Izandiso zibizwa ngokuba zizo iintlobo zonxibelelwano ezisetyenziselwa ukwandisa okanye ukunyusa. Izandiso ziyafuneka, umzekelo, kuba ubude okanye ububanzi beeshiti abukhoyo abanelanga, kwaye ngexesha lofakelo ziyafuneka ngenxa yokunciphisa imilinganiselo nobunzima bezinto ezithuthwayo nganye nganye. Ii-clamp zibizwa ngokuba zizishiti ezigquma ikhefu kwisandiso. Zonke ezinye iindlela zonxibelelwano, ingakumbi ezo ziphakathi kweentonga zethiyori zeendlela ezahlukeneyo nabathwali abakwiindawo ezahlukeneyo, zibizwa ngokuba zii-connection.},{
Kwiindawo eziqhelekileyo zokudibanisa, ii-clamp kunye ne-rivets zeendawo zokudibanisa ziyalinganiswa ngokwamandla apheleleyo. Ngoko ke, kudibaniso oluqhelekileyo akufuneki ukuba imiphezulu yeendawo zokudibanisa ichukumisane.
Eyona ndawo iphambili yokusetyenziswa kweentonga ezitsalwayo nezixinanisiweyo (ezi ziintonga zokwenene, ezithwala ikakhulu imithwalo eqhelekileyo) zi rešetke. Iingxoxo zeli candelo azijongi ingozi yokugoba kweentonga ezixinanisiweyo. Kuqala kuya kujongwa amandla e-static.
Ukutsalwa kwemingxuma kwiintonga ezitsaliweyo
Ukuthwala umthwalo: Imeko yoxinzelelo kwintonga etsaliweyo itshintshwa kakhulu ekuhlaleni ngenxa yeemingxuma/izivulo. Kwindawo yobungakanani obulinganayo, ukuhanjiswa koxinzelelo kuhambelana necandelo elibuthathaka (sl. 1). Uxinzelelo olukhulu lobude kwintonga engunxande ngokwe-A. Henning ngu:
maxσ = σm*[3-(d/b) + 0,8(d/b)2]
Sl. 1 - Iingcinezelo zobude nezinqamlezileyo kwintonga egqojoziweyo a) ngokuka A. Henning; b) ngokuka M. Rudeloff
Kwimeko yomda d/b = 0 yeelamella ezibanzi kakhulu kuvela ke maxσ = 3σm yaye kwimeko eboniswe kwis. 1a d/b = 1/3 yi maxσ = 2,42 σm. Ngaphandle koxinzelelo lobude kukho nezinxunguphalo ezithe tye nezesheya. Eyona ngxinzelelo inkulu ikumgquba womngxuma. Apho kuqala ukuvela ukuguquka okungaguqukiyo, oko kukuthi iincopho zoxinzelelo ziyaphululwa kuze kuvele ukulingana koxinzelelo kulo lonke icandelo. Ukuguquka okungaguqukiyo okubonakalayo kummandla wemingxuma kuqala kuphela xa uxinzelelo oluphakathi σm kwicandelo elibuthathaka ludlula umda wokolulwa σFO. Ukwandiswa ngokupheleleyo kwentsimbi kwi SF = Fm * σF kuba kancinane kuphela ngaphezulu kunakwintsimbi engenamingxuma. (Fm ngumphezulu wecandelo elibuthathaka kakhulu)
Kuvavanyo lokutsalwa olunemivalo ebethelelweyo kuhlala kuvela ukwaphuka kumacandelo abuthathaka. Umthwalo ekwaphukeni, phantsi kweemeko eziqhelekileyo, uchanekile ngokwaneleyo SB = Fn * σB. Iimvavanyo zokukrazula kwimivalo etsalwayo enemingxuma evulekileyo zibonise imbonakalo yokuqhekeka njengoko kubonisiwe ku sl. 2.
Umz. 2 - Imifanekiso yokuqhekeka kweentonga ezitsalwayo
Kwiimvavanyo ezinxulumene neendawo ezibotshiweyo ngezikhonkwane kubonisiwe ukuba iilug ezinecandelo elinye lezikhonkwane zinokuxhathisa okuncinane kunezo zineemigca ezininzi zezikhonkwane zilandelelene. Ngoko ke uxinzelelo oluphakathi ekwaphukeni σB kwicandelo elisebenzayo lwaluyi:
Inkqubo yokulinganisa imivalo etsaliweyo: Ngokweendlela eziqhelekileyo zokubala, kuxinzelelo oluphakathi lokutsalwa kufuneka kusebenza σm = S/Fm ≤ dozσ yaye oko kuzo zonke iindawo eziphambili ze-Fm. Ukutsalwa kweemingxuma kuchongwa kwicandelo elithe nkqo elinenani elikhulu leemingxuma, yaye kunokwenzeka ukuba icandelo elaphukileyo elineemingxuma ezininzi linike ixabiso elincinci le-Fm (sl. 2). Ngale ndlela, kwiiprofayili eziqengqelekayo i-Fm ibalwa ngokuvulwa. Kwiindawo ezidibeneyo kusetyenziswa ngendlela efanayo.
