Inqaku lobuchwephesha elibalulekileyo: Lo nguvimba wezemfundo wesicatshulwa, hayi indlela yoyilo lwangoku, ubalo olungatshintshiyo, ubungqina bomthamo womthwalo okanye imiyalelo yokwenziwa kunye nokudibanisa. Uyilo lwezakhiwo zetsimbi kufuneka lubandakanye izenzo zangempela, ukudibanisa, ukuzinza, ukukhathala, umlilo, ukubola kunye nazo zonke ezinye iimeko ezifanelekileyo ngokwemigaqo kunye nemigangatho efanelekileyo, kunye noxanduva lomyili ogunyazisiweyo.
Uyilo kunye nokwakhiwa kwezakhiwo zetsimbi azikho inxalenye yesibonelelo sikawonkewonke sangoku seSavo Kusić. Imveliso yanamhlanje ibandakanya iifestile zomthi, iifestile zomthi-aluminiyam kunye neengcango zesiko.
Izakhiwo zetsimbi zinento eqhelekileyo ekubeni ininzi yenziwe ngentsimbi eshushu. Ukudibanisa kwenziwa ngokusebenzisa i-rivets, izikrufu okanye i-welding. Oku kubandakanya izakhiwo zetsimbi zeebhulorho, izakhiwo, imboni kunye nemigodi, ubunjineli be-hydraulic, iintsika, iinqaba, iitanki, kwingqiqo ebanzi kunye ne-cranes, i-shipbuilding, i-boilers, njl.
Izinto
Izinto eziphambili zokwakha zezakhiwo zetsimbi ziqengqeleka iiprofayili ezivela kwintsimbi yokwakha esemgangathweni S235, S275, S355, S420, S450. Ngokuxhomekeke kumgangatho, kukho iindidi ezininzi ezahlukeneyo zentsimbi yokwakha, apho inani kwi-classification lihlala libonisa amandla okuqina kwentsimbi. Kukho iisimboli ezininzi zeleta, apho kulo mzekelo i-S imele intsimbi yesakhiwo. Iifom eziqhelekileyo ezisetyenziswayo ziyi-S, B (i-concrete steels, i-reinforcement) kunye ne-Y (i-prestressing steel).
Izixhaso eziqengqelekayo zentsimbi
Kukho uluhlu olubanzi lweeprofayili zensimbi ezixhasayo kwaye nganye inenjongo yayo, izibonelelo kunye nokungonakali.
- Iiprofayili ze-U
- Iiprofayile ezinemilenze emxinwa (IPE, IPN)
- Iiprofayile ezinemilenze ebanzi (HEA, HEB, HEM, HD)
- Iiprofayile/iibhokisi ezingenanto (engqukuva, isikwere, uxande)
- Amaphepha
- Iimveliso ezibandayo (ezifunyenwe ngokuqengqeleka okubandayo umcu osicaba kunye nokujija umcu osicaba)
Nganye kwezi iinkangeleko ziyahluka ngokwemilo, imilinganiselo, injongo, njl. Umzekelo, kukho phezu20iiprofayili ezahlukeneyo ze-IPN, ezahlukileyo ngokwemilinganiselo; Iiprofayili ezinkulu zinokumelana ngcono ne-buckling (i-flexural kunye ne-lateral-torsional), i-deflections, njl.
Kukho iiklasi ezine zetsimbi kuxhomekeke ekubeni zifikelela kwinqanaba lesivuno xa uxinzelelo lwanda, nokuba uhlalutyo luyiplastiki okanye i-elastic, yintoni umthamo womthwalo wecandelo lomnqamlezo, njl. Okunye malunga nesakhiwo kunye namandla entsimbi inokufundwa apha.
Ukulinganisa kwamandla ombane kunye nomthamo wokuthwala kumthwalo ozinzileyo
Umthamo wokuthwala. Imilinganiselo yezakhiwo zetsimbi inqunywe ukwenzela ukuba ukuguqulwa okubalulekileyo okusisigxina kungabandakanywa. Umthamo wokuthwala, kwelinye icala, kwiimeko ezininzi awuphelelwanga nangayiphi na indlela xa uxinezeleko oluphezulu lothelekiso lufikelela kwinqanaba lesivuno - ke ukhubalo lukhula ngokukhawuleza kunoxinzelelo. Kwintsimbi yolwakhiwo, ukuxhomekeka okufanayo njengaxa ukunikezela kungathathwa njengomda womthetho kaHooke woxinzelelo jikelele. Kwimeko ye-homogeneous stress states, ezilingana kuyo yonke indawo, akukho lutshintsho lwenzekayo xa umda wokulinganisa ugqithisiwe, ngaphandle kokuba i-deformations iyonke ikhula ngokukhawuleza kunoxinzelelo.
