Tính toán ổn định của xuồng chữa cháy rừng tràm

NGHIEN COU-TRAO 061 TfNH TOAN N ! N H CUA XUONG CHU'A CHAY RLTNG TRAM STABILITY CALCULATION OF MANGROVE FOREST FIRE FIGHTING BOAT Dfldng Van Tai', Cao Hung Phi^ ThS Nguyin Thai Van^ 'Trfldng Dai hoc Lam nghiep ^Trfldng Dai hoc Sfl pham Ky thuat Vinh Long TOM TAT Riing tram d Viet Nam chu yeu tap trung d mien Tay Nam bd, ddy la loai riing ddc biet qui, dd dUdc Lien hdp quoc xep vdo khu dU trU sinh quyen cua the gidi Do ddc diem ve thUc bi, ve thdi tiet nen nguy cd chdy riing rat cao, ndm 2002 dd xay vu chdy riing tram lam mdt khoang 5000 Viec chUa chdy riing tram hien chii yeu la dung mdy bdm nUdc khieng tay, nen tinh cd dgngkhdng cao, hieu qud chUa chdy riing thap De tdi trgng diem cap Nhd nUdc KC07J3/06-10 da xay dUng dUdc cd sd ly thuyet tinh todn dn dinh cua xuong chUa chdy riing cdc trUdng hdp hoat ddng ddc biet cua xudng dd Id: Khi ngUdi vd cdc thiet bi lech sang mdt ben, xuong vUdt can de chuyen tii kenh ndy sang kinh khdc, xuong quay vdng re nhdnh vdo kinh vudng gdc vd cdc thiet bi chUa chdy rUng tren xudng hoat ddng De tdi da sii dung ly thuyet tinh todn dn dinh ndy vdo thiet ke che tao xudng chUa chdy riing tram, ket qud khdo nghiem cho thay xudng cd tinh cd ddng cao, nhanh chdng tiep can ddm chdy vd on dinh moi trUdng hdp hoat ddng ciia xudng Tfl khda: Xuong chUa chdy riing; ChUa chdy riing tram; On dinh xudng chUa chdy riing; On dinh xudng vUdt can ABSTRACT Mangrove forest in Vietnam is mainly located in the southwest This is very valuable forest, is being classified by UN as a biosphere reserve of the world Due to the vegetation and weather, the risk of forest fire is very high In 2002, about 5000 hectares of mangrove forest lost because of fire Currently, mangrove forest fire fighting work is done mostly by using hand carried water pumps that have low portability and efficiency of forest fire fighting The state level mam project KC07.13/06-10 has established a theoretical basis of stability calculation offorest fire fighting boat in special activity cases: people and equipments are at a same side; the boat move from canal to another canal; the boat rotate and move to perpendicular canal; equipments in boat works The research has applied theory of stability calculation into designing and manufacturing a mangrove forest fire fighting boat The test results show that the boat has high mobility, rapid access to fire places and stability in all operation cases of boat Keywords: Forest fire boat; Mangrove forest fire fighting; Forest fire fighting boat stabilization TAP CHi CO KHi VIET NAM, Sd 12 nam 2013 NGHIEN CljrU-TRAOe6l I.DATVANDE trfldng hdp hoat ddng chfla chdy rflng Viet Nam cd khoang 300 ngan dien tich rflng tram, tap trung chu yeu d miln Tay Nam bd, ddc dilm cua rflng tram Id ddy leo bui ram nhieu, tham muc Idn, dong thdi vdi hau khd ndng keo dai nen nguy ccf chay rflng Id rat cao, hang nam van xay chay rflng Dac biet la vu chay rflng trdm nam 2002 d Vfldn quoc gia U Minh Thflgfng va U Minh Ha da thieu buy khoang 5000 rflng trdm nguyen sinh, thiet hai ve kinh te hang chuc ty ddng 2.2 Phfldng phap nghiin cufu Phflpng phap nghien cflu dflpc sfl dung la dp dung ly thuyet tau thuy de thiet lap md hinh va cdng thflc tinh todn