Kwiimeko ezahlukeneyo zolwakhiwo, iinjineli zinokudinga ukuvavanya ukomelela kwamalungu enziwe zii-welds kunye ne-fasteners yoomatshini.Namhlanje, iziqhoboshi zoomatshini zihlala zizibholiti, kodwa uyilo oludala lunokuba neerivethi.
Oku kunokwenzeka ngexesha lokuphucula, ukulungiswa, okanye ukuphuculwa kweprojekthi.Uyilo olutsha lunokufuna ibholithi kunye ne-welding ukuze isebenze kunye kwindawo edibeneyo apho izinto eziza kudibaniswa ziqale ziboshwe kunye kwaye zidibanise ukunika amandla apheleleyo kwi-joint.
Nangona kunjalo, ukugqiba umthamo opheleleyo womthwalo wejoyinti akukho lula njengokudibanisa isixa samacandelo ngamnye (i-welds, iibholiti, kunye ne-rivets).Ingcinga enjalo inokukhokelela kwimiphumo eyintlekele.
Ukudityaniswa kweBolted kuchazwe kwi-American Institute of Steel Structures (AISC) iNkcazo yeSakhiwo esiHlangeneyo, esebenzisa i-ASTM A325 okanye i-A490 iibholiti njenge-tight mount, preload, okanye isitshixo sesilayidi.
Qinisa uqhagamshelo oluqiniweyo ngesitshixo esinempembelelo okanye isitshixo usebenzisa isitshixo esinamacala amabini ukuze uqinisekise ukuba iileya zibambene ngokuqinileyo.Kuxhulumaniso olugxininisiweyo, iibholiti zifakwe ukwenzela ukuba zibe phantsi kwemithwalo ebalulekileyo yobunzima, kwaye iiplate ziphantsi kwemithwalo yoxinzelelo.
1. Jika i-nut.Indlela yokuguqula i-nut ibandakanya ukuqinisa i-bolt kwaye emva koko uguqule i-nut inani elongezelelweyo, elixhomekeke kububanzi kunye nobude bebholiti.
2. Linganisa isitshixo.Indlela yokulinganisa i-wrench ilinganisa i-torque ehambelana noxinzelelo lwebholithi.
3. Ibholithi yohlengahlengiso loxinzelelo lohlobo lweTorsion.Iibholithi ezijijekileyo zineentsimbi ezincinci ekupheleni kwebholithi ejongene nentloko.Xa i-torque efunekayo ifikelelwe, i-stud ikhutshwe.
4. Isalathisi sokutsala ngokuthe tye.Izalathi zoxinzelelo oluthe ngqo ziziwasha ezikhethekileyo ezineethebhu.Ubungakanani boxinzelelo kwi-lug bubonisa izinga loxinzelelo olufakwe kwi-bolt.
Ngokwemigaqo yabantu abaqhelekileyo, iibholithi zisebenza njengezikhonkwane ezidityanisiweyo kunye namalungu adityaniswe ngaphambili, okufana nentsimbi yobhedu ebambe isipaki sephepha elinemingxuma kunye.Amalungu okutyibilika abalulekileyo asebenza ngokukhuhlana: ukulayishwa kwangaphambili kudala ukunyanzeliswa, kwaye ukukhuhlana phakathi kweendawo zoqhagamshelwano zisebenza kunye ukuxhathisa ukutyibilika komdibaniso.Kufana nomdibanisi obamba amaphepha ndawonye, ​​kungekhona ngenxa yokuba imingxuma igqojozwa ephepheni, kodwa ngenxa yokuba i-binder icofa amaphepha kunye kunye nokukhuhlana kubambe isitaki kunye.
Iibholiti ze-ASTM A325 zinamandla asezantsi e-150 ukuya kwi-120 kg nge-intshi nganye yesikwere (KSI), ngokuxhomekeke kwidayamitha yebholithi, ngelixa iibholiti ze-A490 kufuneka zibe namandla okuqina ka-150 ukuya kwi-170-KSI.Amalungu eRivet aziphatha ngakumbi njengamajoyinti aqinileyo, kodwa kule meko, izikhonkwane ziirivethi eziqhelekile malunga nesiqingatha somelele njenge-A325 bolt.
