M'mapangidwe osiyanasiyana, mainjiniya angafunikire kuwunika mphamvu ya ma welds ndi zomangira zamakina.Masiku ano, zomangira zamakina nthawi zambiri zimakhala ma bawuti, koma mapangidwe akale amatha kukhala ndi ma rivets.
Izi zitha kuchitika pakukweza, kukonzanso, kapena kupititsa patsogolo ntchito.Kapangidwe katsopano kangafunike kutchingira ndi kuwotcherera kuti agwire ntchito limodzi pomwe zinthu zomwe zilumikizidwe zimalumikizidwa kaye kenako ndikuwotcherera kuti zipereke mphamvu zonse zolumikizana.
Komabe, kudziwa kuchuluka kwa katundu wa olowa sikophweka monga kuwonjezera kuchuluka kwa magawo omwewo (welds, bolts, ndi rivets).Kulingalira koteroko kungadzetse zotulukapo zowopsa.
Kulumikizika kwa bolted kumafotokozedwa mu American Institute of Steel Structures (AISC) Structural Joint Specification, yomwe imagwiritsa ntchito mabawuti a ASTM A325 kapena A490 ngati phiri lolimba, lolowetsa, kapena kiyi yotsetsereka.
Limbani zolumikizira zolimba kwambiri ndi wrench kapena locksmith pogwiritsa ntchito wrench yambali ziwiri kuti muwonetsetse kuti zigawozo zikugwirizana kwambiri.Pakulumikizana kolimba, ma bolt amayikidwa kuti azitha kunyamula katundu wambiri, ndipo mbalezo zimangolemedwa.
1. Tembenuzani mtedza.Njira yosinthira nati imaphatikizapo kumangitsa bawuti ndiyeno kutembenuza natiyo kuchuluka kowonjezera, zomwe zimadalira m'mimba mwake ndi kutalika kwa bawuti.
2. Sanjani kiyi.Njira yolumikizira ma wrench imayesa torque yomwe imalumikizidwa ndi kugwedezeka kwa bawuti.
3. Torsion mtundu tension kusintha bawuti.Maboti opindika amakhala ndi timizere tating'ono kumapeto kwa bawuti moyang'anizana ndi mutu.Pamene torque yofunikira ifika, stud imachotsedwa.
4. Mlozera wachikoka wowongoka.Zizindikiro zowongoka zachindunji ndi ma washer apadera okhala ndi ma tabu.Kuchuluka kwa kupanikizana pa lug kumawonetsa kuchuluka kwa zovuta zomwe zimagwiritsidwa ntchito pa bawuti.
M'mawu a layman, mabawuti amakhala ngati mapini olumikizana olimba komanso okhazikika, monga pini yamkuwa yonyamula mulu wa pepala lobowoka pamodzi.Magulu otsetsereka ofunikira amagwira ntchito mokangana: kuyika patsogolo kumapangitsa kuti pakhale mphamvu, ndipo mikangano pakati pa malo olumikiziranawo imagwirira ntchito limodzi kukana kutsetsereka kwa olowa.Zili ngati chomangira chomwe chimagwirizira mulu wa mapepala pamodzi, osati chifukwa mabowo abowoledwa papepala, koma chifukwa chakuti chomangiracho chimakanikizira pamodzi mapepalawo ndipo kugundana kumagwirizanitsa muluwo.
Mabawuti a ASTM A325 ali ndi mphamvu yocheperako ya 150 mpaka 120 kg pa mainchesi lalikulu (KSI), kutengera kukula kwa bawuti, pomwe mabawuti a A490 ayenera kukhala ndi mphamvu zolimba za 150 mpaka 170-KSI.Malumikizidwe a Rivet amakhala ngati malo olimba kwambiri, koma pakadali pano, mapiniwo ndi ma rivets omwe amakhala pafupifupi theka lamphamvu ngati bawuti ya A325.
