Haɗin da ƙusoshi da bolts – Ɗaukar nauyi da ke lanƙwasawa

Ƙarfin ɗaukar nauyi na mai ɗauka a kusan dukkan lokuta ana iyakance shi ne ta lankwasawar belin da ke ƙarƙashin matsawa. Wannan yana faruwa ne kawai bayan an kai iyakar yield bayan da aka daidaita damuwa ko’ina cikin sassan da ke ƙarƙashin matsawa. Sai kawai idan akwai ƙarfafan goyon bayan gefe za a iya ƙara damuwar gefen da ake iya ɗauka zuwa yankin ƙarfafa ƙarfen gini. A wajen kimanta ƙarfin ɗaukar nauyi, ya kamata a yi la’akari da ainihin rabon damuwa. Da a ɗauki rabon damuwa madaidaiciya, ƙarfin ɗaukar nauyi zai zama an raina shi. Ya kamata a binciki abubuwan rauni musamman.

Rage ramuka a cikin masu ɗaukar nauyin da aka ɗora wa lanƙwasawa

A bangaren da aka ja na katako, raunin ɓangaren yana aiki kamar yadda yake ga sandunan ja (tsagewar ɓangaren da aka ja a wurin da ya raunana). Don ƙin ramuka a wannan ma’ana, ƙa’idoji iri ɗaya ne da na sandar ja.

Saboda ramukan da aka cika da rivets a ɓangaren da ake matsawa na ɗauka suna da ƙananan tasiri sosai a kan rabon matsin lamba da nakasa, kuma ƙarfin ɗauka galibi yana takaitu da lanƙwasawar gefe na ɓangaren da ake matsawa, girman raunana yankin a ɗaukar masu yanke masu siffa iri ɗaya ba ya tasiri sosai ga nauyin ɗauka. Saboda haka tun da daɗe F. Hartmann ya ɗaga tambayar ko ya zama dole ma a lissafa raunana da ramuka ga ɗaukar masu siffa iri ɗaya. A cikin yankuna marasa daidaito (ɓangaren da ake matsawa ya fi ƙarfi) ƙididdigar ramuka a ɓangaren da ake ja na ɗauka na iya zama abin da ke ƙayyade ƙarfin ɗauka. A ƙarƙashin nauyi da ake maimaitawa sau da yawa, ramuka suna da tasiri mai yawa, ko da suna nesa da zaruruwan gefen.

A yau, wajen ƙididdige ƙarfin ɗaukar nauyi na sashen da ke cikin lanƙwasawa, ana amfani da ɓangaren gross da ɓangaren net (tare da sauran nau’o’in karyewa masu dacewa). Karyewar gross tana faruwa a ɓangaren sashen da ba a raunana da ramuka ba. Karyewar net tana faruwa a kan sashen da ramuka suka raunana, kuma yankin da ake la’akari da shi shi ne yankin gross da aka rage masa jimillar yankunan dukkan buɗe-buɗe.

Zakivci a wuya da a kai

A lokacin lankwasawa, ban da matakan al’ada, ana kuma samun matakan yanka waɗanda, a ga goya masu bel ɗin daidai, suke daidai da ƙarfin transversal Q. A cikin sassan haɗaɗɗu, rivets ɗin da ke haɗa profailolin da aka birgima daban-daban ne ke ɗaukar matakan yanka a wuraren hulɗarsu. Rarrabuwar ƙarfin yanka T a cikin rijiya tana da siffar parabola, a cikin bel ɗin kuma kusan madaidaiciya ce. A goya masu bel masu nauyi, T a cikin rijiya ba ta bambanta sosai da matsakaiciyar ƙima Tm, wadda sau da yawa tana isa domin kimanta farko.

Hoto. 1

Rivets a cikin kan (siffa 1b) dole ne gaba ɗaya su karɓi ƙarfin ɗaurewa TK < TH. Ƙarfin ɗaurewa tsakanin lamellin bel ɗin daban-daban ma ya fi ƙanƙanta kuma a wannan yanayin ana rarraba shi kamar a siffa 1c zuwa ga adadi mafi yawa na rivets.

