Qhov tseem ceeb ntawm cov kws tshaj lij: Qhov no yog cov ntawv sau cia, tsis yog cov qauv tsim tam sim no, kev suav cov lej zoo li qub, lossis cov lus qhia tsim khoom thiab sib dhos. Dimensioning thiab ua tiav cov qauv steel yuav tsum ua raws li cov kev cai thiab cov qauv siv tau, qhov project ntawm tus kws tshaj lij kev tso cai, cov ntaub ntawv tsim khoom, tswj cov khoom siv thiab cov welded lossis mechanical pob qij txha, nrog rau kev ntsuas kev nyab xeeb.
Kev tsim thiab kev tsim cov qauv hlau tsis yog ib feem ntawm kev muab pej xeem tam sim no ntawm Savo Kusić. Niaj hnub no lub hom phiaj tsim khoom muaj xws li ntoo qhov rais, ntoo-aluminium Qhov rais thiab kev cai qhov rooj.
Hauv kev tsim steel muaj cov pas nrig, kab teeb, cov hlab ntsha, kev txhawb nqa saum npoo, thiab lwm yam. Kev sib txuas yuav tsum txuas tus kheej cov profiles hauv txoj hauv kev uas lawv tsim cov txheej txheem uas ua raws li ib chav tsev. Qhov no tsuas yog ua tiav yog tias cov kev sib txuas tuaj yeem hloov pauv cov kev ntxhov siab uas tshwm sim ntawm tus kheej. Thaum tsuas muaj lub siab nyob rau hauv kev sib txuas ntawm ob qhov chaw, qhov kev ntxhov siab yog pauv los ntawm kev sib cuag ncaj qha ntawm kev sib txuas lus thiab cov khoom. Ntxiv nrog rau kev sib txuas ruaj khov, kuj tseem muaj cov kev sib txuas uas txav tau los ua kom muaj kev txav mus los (pob qij txha, lub hauv paus plugs, rubers, bearings, thiab lwm yam).
Rivets
Tsuas yog cov hauv paus ntsiab lus yuav hais txog rivets, vim hnub no lawv yuav luag tsis siv - lawv tau hloov los ntawm cov ntsia hlau. Cov no yog cov ntsaws ruaj ruaj, zoo ib yam li cov ntsia hlau, uas nyob hauv qhov qhib hauv qhov chaw yuav tsum tau koom nrog thiab tom qab ntawd riveted. Raw rivets (daim duab. 1) yog tsim los ntawm cov dov puag ncig steel. Nyob rau hauv cov ntaub ntawv ntawm steel tsim, cov rivets yog riveted nyob rau hauv ib tug kaj liab glow. Thaum riveting, lub taub hau raw rivet uas twb muaj lawm tau txais kev txhawb nqa zoo nrog cov cuab yeej tsim nyog. Lub taub hau kawg yog zoo li siv rauj, feem ntau pneumatically tsav, tsuas yog tom qab lub caj dab rivet tau tag nrho tsav. Rau qhov zoo ntawm riveting, nws yog ib qho tseem ceeb heev uas lub caj dab ntawm lub rivet yuav tsum tau sau tag nrho cov qhib. Txoj kab uas hla ntawm lub rivet yog 1mm me dua txoj kab uas hla ntawm lub qhov, lub caj dab ntawm lub rivet yuav tsum tau compacted los ntawm lub siab los yog xuas nrig ntaus ua ntej lub taub hau kawg yuav zoo li.
Daim duab. 1 - a) Raw rivet; b) Rivet nrog lub taub hau semicircular; c) Rivet nrog countersunk taub hau; d) Rivet nrog semicircular taub hau rau boilers
Kev ntxhov siab thiab lub zog ntawm tus kheej rivets (static)
Shear kev sib txuas (daim duab 2) tsim qhov tseem ceeb tshaj plaws ntawm kev siv cov rivets hauv cov qauv hlau. Raws li tus naj npawb ntawm shear loaded seem ntawm lub caj dab rivet, ib-thooj, ob-thooj thiab ntau qhov sib txuas yog qhov txawv (daim duab 3). Nrog rau kev sib txuas qhia hauv daim duab. 4 (ob chav sib txuas) muaj qhov sib npaug ntawm lub xeev voltage.
Daim duab. 2
Daim duab. 3 - Ib-thooj thiab ob-thooj kev sib txuas
Lub siab ntawm lub qhov rooj thiab lub qhov ntawm lub qhov yog nyob ntawm qhov tuab ntawm cov rivets thiab qhov ntev ntawm cov khoom sib koom; lawv cov kev faib yog muab los ntawm fig. 4a. Rau qhov kev xam pom, qhov kev faib tawm tsis sib xws ntawm qhov hluav taws xob dhau ntawm daim ntawv tuab tau xav tias (daim duab 4b). Cov kev ntxhov siab faib nyob ib ncig ntawm lub voj voog ntawm lub caj dab rivet yog muab rau hauv daim duab. 4c. Rau dimensioning, nws yog xam nrog ib tug txawm tis tshaj txoj kab uas hla raws li daim duab. 4d. Tus nqi nruab nrab ntawm σlm yog qhov hluav taws xob thoob plaws lub hnab ntawv.
