Muzochitika zosiyanasiyana za kapangidwe kake, mainjiniya angafunike kuwunika mphamvu ya maulumikizidwe opangidwa ndi ma weld ndi ma mechanical fasteners. Masiku ano, ma mechanical fasteners nthawi zambiri amakhala mabolts, koma mapangidwe akale amatha kukhala ndi ma rivets.
Izi zitha kuchitika panthawi yokonzanso, kukonzanso, kapena kukonzanso pulojekiti. Kapangidwe katsopano kangafunike kulumikiza maboliti ndi kuwotcherera kuti zigwirizane pamodzi mu cholumikizira pomwe zinthu zomwe ziyenera kulumikizidwa zimalumikizidwa poyamba pamodzi kenako zimawotcherera kuti zipereke mphamvu zonse ku cholumikiziracho.
Komabe, kudziwa mphamvu yonse ya katundu wa cholumikizira sikophweka monga kuphatikiza kuchuluka kwa zigawo zake (zolumikizira, mabotolo, ndi ma rivets). Kuganiza koteroko kungayambitse zotsatirapo zoopsa.
Malumikizidwe a maboliti afotokozedwa mu American Institute of Steel Structures (AISC) Structural Joint Specification, yomwe imagwiritsa ntchito maboliti a ASTM A325 kapena A490 ngati makiyi olimba, oyika kale, kapena otsetsereka.
Limbitsani zolumikizira zolimba kwambiri pogwiritsa ntchito wrench yokhudza mphamvu kapena locksmith pogwiritsa ntchito wrench yachikhalidwe yokhala ndi mbali ziwiri kuti muwonetsetse kuti zigawozo zikulumikizana bwino. Pa cholumikizira chokhazikika, mabotolo amayikidwa kuti azigwira ntchito yolimba kwambiri, ndipo mbalezo zimagwiridwa ntchito yokakamiza.
1. Tembenuzani nati. Njira yozungulira nati imaphatikizapo kulimbitsa botolo kenako kutembenuza natiyo pang'ono, zomwe zimatengera kukula ndi kutalika kwa botolo.
2. Linganizani kiyi. Njira yolinganizira ya wrench imayesa mphamvu yomwe imagwirizanitsidwa ndi mphamvu ya bolt.
3. Bolodi yosinthira mphamvu ya Torsion. Mabolodi opindika amakhala ndi tinthu tating'ono kumapeto kwa bolodi moyang'anizana ndi mutu. Mphamvu yofunikira ikafika, strodiyo imachotsedwa.
4. Chizindikiro chokoka molunjika. Zizindikiro zoyendetsera mphamvu ndi makina apadera ochapira okhala ndi ma tabu. Kuchuluka kwa kukanikiza pa lug kumasonyeza kuchuluka kwa mphamvu yomwe imagwiritsidwa ntchito pa bolt.
M'mawu a anthu wamba, mabotolo amagwira ntchito ngati mapini m'malo olumikizirana olimba komanso omangika kale, mofanana ndi pini yamkuwa yogwirizira mulu wa mapepala obowoka pamodzi. Mapaipi otsetsereka ofunikira amagwira ntchito chifukwa cha kukangana: kuyika zinthu patsogolo kumabweretsa mphamvu, ndipo kukangana pakati pa malo olumikizirana kumagwira ntchito limodzi kuti kupewe kutsetsereka kwa cholumikizira. Zili ngati chogwirizira chomwe chimagwirizanitsa mulu wa mapepala pamodzi, osati chifukwa mabowo abowoledwa mu pepala, koma chifukwa chogwirizira chimakanikiza mapepala pamodzi ndipo kukangana kumagwirizira mulu pamodzi.
Maboluti a ASTM A325 ali ndi mphamvu yocheperako yogwira ntchito ya 150 mpaka 120 kg pa sikweya mainchesi (KSI), kutengera kukula kwa boluti, pomwe maboluti a A490 ayenera kukhala ndi mphamvu yogwira ntchito ya 150 mpaka 170-KSI. Maboluti a rivet amachita ngati ma boluti olimba, koma pankhaniyi, ma pini ndi ma rivets omwe nthawi zambiri amakhala olimba pafupifupi theka la boluti ya A325.