Chimodzi mwa zinthu ziwiri zimatha kuchitika ngati cholumikizira cholumikizidwa mwamakina chimagwiritsidwa ntchito ndi mphamvu zometa ubweya (pamene chinthu chimodzi chimakonda kutsetsereka chifukwa cha mphamvu yogwiritsidwa ntchito).Ma bolts kapena ma rivets amatha kukhala m'mbali mwa mabowo, zomwe zimapangitsa kuti ma bolts kapena ma rivets ametedwe nthawi imodzi.Kuthekera kwachiwiri ndikuti mikangano yobwera chifukwa cha kukakamiza kwa zomangira zongoyerekeza zimatha kupirira katundu wometa ubweya.Palibe kutsetsereka komwe kumayembekezereka pakulumikizana uku, koma ndizotheka.
Kulumikizana kolimba ndikovomerezeka pamapulogalamu ambiri, chifukwa kutsetsereka pang'ono sikungawononge mawonekedwe a kulumikizanako.Mwachitsanzo, taganizirani nkhokwe yosungiramo zinthu za granular.Pakhoza kukhala kuterera pang'ono potsegula koyamba.Kutsetsereka kukangochitika, sizichitikanso, chifukwa katundu wotsatira ndi wofanana.
Kubweza katundu kumagwiritsidwa ntchito m'mapulogalamu ena, monga zinthu zozungulira zikakhala ndi katundu wosinthasintha komanso wopanikiza.Chitsanzo china ndi chinthu chopindika chomwe chimakhala ndi katundu wolemetsa.Pakakhala kusintha kwakukulu pamayendedwe onyamula katundu, kulumikizana komwe kudalowetsedwa kumatha kufunikira kuti muchepetse kutsika kwa cyclic.Kutsetsereka kumeneku pamapeto pake kumabweretsa kutsetsereka kochulukira m'mabowo aatali.
Magulu ena amakhala ndi zozungulira zambiri zomwe zingayambitse kutopa.Izi zikuphatikizapo makina osindikizira, zothandizira crane ndi malumikizidwe mu milatho.Malumikizidwe otsetsereka ofunikira amafunikira pamene kugwirizanako kuli ndi katundu wotopa mozungulira.Pazikhalidwe zamtunduwu, ndikofunikira kwambiri kuti cholumikizira chisasunthike, chifukwa chake pamafunika kulumikizana kofunikira.
Malumikizidwe omwe alipo atha kupangidwa ndikupangidwa mogwirizana ndi ili yonse mwa miyezo iyi.Kulumikizana kwa Rivet kumaonedwa kuti ndi kolimba.
Ma welded olowa ndi olimba.Zolumikizana za solder ndizovuta.Mosiyana ndi zomangira zolimba zolimba, zomwe zimatha kutsika pansi pa katundu, zowotcherera siziyenera kutambasula ndikugawa katundu wogwiritsidwa ntchito kwambiri.Nthawi zambiri, ma welded ndi kubala mtundu makina fasteners musati deform chimodzimodzi.
Pamene ma welds amagwiritsidwa ntchito ndi zomangira zamakina, katunduyo amasamutsidwa kudzera mu gawo lolimba kwambiri, kotero kuti weld amatha kunyamula pafupifupi katundu wonse, ndikugawana pang'ono ndi bolt.Ichi ndichifukwa chake kusamala kuyenera kuchitidwa pakuwotcherera, kuwotcherera ndi kuwotcherera.Zofotokozera.AWS D1 imathetsa vuto lakusakaniza zomangira zamakina ndi ma welds.Mfundo 1: 2000 pakuwotcherera kwamapangidwe - chitsulo.Ndime 2.6.3 ikunena kuti ma rivets kapena mabawuti omwe amagwiritsidwa ntchito pazolumikizana zamtundu wamtundu (ie pomwe bolt kapena riveti imagwira ntchito ngati pini), zomangira zamakina siziyenera kuganiziridwa kuti zimagawana katundu ndi weld.Ngati kuwotcherera kukugwiritsidwa ntchito, ziyenera kuperekedwa kuti zinyamule katundu wathunthu mu mgwirizano.Komabe, zolumikizira zowotcherera ku chinthu chimodzi ndi zokongoletsedwa kapena zomangirira ku chinthu china zimaloledwa.
