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KHOA H Q C - CONG N G H E

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TfNH TOAN KHA NANG LAM VIEC

CUA XE CHUA CHAY RLfNG DA NANG

N^xyinXdHgi', Duang Vdn Tdi^

d Viet Nam, hdng nam xdy ra hdng trdm vu chdy rimg, ldm mdt hdng ngdn ha rimg, gdy thiet hgi Idn vi kinh te vd moi tnrdng sinh thdi. Hiin nay cdc thiit bf chira chdy rirng d nudc ta rdt hgn chi, nen viec dgp tdt cdc ddm__^

chdy rOng Id kho khdn. De tdi trgng diim cdp nhd nudc KC07.13/06-10 da thiit ki che tgo (^xe chua chdy rirng da ndng, thiet bf ndy dd dugc Idido nghiem cho hiiu qua chira chdy rimg cao. Di sic dyng cd hiiu qud vd an todn xe chira chdy rirng da ndng ndy thi cdn thiet phdi nghiin ciru khd ndng hogt dgng cua xe khi chira chdy rimg trong khu rimg khong co dudng. Kit qud nghien cuu dd thiit Igp dugc md hinh tinh todn, xdy dyng dugc phuang trinh cdn bdng lyc theo diiu kien lyc keo vd phuang trinh cdn bang lyc theo dieu kiin lyc bdm, da khdo sdt phuang trinh cdn bdng luc theo dieu kien keo vd bdm vd dd xde djnh dugc d6 ddc dgc Idn nhdt cua khu rimg khong cd dudng md xe chira chdy rimg da ndng cd the ldm vi0c dugc. Kit qud nghiin cuu Id ca sa khoa hgc de xde dfnh dieu ki§n ldm vi$c an todn vd hieu qud cua xe khi chira chdy trong khu rimg.

^Tf)

I. D^T VAN Di:

Riing Id nguIn tdi nguydn vd ciing qui gia ddi vdi con ngudi, nhung didn tich rimg ndy cang suy giam, mgt trong nhiing nguydn nhan Id do chdy riing gay ra.

(3 Vidt Warn hdng ndm vSn xiy ra hdng ttdm vu chdy riing, dd ldm mat hang ngdn ha rimg, thidt hgi ve kinh te hdng tt^ty dong, dnh hudng xau den mdi trudng sinh thdi. Hi?n nay thiet bj chiia chdy riing cdn hgn che, ndn hidu qud chita chdy rimg rat thap.

D I tdi trgng dilm cip nha nudc " Nghien ciiu cdng ngh? vd thiet ke che tgo cac thiet bj chuyen dyng chita chdy rimg", md s l KC07.13/06-10, da tiiiit kl che t g o ^ xe chiiB chdy rimg da ndng. Xe chua chdy riing da ndng dupc thilt kd tidn ca sd tfch hgp nhidu cdng nghd chiia chdy riing, vdi nhidu tinh ndng chOa chdy riing tten mgt xe co sd la xe td to Ural. Nguyen ly hogt dgng ciia xe la khi c6 ddm chay r i m g ^ ^ ra xe di chuyin den noi cd dam chay sii dyng hd thdng Idm bdng cdeh ly dk khoanh viing cd ldp cdeh ly ddm chdy, sii dyng h? thong phun dit cdt, nudc dk ddp liia.

Nhu vgy Id khi hogt dgng chiia chdy riing xe phdi di dpng d tiong khu rimg khdng c6 dudng, vdi cac dp doc khdc nhau vd nhilu vdt cdn cila khu riing. Vdi nhimg ly do dd trinh bdy trdn, chiing tdi tiln hanh n^idn cdu khd ndng hogt dgng ciia xe ttong khu rimg.

II. D 6 I TiTgfNG & PHirofNG PHAP NGHIEN ciru 2.1. s i i ttrpng vd thilt bj nghien cuu Doi tupng nguyen curu Id mpt so khu rimg cd nguy ' Ths. Truimg Dgi hpe Jii6ng chiy chfla chdy.

^TS. Trudng D?i hgc Lim nghidp.