can bang va on dinh cfla xudng chfla chdy rflng tram cdc trfldng hop hoat ddng dac biet cua xudng chfla chdy rflng KET QUA VA THAO LUAN 3.1 Bo tri cac thiet hi cong tac trIn xudng Hien nay, viec chfla chdy rflng trdm chu yeu la sfl dung may bom nfldc khieng tay, nen tinh CO dpng thap, khdng kip thdi tiep can dam chdy, tfl hieu qua chfla chay rflng thap De tdi trpng dilm cap Nha nfldc "Nghien cflu cdng nghe vd thilt ke che tao cac thiet hi chuyen dung chfla chay rflng", ma so KC07.13/0610, da tinh toan thiet ke che tao xudng chuyen dung d l chfla chay rflng tram Kit qua khao nghiem cho thay thiet bi cd tinh co ddng cao, nhanh chdng tilp can dam chay va chfla chay kip thdi Yeu cau cua xuong chfla chay rflng tram Id phai dn dinh moi dieu kien chfla chay rflng nhfl ngfldi va thilt bi lech sang mdt ben, xuong quay vdng re nhanh vdo kenh vudng gdc va xudng vflpt can d l chuyin tfl kenh sang kenh khac Di dap flng dflpc yeu cau ve tinh dn dinh nhfl da neu d tren thi viec nghien cflu tinh toan dn dinh cua xudng chfla chay rflng la rat quan trpng Vdi ly da trinh bay d tren, de tai da nghien cflu tinh todn on dinh cua xudng vd da flng dung tinh todn dd vdo thilt ke chi tao xudng chfla chay rflng DOI TirONG VA PHl/ONG P H A P NGHIEN cCu 2.1 Ddi tfldng nghien cflu Ddi tflpng nguyen cflu la xudng chfla chdy rflng tram thda man tinh dn dinh cac Bd tri cac thiet bi cdng tdc tren xudng la khau rat quan trpng qua trinh thilt ke xudng Cdng viec bo tri lap dat dnh hfldng trflc tiep den yeu cau sfl dung, khd ndng hoat ddng va dac biet lien quan tdi can bang 6n dinh cua xuong, bd tri cac thiet bi tren xudng nhfl tren hinh Hinhl: Sd bd tri chung cua xuong 1) Dong cd thuy; 2) Hop gidm tdc; 3) Trong tdi; 4) Bo truyen xich; 5) Bdm nUdc 3.2 Tinh toan can bang va on dinh cho xu6ng chfia chay riing tram Viec tinh toan dn dinh cho xuong dfla tren cp sd xdc dinh cdc dfldng cong canh tay d6n on dinh tinh ^ f(e) vd dpng d = f(9) Sau xac dinh gdc nghieng Idn nhat 0^^ vd tay ddn on dinh ddng Idn nhat Tim tri sd md men nghieng cho phep, sau dd so sanh vdi tieu chuin on dinh xem cd du on dinh khdng Tinh toan dn dinh Id mdt khdu rat quan trpng qua trinh thilt k^ xudng Tinh todn dn dinh dflpc tien hanh tfl cong viec xdy dflng cdc hp cdc dfldng cong thtiy lflc Pantokaren dfla tren mdt sd trang thai tinh toan TAP CHi CO KHi VIET NAM, 86 12 nam 2013 NGHIEN CUfU-TRAO061 ban dau Phan dfldc tien hanh tinh todn tfl xay dflng tuyin hinh xudng Mdt tuyin hhih xudng dam bao dfldc cac yeu cau v l Ifldng chilm nfldc, sflc can, tinh tham my, khdng gian sfl dung cdn phai dflpc kilm tra sd bd ve tinh cdn bang vd on dinh ban dau theo tilu chuan xudng, dilm M !a tdm dinh khuynh cua xudng, dilm B la trpng tam phan choan nfldc a) Tinh todn khd ndng chdng chdnh cua xudng Khi xudng boat ddng chfla chay rflng thi ngfldi va thiet hi ho?it ddng tren dd, tfl dd gay hien tflpng chdng chdnh cua xudng, lam cho xuong cd the hi lat, vay, tinh toan thilt k l phai kilm tra dieu kien chdng chdnh theo qui pham Dang kiem Vilt Nam Hinh Sd tinh on dinh cua xuong Dai Ifldng dac trflng d i k i l m tra, tinh toan on dinh ban dau la chiiu cao tdm dn dinh ban dau GM va dflpc tinh nhfl sau: GM='KM-'KG Chu ky chdng chanh cua xudng lien quan tdi khd nang lam viec dflpc cua