Enye yezinto ezimbini inokwenzeka xa umdibaniso obotshelelwe ngoomatshini uphantsi kwamandla okucheba (xa into ethile ithanda ukutyibilika phezu kwenye ngenxa yamandla asetyenziswayo).Iibholiti okanye iirivethi zinokuba kumacala emingxuma, zibangele ukuba iibholiti okanye iirivethi zichetywe ngaxeshanye.Okwesibini okunokwenzeka kukuba ukukhuhlana okubangelwa amandla okubamba i-fasteners eyenziwe ngathi inokumelana nemithwalo yokucheba.Akukho kutyibilika kulindelweyo kolu xhulumaniso, kodwa kuyenzeka.
Uqhagamshelo oluluqilima lwamkelekile kwizicelo ezininzi, njengoko ukutyibilika okuncinci akunakuchaphazela kakubi iimpawu zoqhagamshelo.Ngokomzekelo, qwalasela isisele esenzelwe ukugcina imathiriyeli yegranular.Kusenokubakho ukutyibilika okuncinci xa ulayisha okokuqala.Nje ukuba ukutyibilika kwenzeke, akusayi kuphinda kwenzeke, kuba yonke imithwalo elandelayo ikwimo efanayo.
Ukubuyiselwa umva komthwalo kusetyenziswa kwezinye iinkqubo, njengaxa izinto ezijikelezayo ziphantsi kokutshintshana kwe-tensile kunye nemithwalo ecinezelayo.Omnye umzekelo yinto yokugoba ephantsi kwemithwalo ebuyela umva ngokupheleleyo.Xa kukho utshintsho olubalulekileyo kwicala lomthwalo, uqhagamshelo olulayishwe kwangaphambili lunokufuneka ukuphelisa ukutyibilika kwebhayisikile.Oku kutyibilika ekugqibeleni kukhokelele ekutyibilikeni ngakumbi kwimingxuma emide.
Amanye amalungu afumana imijikelo emininzi yomthwalo enokukhokelela ekudinweni.Ezi ziquka ii-presses, i-crane inkxaso kunye nokudibanisa kwiibhulorho.Ukudibanisa ukudibanisa okubalulekileyo kuyafuneka xa uxhulumaniso luxhomekeke kwimithwalo yokudinwa kwicala elingasemva.Kwezi ntlobo zeemeko, kubaluleke kakhulu ukuba i-joint ayityibiliki, ngoko ke kufuneka i-slip-critical joints.
Imidibaniso ekhoyo ebholithiweyo inokuyilwa kwaye yenziwe kuyo nayiphi na le migangatho.Uqhagamshelo lwe-rivet luthathwa njengoluqilima.
Amalungu adityanisiweyo aqinile.Amalungu e-Solder akhohlisayo.Ngokungafaniyo nokudibanisa okuqinileyo, okunokuthi kuhla phantsi komthwalo, i-welds ayifuni ukunweba kwaye isasaze umthwalo osetyenzisiweyo kumlinganiselo omkhulu.Kwiimeko ezininzi, i-welded kunye ne-bearing type fasteners ayiguquki ngendlela efanayo.
Xa i-welds isetyenziswe kunye ne-fasteners yomatshini, umthwalo udluliselwa ngenxalenye enzima, ngoko i-weld inokuthwala phantse yonke imithwalo, kunye nencinci ekwabelwana ngayo kunye nebholiti.Yiyo loo nto kufuneka kuthathelwe ingqalelo xa ufaka i-welding, i-bolting kunye ne-riveting.Iinkcukacha.I-AWS D1 isombulula ingxaki yokuxuba i-fasteners mechanical kunye ne-welds.Inkcazo 1: 2000 ye-welding yesakhiwo - intsimbi.Umhlathi 2.6.3 uchaza ukuba kwiirivets okanye iibholithi ezisetyenziselwa ukuhlanganisa uhlobo lwe-bearing-type (okt apho ibholithi okanye i-rivet isebenza njengephini), izibophelelo zomatshini akufanele ziqwalaselwe ukwabelana nomthwalo kunye ne-weld.Ukuba i-welding isetyenzisiweyo, kufuneka inikezelwe ukuthwala umthwalo opheleleyo kwindawo edibeneyo.Nangona kunjalo, uqhagamshelo oludityanisiweyo ludityaniswe nelinye kwaye lubotshwe okanye lubotshelelwe kwenye into luvumelekile.