Daim duab. 4 - Voltages ib lub hnab ntawv; a) thiab c) tiag; b) thiab d) ib txwm suav cov kev xav
Ib txwm suav ntawm rivets
Lub zog shear nyob ntawm cov khoom siv rivet feem ntau. Thaum ntsuas qhov ntsuas tau, nws yuav tsum nco ntsoov tias cov khoom ntawm cov rivets txawv ntawm qhov uas cov nplooj ntawv tau koom nrog thiab lub zog ntawm cov khoom siv rivet yog nce los ntawm riveting.
Lub zog compressive ib lub hnab ntawv, raws li tus nqi siab tshaj plaws, tsis tau hais meej meej raws li lub zog shear. Thaum qhov kev ncua deb e los ntawm qhov kawg ntawm daim ntawv tsis zoo heev, cov rivets rhuav nws; Fig. 5 qhia cov duab tawg. Lub crushing kev nyuaj siab nyob rau hauv lub hnab ntawv, yuav tsum tau rau shearing kawg ntawm nplooj ntawv, yuav ua tau rau e < 2,5d prikazati obrascem σlB = σB e/d. Širina b je bez primetnog uticaja na jačinu gnječenja po omotaču rupe, σB je jačina na kidanje spojenih limova.
Daim duab. 5 - Hom pob txha
Keeb Kwm Rivet Txoj Cai
Rivet Spacing. Rivet spacing e (wheelbase) yog txwv downwards vim yooj yim riveting, siab siab peaks thiab txo qhov tsis kam. Qhov siab tshaj plaws qhov sib txawv ntawm cov rivets yog txwv, yog li cov khoom sib txuas yuav tsum tsis txhob qhib vim muaj kev pheej hmoo ntawm xeb, thiab cov nplooj ntawv yuav tsum tau khoov rau hauv siab. Qhov kev ncua deb tshaj plaws nyob ntawm daim ntawv thickness t. Qhov ib txwm rivet qhov sib txawv rau cov choj kev tsheb ciav hlau thiab lwm cov qauv hlau sib txawv hauv qee qhov kev txwv. Qhov kev ncua deb ntawm qhov kawg yog e1, thiab nws yog nyob rau hauv kev coj ntawm lub zog. Qhov kev ncua deb ntawm qhov kawg e2 yog perpendicular mus rau qhov kev taw qhia ntawm kev quab yuam.
Position of rivets. Cov rivets feem ntau yog teem rau hauv cov qauv rivet tsis tu ncua thiab muab tso rau hauv cov kab ncaj nraim tom qab ib leeg. Nrog rau qhov dav dav, ntau kab ntawm rivets xav tau (daim duab.6), qhov twg lub rooj yuav tsum tau ua raws1. Rau cov txheej txheem sab hauv rivets ntawm dav nro rods, nws tuaj yeem nce mus txog ob npaug ntawm qhov tseem ceeb ntawm lub rooj.1.
Sl.6
Sl.7- Piv txwv ntawm rivets rau profiled steel
Screws thiab plugs
Cov ntsia hlau yuav luag txhua zaus siv hauv kev tsim kho qhov twg nws yog qhov tsim nyog los tiv thaiv kev sib txuas. Bolts ua los ntawm cov khoom siv zoo yuav tsum xa cov quab yuam los ntawm kev sib txhuam, thaum lub zog shear thiab compressive stresses ntawm lub plhaub ntsaws tsis ua rau muaj txiaj ntsig zoo. Hauv cov qauv steel, screws nrog metric threads yog siv. Cov kev cai rau kev thov screws sib haum rau cov rivets ntawm tib lub qhov taub d. Txawm li cas los xij, qhov deb tsawg tshaj plaws yuav tsum tsis txhob tsawg dua e =3,5d ,zoo4d. Lwm qhov kev ncua deb, cov hauv paus hniav thiab kev ntsuas linear yog tib yam li rau rivets. Cov bolts yuav tsum tau sib txuas ntxiv los ntawm ib leeg tshaj li cov rivets, vim qhov xav tau ntau dua rau qhov chaw rau cov txiv ntseej thiab ntsia liaj qhov rooj.
Rau kev tsim kho steel, feem ntau yog cov ntaub ntawv hauv qab no tau txiav txim siab:
_Raw hex bolts: _ muaj hex txiv ntseej thiab lub tshuab ntxhua khaub ncaws xov kab d =10rau33 mmnrog qhov diameters d1=11rau34 mm. Cov screws no tsuas yog machined nyob rau hauv threads, yog li koj yuav tsum xam nrog ib tug clearance ntawm0,5rau2 mmnruab nrab ntawm lub cev thiab lub qhov. Kev saib xyuas yuav tsum tau ua nrog lub zog siab dua vim tias kev sib txuas bolted feem ntau pom muaj qhov deformation ntau.