Tsawaita ɗaukar nauyi

Tsawaitar tsaye na farantin vertikal ana buƙata idan tsayin farantin ya fi faɗin faranti da ake da su. Haka kuma, yana iya zama dole idan aka yi la’akari da ƙira da sufuri. Tacks da rivets a cikin tsawaitar tsaye na wata ƙofa ya kamata su ɗauki daidai wannan ƙarfi TL, wanda farantin da ba a tsawaita ba zai samu a haɗin tsaye. Tunda raunana ta ramuka a cikin tack ɗin daidai take da ta cikin farantin tsaye, kaurin tack ɗin dole ne ya fi ko ya yi daidai da kaurin rib ɗin.

Sl. 2 - Tsawaitaccen ɓangaren a tsaye na farantin ƙarfe

Ƙarin sashi na gefe ƙarƙashin lodi na lankwasawa ana iya rufe shi ta hanyoyi daban-daban da ƙugiyoyi. Sl. 3 yana nuna zaɓuɓɓuka da dama na ƙarin sashin wajen bita, a cikinsa an ƙara kawai farantin tsaye. Idan ƙugiyoyin suna kawai tsakanin kusurwoyin bel (sl. 3a), sai a bar ƙananan sassan farantin tsaye da ba a rufe ba a ƙarƙashin kusurwoyin bel. A wannan yanayi kusurwoyi da rivets a yankin ƙarin sashin farantin tsaye suna ɗaukar nauyi sosai, saboda haka ya kamata a takaita irin wannan haɗin ga muhimman haɗe-haɗe da ƙananan ƙarfi. A koyaushe ya kamata a fi son ƙarin sashi gaba ɗaya an rufe shi. Ƙugiyoyi na musamman a kan kafafu na tsaye na kusurwoyi suna karɓar damuwar tsayi ta wannan tsiri, amma kawai kaɗan suke shiga wajen karɓar ƙarfin gefe. Wani ɗan ingantawa a wannan yana bayar da sl. 3c. A wajen manyan ƙarfi ya kamata a nufa zuwa ƙugiyoyi a duk tsayin farantin tsaye (sl. 3d), wanda ke nufin dole ne a katse kusurwoyin bel. Ƙugiyoyin suna samun kaurin kafar kusurwa, kuma a manyan kaurace-kauracen kusurwa ana amfani da shimfiɗa na daidaitawa domin rage yawan kaurin ƙugiya da bai zama dole ba.

Sl. 3 - Haɗin ketare (na masana’anta) na farantin tsaye

Ci gaban farantin tsaye a ƙarƙashin nauyin ƙarfin ketare: Mai ɗaukar nauyi a wurin haɗin yana ɗauke da Q kaɗai (M = 0). Don haɗi da tazara iri ɗaya tsakanin ƙusa-ƙusai (sl. 4), ya kamata a ɗauka cewa ƙarfafan cikin ƙusa NiQ sun kusan dacewa da sashen yankin e*t na haɗin gwiwar haɗin, wato cewa ƙarfafan cikin ƙusa an rarraba su kamar yadda matsin yanke yake a tsayin mai ɗaukar nauyi, NiQ = e*t*τi = e*Ti. Duk da haka, wajen girman girma ana ƙididdigewa da rabawa iri ɗaya ga duk ƙusa n, NiQ = Q/n.

Sl. 4 - Ƙarin farantin a tsaye tare da rarraba ƙarfin yanka na gefe

Sl. 5 yana nuna ci gaban masana’anta na ƙarshen farantin a tsaye (angular kayan ƙarfafawa da lamellae an ci gaba da su a wani wuri dabam).