Xa usebenzisa i-bearing-type fasteners mechanical kunye nokongeza i-welds, umthamo womthwalo we-bolt awuhoywa kakhulu.Ngokwalo malungiselelo, i-weld kufuneka yenzelwe ukudlulisa yonke imithwalo.
Oku kuyafana ne-AISC LRFD-1999, igatya J1.9.Nangona kunjalo, umgangatho waseKhanada we-CAN/CSA-S16.1-M94 uphinde uvumele ukusetyenziswa kwe-stand-alone xa amandla e-fastener yomatshini okanye i-bolt iphezulu kune-welding.
Kulo mbandela, iikhrayitheriya ezintathu zihambelana: amathuba okubopha oomatshini bohlobo lokuthwala kunye namathuba e-welds awadibanisi.
Icandelo 2.6.3 le-AWS D1.1 lixubusha kwakhona iimeko apho iibholithi kunye ne-welds zinokudibaniswa kwi-joint-part-part, njengoko kuboniswe kuMzobo 1. Ii-Welds ngakwesobunxele, ziboshwe ngakwesokudla.Amandla apheleleyo e-welds kunye neebholiti angaqwalaselwa apha.Inxalenye nganye yoxhulumaniso lonke lusebenza ngokuzimeleyo.Ngaloo ndlela, le khowudi ihlukile kumgaqo oqulethwe kwinxalenye yokuqala ye-2.6.3.
Le migaqo isandul’ ukuxoxwa isebenza kwizakhiwo ezitsha.Kwizakhiwo ezikhoyo, igatya 8.3.7 D1.1 lichaza ukuba xa izibalo zesakhiwo zibonisa ukuba i-rivet okanye ibholithi iya kulayishwa ngokugqithisileyo ngumthwalo omtsha opheleleyo, ngumthwalo okhoyo kuphela omele unikezelwe kuwo.
Imithetho efanayo ifuna ukuba i-rivet okanye i-bolt igcwele kuphela imithwalo ye-static okanye ixhomekeke kwi-cyclic (ukukhathala) imithwalo, isiseko esaneleyo sentsimbi kunye ne-welds kufuneka yongezwe ukuxhasa umthwalo opheleleyo.
Ukuhanjiswa komthwalo phakathi kwe-fasteners yomatshini kunye ne-welds kuyamkeleka ukuba isakhiwo silayishwe ngaphambili, ngamanye amagama, ukuba i-slippage yenzeke phakathi kwezinto ezidibeneyo.Kodwa imithwalo ye-static kuphela inokubekwa kwii-fasteners zoomatshini.Imithwalo ephilayo enokukhokelela kwi-slippage enkulu kufuneka ikhuselwe ngokusetyenziswa kwee-welds ezikwaziyo ukumelana nomthwalo wonke.
Iiwelds kufuneka zisetyenziswe ukumelana nazo zonke izinto ezifakiweyo okanye eziguqukayo.Xa izibophelelo zoomatshini sele zigcwele, ukwabelana ngomthwalo akuvumelekanga.Ngaphantsi kokulayishwa kwe-cyclic, ukwabelana komthwalo akuvumelekanga, ekubeni umthwalo unokukhokelela kwi-slippage esisigxina kunye nokugqithiswa kwe-weld.
umzekeliso.Qwalasela umjikelo owawubotshelelwe ngokuqinileyo ekuqaleni (jonga uMfanekiso 2).Isakhiwo songeza amandla angaphezulu, kwaye ukudibanisa kunye nezixhumi kufuneka zongezwe ukunika amandla aphindwe kabini.Kwikhiwane.I-3 ibonisa isicwangciso esisisiseko sokuqinisa izinto.Uqhagamshelwano kufuneka lwenziwe njani?