Ukulinganisa uxinzelelo ngexesha lokugoba. Kwimeko yokugoba kwe-beam, ukusabalalisa uxinzelelo lwe-rectilinear ngokwe-hypothesis ye-Navier iyasebenza, de kube i-edge stress σ=M / W ayidluli umda wokulinganisa. Ukwandiswa kobude obubude ε = ε(σ). Oku kuyinyaniso ubuncinane kumagophe amancinci. Uxinzelelo oluphezulu kunoxinzelelo olulinganayo lunokukhula kancinci kancinci kunolwandiso ε. Kumkhiwane. 1 ibonisa ukuhanjiswa koxinzelelo lokugoba kumzobo onikiweyo wokusebenza kunye namaxabiso ahlukeneyo okwandiswa komphetho. Indawo yolungelelwaniso (ephawulwe ngesangqa kuyo yonke imigca yombane) ke ngoko iba ncinci kwaye ibe ncinci ngokunyuka komphetho wokwandiswa. Amandla ombane edge aqale acuthwe ngu σF. Kuphela emva kokuguqulwa okubaluleke kakhulu apho uxinzelelo oluphezulu luphakama ngaphezu kwe-σF, ukwenzela ukuba impembelelo yokuqinisa insimbi yesakhiwo ibonakala (imeko 5).
Fig. 1 -Ukugoba ukulingana kwamandla ombane
Ukulingana kweencopho zoxinzelelo. Ukusasazwa koxinzelelo lwexesha elide kulo lonke icandelo phakathi komngxuma kwintonga egrunjiweyo ecinezelweyo ihambelana nomgca 2 kwifig. 2. Incopho yombane σmax ixhomekeke kumlinganiselo wed/b. Ubukhulu becala ijikeleze σmax = 2-3 σm, apho σm = S/FM ibonisa ixabiso eliphakathi loxinzelelo lwe-tensile kwicandelo elenziwe buthathaka ngumngxuma kwi-FM. Sl. 2 iyasebenza de i-voltage state idlule i-P-limit. Kwimithwalo ephezulu, ukwenzela ukuba kuphunyezwe ukuhlanjululwa okuthile, i-voltage ephantsi kunokuba ngokomthetho womgca ochanekileyo ifunwa kuphela kufuphi nomngxuma. Kwezona ndawo zigxininisiweyo, uxinzelelo alusayi kuphinda lunyuke ngokulinganayo no-S, kodwa lucotha ngakumbi. Kumda, ulwabiwo olulinganayo loxinzelelo lwelongitudinal σm = σf luya kufunyanwa phezu kwecandelo lonke 2-2. Ukucheba kunye noxinzelelo olunqamlezayo aluhoywanga. Iziganeko zokulinganisa uxinzelelo ngexesha lokunyuka okucothayo kwamandla e-S kwintonga zibonakalisa ukuba indlela eqhelekileyo yezakhiwo zetsimbi phantsi kwempembelelo yomthwalo we-static ifanelekile, ukungazinaki iincopho zoxinzelelo ngexesha lokulinganisa kunye nokuthelekisa kuphela uxinzelelo oluphakathi σm=S/Fm kwicandelo elibuthathaka Fm ngexabiso elivumelekileyo.
Fig. 2
Inkqubo yokulinganisa ngokomthamo womthwalo
Njengoko umthwalo usanda, ukulinganisa kombane kwenzeka kwicandelo. Ngokwenza njalo, uxinzelelo luyadityaniswa ukusuka kwezona ndawo zigxininiswe kakhulu kwicandelo ukuya kwezona zinoxinzelelo oluncinci. Ngethuba nje i-deformations ayikho enkulu kangangokuthi kufuneka ithathelwe ingqalelo xa ibeka iimeko zokulingana, le nkqubo ayikwazi ukutshintsha nantoni na kubukhulu bempembelelo ye-S, M, njl.
