Iingcinezelo eziqhelekileyo kwizinti ezithe tye nakwizinti ezinomgca ogobile kancinane
Inkcazelo yamandla asikiweyo
Makube ngumqadi othe nkqo otshajwe ngemikhosi enesalathiso esingacwangciswanga, ekucingelwa kuphela ukuba zonke zilele kwinqwelo-moya enye (inqwelo-moya yemikhosi) edlula kwi-axis yomqadi (umgca odibanisa amaziko obunzima eecandelo ezinqamlezayo).
Umz. 1
Ukuze kubalwe uxinzelelo olusebenza kwicandelo lomnqamlezo n – n (umz. 1), kufuneka kwaziwe amandla agqithiselwa ngeli candelo ukusuka kwenye inxalenye yentonga ukuya kwenye. Ngokuqinisekileyo, ngobukhulu nangesikhundla, lilingana neresulti yawo onke amandla ahlasela inxalenye enye yentonga. Esi siresulti sahlulwa sibe zizakhi kwinkqubo yolungelelwaniso apho i- x-axis ihambelana ne-axis yentonga, yaye i- z-axis ngumgca apho inqwelomoya yecandelo lomnqamlezo isika khona inqwelomoya yamandla. Isakhi kwicala le-axis z sibizwa ngokuba ngamandla e-transversal Q okanye Qz yaye kwibim elula kuthathwa njengelilungileyo xa ngasekhohlo kwecandelo lisenza phezulu, kanti ngasekunene lisihla.
Xa umqadi ugobile, ii-axis ezilungelelanisiweyo x no z kwicandelo ngalinye zinendlela eyahlukileyo, kwaye kusoloko kunjalo ukuba i-x-axis yitangent kwi-axis yomqadi. Ukuba inqwelo-moya ekuyo i-axis yomqadi ayihambelani nenqwelo-moya yemikhosi, okanye ukuba i-axis yomqadi ligophe elisemathathu, isiphumo semikhosi ngasekhohlo kwecandelo sinento yesithathu nayo, amandla anqamlezileyo Qy. Nge N, Qz kunye Qy kugqitywa ubukhulu kunye nendlela yamandla adluliselwa ngecandelo, kodwa hayi indawo yawo. Kule nto kuyimfuneko ukuba kwaziwe nemizuzu yawo ngokubhekiselele kwi-axis ezilungelelanisiweyo. Kwimeko yokugoba okuthe tye kwanele ukuba yaziwe umzuzu wokugoba M okanye My. Kwimeko eqhelekileyo kakhulu kuvela omnye umzuzu wokugoba Mz kunye nomzuzu ojikeleze i-x-axis, Mx.
Amandla nemizuzu emithandathu echazwe kwingxoxo engaphambili zibizwa ngegama elidibeneyo elithi „imigudu yesiqendu“. Ukuzimisela kwazo yenye yemisebenzi esisiseko yeestatiki yezakhiwo zobunjineli.