TAP CHl CONG NGHliP NONG THON - SO 6 -

CO chdy cao, thilt bi nghien ciiu Id xe chiia chdy riing da ndng do dk tai KC07.13/06-10 tiiiet ke chl tgo.

2.2. Phmmg phdp nghidn cihi

Phuang phdp nghidn ciiu dupc sii dyng Id dp dung ly thuyet 6 td may keo dl xay dyng md hinh vd thiet Igp phuong trinh cdn bdng luc theo dilu kidn keo va ban, khao sat phuong trinh Igp dupc de xac dinh dupc dp die lan nhat xe ^ hogt dpng dupc ttong khu rimg khong cd dudng. ~ " — —

m . KET QUA VA THAO L U ^

3.1. Cdc lyc tdc d^ng Idn xe chihi chdy rimg da ndng khi hogt dgng chira chay riing

Xet truong hpp ting quat khi xe dang chgy t f ^ ^ / i * khu rimg vdi dg doc a vdi vgn tic v khdng ddi, ding thdi h? thdng cat cay phia trudc, h? thing phay cd rdc lam bdng Udng cdeh ly ddm chdy d phia sau van hogt dpng, tien xe cd chd day nudc. So do lyc tdc dyng Idn xe dupc thd hidn tidn hinh I.

- Trgng lupng ciia xe bao gdm cdc bd phgn cdng tac, nudc d tien xe vd todn bg tdi trgng cua xe: ky hidu G ddt tgi tigng tdm cita xe va dupc phdn lam 2 thdnh phan:

Gz = G.cosa va Gx = G.sinflr Tgi cac dilm tilp xuc giii'a banh xe vdi mdt dudng cd lyc kdo tilp myen FKI, F O , FKS ddt tai edc bdnh chu ddng vd cd lyc cdn Idn FQI, F02, F03 cung d^t tgi cdc banh chii dgng.

- Tgi tryc ciia banh xe cd momen ehii dpng tir dgng CO tmydn din Mi, M2, M3.

- Tgi diem tiep xiic ciia bdnh xe vdi m§t dudng cd phdn lyc phdp tiiyen N[, N2, N3, va momen can Idn m,,

2012 23

TJ

T

KHOA HQC - CONG NGHf m2, ms, ngupe chieu voi mdmen chii dpng Mj, Mj,

^'- . . . .

- Gpi lyc cat cay va diy cssy ciia he thdng cdt cdy Id Fci, lyc can ciia hd thing phay dit lam sgch cd rdc l^iia sau xe Id Fc2-

- Ggi lyc cdn qudn tinh khi xe chimin ddng tinh tiln vd cac chuyen dpng q u ^ cuaxe^Ia F ,

:T3O xe chuyen dong voi ^gn td^van tdc thap nen bd qua lyc cdn ciia khdng khi.

3.2. niuong trinh dtoyea dpng cua xe khi hogt d$ag chira cfaiy rirng tmh theo lyc keo

Ctiieu cdc lyc tac dung len xe theo tryc X. Ta co phuong trinh cdn bdng lyc keo.

FKI + FK2 + FK3 = Csuitt + FQI + F02 + F03 +

Fci + Fc2 + Fv + Fq, (1) Trong dd:

FKI ; F|Q ; FK3 - lyc keo o cdc bdnh chii dpng ciiaxe.

Foi; Foi; FO3 - lyc cdn Idn d CM; bdnh xe.

FCI - lyc can do h? tiling cdt cdy d tiirdc xe Fc2 - luc cando b? tiling cdt co rdc gay ra.

FV - luc cdn duong vdng.

Fqi - lyc can qudn tinh.

- ' ^

Huih 1. Sa dd lyc tdc dfpig lin xe khi hogt dgng chSa chdy riing a) Tmh lyc keo (FK):

Ta co: FKI + FK2 * FK3 = FK

Tror^ dd FR Id lyc keo tiep tuy&i ciia cdc bdnh xe chii dpng (N).

£>oi vdi xe chiia chay riing da ndng tit cd cdc banh xe deu td tianh chii ddng, nen FK chinh Id lyc kdo do d^ig CO sinh ra.

^«:—~ P)

Trong d6:

MK - MO men quay cOa cac banh xe chu dpng, (Njn).