Inkxaso eqhubekayo kunye nesakhelo: phantsi kwengqikelelo yomthetho kaHooke, ifunyenwe ngenkxaso enye eqhubekayo yecandelo eliqhubekayo (umkhiwane.3) umgca womzuzu oboniswe phantsi kwe. Uxinzelelo lokugoba luhambelana namaxesha okugoba M. Ukuba imithwalo yomibini inyuka ngokulinganayo, i-P-limit iya kuqala igqithwe kwinkxaso ephakathi B. Umda wokuthwala ufikeleleke xa umzuzu wokukhawulela i-MDF ifikeleleke kwintsimi ngokunjalo. Kwimeko yomqadi ebotshelelwe kumacala omabini ecandelo elilinganayo elingaguqukiyo elinamandla agxininisiweyo (umkhiwane.4) ukulingana komzuzu kukho ukususela ekuqaleni. Xa i-P-limit igqithiwe, akukho tshintsho kulwabiwo lomzuzu. Ngokuchasene noko, kwimeko yomthwalo owabiwe ngokulinganayo (Fig.5) ukulingana kwemizuzu kukhokelela ekuncitshisweni komzuzu wokucinezela nge -2/3 Mmalunga noku-1/2 Mo.
Sl.4
Sl.3njl.5, ngokulandelelanayo: amaxesha okugoba: a) phambi, b) umda welizwe emva kokuhlanganisa amandla kwakhona; a) ngaphambili, b) emva kokulinganisa amandla
Ulwakhiwo lwe-Lattice: ngeetruss zangaphakathi ezingenammiselo, kukho ukuxhomekeka okufanayo kunye nolwakhiwo lwesakhelo. Uxinzelelo lwesibini, oluhambelana neendawo eziqinileyo zokugoba, zinokungahoywa kuqikelelo lokuqala xa kuhlolwa umthamo womthwalo. Amacandelo ePlastiki asebenza ngokufanayo kumalungu, ukwenzela ukuba isenzo se-static ye-girder phantsi komthwalo wokugqibela usakwazi ukuthwala sisondele kwi-truss efanelekileyo kunye namalungu kwiinqununu. Kwimeko yolwakhiwo olunemithwalo ephindaphindiweyo, apho iimeko zamandla okukhathala kufuneka zithathelwe ingqalelo, ngoko kukho amathandabuzo amakhulu malunga nokuthatha ukulingana kwamandla ngexesha lokulinganisa. Ngokuchasene noko, kubaluleke kakhulu ukugqiba ngempembelelo yokufuduswa kweenkxaso. Ekubeni amandla okusebenza kwezinto zokwakheka komntu ngamnye axhomekeke kuphela kwimida yoxinzelelo, kwaye kungekhona kubukhulu be-deformations iyonke, ukufuduka kwezixhaso akunampembelelo kumandla okuthwala.
Umthwalo otshintshanayo: ukucingelwa kwetyala lomthwalo osisigxina alufane luqondwe. Ngamabhanti ebhulorho, kukho iimeko zomthwalo oguquguqukayo. Iingcamango malunga nemikhosi kunye nokusabalalisa uxinzelelo kwizinto zokwakheka komntu ngamnye, ezenza lula, ziqhelekile kumsebenzi osebenzayo kunye nezakhiwo zetsimbi, ngokutsho kwangaphambili, zifanelekile phantsi kweemeko eziqhelekileyo. Oku kuyinyani ngakumbi ngokutyeshela iincopho zombane zasekuhlaleni. Akunakucetyiswa ukuba kusetyenziswe indlela yokulinganisa ngokomthamo womthwalo phantsi (oguquguqukayo) ukulayisha ukukhathala. Ke ngoko, inkqubo yokulinganisa ngokomthamo womthwalo ulinganiselwe kwimeko yomthwalo omileyo kakhulu, ngakumbi kulwakhiwo kushishino lokwakha. Kwezinye iimeko, apho ingqwalasela kufuneka ihlawulwe ekubonakaleni kokukhathala, ukuguqulwa okuphawulekayo kuya kufuneka kukhutshelwe ngaphandle kwaye ithiyori ye-elasticity ithathwe njengesiseko. Ngokwenza njalo, umntu kufuneka azabalazele umgama omkhulu ngokwaneleyo ukusuka kwindawo yesivuno. Ukuqina kwentsimbi yokwakha ke kunika ukhuseleko olongezelelweyo.
Ukutshintshana koxinzelelo
Ukolula okubandayo kunye nokwaluphala: Kwifig. 6 umgca we-stress-dilation wentonga ejikelezayo, evezwe kwi-alternating tensile kunye noxinzelelo loxinzelelo, isetyenziswe. Iinkqubo zomthwalo ngamnye ziphawulwa ngamanani ngokulandelelana kwawo. Ukwandiswa kwe-elastic okubuyayo xa kukothulwa kwenzeka emva kokwaluleka okukhulu ngokomlinganiselo woxinzelelo. Xa utshintsha uphawu lombane, i-P-limit iphantse yanyamalala ngokupheleleyo. Ngoko ke, iipropathi ezi-elastic zensimbi yokwakha ezitsalwe kwimeko ebandayo azivumelani nemilinganiselo yokuqala. Kuxhomekeke kuqhubekeko lwangaphambili, umahluko omkhulu unokuboniswa.