Chimodzi mwa zinthu ziwiri chingachitike pamene cholumikizira chomangiriridwa ndi makina chikukhudzidwa ndi mphamvu zodula (pamene chinthu chimodzi chimatha kutsetsereka pamwamba pa china chifukwa cha mphamvu yogwiritsidwa ntchito). Mabotolo kapena ma rivets akhoza kukhala m'mbali mwa mabowo, zomwe zimapangitsa kuti ma bolt kapena ma rivets azidula nthawi imodzi. Kuthekera kwachiwiri ndikuti kukangana komwe kumachitika chifukwa cha mphamvu yolumikizira ya zomangira zomwe zimayesedwa kumatha kupirira kudulidwa. Palibe kutsetsereka komwe kukuyembekezeka pa kulumikizana kumeneku, koma n'kotheka.
Kulumikizana kolimba ndikovomerezeka pa ntchito zambiri, chifukwa kutsetsereka pang'ono sikungakhudze kwambiri mawonekedwe a kulumikizanako. Mwachitsanzo, taganizirani silo yopangidwira kusungira zinthu zopyapyala. Pakhoza kukhala kutsetsereka pang'ono potsegula koyamba. Kutsetsereka kukachitika, sikudzachitikanso, chifukwa katundu wonse wotsatira ndi wofanana.
Kutembenuza katundu kumagwiritsidwa ntchito m'mapulogalamu ena, monga pamene zinthu zozungulira zimayikidwa m'makokedwe osinthasintha komanso opanikizika. Chitsanzo china ndi chinthu chopindika chomwe chimayikidwa m'makokedwe obwerera m'mbuyo kwathunthu. Pakakhala kusintha kwakukulu kwa kayendetsedwe ka katundu, kulumikizana koyikidwa kale kungafunike kuti kuthetse kutsetsereka kwa cyclic. Kutsetsereka kumeneku pamapeto pake kumabweretsa kutsetsereka kwambiri m'mabowo ataliatali.
Malumikizidwe ena amakumana ndi zochitika zambiri zolemetsa zomwe zingayambitse kutopa. Izi zikuphatikizapo makina osindikizira, zothandizira ma crane ndi maulumikizidwe m'milatho. Malumikizidwe otsetsereka ofunikira amafunika pamene kulumikizana kukukhudzidwa ndi katundu wotopa motsatira njira yosiyana. Pa mitundu iyi ya matenda, ndikofunikira kwambiri kuti cholumikiziracho chisaterereke, kotero malumikizidwe otsetsereka amafunika.
Malumikizidwe omwe alipo kale amatha kupangidwa motsatira miyezo iyi. Malumikizidwe a rivet amaonedwa kuti ndi olimba.
Malumikizidwe olumikizidwa ndi olimba. Malumikizidwe olumikizira ndi ovuta. Mosiyana ndi malumikizidwe olumikizidwa ndi ma bolt olimba, omwe amatha kutsetsereka pansi pa katundu, malumikizidwe safunika kutambasula ndikugawa katundu wogwiritsidwa ntchito kwambiri. Nthawi zambiri, zomangira zamakina zolumikizidwa ndi zonyamula sizimawonongeka mofanana.
Pamene ma weld akugwiritsidwa ntchito ndi zomangira zamakina, katunduyo amasamutsidwa kudzera mu gawo lolimba, kotero weld imatha kunyamula katundu wonse, ndipo pang'ono kwambiri imagawidwa ndi bolt. Ndicho chifukwa chake chisamaliro chiyenera kutengedwa polumikiza, kulumikiza ndi kulumikiza. Mafotokozedwe. AWS D1 imathetsa vuto losakaniza zomangira ndi zomangira zamakina. Mafotokozedwe 1:2000 a zomangira - chitsulo. Ndime 2.6.3 imati pa ma rivets kapena mabolts omwe amagwiritsidwa ntchito m'malo olumikizirana (monga momwe bolt kapena rivet imagwirira ntchito ngati pini), zomangira zamakina siziyenera kuganiziridwa kuti zimagawana katundu ndi weld. Ngati zomangira zimagwiritsidwa ntchito, ziyenera kuperekedwa kuti zinyamule katundu wonse mu cholumikizira. Komabe, zomangira zomangira ku chinthu chimodzi ndi kulumikiza kapena kulumikiza ku chinthu china zimaloledwa.