Umyinge Fm/F ngokuqhelekileyo uhleli phakathi kwe 0,8 ne 0,9, oko kukuthi, ukuncitshiswa kwemingxuma ΔF = F – Fm kungu 10% ukuya ku 20% womnqamlezo opheleleyo F walo mvalo. Kwizakhiwo ezinkulu ΔF inefuthe elikhulu kubunzima, ngoko ke kufanelekile ukufumana iminqamlezo enokuncitshiswa kwemingxuma okuncinci.
Ukukhubazeka: Ukwandiswa okwelastiki kweentonga ezitsaliweyo ezinemingxuma kuncinci nje ngakumbi kunezo ntonga zingagqobekanga ezifanayo. Ukwandiswa ngokupheleleyo kwamalungu ongezelelweyo kuphantse kufane ncam nokwendlela yelamela eziqhubekekayo. Ngoko ke, kwanele ukuba ukuze kubalwe ukukhubazeka kwezakhiwo zentsimbi kumiselwe ukwandiswa okwelastiki ngamaxabiso e-E ne-F eentonga ezingabuthathaka. Ukhuseleko ekubeni zifikelele kumda wokuhamba lukhulu kwiintonga ezinomthotholo kunokuba, umzekelo, kwiintonga ezicinezelweyo.
Ukuhanjiswa kwemikhosi kwiirivet
Umz. 3
Ukwabiwa kwamandla S kwintonga kwiirivethi ezahlukeneyo zoxhulumaniso kuxhomekeke kwiimpawu zayo zokuqina, kwaye “akuchazwanga ngokwe-static”. Kwimeko yomz. 3 ukwabiwa N1, N2, … kuxhomekeke kuguquko lwerivethi kunye neephepha ezidityanisiweyo, lutshintsha ngokobudlelwane Fpodvezice/Fštapa. Kwi Fpodvezice ≠ Fštapa amandla okugqibela kwiirivethi awasalingani ngokulinganayo (umz. 50a). Ngokwehla kobudlelwane Fpodvezice/Fštapa kuba iNn incinci, N1 isondela kuS. Ukudibanisa ii-lamela ezinobukhulu obahluke kakhulu (umz. 4b) akuyondlela ifanelekileyo ngenxa yokulayishwa kakhulu kwerivethi yokuqala.
Umz. 4 - Umthwalo kwiirivethi xa Fštap > Fpodvezice
Iilamela kunye nezibophelelo ziqinile, ziirivethi kuphela ezithambileyo (sl. 5a). Emva koko zonke ii-rivethi zifumana ukugoba okufanayo, onke amandla kwiirivethi kufuneka abe alinganayo.
Iirivethi ziqinile, yaye ziilamella kunye neebhendi zibonisa ukuguquguquka kuphela (umz. 5b). Kuba ukolulwa kwintonga nakwiibhendi phakathi kwerivethi yokuqala neyekugqibela kufuneka kufane, kulandela N2 = N3 = … = Nn-1 = 0, ngaphandle kwe N1 = S * x1.
Umz. 5
Ukwabiwa kokwenene kwamandla kuseluphakathi kwezi meko zigqithisileyo. Xa umthwalo usanda, okokuqala kuvela ukuguquka okungapheliyo kwiirivethi zokuphela, iirivethi ezithwele umthwalo omkhulu ziyathotywa umthwalo, yaye ukwabiwa kwamandla kuba ngakumbi nangakumbi kufanayo. Emva kokuvela kokuguquka okukhulu, ukwabiwa kwamandla kusondela kwimeko apho ii-lamela kunye nee-strut ziqinile, oko kukuthi, amandla kwiirivethi aphantse alingane, kwimeko apho ukutshexa kweerivethi kuyinto ephambili.