Ekubeni intsimbi entsha kwakufuneka idityaniswe nentsimbi endala ngeentsimbi zentsimbi, injineli yagqiba ekubeni yongeze iintsimbi zokudityaniswa kwefillet.Ekubeni iibholiti zazisekho, ingcamango yokuqala yayiyokongeza kuphela i-welds efunekayo ukuhambisa amandla angaphezulu kwintsimbi entsha, ilindele ukuba i-50% yomthwalo ihambe ngeebholiti kunye ne-50% yomthwalo wokuhamba nge-welds entsha.Yamkelekile?
Masiqale sicinge ukuba akukho mithwalo engatshintshiyo esetyenziswayo ngoku kuqhagamshelo.Kule meko, umhlathi 2.6.3 we-AWS D1.1 uyasebenza.
Kolu didi lokuthwala oludibeneyo, i-weld kunye ne-bolt ayinakuqwalaselwa ukwabelana nomthwalo, ngoko ke ubungakanani obuchaziweyo be-weld kufuneka bube bukhulu ngokwaneleyo ukuxhasa yonke i-static kunye nomthwalo oguqukayo.Umthamo wokuthwala iibholiti kulo mzekelo awunakuthathelwa ingqalelo, kuba ngaphandle komthwalo we-static, uxhulumaniso luya kuba kwimeko ye-slack.I-weld (eyenzelwe ukuthwala isiqingatha somthwalo) iqala ukugqabhuka xa kufakwe umthwalo opheleleyo.Emva koko i-bolt, nayo eyenzelwe ukuhambisa isiqingatha somthwalo, izama ukudlulisa umthwalo kunye nokuphuka.
Ngokubhekele phaya cinga ukuba kufakwe umthwalo ongatshintshiyo.Ukongezelela, kucingelwa ukuba uxhulumaniso olukhoyo lwanele ukuthwala umthwalo okhoyo okhoyo.Kule meko, umhlathi 8.3.7 D1.1 uyasebenza.Iiweld ezintsha zifuna kuphela ukumelana nokwanda kwe-static kunye nemithwalo ephilayo jikelele.Imithwalo efileyo ekhoyo inokwabelwa kwizibophelelo zoomatshini ezikhoyo.
Ngaphantsi komthwalo oqhubekayo, uxhulumaniso alunciphisi.Kunoko, iibholithi sele ziwuthwele umthwalo wazo.Kubekho ukutyibilika kuqhagamshelwano.Ke ngoko, iiwelds zinokusetyenziswa kwaye zinokuthumela imithwalo eguqukayo.
Impendulo kumbuzo othi "Ngaba oku kwamkelekile?"kuxhomekeke kwiimeko zomthwalo.Kwimeko yokuqala, ngokungabikho komthwalo omileyo, impendulo iya kuba yimbi.Phantsi kweemeko ezithile zemeko yesibini, impendulo nguewe.
Kungenxa yokuba kufakwe umthwalo ongatshintshiyo, akusoloko kunokwenzeka ukwenza isigqibo.Umgangatho wemithwalo ye-static, ukwanela koxhumo lwemishini ekhoyo, kunye nohlobo lwemithwalo yokugqibela-nokuba i-static okanye i-cyclic-inokutshintsha impendulo.
UDuane K. Miller, MD, PE, 22801 Saint Clair Ave., Cleveland, OH 44117-1199, uMphathi weZiko leTekhnoloji yeWelding, iLincoln Electric Company, www.lincolnelectric.com.ILincoln Electric yenza izixhobo zokuwelda kunye nezixhobo zokuwelda kwihlabathi liphela.Iinjineli zeZiko leTekhnoloji yeWelding kunye namagcisa anceda abathengi ukusombulula iingxaki zokuwelda.
American Welding Society, 550 NW LeJeune Road, Miami, FL 33126-5671, ifowuni 305-443-9353, fax 305-443-7559, website www.aws.org.
ASTM Intl., 100 Barr Harbour Drive, West Conshohocken, PA 19428-2959, ifowuni 610-832-9585, fax 610-832-9555, website www.astm.org.
American Steel Structures Association, One E. Wacker Drive, Suite 3100, Chicago, IL 60601-2001, ifowuni 312-670-2400, fax 312-670-5403, website www.aisc.org.
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