Phakathi komthwalo osasazeke ngokuqhubekayo p (umlinganiselo: amandla kwiyunithi yobude), amandla e-transverse Q kunye nomzuzu wokugoba M kukho, kwimeko yokugoba okuthe tye, ubudlelwane obulula. Oko kukuthi, ukusuka kwimeko yokulingana kwento enye yebha (sl. 2) kufumaneka
dQ + p dx = 0,
dM = Q dx;
ke ngoko
Q = dM/dx,
p = - dQ/dx = - d2M/dx2. (1a, b)
Fig. 2
Ukwabiwa koxinzelelo oluqhelekileyo
Ukuba intonga ilayishwe kuphela ngamandla e-axial, kwisiphambuka kuvela kuphela uxinzelelo oluqhelekileyo olusabalalisiweyo ngokufanayo σ (intonga etsalwayo, okanye ecinezelweyo). Ukuba kunye nalo kuvela i-moment yokugoba, ezi ngxinzelelo kufuneka ngandlel’ ithile zisasazwe ngokungalinganiyo, ukuze umphumo wazo onzulu ungadluli kwakhona kumbindi wesiphambuka. Ukuze kumiselwe olu lwabiwo, ithiyori yobunjineli yokugoba ayiqali ngesisombululo esingqongqo see-equation ezisisiseko, koko ithatha indawo yendawo yazo ngengcinga enengqiqo, ethi kwimeko enye elula kakhulu nayo izalisekiswe ngokungqongqo. Le meko ikhethekileyo kukugoba kwentonga yeprism ethe tye ngaphandle kwesenzo samandla athambekileyo (sl. 3). Zonke iindawo zentonga ezikude ngokwaneleyo kwiziphelo zayo zifumana ukuguquka okufanayo, okuvela ngqo ekubeni umgca ophakathi wentonga uguquka ube sisangqa esithile, kwaye zonke iiplani zeesiphambuka ebezithe nkqo kumgca ophakathi wentonga ekuqaleni zihlala zithe tyaba ngexesha lokuguquka, kuba nganye kuzo yiplani yokulinganisa yamalungu akufutshane entonga egogekileyo. Ngokwendalo kuvele ingcinga yokuba iziphambuka zihlale zimalunga neflat naku xa i-moment yokugoba kunye nesiphambuka sentonga zingengqinelani, koko zitshintsha kancinci kancinci ecaleni kwentonga. Le ngcinga, ebizwa ngokuba yi-Navier-ov ingcinga, isisiseko sethiyori yokugoba.
Umz. 3
Ubungakanani boxinzelelo oluqhelekileyo
Xa into ethe tye yomqadi igotywa, inxalenye ye “fayibha” zayo, oko kukuthi, imigca yezinto ehambelana ne-asi yentonga, iyoluleka, logama enye inxalenye iyafutshanezwa (umz. 4). Phakathi kwezi nxalenye zimbini kukho iifayibha ezingathathi cala z=0, ubude bazo abutshintshi xa kugotywa. Makube semitha yokugoba yala fayibha kwimeko egotyiweyo ϱ kwaye makube ilele kwindiza x-z. Ukusuka kumz. 4 m kunokufundwa
Δ dx/z = _dx/_ϱ
kwaye ukusuka apho ukunyuka kwemicu okubalwa kumgama z ukusuka kwi-asi engathathi cala, okulingana
ε = Δ dx/dx = _z/_ϱ
ngoko ke, ngokusekelwe kumthetho ka Hooke-, uxinzelelo
σ _= Ez/_ϱ (2)
Fig. 4
Olu xinzelelo lulingana nomgama ukusuka kwiintsinga ezingathathi cala. Isiphumo esinjalo sixhomekeke kwingqikelelo yokuba ngaphambi kokuguquka zonke iintsinga zento yebha zazilingana ngobude, ukuze ibha ekuqaleni ibe ngqo, okanye ubuncinane igobe kancinci kangangokuba impembelelo yokugoba inokungahoywa. Umgca othe ngqo apho umaleko ongathathi cala kunye neplane yecandelo zidibana khona ubizwa ngokuba yi-axis engathathi cala. Siyamkela le yathi y-axis (umz. 5). Isikhundla se-axis engathathi cala kumacandelo anqamlezayo sifunyanwa ngokwemeko yokulingana kwamandla kwicala le-x-axis: ukuba amandla aqhelekileyo N=0 (ukugoba ngaphandle kwamandla aqhelekileyo), ngoko ke nesiphumo samandla angaphakathi esichazwe ngoxinzelelo oluqhelekileyo kumacandelo kufuneka silingane noziro:
I-integral kwicala lasekunene ngumzuzu wokuqina wommandla ngokunxulumene ne-axis y. Ukuze ube zero, le axis kufuneka ibe yenye ye-axes yendawo yeziko.
Umzuzu M obangela ukuguquka unezinto kumba we-axes y no z kwinqwelo yecandelo lomnqamlezo (umz. 5):
Iyun. (3)
apho Iy, Iyz ziyi-equatorial kunye ne-centrifugal moment ye-inertia yecandelo ngokumalunga nee-axis ezichaziweyo.