TK - Ban kinh lam viec ciia bdnh xe chii dong

Trong dd:

A - He so biln dang tjanh xe.

'fee - Ban kinh ciia tjanh xe chii dpn^ (m).

Momen quay cua cac bdnh xe chu dgng dupc tinh nhu sau:

MK = M.iK.ip.io.11 Trong dd:

M - Md men quay cyc dgi o ddu tryc co.

IK - Ty so truyen cua hOp sd chinh.

ip - Ty s l truyen a hgp s l phy.

io - Ty s l truyen d cdu chii d$ng.

11 - Hidu suit bp truydn lyc.

b) Tinh lyc cdn lan (FQ):

Ta cd: FQ = Foi + F02 + F03 (3) Trong do: FQ - Lyc can Ian, (N).

Lyc cdn Idn dupc tinh nhu sau:

Fo = G . t (4) Trong dd:

:^ - He s l cdn lan giiia banh xe vdi m$t dit riing, hd s6 ndy phy thu^c vao trgng thai be mdt ddi rimg.

G - Trpng lupng todn bg xe, (N).

Fo = fi,i. K1.iC2.K3.K4 Trong dd:

f;,i - Hd s6 can Idn ca ban.

Kl - Hd s6 tinh den lli ldm, mdp md cua mdtditriit^

K2 - Hd s6 tuih din tham mi^, cd kho. Id khd otidn be m|it dit rimg.

K3 - H§ so tinh ddn chudng nggi vgt nhu gdc cay, cdy ndm chdn ngang, rdnh nudc chdy.

K4 - H§ so tinh ddn to?ng thai ciia lop xe vdi be matddtrur^

c) Lyc cdn cdt FQI dirge tinh nhu sau:

Theo nguydn ly cdt gpt g5 [1], khi h? tiling cdt cay tfli smh ra lyc cdt Pc vd lyc d ^ Q. Qud trinh cdi cay dupc thd hidn tren sa dd hinh 2.

Hmh 2.Sadd tinh todn lyc cdt vd lyc day cua h4 thdng chgt hgc^

24 TAP CHI CONG NGHieP NONG THON - s 6 6 • 2012

KHOA HQC - CONG NQHE - Lyc cdt cua luSi cua dupc tinh tiieo cdng thtrc:

Pc = k.b.h.z U (5) Trong dd:

Pc - Lyc cdt ciia dia cua k - H^ s l cdn cdt ridng b - Chieu rpng mach edt b = D,

(D - duang kinh cdy) h - Chilu ddy lu5i edt

z - s l rdng tham gia vdo qua trinh cdt U - Vdn tic diy cua vdo cdy m/s - Lyc ddy Q dupc tinh nhu sau:

Trong qud trinh cdt bdng lu&i cua dia, lyc cdt PC cd phucmg theo tie dp cdt, thdnh phin lyc diy Q cd phuong vudng gdc vdi lyc cdt. Theo tdi Ii$u [1] lyc diyQ = ( 0 , 2 - 0 , 7 ) P c .

Nhu vgy lyc diy cua vdo go dupc tinh theo cdng thiic:

Q = 0,5.Pc (6) Tuy theo vj tri ciia lu5i cdt so vdi tryc cQa cdy gpi Id gdc gdp tfid (p, gdc ggp thd bien dii tir 0 - 90°.

- Trong tnrdng hpp gde ^ , la co lyc cdt va lyc diy dupc tinh theo cdng thitc sau:

S„ =Psina ±Qcosa Sj =Pcosa±Qsma

- Truong hpp mJt phdng eiia dia cua vudng gdc vdi thd go (tryc thdn cdy), lyc cdt vd lyc diy dupc tinh theo cdng thiic sau:

S=P

s,-Q

(7)

cay dao cdt ty trupt qua khdng Idm tdng lyc cdt, khdng anh hudng ddn lyc cdn cdt So do tinh toan lyc cdt 6 dang biia dupc the hi^n trdn hinh 3.