nhdn vien, cdc he thdng cdng tac tren xuong Theo tai lieu [1], chu ky chdng chdnh thflc t l ciia xudng dflpc tinh theo cdng thflc sau: T =C (1) Trong dd: Tg: Chdng chdnh xudng, m; C: He chdng chdnh xudng; B: Bl r0ng cua xudng, m; h^: Cao dp trpng tam cua xudng theo thilt kl, Chdng chanh cua xudng phu thupc vao kich thfldc chinh cua xudng, hinh ddng phan chim cua xuong, xudng phdi thda mdn dilu kiln chdng chdnh Id: Trong do: [Tg] - Chdng chdnh theo qui pham cho phep, [TJ = (3-12)m Trong do: KM : Khoang each tfl dilm K din dilm M, ddn vi tinh m; KG : Khoang each tfl trpng tam xuong d i m ddy xudng, m KM = KB+BM=KB +— V Trong dd: J: Md men dnh hfldng mat thodng, Tan.m; V: Thi tich nfldc chiem chd Tan Chieu cao tren day phu thupc vdo dp dang chieu cao tam xudng: - Nlu G dang cao hdn M chiiu cao GM < xudng mat dn dinh - Nlu G trung vdi M thi GM = - Gia tri GM > neu G ndm thap hdn M, xuong on dinh h) Tinh todn dn dinh cua xudng khong cd thiet bi hoat ddng Dp ddc cua dfldng on dinh tai thdi dilm ban dau dfldc xac dinh bdng dao ham cua hoac xdc dinh bdng tg(p M6 hinh tinh todn dn dinh dflpc t h i hi?n tren hinh dd dilm G ky hieu la trpng tdm Neu GM Idn giai doan dau dfldng GZ tang rat nhanh din gdc tam 30" trd l^i thi G Z " ^ TAP CHi CO KHi VIET NAM, Sd 12 nam 2013 NGHIEN ClJU-TRAOeOl dat max, sau dd giam dan, trfldng hpp ndy gdc lan thfldng khd Idn Ngfldc lai GM nhd dfldng GZ cd t h i 1dm giai doan dau, xu the tang rat cham, GZmax khdng Idn dd gdc lan cd the vflpt qua 40" Neu xet tdi on dinh xudng, GM cang Idn thi cdng tdt vi nd keo theo GZ vd gdc lan Idn Khi dd chdng chdnh cua xuong se nhd Kp : He so thflc n ^ l m phu thupc vao dang dfldi^ nfldc, chpn Kp ~ 1,03 B - Be rpng thilt k l cua xudng B= l,8m;!!f 6: H I sd bed the tich =0.45; a: He sd beo dien tich dfldng nfldc = 0,68; T: Chieu cao thilt ke cua xudng T= 0,75mi Cao dd tam noi Z_ dfldc tinh theo cong thflc sau: Z = K a+5 Cdnh tay ddn md men phuc hoi dfldc tinh theo cdng thflc: GZ = - KG sin cp K^: He so thflc nghiem, chpn K^, = 1,2 Vdi Ij la tay ddn tinh tfl dilm K d i n dfldi dfldng tdc ddng lflc ndi trang thai tau nghieng gdc (p" - Cao dp trpng tam cdng thflc sau: - Dilu kien dn dinh cua xudng phai thda man dieu kien nhfl sau: (2) Trong dd: Z = K -T Z dfldc tinh theo (6) Vdi K : He sd thflc nghiem; K = 0,8 ^ 0,9, chpn K = 0,9' 3.3 Tinh toan can bang dn dinh cac trfldng hdp hoat ddng dac bilt cua xudng GM|j: Chieu cao tam nghieng, m \^^^'- Chieu cao trpng tam ban dau tinh theo thiet kl, m - Chieu cao tdm nghieng thflc t l dfldc xac dinh theo cdng thflc: GM„=+Z^^Z^+Ah„ (3) Trong do: Trong thflc t l sfl dung cua xudng chili chay rflng tram trfldng hpp nguy hiem nhdt ma xudng hay bi lat dd la ngfldi va thiet bi lech sang mpt ben Trong qud trinh chila chay rflng ylu cau ddi hdi can phai khan trflPng, nhanh chdng nen ngfldi va thiet hi cd t h i lech sang mpt bin vd nhil vay xudng phai dam bao yeu cau cdn bang va on dinh D l tinh toan trfldng hdp gdy mat 6n dinh nhat ndy chflng tdi thiet lap md hinh tinh toan tren hinh pi Ban kinh tam nghieng ngang, m: Z^: Cao dp tam noi, m; Z : Cao trpng tam,m; Ahj,: Anh hfldng cua mat thodng ban dau, chpn Ahg = 0,1 m - Ban kinh tam nghieng dfldc tinh theo cdng thflc sau: P = Kp (4) '121 Vdi: Hinh 3: Md hinh