Umthwalo wokugqabhuka: Indlela yokubethelwa kwee-rivet phantse ayinampembelelo ku τBV. Amandla okushelela τBV eqhagamshelo phantse azimele kwinani lee-rivet, ulungelelwaniso lwazo, imilo yokuqhagamshela kwerivet; umthwalo wokugqabhuka uhambelana, ngokusondeleyo ngokwaneleyo, nomthwalo ofanayo kuzo zonke iirivet. Ezi ngxelo zisebenza kwakhona nakwiqhagamshelo eziqhelekileyo ezinezikhonkwane zokujika, nto leyo ethi ikhokelele kwisigqibo sokuba ukuxhathisa ekutyibilikeni akunampembelelo ibalulekileyo kumthamo wokuthwala umthwalo.
Ubungakanani: Kwiinkqubo zentsimbi nakwizinti ezithwala umthwalo oneziko, kubalwa ngokusasazwa okufanayo, oko kukuthi kwirivethi nganye N = S/n. Kuba kumalungu alandelelanayo amade iirivethi zokuqala sele zixinaniswa kakhulu kwangethuba, kungcono ukunqanda ngaphezu kwe6 iirivethi zilandelelana enye emva kwenye xa kunokwenzeka.
Ukuxhathisa ukutyibilika: Ukutyibilika kwiidibaniso kuvela sele kumthwalo oncinane ngokwentelekiso. Ukuxhathisa ukutyibilika kuxhomekeke ikakhulu kumandla okuqinisa, wona atshintshwa zizinto ezininzi. Oku kushiywa kungahoywanga xa kubalwa iintlanganiso ezinee-rivethi neesikrufu ebezisetyenziswa ngokwesiqhelo ukuza kuthi ga ngoku. Kubhekiswa kwiintlanganiso ezineesikrufu ezomeleleyo.
Ukwabiwa kwamandla kwiirivethi ngobubanzi: Xa izithuba zeerivethi zilingana kwaye zithe nkqo kwicala lamandla (sl. 6a), kwiirivethi nganye zabelwa imitya yobubanzi obulinganayo a yeqhekeza elinqamlezayo, ngoko ke kuqikelelo lokuqala amandla kwiirivethi N = a t σ alingana. Ukwabiwa xa izithuba zeerivethi zingalinganiyo akusonjululwanga ngokwe-static; kwimeko esesl. 6b kwenzeka ngokomthetho wesibonda.
Fig. 6
Intonga etsaliweyo
Ukuqhubekeka: Ukuqhubekeka ngeehangeri ezilinganayo (umz. 3 kunye 4). Amandla S kwintonga kwindawo yokuqhubekeka kufuneka athwalwe kuphela yihangeri. Iintsimbi zokudibanisa ekuqhubekekeni nazo kufuneka zilungiselelwe ngokwe S, kuba kufuneka zithumele onke amandla asuka kwintonga eqhubekayo aye kwiihangeri.
Amadibaniso anebhande elinye elingaphambili anxulunyaniswa noxinzelelo olongezelelekileyo olukhulu lokugoba kwiipleyiti ezidibeneyo, kwiibhande naserivet. Ukugqunywa kwelinye icala kwamadibaniso kusetyenziswa ngenxa yokuguquka okukhulu kuphela xa (sl. 7) umqadi uqinile ekugobeni okanye xa ubotshelelwe ecaleni ukuze ungakwazi kugobeka.
Umz. 7
Ulwandiso olungathanga ngqo – Xa imitya yokubamba ingenakubekwa ngqo phezu kwamaphepha aqhubekileyo, iirivethi kunye namaphepha zifumana uxinzelelo olukhulu ngakumbi lokugoba. Ngenxa yoko, ngokwenani m leemaleko kuphakathi kukhethwa inani elikhulu n’ leerivethi kunenani n ekugutyungelweni ngokuthe ngqo kweendawo zokudibanisa.
Umz. 8
Kwiindawo ezidibeneyo iintsimbi ezibophelelayo zicwangciswa ukuze kuphetshwe ukunyuka kwendawo koxinzelelo, ngoko ke umphezulu ngamnye weentambo zokubopha umiselwa ngokommandla wendawo yecandelo abaligubungelayo, kangangoko kunokwenzeka kugcinwa indawo yeziko lobunzima. Ukuhanjiswa kwemimandla yeentambo zokubopha okuphambukayo kuxhunywe notshintsho ekuhanjisweni koxinzelelo. Kwi-sl. 9 kuboniswe ukuqhubekeka kwentsimbi enodonga olunye, kwi-sl. 10 yentsimbi enamalungu amabini nge-4 amacwecwe athe nkqo kunye nobuso obunye phakathi kwee-angle bars.