Hmh 3. Sa do tinh todn lyc cdt d dgng bua - Lyc can do hd thong cdt cd rdc Iam bdng cdeh ly dupe tinh nhu sau:

Pc2 = Pcd + Pee + q-sm a (9)

Trong do: ^ ^ Pcij - Lyc cdt dit ciia dao cdt

Pel - Luc can Idn ciia he thong ldm sach cd rac q - Trpng lupng ctia hg thong Idm sgch ed rdc - Lye cdt dit Pcd dirpc tinh nhu sau:

Theo nguydn ly cdt ddt d dgng biia [3], lyc cdt do xung lyc va chgm ciia dao cdt tgo ra dupe tinh nhu sau:

(Rf,+l)a} m

^[gM 't ,\R,-l)

- Nhu vdy lyc cdn cdt do hd thing cdt cay d dau xe tgo ra dupc tinh nhu sau;

Pci = 0,5.Pc. n (8) Trong dd:

Pc - Lyc edt cua dia cua dupc tinh theo cdng thii:c (5).

n - Sl dTa cua ciing tham gia vao qua trinh cdt.

d) Tinh lyc cdn do he thong phay cd rdc Pc2 Trong qua trinh hogt dpng phay cd rdc tgo bdng trdng edch ly, hd thing phay cd rdc vira chuyin dOng quay vira chuyin d^ng tjnh tiln eClng v6i vgn toe cua xe.

Cdc dao cdt dit chuyen dgng quay trdn xung quanh tryc cua tring dao, cdt dit theo nguyen ly cdt dit d dgng bua. Nguydn 1^ cdt dit d dgng biia ndy cd uu dilm Idn nhat dd Id khi gdp goc cay, md d4 cdnh TAP CHf CONG NGHlfP NONG THON - SO 6 • 2012

(N) (10) Trong dd:

Ro - Ban kinh cua dia dao, m I - Chieu dai cao cat, m Joi - Md men qudn tinh dao cdt, kgm^

to - Van tdc gdc ciia dao cdt dat va cd rdc, 1/s g - Gia t i c tipng trudfng, m/s^

" * - Dg lun ciia nIn dit sau va chgm, mm t - Thdi gian va chgm, giay

m - So dao cdt ciing tham gia vao qud trinh cdt - Lyc can Idn (Pc^) dupc h'nh nhu saii^_^

Pd = q.fi (11) Trong do:

q - Trgng Iupng ciia hg thong, N

fi - H$ s l cdn Ian ciia hg thing vdi mat <Jit rimg Thay cdng thurc (10) va (11) vdo cong thurc (9) ta cd cdng thuc tinh lyc can do h? thing cdt cd rac nhu sau:

Pci = m{R^-l)

t.l' •'

4gM

•• qf,-^q.s\na (12) e) Tinh luc cdn xe chgy tren duang vong Trong qua tiinh xe chira chdy rimg hogt dgng.xe phai quay vong. qui tiinh xe quay vdng sinh ra'lyc

25

KHOA H p e - CONG N G H $

V

can do CO sy xe djch q i ^ d ^ chuyen dpng cua banh quan tinh do cac bp phgn chuyin dpng quay, lyc truoc va banh s ^ 1 ^ can do quay vong dupc tinh can qiidn ti'nh cd the tinh gan diing nhu sau:

tiieo cdng thuc sau: „ ^G dv

(14)

^ (13) Trong do:

Trong dd: v - vgn tdc ehuyin dpng ciia xe Cv-hdsd can duong vdng S = \-¥ail ; ^ - h ^ s o ; R - bdn kinh duang vdng , . ^

AT' Ul • ' ^ L a-h?so;

j) Tmh luc can quan tmh ^- -t.._ i , , . , . , , 3. , . . lit - ty so truron Lyc can quan tinh cua xe bao gom lyc can quan

tinh do chuyin dpng tinh tiln ciia xe vd lyc can

g) Phuang trinh tdng qudt khi xe chQa chgy rung hogt dgng chSa chdy a trong khu rimg.