Pogwiritsa ntchito zomangira zamakina zonga bearing ndi kuwonjezera ma weld, mphamvu ya bolt yonyamula katundu imanyalanyazidwa kwambiri. Malinga ndi lamuloli, weld iyenera kupangidwa kuti isamutse katundu yense.
Izi ndizofanana ndi AISC LRFD-1999, gawo J1.9. Komabe, muyezo wa ku Canada wa CAN/CSA-S16.1-M94 umalolanso kugwiritsidwa ntchito payekha pamene mphamvu ya chomangira chamakina kapena bolt ili yokwera kuposa ya kuwotcherera.
Pankhani iyi, mfundo zitatu ndizofanana: kuthekera kwa zomangira zamakina zamtundu wonyamula ndi kuthekera kwa ma welds sikukwanira.
Gawo 2.6.3 la AWS D1.1 likufotokozanso za momwe mabolts ndi ma welds angagwirizanitsidwire pamodzi m'malo olumikizirana a magawo awiri, monga momwe zasonyezedwera pa Chithunzi 1. Ma welds kumanzere, omangidwa kumanja. Mphamvu yonse ya ma welds ndi ma bolts ikhoza kuganiziridwa pano. Gawo lililonse la kulumikizana konse limagwira ntchito palokha. Chifukwa chake, code iyi ndi yosiyana ndi mfundo yomwe ili mu gawo loyamba la 2.6.3.
Malamulo omwe angokambidwa kumene amagwira ntchito pa nyumba zatsopano. Pa nyumba zomwe zilipo kale, gawo 8.3.7 D1.1 limanena kuti pamene mawerengedwe a zomangamanga akusonyeza kuti rivet kapena bolt idzadzazidwa ndi katundu watsopano wonse, katundu wokhazikika womwe ulipo ndi womwe uyenera kuperekedwa kwa iyo.
Malamulo omwewo amafuna kuti ngati rivet kapena bolt yadzaza ndi katundu wosasinthasintha kapena yodzaza ndi katundu wozungulira (wotopa), zitsulo zoyambira ndi ma weld okwanira ziyenera kuwonjezeredwa kuti zithandizire katundu wonse.
Kugawika kwa katundu pakati pa zomangira zamakina ndi zomangira ndikovomerezeka ngati kapangidwe kake kakonzedwa kale, mwa kuyankhula kwina, ngati kutsetsereka kwachitika pakati pa zinthu zolumikizidwa. Koma katundu wokhazikika yekha ndi amene angaikidwe pa zomangira zamakina. Katundu wamoyo womwe ungayambitse kutsetsereka kwakukulu uyenera kutetezedwa pogwiritsa ntchito zomangira zomwe zimatha kupirira katundu wonse.
Zosefera ziyenera kugwiritsidwa ntchito kupirira kunyamula konse komwe kwagwiritsidwa ntchito kapena kosinthasintha. Pamene zomangira zamakina zadzaza kale, kugawana katundu sikuloledwa. Pakukweza kwa cyclic, kugawana katundu sikuloledwa, chifukwa katunduyo ukhoza kupangitsa kuti choseferacho chigwedezeke komanso kuti chichuluke kwambiri.
chithunzi. Taganizirani cholumikizira cha m'chiuno chomwe poyamba chinali cholimba (onani Chithunzi 2). Kapangidwe kake kamawonjezera mphamvu yowonjezera, ndipo zolumikizira ndi zolumikizira ziyenera kuwonjezeredwa kuti zipereke mphamvu yowirikiza kawiri. Pa chithunzi 3 chikuwonetsa dongosolo loyambira lolimbitsa zinthu. Kodi kulumikizanako kuyenera kupangidwa bwanji?