Eyona meko ikhethekileyo ibalulekileyo yile xa Mz=0. Le meko yenzeka xa Iyz=0, oko kukuthi xa y ne z zizixhobo eziphambili ze-inertia zecandelo. Oku kuthetha ukuba iplani yokugoba, ethatyathwe apha njengokuhambelana ne x-z-plani, iyahambelana neplani apho kusebenza khona umzuzu wokugoba M=My, oko kukuthi neplani yamandla.
Umz. 5
Ukuba kwizibalo (2) no (3) kususwa _E/_ϱ, kufumaneka ifomula yokumisela uxinzelelo ekugobeni okulinganayo (Iy=I):
σ = M/I * z (4)
kwiindawo zomphetho 1 kunye 2 ngokukodwa luthi:
σ1 = M/I * h1 = M/W1, σ2 = - M/I * h2 = - M/W2. (5)
Iimilinganiselo W1,2 = I/h1,2 (umlinganiselo: ubude ukuya kweyesithathu) zibizwa ngokuba ziimomenti zokuxhathisa. Ukuba i-axis ethe tye yesikhuselo sobunzima ikwangumyinge wokulingana kwesiqwenga, ngoko W1 = W2, ngoko ke iingcinezelo zomphetho ziyalingana ngobukhulu obupheleleyo.
Umgca wokunwebeka
Fig. 6
Ukubaluleka kwezi fomula zikhankanywe ngasentla kunxulunyaniswe nomthetho kaHooke. Oko kufuna ukuba σ << E, ngoko ngokwe (2) h << ϱ. Ukugoba nangona kunjalo kunokuthi kube kungako kangangokuba ϱ ibe ngolungelelwano olufanayo nobude bentonga l. Kwimivalo egobileyo efikelelwa kulwakhiwo imeko le ayiveli; rhoqo ϱ inkulu kakhulu kune l yaye ke ngoko ukugoba w << l (umz. 6). Emva koko kusemgangathweni ngokuqikelela:
1/ ϱ = - d2w/dx2 = -w’’
kwaye ngokusekelwe ku (3):
w’’ = - M/EI.
Le equation kunye nemeko yokulingana (1b) zenza inkqubo yee-equation zediferenshile yentonga egobileyo. Zingancitshiswa ngokususa zibe yi-equation enye yesidanga sesine:
wIV = + p/EI
okanye, xa umzuzu we-inertia uguquguquka:
(EIw’’)’’ = +p.
Kuzo ngokudibanisa kunokufunyanwa imilo yomgca we-elastic xa umthwalo unikiwe p=p(x) yaye xa kwizakhi zentonga nganye kusaziwa iimeko ezimbini zomda. Kuzo, ubuncinane ezimbini kufuneka zibhekiselele ekuguqukeni. Ngokweenkcukacha jonga inqaku Statika građevinskih konstrukcija.
Undoqo wecandelo lomnqamlezo
Ukuba i-asi engathathi hlangothi isika icandelo elinqamlezileyo, iyahlula ibe yindawo yoxinzelelo lokutsala kunye nendawo yoxinzelelo lokucinezela. Kwizinto ezinokuqina okuncinane ekutsalweni kuvela umbuzo wokuba amandla oxinzelelo kufuneka asebenze phi, ukuba kwicandelo elinqamlezileyo akufanele kubekho tsalo naphi na. Indawo yesigxina samandla ngoko ke isikelwe kwindawo ebizwa ngokuba yi core yesiqendu. Umda we-core ngokucacileyo yindawo yeendawo apho ii-asi ezingathathi hlangothi zichukumisa icandelo elinqamlezileyo kumjikelezo walo. Ngale nto kwangaxeshanye kunikwa nendlela yokwakhiwa kwayo.
Umgama womda wengqikithi ukusuka kumbindi wobunzima, olinganiswa nakweyiphi na indlela, siya kuwuchaza ngo k isalathisi esihambelana naloo ndlela. Kwiiaxis eziphambili ze-inershiya ngokomgca
σ = N/F + Mz/Iz y + My/Iy z (6)
amabinzana alandelayo ngala:
ky = i2z / ey, kz = i2y / ez. (7)
Kumqolo wesangqa onomlinganiselo werediyasi r umgama we-nucleus ngu k = r/4, yaye kwiringi yesangqa (iirediyasi: engaphandle R, engaphakathi r) k = (R2 + r2) / 4R.