Umz. 9
Fig. 10
Isidibaniso: Kwiidibaniso zeentonga ezitsaliweyo, ngokusisiseko kusebenza ubudlelwane obufanayo nobo bokuqhubekeka. Uvavanyo lubonise inzuzo enkulu yokungeniswa kwamandla ngokulinganayo. Kwisidibaniso esisecaleni elinye, kubakho ukugoba okukhulu kwicala lobude nakwicala elinqamlezayo (umz. 11). Nangona kukho uxinzelelo olongezelelekileyo lokugoba, iintonga ze-L ne-C ezixhonywe kwicala elinye zinokuxhatshazwa phantse ngokupheleleyo. Umthamo wokuthwala wesidibaniso esinye unokwehla ube sisiqingatha ukuba amanyathelo okulinganisa iimeko ezongezelelekileyo zokugoba engathathwanga.
Umz. 11
Ukugquma amadibaniso akufuneki kuthathwe iipleyiti zamajoyinti, ngenxa yoko kufuneka kuqikelelwe iibhandi ezikhethekileyo. Ukudityaniswa kwepleyiti yejoyinti kuququzelelwa xa inxalenye enkulu yecandelo lomqadi iwela kwinqwelo-moya yepleyiti yejoyinti.
Sl. 12 - Unxibelelwano olunekona yonxibelelwano kunye nolungenayo
Intonga ecinezelweyo
Kwandiso nokudityaniswa kweentonga ezicinezelweyo kusebenza imigaqo efanayo naleyo yeentonga ezitsalweyo, yaye kuzo umthamo wonke udluliselwa ngeerivethi kunye neebhanti zokubopha, oko kukuthi, ngokommandla ogcweleyo F wentonga kuyilinganiswe Fpodvezica kunye ne Fs, oko kukuthi Fl. Ngokomgaqo imimandla yokwandiswa ayihambelani ngokuchanekileyo. Kwiinkqubo zentsimbi zokwakha izakhiwo, kwiintsika ezihamba kwimigangatho emininzi, ezilayishwe kuphela ngoxinzelelo, kusetyenziswa ithuba lokudlula ngokugqunywa okuncinci kweendawo zokwandiswa. Umthamo wokuthwala weentonga ezicinezelweyo uphelile, ukuba ngaphambi koko azivelanga iimeko zokungazinzi, ngokufika komda wesivuno, kuba ngelo xesha kuvela ukuguquka okukhulu yaye intonga iyagoba ecaleni. Imingxuma egcwaliswe ngeerivethi ayinampembelelo, enokuqinisekiswa, kwindlela intonga eziphatha ngayo.
Amandla ekudinweni kweentlobo ezirivetiweyo
Komelela kokudinwa kwee-joini ezirivetiweyo, kuqala kuqwalaselwa iincopho zoxinzelelo ezivela kumaqhuqhuva emingxunya. Amandla okudinwa ancitshiswa kakhulu sele yimingxunya ngokwayo. Imivalo enemingxunya evulekileyo iyaphuka kwiimvavanyo zokudinwa phantsi kokutsalwa kwiindawo ezibuthathaka, yaye ukophuka kokudinwa kuqala ngeentanda emaphethelweni omngxuma, ezihlala ziqhubeka zisasazeka ngaphesheya kwecandelo. Ngoko ke, imingxunya egudileyo ibaluleke ngokukhethekileyo. Kwi. 13 kunikwe amandla okudinwa eemivalo ezithe tyaba kwiindidi ezahlukeneyo (ngasekunene kukho udidi oluphezulu lwentsimbi). Kumaqondo omthwalo wangaphambili aphezulu σu, zombini izixhobo zimelana namandla okudinwa σDz angaphezulu komda wokuvuma ukuhamba. I-amplitude yoxinzelelo ifana phantse kuzo zombini iindidi.
Umz. 13 - Amandla okuchasana nokudinwa σDz
Kumthwalo otshintshanayo wokutsalwa noxinzelelo lwezixhumanisi ezirivetiweyo, zisebenza ngokusisiseko iindlela ezifana nezo zemithwalo engaguquguqukiyo. Kuyafaneleka ukuqaphela ukuba i-amplitude yoxinzelelo phantsi komthwalo otshintshanayo inkulu malunga 1,5 amaxesha (fig. 14), kodwa ii-rivets phantsi kwalo mthwalo zisengozini enkulu kakhulu kunaphantsi komthwalo ongaguquguqukiyo.
Sl. 14 - Amandla ekudinweni ekuqiniseni kweentsebenziswano ezirivethiweyo