Fig. 6
Kunye naloo nto iza neempawu ezininzi zokuguga. Eli gama libandakanya zonke iinguqu kwiipropati ezenzeka ngexesha ngaphandle kwempembelelo yangaphandle. Ukolula ukuguga kunokubonwa emva kokuguqulwa okusisigxina ngokuzolula okubandayo. Ukuba iisampuli zovavanyo ezoluliweyo ngokusisigxina zishiywe ixesha elithile ngaphandle komthwalo kwiqondo lokushisa, ukuqina kwamandla kwaye, kuncinci, amandla okukrazula aphakama ngaphezu kwexabiso lokuqala, ngelixa i-elongation kwikhefu iyancipha (Fig. 7). Inkqubo yokuguga ithatha iintsuku, kodwa iyancipha kwiiyure ezimbalwa okanye imizuzu nje, ukuba insimbi yesakhiwo ishushu malunga ne-300 oC. Kufuneka kwakhona kukhankanywe ukuba ukuguga ukuguga kwenzeka ngaxeshanye kunye nokwelula, ukuba oku kwenzeka kwi-temp. 200 – 400 oC, o.k.t kwindawo yokubengezela okwesibhakabhaka.
Fig. 7 - a) umgca wokwandisa wentonga elayishwe kabini; b) umgca wokwandisa intonga eyoluliweyo kwindawo ebandayo
Isenzo esilandelayo kunye ne-hysteresis: Kwizinto ezilastiki ngokupheleleyo, kukho ukuxhomekeka okungafaniyo phakathi koxinzelelo kunye nemeko ye-deformation, ukwenzela ukuba uxinzelelo oluthile luhlala luhambelana ne-deformations efanayo kunye ne-vice versa. Ngomthetho onikeziweyo we-elasticity, i-deformations ayixhomekeke kwixesha elidlulileyo ukususela ekubeni umthwalo usetyenziswe, kwaye kungekhona kwindlela apho umthwalo usetyenziswa khona. Ukuphambuka kwindlela yokuziphatha e-elastiki echanekileyo kunokuchazwa ngamadigri amabini oqikelelo: kwingingqi ye-elastic kukho ukuphambuka okuncinci; zinokungahoywa kuqikelelo lokuqala. Ziyakwazi ukumiselwa ngemilinganiselo echanekileyo, ngakumbi xa kuthelekiswa noxinzelelo olusondeleyo kumda we-elastic. Okukuthi, ukuhlanjululwa akuwona nje umsebenzi we-voltage, kodwa kunye nomjikelezo womthwalo ovaliweyo kunye nombane ofanayo, uhlala uncinci kancinci ngexesha lokukhulula kunexesha lokulayisha. Ukutenxa kwi-elasticity epheleleyo, okt. Umahluko phakathi kokwandiswa okuhambelanayo kuxinzelelo olufanayo kuthiwa yi-elastic hysteresis. Ukuba umjikelo womthwalo uphindwa ngokuphindaphindiweyo, oku kufumaneka kwii-voltages ezingekho phezulu kakhulu - i-loop evaliweyo ye-hysteresis okanye i-damping. Sl. 8 ibonisa iilophu zokudambisa kumaxabiso ahlukeneyo omthwalo we-AC. Ububanzi be-loops bukhula ngamandla kunye nokuphakama kombane. Indawo yelophu ilingana nomsebenzi wokuguqula, olahlekileyo kumjikelo ngamnye kwaye uguqulwe ube bubushushu. Kwakhona, i-deformations iyaguquguquka kungekhona nje ngokuphakama kombane kodwa kunye nexesha, zixhomekeke kwisantya kunye nendlela yokulayisha. Inxalenye ye-deformation, exhomekeke kwixesha, ibizwa ngokuba yi-aftereffect. I-Hysteresis kunye nesiphumo senzeke ngaxeshanye. Njengomthetho, azikho ukubaluleka okusebenzayo kwezo ntlobo zentsimbi yokwakha eyenzeka kwizakhiwo zetsimbi kwiqondo lokushisa.
Sl. 8
Inqaku leSicelo: Izakhiwo zemathiriyeli yembali, uqikelelo, imizobo kunye neenkqubo kwisicatshulwa akufuneki zisetyenziswe endaweni yemigangatho yangoku, iimpawu ezithile zemveliso, imodeli yokubala kunye noqinisekiso lobuchwephesha kulwakhiwo lulonke.