Kwirekhthangile (umz. 7) ky = 1/6 b, kz = 1/6 h. Ngoko ke, xa kutyityelwa icandelo lekhonkrithi elingunxande kwenye yeenqwelomoya zokulinganisa (kodwa kuphela apho) kwanele ukuba isiphumo sokusebenza sichaphazele isithathu esiphakathi sobude okanye sobubanzi becandelo elinqamlezileyo, ukuze iintsimbi zoxinzelelo kwicandelo zibe nophawu olufanayo.
Umz. 7
Ukugoba kummandla weplastiki
Xa umda wokunwebeka ufikelelwe kwimicu esemaphethelweni yalo mvalo ogobekileyo, amandla awo awaka agotyi ngokupheleleyo, kuba ngoxa imicu yangaphandle iguquka ngokweplastiki phantsi koxinzelelo olungatshintshiyo, kumacandelo asondele kakhulu kwi-asi engathathi cala, apho umda wokunwebeka ungakafikiwa khona, uxinzelelo luyenyuka, ngaloo ndlela kunyuka nembalelwano yokugoba enokuthwalwa licandelo.
Ukuba kwaziwa ngokuthe ngqo indlela edlula ngayo idayagram yoxinzelelo kunye nokuguquka, inkqubo yeendawo ezine-symmetry ephindwe kabini (ubude h) inokulandelwa ngokulula ngokubala ngolu hlobo ukuba, phantsi kwengcinga yokuba amacandelo ahlala ethe tye, kwidayagram yoxinzelelo kunye nokuguquka kumiselwe ulungelelwaniso loxinzelelo σ oluphuma ekugobeni oluhambelana nokolulwa kwamafayibha okugqibela ε__r okukhethiweyo, yaye ukusuka apho ngomdibaniso kumiselwe umzuzwana wokugoba. Ukuba oku kwenziwa ngee- ε__r ezahlukeneyo yaye kwelinye icala kubalwe igophe elihambelanayo lomgca wokugoba w’’ = 2 ε__r / h, kufumaneka uluhlu lwamanqaku apho kunokutsalwa umgca onika unxibelelwano phakathi komzuzwana wokugoba kunye negophe M = M(w’’); olu nxibelelwano alusiseyomgca tye, kwaye xa sele lwaziwa kunokwenzeka ngokudityaniswa komzobo ukumisela umgca wokugoba ohambelana nolungelelwaniso olunikiweyo lweemomenti. Ukuba icandelo alinasymmetry, ukubala kuba nzima ngakumbi, kuba kwisebe ngalinye ε__r kusafuneka kumiselwe nendawo ye-asi engathathi cala.
Umz. 8
Ukubala kuthungelwa ngandlel’ ithile ukuba, ngaphandle kokufana kwesigaba, kucingelwa kwakhona unxibelelwano olulula phakathi kweengcinezelo neenguqu ngokwe sl. 8. Emva koko iingcinezelo ngenxa yokugoba emva kokudlula umda wesivuno zinolungelelwaniso oluboniswe kwi sl. 9 yaye umzuzu wokugoba ngu:
yaye igophe lomgca wokugoba lifunyanwa xa isibalo (2) sisetyenziswa kwindawo yecandelo enezixinzelelo ezikwindawo ye-elastic w’’ = σf / Ez’. Ukuba imilo yecandelo iyaziwa kuyo yonke z’ eyamkelweyo, ii-integral zingabalwa. Umzekelo, kweyona meko ilula yecandelo elixande elinobubanzi b nobude h ngu
Ukuba apha z’ ichazwa kusetyenziswa w’’, kufumaneka
Kwii-I-sections nakwezo zifana nazo, indlela ye-M-w’’ curve kummandla weplastiki ithe tyaba ngakumbi, yaye umzuzu apho kuqala ukuhamba kwezinto ngoku ulingana phantse nomzuzu omkhulu wokugoba onokuthi elo candelo likwazi ukuwuthwala. Ngoko ke, ukubaluleka kokugoba kweplastiki kulwakhiwo alukho ekwandiseni umzuzu wokugoba onokuthwalwa licandelo, koko kusekutheni ukuguquka okukhulu kwendawo okuvela kumda wokuhamba kunokukhokelela kutshintsho oluluncedo kulwabiwo lwamandla kwiinkqubo ezineengongoma ezingamiswanga ngokwezibalo.