Hoto 5

Lankwasawa tare da ƙarfin al’ada: Masu ɗaukar nauyi da ake ɗora musu lokaci guda da lokutan lanƙwasawa da ƙarfin al’ada ana ƙididdige su bisa ƙa’idoji iri ɗaya kuma bisa zato na rabon damuwa a madaidaiciya. Idan an cire ƙusoshi gaba ɗaya a cikin duka bel, ɓangaren da yake da amfani da matsayin layin sifili ba ya dogara da yanayin nauyi, saboda haka damuwar daga M da N za a iya tarawa kai tsaye. Nauyin ƙusoshi a ci gaba ana samu ta haɗa ƙarfin da suka fito daga sassa daban-daban na nauyi M, wato N.

Dogaro da haɗaɗɗen ɗaurewar ɗaukar kaya

A nan za a tattauna ne kawai mafi yawan abin da ake amfani da shi daga cikin hanyoyi masu yawa. A lokacin kimantawa, dole ne a ko da yaushe a yi tunani kan ƙarin ƙarfi da ake samu daga karkacewa daga ƙididdigar ƙarfin jurewa waɗanda suka fi ko ƙasa da matakin gaske.

Sauƙaƙƙen jingina na ɗaya daga cikin masu ɗaukar kaya a kan saman igiyar wani ɓangaren gini na daban yana zuwa a matsayin zaɓi idan akwai babban tsayin gini a hannunmu. Yanayin al’ada shi ne ƙaƙƙarfan haɗi da ƙusoshi ko sukurori. A cikin hoto 6 an nuna yadda ake jinginar da I-ƙafafun katako masu ci gaba a gine-gine ta hanyar al’ada, wanda kuma ke guje wa huda a ƙananan ƙafafun I. Ya kamata a tsare masu ɗaukar kaya a wannan hali daga juyewa da kuma daga ƙarfin gefe (hoto 7 da 8). A aikin gina gada, sau da yawa ana haɗa masu ɗaukar kaya biyu-biyu (hoto 9); jingina mara motsi na mai ɗaukar kaya mai tsawo a kan mai ɗaukar kaya na kwance (hoto 10). Idan ƙarfin jingina ya fi girma, ya kamata a ƙarfafa masu ɗaukar kaya da kusurwoyi masu dacewa ko bayanan ƙarfe da aka walda (hoto 8 zuwa 10). A wajen masu ɗaukar kaya masu rikitarwa, ya kamata a wuce da nauyin zuwa cikin haƙarƙari.

Hoto 6 - Ƙarfafa rožnjače

Hoto 7 da 8

Hoto 9 da 10

Haɗin ƙarin tsani: A cikin siffa 11 da 12 an nuna haɗin I-beam, waɗanda ake amfani da su a gine-gine a matsayin haɗi na yau da kullum. Yankewar tana samun babban zagaye don a guji fashewar ƙashin ɗaukar nauyi. Ƙunshewar roba daga haɗin ƙarin tsani tana kawo ɗan ƙarin ƙarfin ɗauka. Sauye-sauyen da aka bayyana ba su da haɗari idan nauyin ya fi zama mai natsuwa, kamar yadda yake a tsofaffin gadarori.

Sl. 11. - Haɗe-haɗen daidaitattun I-bim da ɓangaren ƙarshe mai daidaiton kusurwa

Fig. 12 - Haɗe-haɗen al’ada tare da ƙarshen I-bim da aka yanke

Hanyoyin haɗi masu tsauri a lanƙwasawa ana yin su ne idan ana buƙatar haɗi ba tare da canjin kusurwa ba (manyan ɗaukar kaya masu ci gaba, kusurwoyin firam masu tsauri) ko idan akwai barazanar karyewa sakamakon gajiya a ƙarƙashin nauyi mai canzawa, musamman a gadar jirgin ƙasa. Ana iya amfani da faranti don ci gaba, haɗin gwiwa masu tsauri a lanƙwasawa. kusurwoyi masu tsauri a lanƙwasawa, kusurwoyin firam.

• Lemun haɗin ci gaba – Idan ya zama dole a haɗa masu ɗaukar kaya da ke kwance a cikin wannan mataki ɗaya, to ana haɗa bel ɗin sama biyu da lemu ko ɗaurin haɗin ci gaba. Ta haka an ’yantar da rivets ɗin haɗin daga ƙarfin ja kuma an kauce wa manyan nakasu.