Mukamagwiritsa ntchito zomangira zamakina ndi kuwonjezera ma welds, mphamvu yonyamula katundu ya bawuti imanyalanyazidwa.Malinga ndi makonzedwe awa, weld ayenera kupangidwa kusamutsa katundu onse.
Izi ndizofanana ndi AISC LRFD-1999, clause J1.9.Komabe, muyezo wa ku Canada CAN/CSA-S16.1-M94 umalolanso kugwiritsa ntchito kudziyimira pawokha pomwe mphamvu ya chomangira kapena bawuti ndi yapamwamba kuposa yowotcherera.
Pankhani iyi, njira zitatu ndizofanana: kuthekera kwa zomangira zamakina zamtundu wonyamula komanso kuthekera kwa welds sikuwonjezera.
Gawo 2.6.3 la AWS D1.1 limakambirananso za zochitika zomwe ma bolts ndi welds angaphatikizidwe mumagulu awiri, monga momwe tawonetsera pa Chithunzi 1. Ma welds kumanzere, otsekedwa kumanja.Mphamvu zonse za welds ndi ma bolts zitha kuganiziridwa pano.Gawo lirilonse la mgwirizano wonse limagwira ntchito palokha.Choncho, malamulowa ndi osiyana ndi mfundo yomwe ili mu gawo loyamba la 2.6.3.
Malamulo omwe takambiranawa amagwira ntchito ku nyumba zatsopano.Pazinthu zomwe zilipo kale, ndime 8.3.7 D1.1 imati pamene kuwerengera kwapangidwe kumasonyeza kuti rivet kapena bolt idzalemedwa ndi katundu watsopano, katundu wokhazikika yekha ndi amene ayenera kuperekedwa kwa izo.
Malamulo omwewo amafuna kuti ngati rivet kapena bawuti ingolemedwa ndi katundu wokhazikika kapena kunyamula katundu wa cyclic (kutopa), zitsulo zokwanira zoyambira ndi ma welds ziyenera kuwonjezeredwa kuti zithandizire katundu wonse.
Kugawidwa kwa katundu pakati pa zomangira zamakina ndi ma welds ndikovomerezeka ngati kapangidwe kake kadayikidwa kale, mwa kuyankhula kwina, ngati kutsika kwachitika pakati pa zinthu zolumikizidwa.Koma katundu wokhazikika okha ndi omwe angayikidwe pazitsulo zamakina.Katundu wamoyo womwe ungayambitse kutsetsereka kwakukulu uyenera kutetezedwa ndi kugwiritsa ntchito ma welds omwe amatha kupirira katundu wonse.
Ma welds ayenera kugwiritsidwa ntchito kupirira zonse zomwe zimagwiritsidwa ntchito kapena zosinthika.Zomangira zamakina zikadzaza kale, kugawana katundu sikuloledwa.Pansi pa kutsitsa kwa cyclic, kugawana katundu sikuloledwa, chifukwa katunduyo angayambitse kutsetsereka kosatha ndi kudzaza kwa weld.
fanizo.Ganizirani zolumikizira zingwe zomwe zidamangidwa molimba (onani Chithunzi 2).Mapangidwewo amawonjezera mphamvu zowonjezera, ndipo zolumikizira ndi zolumikizira ziyenera kuwonjezeredwa kuti zipereke mphamvu ziwiri.Pa mkuyu.3 ikuwonetsa dongosolo loyambira pakulimbitsa zinthu.Kodi mgwirizano uyenera kupangidwa bwanji?