Umz. 9
Oku kunokucaciswa ngomzekelo wesinqe esiqhubekayo phezu kwamacandelo amabini. Masithi isinqe (sl. 10) sinamacandelo anobude obulinganayo, umnqamlezo ongatshintshiyo yaye silayishwe ngomthwalo osasazwe ngokulinganayo. Ngoko ke, ngaphambi kokufikelela kumda wesivuno, umzuzu ngaphezu kwenkxaso MB = _pl_2/8. Ukuba umthwalo p wandiswa kangangokuba umzuzu kwicandelo lenkxaso ufikelele kwixabiso Mf apho kuqala isivuno, xa umthwalo uqhubeka ukwandiswa kule ndawo kugoba kuya kunyuka nakhona ngaphandle kokunyuka okubonakalayo komzuzu. Kwenzeka oko kubizwa ngokuba yi-plastični zglob, oko kukuthi isinqe siziphatha phantsi komthwalo owongezelelekileyo ngokungathi kukho ihinji ngaphezu kwenkxaso ephakathi. Umthwalo unokunyuswa ngakumbi de kuqalise isivuno nakwindawo yomzuzu omkhulu kwicandelo. Ukunyuswa ngakumbi komzuzu wokugoba akusavumelekanga yaye amandla okuthwala isinqe aphelile. Umthwalo apho le meko iqala khona ubizwa ngokuba ngumthwalo womda.
Fig. 10
Ngokubanzi kunokulindeleka ukuba kwinkqubo enye engamisiweyo ngokomstatshiyo izihlandlo n kuya kufuneka kuvele (n+1) amahenjisi eplastiki ngaphambi kokuba inkqubo ibe nentshukumo, yaye ngaloo ndlela ifikelele kumda wayo wokuthwala umthwalo. Lo mgaqo, nangona kunjalo, unamathuba okungqinelani macala omabini. Njengoko umzekelo okhankanyiweyo ubonisa, kumda wokuthwala umthwalo kunokuvela ngaxeshanye amahenjisi amabini amatsha eplastiki (kwizithuba zombini), ukuze inkqubo ebisesezime ngendlela engashukumiyo ide ngoku ngexesha elinye ibe yinkqubo enenkululeko ezimbini zokuhamba. Kwelinye icala kunokwenzeka ukuba kwanxa kukho ngaphantsi kwe (n+1) amahenjisi eplastiki, umthamo wokuthwala uphelelwe ekuhlaleni, umzekelo xa kwityhubhu eqhubekayo kusilela isithuba esinye kuphela. Sl. 11 sibonisa ukuba oku kunokwenzeka njani kwinkqubo enye engamiswanga ngokomstatshiyo kabini enama n=2 amahenjisi eplastiki. Ukuba kwicala lasekunene lomhambisi kongezwa nesithuba sesine, umhambisi uba ngongamiswanga ngokomstatshiyo kathathu, ngoko ke kwanele (n-1) amahenjisi eplastiki ukuze kuphela isithuba sasekhohlo siziswe kumda wokuthwala umthwalo.
