd: (j)-pha dao ddng; Uj ^ u ^ c o s ( | ) - v e c ta chuyin vi phan thuc; u,^u,^sin(J) - vec to chuyen vi phan do. Thay (2) va (3) vao (1), phuang trinh DLH chiu kich thich dieu hda:
( K - n ' M + i n c ) ( u , +iu,) = (F; -hiF,) (4) Luc kich thich dao ddng tir ddng co chu ylu theo UY va UZ, truyln qua cao su gdi dd den
khung satxi. Vdi muc dich nghien ciiu phan iing ciia kel cdu khi chiu kich thich dieu hda d cac tansd khac nhau, ma khdng quan lam tdi do ben cua kit cau. Vi vgy, bien do luc kich thich cho bang 1 dan vi, tan sd kich thich tu 0 Hz -^ 120 Hz, d trang thai xe day tai, diem ddt lire tai tigng tam dgng ca. Khao sat bi6n do dao ddng tai ba diem niit thugc phan trudc (node 66596), phan gifta (node 71168) va phan cudi (node 81475) cua mdng san.
e 1B
LJ^'. ^ J V . . ^ _
TinsAitlchihfchdb)
Hinh 3. Kich thich theo UY_dao dpng theo UY
Tans6kieh!Wch{H2)
Hinh 4. Kich thich iheo UYjiao dong theo UZ
l^M^
TkatiUsh thich (Hz)
Hinh 5. Kich thich theo UZ_dao dgng theo UY
Tin sAUoh thich (Hz)
Hinh 6. Kich thich iheo UZjJao dgng theo UZ
Kich thich dieu hoa theo UY: Bien do dao ddng cua cdc diem mil khao sdt theo UY va UZ nhu hinh 3 va hinh 4 the hien. Dien nut 81475 nSm ngay phia tien ddng co nen bien do dao ddng Idn ban so vdi cac diem niit khac. Ket hgp vdi kit qua phan tich dao ddng rieng, cac dinh cd bi8n do dao ddng Idn cd tan sd gan dung vdi cac tdn sd dao dgng rieng ciia ket cau va ndm tiong khoang OHz-^20Hz la ngoai vung kich thich khi ddng ca lam viec dn dinh.
Kich thich dieu hoa theo UZ: Bien do dao ddng cua cac dilm mit theo phuang UY va UZ nhu hinh 5 va hinh 6 the hien. Diem bdt ihudng cd bien dg dao dgng ldn ciia cdc diem mil khdo sat tai tan sd cao I14.05Hz, nam trong viing tdn sd kich thich ciia ddng ca. Theo ket qud phan tich dac trung dao ddng neng, dgc tnmg rieng thii 201 va 202 cd dgng dao dgng rieng la cao su gli dd dgng ca dao dgng theo UZ, tucmg iing tdn sd dao ddng rieng Id 114.2IHz va lI4.77Hz.
De ban che hien tugng nay cdn thay ddi do cirng cua cao su gdi dd ddng co.
126 Tgp chi K H O A H Q C GIAO T H O N G VAN TAI So d a c b i f t - 1 1 / 2 0 1 5
Cdng trinh Khoa hpc V. CAI TIEN BQ CLTNG CAO SU GOI DCf DONG CO
Vi tdn sd 114.05Hz gSn vdi lan sd kich thich ldn nhat cua ddng ca (115Hz), bai bao chgn phucmg an tang dg ciing theo UZ ciia cao su gdi dd len 1.5E6 N/md^ giam bien do dao dgng ciia cac diem mil. Ket qua phan tich DLH kit cau khi chiu kich thich dieu hda tir dgng co theo UZ nhu hinh 7 vd hinh 8 the hien. So sanh vdi hinh 5 va hmh 6, cd sir thay ddi dang kl bien do dao dgng cua cac diem mit tai tdn sd kich thich 114.05 Hz. Cu the, bien do dao dgng Idn nhdt theo UY giam khoang 6 lan va bien do dao ddng ldn nhat theo UZ giam khoang 4 Idn.
ZM
!^ zoa E l M E, N 100 Z3
fto«fl65ee
1 \
ii - •
k 1.
—-N«I,T11(18
lil^, M
.J^^-':i^^^iftI^
.—uoot&im
-
J ' " ' • " '
" ^ , ,^^ = . . iw.^ lAw i 4 0 0 20 4C fiO flO i o n 17(1 140 Tin s6krch thich (Hz) "" T%nildcblh[ch(Hz)
Htnh 7. Kich thich theo UZ_dao dpng theo UY Hinh 8. Kich thich theo UZ_dao ddng theo UZ VI. KET LUAN
Nghien cuu dac tinh DLH ket cdu khung xuong d Id khach thanh phd vdi phdn lich dao ddng rieng va phan tich DLH kit cdu chiu kich thich dieu hda, bai bdo cd nhung kit luan sau:
- Tan sd dao ddng riSng theo phuang thang diing phdn dugc tieo dap iing yeu can theo QCVN09:2011/BGTVT. Cac ddc trung cdc ddc Inmg bac thap cd tan sd rieng nam trong khoang tii 5Hz-^20Hz phu hgp vdi yeu cdu thilt ke ddi vdi khung xuong d td khach;
- Ket hgp phan ti'ch dao ddng rieng va phan tich DLH ket cau chiu kich thich dieu hda la phuang phap hiiu hieu va cd y nghia thuc tien trong thiet ke khung xuong d td khach. Khdng nhiing cd kha nang du doan cac vimg tan sd cd the gay cdng hudng cua ket cau, ma cdn xac dinh dugc nguyen nhan va cd bien phap thich hgp de giam bien do dao ddng tai cac viing tan sd nay.
Ngay nhin bdi l^n diiu: 24/9/2015 Ngay nhan bdi sua: 4/10/2015 Ng^y chip nh^D dang bai: 1/10/2015
Tai li^u tham khao
[1]. Vd Tudn Dgt (2014). Phan tich dao dgng rieng cho kit cdu khung cua to hgp ra-mooc thuy luc. Tap chi khoa hpc Giao thong Vdn tai - DH GTVT, S6 dac biet thanglO/ 2014
[2]. Y. 5'aarf(2011). Numerical Methods for Large Eigenvalue Problems. Society for Industrial & Applied Mathematics Published.
[3]. QCVN 09: 2011/BGTVT (2011). Quy ehuin ky thuat quIc gia vl chdt lugng an loan ky thuat va bao ve mot trudng doi vdi 6 to. Bg Giao thong Van tai.
[4]. Chen Y. J (2007). Research on Finite Element Modeling and Optimization Analysis for Coach- Body Frame. China: Hefei University of Technology, Thesis of Master Degree.
[5]. WeiN. B (2011). The Finite Element of Analysis of Integrated Coach Body Based on ANSYS. China.
Changan University, Thesis of Master Degree*
Phdn bi6n; Nguyin Thdnh Cong, Nguyin Van C u ^ g
Tgp chi KHOA H Q C GIAO T H O N G VAN TAI So d a c biet - 11 /2015 127