Daim duab. 8 - Screw
Screws: lawv qhov ntev sib haum rau cov tawv hex ntsia hlau, tab sis lawv muaj lub cev cylindrical uas tau ua tiav kom lawv sau lub qhov zoo. Fitted screws hloov cov raw khoom thaum loj zog yuav tsum tau kis los yog thaum tsiv nyob rau hauv kev sib txuas yuav tsum nyob twj ywm nyob rau hauv me me txwv.
Backing plates: Cov ntsia hlau yog siv nrog cov ntawv thaub qab. Lub thickness ntawm lub phaj nyob ntawm qhov loj ntawm cov ntsia hlau siv.
Markings: cov cim, qhov thiab qhov loj me yog muab rau hauv cov lus hauv qab no:
Daim duab. 9 - Screw marks
Static stress ntawm tus kheej screws
Shear Connections: Lub xeev kev ntxhov siab hauv kev sib txuas bolted zoo ib yam li hauv kev sib txuas riveted. Thaum dimensioning, nws yog xam nrog qhov nruab nrab qhov tseem ceeb ntawm shear stress τm thiab lub siab ntawm lub casing ntawm lub qhov σlm. Nws yog paub tias lub siab ntawm lub casing ntawm lub qhov nce ntau heev thaum cov threads nkag mus rau hauv lub qhov, uas yuav tsum tau zam.
Cov kev sib txhuam tsis sib haum nyob rau hauv ib txwm sib txuas nrog cov ntsia hlau yog qis dua hauv cov khoom siv riveted, vim hais tias thaum tuav cov txiv ntseej, tsuas yog me me zawm zog tuaj yeem ua tiav. Tightening ntau dhau yuav ua rau cov xov puas. Nws yog hais txog tus nqi siab ntawm cov ntsia hlau uas ua rau muaj kev sib txhuam hauv kev sib txuas tseem ceeb heev rau lawv tus cwj pwm.
Lub zog shear ntawm haum cylindrical plugs yog tib yam li cov rivets. Kev kuaj kua muag zoo li qub tsis tuaj yeem, nyob rau hauv ib txwm muaj xwm txheej, txiav txim siab qhov sib txawv ntawm cov ntsaws ruaj ruaj thiab rivets nyob rau hauv cov nqe lus ntawm compressive zog ib lub hnab ntawv. Thaum lub sij hawm qaug zog loading, qhov proportionally qis frictional kuj yog qhov ua rau ntawm tus cwj pwm txawv ntawm kev sib txuas nrog screws.
Crude screws muaj qis dua nyob rau hauv shear-loaded sib txuas mus txog 20% vim qhov sib txawv ntawm lub qhov thiab cov ntsia hlau lub cev. Vim li no, qhov kev tso cai kev ntxhov siab rau cov ntsia hlau nyoos yog qis dua rau cov khoom haum. Rau qhov loj me, qhov tseeb kab ntawm lub cev yuav tsum tau noj d.
Cov kaus mom sib koom
Lub kaus mom sib koom ua ke muab kev sib txuas tiv thaiv kom nruj thiab siab, qhov twg cov khoom sib txuas tuaj yeem tig tau. Daim ntawv thov ntawm cov pob qij txha ntawm Gerber kev txhawb nqa, tshem tawm cov hlua khi ntawm cov hlua txuas txuas txuas, kev sib txuas ntawm cov tensioned rods nyob rau hauv daim ntawv ntawm cov pob qij txha, thiab lwm yam. Grids nrog kev sib txuas ntawm cov pob qij txha ntawm cov pob qij txha, thiaj li hu ua. bridges nrog corks yuav luag tsis ua ntxiv lawm. Kev sib txhuam siab, uas tshwm sim ntawm cov ntsaws ruaj ruaj, tiv thaiv kev txav mus los, thaum kev sib hloov kev sib hloov tsuas yog ua tiav nrog lub sijhawm loj dua.
Daim duab. 10 - Caps, a) cap nrog ntsia hlau; b) cork nrog cais; c) ntsaws ntawm ib tug ncua kev kawm ntawv choj
Cov kev ntxhov siab hauv lub ntsaws yog feem ntau zoo li cov kev sib txuas riveted. Cov plugs yog li dimensioned raws li qhov nruab nrab shear stress τm thiab qhov nruab nrab compressive kev nyuaj siab ib lub hnab ntawv σlm. Txij li thaum cov plugs yuav tsum tau yooj yim tig, txawm li cas los xij, σlm yog noj tsawg dua. Khoov kev ntxhov siab hauv cov plugs feem ntau tsis tseem ceeb, tab sis lawv tuaj yeem ncav cuag qhov tseem ceeb thaum cov khoom sib koom ua ke yog cov concentrated heev.
Cov txheej txheem kev suav tam sim no, cov ntaub ntawv sib koom ua ke thiab cov ntaub ntawv ua haujlwm ntawm tus kws tshaj lij raug tso cai yog siv rau txhua yam khoom tiag. Cov ntawv no yog khaws cia ua ib qho kev kawm keeb kwm.