Umz. 11
Iingcinezelo zokushelela xa kugotywa
Ubalo olusisiseko
Fig. 12
Uxinzelelo oluqhelekileyo σ, oko kukuthi uxinzelelo oluthi eneneni luvele ngenxa yokugoba, ayizizo kuphela iintlobo zoxinzelelo kwintonga egobileyo, koko ukongezelela kuzo kuvela noxinzelelo lokucheba ngenxa yempembelelo yamandla anqamlezayo. Ngenxa yokuba uphawu olusisiseko lwethiyori yobugcisa yokugoba kukuba iinguqu ngenxa yoxinzelelo lokucheba ziyalahlwa, ezi zinokumiselwa kuphela kwiimeko zokulingana. Ukuze oku kumiselwe, into yomqadi dx iyasikwa, njengoko kuboniswe kumz. 12, ngendiza ethe tye ibe ngamacandelo amabini, kuze kubekwe imeko yokulingana kwamandla athe tye asebenza kwicandelo elisezantsi. Kwicala lasekhohlo lawo ngamandla angaphakathi abonakaliswa ngoxinzelelo σ ngenxa yokugoba, ekufuneka kuhlanganiswe ukusuka z’ = z ukuya ku z’ = h2
Kwelasekunene zisebenza iindawo zoxinzelelo ezifanayo, kodwa zonyuswe nge-differential ngokungqinelana nomzuzu wokugoba M + dM. Umahluko phakathi kwemikhosi kumacala omabini e-elementi kufuneka ube semalungwini namandla avela kwiinkxalabo zokucheba τ ezisebenza kumphandle wokusika othe tye t dx:
Apha i-integral imele umzuzu wesatic wenxalenye yecandelo lokunqamlezana elahlulwe ngumqolo owela ngokuthe tye xa kuthelekiswa ne-axis yesiseko yecandelo. Iboniswa ngo S. Ngoku dM/dx = Q ukusuka kwimeko yokulingana kufumaneka:
τ = QS/It. (8)
Ngokwemfundiso yokudityaniswa koxinzelelo lokutsheyisa, oku kukwangumlinganiselo woxinzelelo lokutsheyisa oluthe nkqo olusebenza kumphezulu wenqamlezo kwaye, kunye no S no t, lusebenza njengo msebenzi ka z.
Fig. 13
Umz. 13.1
I-equation (8) inika idatha ethembekileyo kuzo zonke iindawo ezinqamlezileyo ezineendonga ezibhityileyo ukuba iplani yokunqamla ayibekwanga ngaxeshanye ne-axis engathathi cala, koko ibekwe kwicala lobukhulu bodonga. Ngoko ke iprofayili ye-I inqunyulwa ngokunqamlezileyo kwi-web nangokunqamlezileyo kwi-flange, nto leyo efumana ukuhanjiswa koxinzelelo oluboniswe kumz. 13.1. Kwinqamlezo yesangqa (umz. 13) iimeko zokusika zisasazwa ngokulinganayo ngokunxulumene nedayimitha ethe nkqo yaye ekhohlo nasekunene kumgca ongathathi cala zifikelela kubuninzi
τ = Q / πrt.
Ukuba icandelo lisikiwe kwindawo ephezulu kakhulu okanye esezantsi kakhulu, ulungelelwaniso loxinzelelo lweshearing alutshintshi; nangona kunjalo, ukuba lisikiwe ekupheleni kwasekunene komda othe tye (sl. 14), uxinzelelo lwe-shearing kuloo ndawo lulingana no-zero, logama ixabiso lalo liphindaphindeka kabini ekupheleni kwasekhohlo kwaloo mdidi mnye.
Umfanekiso 14
Amacandelo apheleleyo
Kwiiseksyon eziqinileyo zazo nayiphi na imilo ingxaki yoxinzelelo lokucheba inxulumene ngokusondeleyo nengxaki ye-torsion. Ulingano olusisiseko (8) kuloo meko alusekho luthembekile. Kwisection ejikelezayo eneradiyasi r ulingano (8) lunika
τ = 4Q / 3__πr2
njengexabiso eliphakathi loxinzelelo lokucheba ecaleni kwe-asi engathathi cala, yaye ixabiso elichanileyo likhulu kuphela ngeepesenti ezimbalwa.