Sl. 13 - Haɗi da lamella don ci gaba

Hoto 14 - Haɗin dogayen masu ɗaukar nauyi a) na gadar hanya ta babbar hanya; b) na gadar jirgin ƙasa

• Haɗe-haɗen da suka yi tsauri wajen lanƙwasawa – Ana samun irin wannan haɗe-haɗe a cikin cikakkun cantilever na hanyoyin masu tafiya a kan gadar hanya. A kan ƙananan lokutan juyi, farantin sa na tsaye ana haɗa shi ne ta hanya biyu kacal tsakanin kusurwoyin ƙarafawa na babban ɗaukar kaya. Jujjuyawar da aka shigar ana rarraba ta ta hanyar ƙarfafawa zuwa duk tsayin babban ɗaukar kaya, ko kuma a shigar da ita cikin bel ɗinsa a matsayin haɗin ƙarfi.

Hoto 15 da 16

• Kusurwoyi masu tsayayyen lankwasawa – Ya kamata a ƙera kusurwoyin da ke tsakanin ginshiƙai da katakon ƙasa a fannin gini ta yadda kusurwar za ta kasance ba canzawa kuma kada a sami wani ƙeta na matsin lamba na wuri. Ingantattun haɗe-haɗe a kusurwoyi suna samuwa, misali, bisa ga hoto 16 idan an yi amfani da faranti na gefe ko kuma bisa ga hoto 100 idan an ɗauki moment ɗin ɗaurewa a cikin sassan ginshiƙi a matsayin haɗin ƙarfi biyu.
• Kusurwoyin firam – A kan firam-firam na poligonal, ana iya yin ƙarin sashi a wurin lanƙwasa idan bambancin kusurwa ƙanana ne; sandunan da aka haɗa ana rufe su da igiyoyin ɗaure a matsayin sanduna masu jan jiki da matsawa. Ƙarfin juyawa yana tattaruwa a wurin lanƙwasa kuma dole ne a karɓe shi da ƙarfafawa. A siff. 101 a lura da bambanci a rufe ƙarin sashi da ƙarfafawa, dangane da ma’anar moment ɗin lankwasawa da ƙarfin karkata. A yanayin manyan ƙarfi da bambancin kusurwa mai yawa, a guji sa ƙarin sashi ya shiga cikin ɓangaren firam mai matuƙar lankwashe. Ƙarin sashi a gefen kusurwoyin firam yana ba da mafi kyawun siffar ƙira kuma yana sauƙaƙa ƙerawa. Misalai da ƙarin sassa na duniya masu an yi musu ƙusa daga bangarorin biyu na wurin lanƙwasa suna a siff. 102a da siff. 102b, inda kusurwar ta ƙunshi ɓangaren da aka walda. A siff 103 yana nuna haɗin da ke da ƙarfi a lankwasawa na ginshiƙin firam tare da katako mai ci gaba.

Hoto 17a

Hoto 17b

Haɗin kai na karkata: A haɗin da aka duba har yanzu, haƙarƙari suna tsaya wa juna a tsaye. Amma idan kusurwar ba madaidaiciya ba ce, to ana karkatar da kusurwoyin ƙarfe (fig. 18), kuma a kusurwoyi masu matuƙar kaifi ana amfani da shimfida masu siffar ƙyalle. A yi amfani da igiyoyin ɗaure don ci gaba da haɗi da kuma ƙananan kayan tallafi a wannan yanayin kamar yadda ake yi a haɗin kai tsaye. Faranti na haɗi masu lanƙwashe (fig. 19) suna da babban eccentricity da kuma manyan ƙarin ƙarfi. Yin haɗin karkata ya fi sauƙi idan ana amfani da ƙananan faranti na haɗi da aka walda (fig. 20).

Hoto 18

Hoto 19

Fig. 20