Thay cdc cdng thuc (2); (4); (8) ; (12); (13) va (14) vdo cdng tiiuc (1) ta co:

F, = (G+,).sina+G/„+0^P^+^^^.7„,«,.^^+9/; + °^.S^^ (15) tl v^^ g

Nhan xet: Tu phuong trinh chuyen dpng cua xe chiia chay riing tinh theo Iuc keo theo cong thitc (15) chung tdi cd nhgn xet sau:

- Khd ndng di dpng ciia xe d td phy thugc vao nhidu ydu to anh hudng do la:

+ Dp doc cua khu rimg (a)

+ Hg so can lan giiia banh xe vdi mgt dat riing (fg)

+ Dudng kinh cay cin cdt, sd Iudi cua tham gja vao qud trinh cdt + Trpng lupng ciia h? thing cdt cd rdc, trpng lupng ciia todn bp xe dto.

+ Lye cdn do he thong cat cd rac Iam bang each ly.

- E}| xde djnh dupc muc dp anh huang eiia cac yeu tc^ chung ta phdi khdo sdt phuang trinh (IS) is mpt so tnrdng hpp nhit dpih.

- Tu phucmg trinh (15) chiing ta cd the xac dinh bdng ly thuyet dupc gdc a, tii dd co thd xac djnh

"""^^tipy xe c6 the di chuyen dupc d dp doc bao nhieu dp.

3 3 . Xac dJDh kha nang di dpng cua xe theo chii dgng tfii lyc bam dupc xac djnh tiieo cong thirc dilu kifn bdm. sau:

D I cho xe chuyin dpng dupcyngoai dieu kipn Fb = G.u (17) lyc keo cdn phai thod mdn didu k i ^ lyc ban de xe Trong do:

khdng bj tiupt. G - Trpng lupng todn bp xe, (N) '^R *• ^b (16) ji - H? so bam cua banh xe vdi mgt dit riing Trong do: Ciing tuang ty nhu hg sd can Idn h? so bam p.

Fb - Lyc bam (;ua cdc banh xe chu d^ng. phy thupe vdo logi l6p xe, frang thai be mat dit rimg Ddi vdi xe dtd cd tit ca cdc banh xe ddu la bdnh nhu: Id cay, thdm mye, cd khd, dp mip md mdt dat

rimg.

Thay cdng thiic (16) vao cdng thuc (I) ta cd phucmg trinh can bdng lyc tinh theo lyc bam.

ti ^gbX R g at

Nhdn xet Tu phuong tiinh (18) ta cd the xac Dk khao sat kha ndng di dpng cua xe tren dudng dinh dupc dp d6c ma xe cd the di dpng dupc tinh vdi dp die, chung ta jrfiai xde djnh dupc cdc h$ so theo dieu kign lyc bdm. trong phuang trinh (2) va (4). Vigc xde djnh cac hd sd 3,4. Khao s^t kha naag di d^ng cua xe khi b ^ g 'J tiiuydt Id rit phuc tgp. Trong nghidn ciiu ndy hoat dpng chira eh&y tirng tron^ khu rung chting tdi sii dyng phuang phdp thyc nghidm vd tham i

khdo cdc tdi ligu, cac .—. r^l 26 TAP CHf C 6 N G NGHIEP NONG THON • s 6 6 - 2012

K H O A H Q C - C O N G N G H f

^

sd Hgu dd dupc cdng bo, tu dd chpn ra dupc mpt gid trj thieh hpp vd phii hpp vdi bai toan d§t ra.

a) Tinh theo dieu ki$n luc keo F^

Bdi toan dupc khdo sdt vdi cdc s l Ii$u sau:

- Trpng Iupng todn bp xe G = 170.000, N (cd cd nude)

- Mdmen dau tryc ca M = 667, N.m - H$ so cdn lan bdnh xe vd mgt dit rimg fo = 0,3 - Hp so cdn Idn giiia hg thong cat cd rac vdi mdt datfi = 0,3

- Dudng kinh cdy edt D = 25, cm - So Iudi cua tham gia dong thdi cdt la m = 2 - Trpng lupng h§ thing cdt cd rdc q = 5.000 N - Bdn kinh dia thdp Ro = 20cm, I = 12 cm - So vdng quay cfia trong dao = 800 vdng/phut - H | s l cdn cdt ridng eiia gd k = 11,79 Kg/mm^