Popeza chitsulo chatsopanocho chinayenera kulumikizidwa ku chitsulo chakale pogwiritsa ntchito ma fillet welds, mainjiniya adaganiza zowonjezera ma fillet welds pamalo olumikizirana. Popeza ma bolts anali akadalipo, lingaliro loyambirira linali kuwonjezera ma welds okha omwe amafunikira kuti asamutsire mphamvu yowonjezera ku chitsulo chatsopano, kuyembekezera kuti 50% ya katundu idutse m'ma bolts ndi 50% ya katundu idutse m'ma welds atsopano. Kodi ndizovomerezeka?
Choyamba tiyeni tiyerekeze kuti palibe katundu wokhazikika womwe ukugwiritsidwa ntchito pa kulumikizana. Pankhaniyi, ndime 2.6.3 ya AWS D1.1 ikugwira ntchito.
Mu cholumikizira cha mtundu wa bearing, weld ndi bolt sizingaganizidwe kuti zimagawana katundu, kotero kukula kwa weld komwe kwatchulidwa kuyenera kukhala kwakukulu mokwanira kuti kuthandizire katundu wonse wosasinthasintha komanso wosinthasintha. Mphamvu ya bearing ya mabolts mu chitsanzo ichi siingaganiziridwe, chifukwa popanda katundu wosasinthasintha, kulumikizana kudzakhala kofooka. Weld (yopangidwira kunyamula theka la katundu) poyamba imaphulika pamene katundu wonse wagwiritsidwa ntchito. Kenako bolt, yomwe idapangidwiranso kusuntha theka la katundu, imayesa kusuntha katunduyo ndikusweka.
Komanso, tiyerekeze kuti katundu wosasinthika wagwiritsidwa ntchito. Kuphatikiza apo, akuganiza kuti kulumikizana komwe kulipo ndikokwanira kunyamula katundu wokhazikika womwe ulipo. Pankhaniyi, ndime 8.3.7 D1.1 ikugwira ntchito. Ma weld atsopano amangofunika kupirira katundu wowonjezereka wosasinthasintha komanso wamba. Katundu wakufa womwe ulipo ukhoza kuperekedwa kwa zomangira zamakanika zomwe zilipo.
Pakakhala katundu wosalekeza, kulumikizana sikugwa. M'malo mwake, mabotolo ali kale ndi katundu wawo. Pakhala pali kutsetsereka pang'ono mu kulumikizanako. Chifukwa chake, ma weld angagwiritsidwe ntchito ndipo amatha kutumiza katundu wosinthika.
Yankho la funso lakuti “Kodi izi ndizovomerezeka?” limadalira momwe katundu alili. Pachiyambi choyamba, ngati palibe katundu wokhazikika, yankho lidzakhala loipa. Pansi pa mikhalidwe yeniyeni ya chochitika chachiwiri, yankho ndi inde.
Kungoti katundu wosasunthika umagwiritsidwa ntchito, nthawi zina sizingatheke kupeza yankho. Mlingo wa katundu wosasunthika, kukwanira kwa maulumikizidwe amakina omwe alipo, komanso mtundu wa katundu wotsiriza—kaya wosasunthika kapena wozungulira—ungasinthe yankho.
Duane K. Miller, MD, PE, 22801 Saint Clair Ave., Cleveland, OH 44117-1199, Woyang'anira Welding Technology Center, Lincoln Electric Company, www.lincolnelectric.com. Lincoln Electric imapanga zida zowotcherera ndi zogwiritsidwa ntchito zowotcherera padziko lonse lapansi. Mainjiniya ndi akatswiri a Welding Technology Center amathandiza makasitomala kuthetsa mavuto owotcherera.
American Welding Society, 550 NW LeJeune Road, Miami, FL 33126-5671, foni 305-443-9353, fakisi 305-443-7559, tsamba lawebusayiti www.aws.org.
ASTM Intl., 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, foni 610-832-9585, fakisi 610-832-9555, tsamba lawebusayiti www.astm.org.
American Steel Structures Association, One E. Wacker Drive, Suite 3100, Chicago, IL 60601-2001, foni 312-670-2400, fakisi 312-670-5403, tsamba lawebusayiti www.aisc.org.
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