Indawo yokucheba
Ukuba izixininisi zokucheba zibalwa kwicandelo U ngendlela echazwe ngasentla, kufumaneka ulwabiwo loxinzelelo oluboniswe kwifig. 15. Iresultanti yamandla angaphakathi afanelekileyo ngumkhosi wetransversal Q. Kumfanekiso kunokubonwa indawo yawo ngokumalunga necandelo, ngoko ke aludluli embindini wesisindo secandelo, kwaye aluhlali kwinqwelomoya yembambo. Ukuba umkhosi wetransversal obalwe ngokusekelwe kumandla angaphandle awunayo indawo eboniswe kwifig. 15, umqadi awuxinzekelwanga kukugoba kuphela, koko nakwitorhshoni.
Ukuba kwisigaba esinye esinqamlezayo kumiselwa umphumo olingana noxinzelelo lokucheba lomthwalo othile othe tye, kufunyanwa umgca wokuhlasela womkhosi onqamlezayo othe tye. Kwindawo yokudibana kwale migca mibini yokuhlasela kukho indawo ephawulweyo yesigaba esinqamlezayo esinikiweyo, ebizwa ngokuba iziko lokucheba M. Kuxhaso akubonakali iingeni ngenxa yetorshini xa amaziko okucheba azo zonke izigaba ezinqamlezayo alele kumgca omnye, yaye yonke imithwalo ethe nkqo kwi-axis yentonga idlula kulo mgca. Kungenjalo, umzuzu womthwalo ngamnye ngokuthelekiswa nomgca odibanisa amaziko okucheba umele ukucheba kwe-torsional.
Umz. 15
Impembelelo yamandla ewela ngokuthe tye ekugobeni
Ithiyori yobugcisa yokugoba isekelwe ekungathathelweni ngqalelo kweenkohlakalo ezibangelwa ziingcinezelo zokusika. Ngoko ke inokwenziwa ngokwenene kwiintonga ezibhityileyo, apho oku kungathathelwa ngqalelo kufanelekile kwaye apho amandla athe tye angenampembelelo ibonakalayo ekugobeni.
Amava, nangona kunjalo, abonise ukuba ithiyori yezobunjineli yokugoba ingasetyenziswa ngempumelelo ethile nakwizixhaso ezimfutshane, eziphakamileyo, ekungekho njengoko kunjalo ezilungiselelwe yona. Ngelo xesha kuvela imfuno yokuba impembelelo yenguqu ngenxa yoxinzelelo lokucheba, ethe kule thiyori yathatyathwa njengengabalulekanga, ithathelwe ingqalelo, ubuncinane ngokuqikelela, emva koko.
Ngokunjalo njengoxinzelelo lokucheba τ ngenxa yemikhosi enqamlezayo kunye nokutyibilika okuhambelanayo γ_’ =_ τ_/G_ zisasazwa ngokungalinganiyo kuwo wonke umnqamlezo. Ngenxa yoko kufakwa ixabiso labo eliphakathi γ, elichongwa ngolo hlobo lokuba umkhosi onqamlezayo kulo mlinganiselo uphakathi wenguqu wenza kumalungu entonga dx umsebenzi wenguqu olingana nalowo ubuya kufunyanwa ngokudibanisa imisebenzi yoxinzelelo lokucheba kwiindawo ezithile zevolyum eziqulunqa icandelo lembonakalo yentonga:
ukuba ivela phi
Integral ingabalwa xa ulungelelwaniso lweengcinezelo zokusika ngokunqamlezayo lusaziwa. Kuba zonke iingcinezelo zokusika zilingana no Q/F, ke ixabiso layo lilingana no Q2/F2 * F, ngoko ke xa sibeka ukuba ngu κ__Q2/F, kufumaneka
γ = κ__Q / GF.
Isigxina κ sibizwa ngokuba ngumlinganiso wosasazo loxinzelelo lwasika. Kumaqhawulo anguxande κ=1,2.
Fig. 16
Xa i-coeff. κ, yaziwa, yaye ngenxa yoko nokuhexa okuphakathi γ, kunokubalwa ukuhexa okongezelelweyo wQ, okubangelwa yimpembelelo yamandla e-transversal, ekufuneka yongezwe kwihexa w: kuba ngokomz. 16 yi
ngoko ke ngenxa ye Q = dM/dx:
apho ke isalathiso sokudibanisa sifumaneka kumqathango omnye womda.