- H^ s l bdm ciia bdnh xe vdi mdt dat rimg H=0,55

Thay tit cd cac s l lieu d trdn vdo cdng thiic (1S), ta xac djnh dupc gdc a:

Tacd: Sina = 0,32 => a = aicsm0,32= 18°39' Nhu vgy tinh theo ly thuylt khi xe chd 5,lm^

nudc, vura cdt cay, vira edt cd tgo bdng cdeh ly ding thdi chuyin d^ng d trdn dja hinh khdng cd dudng ixn% dO die dpe a, xe cd the di chuyin dupc vdi d$ die dpe ciia dja hinh Id a = 18"39'.

b) Tinh theo dieu ki^n lyc ban Ft

Tuang ty nhu phin tuih theo lyc keo, bdi toan khdo sdt vdi cac so ligu nhu phan tinh theo lyc keo, trong dd h$ s l bdm dupc lay tuong ty nhu h$ sd

bam ciia xe dto vgn chuyin gd di chuyin trong rimg fi=0,55.

Thay tit cd cac gia tij vao cdng thiirc (18), sau khi ti'nh toan ta xde djnh dupc gdc a nhu sau: Sina

= 0.278 => a = arcsinO.278 = 16°8'

Nhu vgy khdo sat theo dieu kign lyc bdm khi hogt dpng chiia chdy d trong khu rung xe cd thi di dpng dupc d dp doc dpe a = 16 8'.

IV. KET L U ^

Bdng cdc nghien ciiu trong ly thuyet 6 to mdy keo, da xay dyng dupc so do tinh toan lyc tde dyng len xe chua chay riing da ndng khi hogt dpng chi^a chdy riing, tii dd da thilt I§p dupc phuang trinh cdn bdng lyc theo dieu kign lyc kdo (14) vd lyc bdm (17). Da khao sdt phudng tiinh can bdng lyc keo vd bdm, tir dd xac djnh dupe dO doc dpe Idn nhat md xe chGa chdy rimg da ndng cd thi hogt dpng dupc tiong khu riing khdng cd dudng khi edc hg thong tien xe cimg hogt dpng Id a = 16°8'.

TAILISUTHAMKHAO

1. Ho^g HUu Nguyen (2008), Mdy vd thi^t bj chi bi^n gO t$p 1. Nxb Ndng nghi$p, Hd N^i

2. NguyIn Quang (l983)^V$n chuyen gS bJbg dudng 6 td, Nxb N6ng nghidp. Hi N^i.

3. D 5 Sanh (1999), Co hgc t§p 1, t ^ 2, Nxb Gi5o dye 4. Duong van Tdi (2010), Bdo cdo kit qua ah t ^ trong dilm c ^ nh^ nudc," Nghifin ctru cdng ngh$ v& thilt kl chl t^o cdc thilt bi chuy&i dyng chOa chfiy rimg" ma s6 KC07.13/06-10, Cvc'pi6ng tin khoa hQc & cdng ngh$ qu6c gia, Hd N^i

OPERATING CALCULATION OF THE MULTI - FUNCTION FOREST FIRE FIGHTING CAR Nguyen Xa Hoi, Duong Van Tai SUMMARY

In Vietnam, there are hundreds of forest fire cases having occurred and thousands of hectares of forest having lost annually, causing considerable economic, environmental and ecological damage. In Vietnam currently, forest fire fighting equipments are very lunited, the issue of forest fire fighting therefore deals with a lot of difficulties. The state project KC07 13/06-10 has successfiilly designed and manufactured a multi- fimction forest fire fitting machine prototype. This machine has been tested and given high efficiency of forest fire fighting. In order to use this machine in the more efficiently and safely way, it is necessary to research the operational capability of the machine in forest condition without roads. As the results of research, the calculation model has been established, force balance equations based on pulling and stick force conditions have been built and tested. The highest vertical slope that multi-function forest fire fighting machine could be able to operate in the forest condition without roads has been identified. The research results are the scientific basic of identifying the safe and efficient working condition for this machine in forest area.

Ngudi phan b i ^ : G & T S K a P h ^ \ ^ L a i i g

TAP CHf CONG NGHliP NONG THON - S6' 6 - 2012 27