Popeza chitsulo chatsopanocho chinayenera kulumikizidwa ku chitsulo chakale ndi ma welds a fillet, injiniyayo adaganiza zowonjezera zowotcherera za fillet pa olowa.Popeza kuti ma bolts adakalipo, lingaliro lapachiyambi linali lowonjezera zowotcherera zokhazokha zomwe zimafunikira kuti zisamutsire mphamvu zowonjezera kuzitsulo zatsopano, kuyembekezera kuti 50% ya katunduyo adutse ma bolts ndi 50% ya katunduyo kuti adutse ma welds atsopano.Ndizovomerezeka?
Tiyeni tiyambe kuganiza kuti palibe zolemetsa zomwe zimagwiritsidwa ntchito pa intaneti.Pankhaniyi, ndime 2.6.3 ya AWS D1.1 ikugwira ntchito.
M'magulu amtundu wamtundu uwu, weld ndi bawuti sizingaganizidwe kuti zimagawana katunduyo, kotero kukula kwake komwe kumayenera kukhala kokwanira kumathandizira katundu wokhazikika komanso wokhazikika.Kulemera kwa ma bolts mu chitsanzo ichi sikungaganizidwe, chifukwa popanda katundu wokhazikika, kugwirizanako kudzakhala kopanda pake.Chowotcherera (chopangidwa kuti chinyamule theka la katundu) poyamba chimasweka pamene katundu wathunthu agwiritsidwa ntchito.Kenako bolt, yomwe idapangidwanso kusamutsa theka la katunduyo, imayesa kusamutsa katunduyo ndikusweka.
Komanso ganizirani kuti static load ikugwiritsidwa ntchito.Kuonjezera apo, zimaganiziridwa kuti kugwirizana komwe kulipo ndikokwanira kunyamula katundu wokhazikika.Pamenepa, ndime 8.3.7 D1.1 ikugwira ntchito.Ma welds atsopano amangofunika kupirira kuchuluka kwachulukidwe kokhazikika komanso kokhazikika.Katundu wakufa womwe ulipo ukhoza kuperekedwa kwa zomangira zomwe zilipo kale.
Pansi pa katundu wokhazikika, kugwirizana sikugwedezeka.M'malo mwake, mabawuti amanyamula kale katundu wawo.Pakhala pali kusokonekera polumikizana.Chifukwa chake, ma welds angagwiritsidwe ntchito ndipo amatha kutumiza katundu wosinthika.
Yankho la funso lakuti "Kodi izi ndizovomerezeka?"zimatengera katundu katundu.Pachiyambi choyamba, ngati palibe static katundu, yankho lidzakhala loipa.Pansi pa zochitika zenizeni za chochitika chachiwiri, yankho ndi inde.
Chifukwa chakuti katundu wa static akugwiritsidwa ntchito, sizingatheke kufotokoza mfundo.Mlingo wa static katundu, kukwanira kwa kugwirizana kwa makina omwe alipo kale, ndi chikhalidwe cha katundu wotsiriza-kaya static kapena cyclic-angasinthe yankho.
Duane K. Miller, MD, PE, 22801 Saint Clair Ave., Cleveland, OH 44117-1199, Welding Technology Center Manager, Lincoln Electric Company, www.lincolnelectric.com.Lincoln Electric imapanga zida zowotcherera ndi zowotcherera padziko lonse lapansi.Akatswiri a Welding Technology Center ndi akatswiri amathandizira makasitomala kuthana ndi zovuta zowotcherera.
American Welding Society, 550 NW LeJeune Road, Miami, FL 33126-5671, foni 305-443-9353, fax 305-443-7559, webusaiti ya www.aws.org.
ASTM Intl., 100 Barr Harbour Drive, West Conshohocken, PA 19428-2959, phone 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, foni 312-670-2400, fax 312-670-5403, webusaiti ya www.aisc.org.
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