tinh todn dn dmh tdi lech sang mdt ben xudng i TAP CHi CO KHi VIET NAM, 86 12 nam 2013 NGHIEN CUfU - TRAO D | Tren hinh 3a tai trpng tren xudng dat d tri tri can bang, trpng tam cua xudng ndm tren true can bdng YY tai dilm O, tai trpng cua xudng ky hilu la G Lflc day dt si met Ps trung vdi true can bdng YY vd dat tai dilm O^ Khi ngfldi va thiet hi lech sang mpt b i n hinh 3b, trpng tdm cua xudng chuyin tfl diem O sang dilm O^ each true can bang mdt khodng la b Lflc day at si met ciing chuyin tfl dilm O^ sang dilm O3, cdch tryc can bang mpt khoang la a Md men gdy lat cho xudng Id: M,^^ = G.b Md men chdng Idt cho xudng M ^ ^ = Ps a D l xudng can bang va on dinh thi M^j^,^ > M,., hay Ps.a>G.b (7) - Chiiu cao trpng tam ban dau theo thilt k l tinh dfldc: h^^^ = 0,35 (m) - Thay cdc sd da bilt vdo cdng thflc ( 4), (5), (6) ta xac dinh dfldc p = 0,68 (m); Z^= 0,72 (m); Z^ = 0,67 (m) - Thay so da tinh toan dflpc vdo cdng thflc (3)tacdGM^^=:0,63m - Kilm tra on dinh theo cdng thflc (2) ta cd GMg = 0,63 (m) => GM^ > h„_^,_, Vay xudng dam bdo dilu kien on dinh 3.5 Thflc n g h i i m k i l m tra dn dinh tai lech sang mpt ben Tfl cdng thflc (7) ta cd D l xac dinh tinh on dinh cua xudng tai trpng dat lech sang mdt ben chung tdi tien hanh G [r^mm ] = 3ni, vay dilu kien vl chdng chdnh thda man theo qui pham ddng kilm Vi^t Nam b) Kiim tra on dinh cdc thiet bi tren xuong khdng hoat ddng Hxnh 4: ThUc nghiim xdc dinh goc lat cua xudng tdi ddt lech sang mot bin TAP CHi CO KHi V I £ T NAM, Sd 12 nam 2013 NGHIEN cflu - TRAO D I Hinh Suphu thuoc cua goc lat (p cua xudng vdi lUdng dat lech G Nhan xet: Gdc lat cua xudng ty le thuan vdi Ifldng dat lech tdm, gdc lat (p> 25 dp nfliSc tran vdo khoang xudng thi xudng mdi bi chim, vay, trpng Ifldng dat lech G= 800 kg thi xuong van on dinh, vdi trpng Ifldng bao gdm todn bp thiet hi va ngfldi dpi hinh chfla chdy rflng KET LUAN Bang ly thuyet tau thuy, dd xay dflng dfldc sd dd tinh toan can bang va on dinh cua xudng chfia chdy rflng tram, tfl da dfla cdng thflc tinh chdng chanh cua xudng (1), dieu kiln dn dinh theo cdng thflc (2), dieu kien on dinh ngfldi va thiet bi lech sang mdt ben (8) Da tiln hanh kiln tra xudng thiet ke theo dieu kien chdng chanh va dn dinh deu thda man qui pham dang kilm Da thi/c nghiem dilu kien dn dinh ngfldi va thilt bi dat lech sang mdt ben, kit qua cho thay xuong on djnS mpi trfldng hpp boat ddng Nhflng kit qua nghien cflu ly thuyet ndy dd dflpc ap dung tiim todn thiet k l che tao xudng chfla chay rflng tram • Ngay nhan bai: 05/11/2013 Ngay phan bien: 06/12/2013 Ngfldi phdn bien: TS Nguyin Thanh Quang, Trfldng Dai hoc Sfl pham Ky thuat Hflng Yin Tai lieu tham khao: [1] Nguyen Dflc An, Nguyen Ban (2004), Ly thuyet tdu thuy tap 1, NXB Giao thdng Van tai Ha N6i [2] Nguyen Dflc An Nguyen Ban (2004), Ly thuyet tdu thuy tap 2, NXB Giao thdng Van tai, Ha Noi [3] Bp Nong nghiep va Phat tnen Nong thdn Cue Kilm lam (2000), Vdn bdn phdp quy ve phong chdy, chUa di^ rUng, NXB Nong nghiep, Ha Npi |4] Dfldng Van Tai (2010), Bao cao ket qua de tdi trgng diem cap Nha niidc, "Nghiin cUu cdng nghi vd tlu^H chi'tao cdc thii't bi chuyen dung chUa chdy rUng" ma so KC07.13/06-10, Cue Thdng tin Khoa hpc & Cong nghe Quoc gia Ha Npi TAP CHi CO KHI VIET NAM, 86 12 nam 2013