Modulus ntawm elasticity ntawm qhob: dab tsi nws yog thiab yuav ua li cas txhais tau?

Yog li ntawd muaj coob tus neeg xav nyob rau hauv yuav ua li cas los txhawb lub tsim ntawm ntau yam pob zeb ua lub dag lub zog thiab tej yam load. Qhob yog ib tug khoom lub cev muaj ib tug ib txwm los kom tiv thaiv deformation thaum raug mus rau sab nraud rog. Nws yog ib lub peev xwm rau elastic deformation (ib ntus xwm) qhia lub pob zeb modulus ntawm elasticity.

Lub magnitude ntawm elasticity tau txiav txim txawv qauv kev ntsuam xyuas rau kuj mus nro los yog compression. Txawm li cas los, yuav tsum paub hais tias lub pob zeb, uas tsis muaj qhov cuab lub zog, tensile tsis ruaj tsis khov. Raws li cov kev xeem tau npaj tawm sab ntawm lub thov cov ntaub ntawv uas rau lub dag zog. Visibility txhawb rau ib tug zoo dua kev nkag siab. Nws tseem yog tsim nyog los paub qhov pib modulus ntawm elasticity ntawm vaj tse thiab tus nqi ntawm cov deformation.

Nyob rau hauv load, deformation nce vim lub fact tias pob zeb ua muaj ib tug xws li nkag. Ua ntej, nyob rau hauv ib tug tej yam siab, muaj tshwm sim elastic deformation. Nws yog ib tug tshwm sim nyob rau hauv uas lub cev yog deformed los ntawm ib tug load rov qab mus rau nws qub daim ntawv tom qab nws lub disappearance. Ces, thaum ntxiv load nyob rau hauv cov ntaub ntawv uas pib tshwm sim, irreversible (yas) deformation. Txawm li cas los, faib yas thiab elastic hloov nyuaj heev. Vim hais tias cov instantaneous hloov nyob rau hauv tus duab nyob rau cov kev ceev ntawm load nce. Vim hais tias ntawm no deformation thaum lub sij hawm load nce yog hu ua elastic, thiab ib tug ntxiv nce nyob rau hauv deformities - yas. Nws yog vim lub creep ntawm qhob. Ntxiv deformation yog twb kev puas tsuaj ntawm tus kwv. Qhov no modulus ntawm elasticity ntawm qhob yog feem ntau kuj hu ua modulus ntawm deformation. Nws yog txiav txim siv ntau hom kev kawm.

Modulus ntawm elasticity ntawm qhob yog txiav txim los ntawm tus thawj nyuaj heev. Txawm li cas los, nws approximate nqi tau muab teev kov. Muaj ntau kab kos secant kab rau qhov nkhaus, reflecting dependence ntawm kev nyuaj siab-lim, ntau heev, tab sis yog tsis ib txwm, thaum uas tig mus rau lub tangent, uas mus los ntawm lub keeb kwm.

Kuj ncaj ncees rau lub assertion uas lub pob zeb modulus ntawm elasticity tsub kom nyob rau hauv ncaj qha kev faib ua feem rau cov hauv paus hniav ntawm nws lub dag lub zog. Txawm li cas los, qhov no yog muaj tseeb tsuas yog rau cov qhov tseem ceeb ntawm lub teeb (kev nyuaj siab-lim) thiab nyob rau ib puag ncig thiab lub xeem tej yam kev mob. Raws li ib qho piv txwv, cov dej-roj nyeem cov ntaub ntawv uas nyob rau hauv kev xeem muaj ib tug ntau dua modulus ntawm elasticity index tshaj qhuav kuaj. Txawm hais tias lawv lub dag lub zog zog yog zoo sib xws.

Nyob rau modulus ntawm elasticity heev cuam tshuam qhov zoo tshaj ntawm ntxhib sau ua ib pawg. Qhov no dependence yog rectilinear. Lawm, lub cev ntawm khaub-ncaws nyias qhob yuav qis tshaj hnyav kuaj. Lub elasticity kuj yuav tsub kom nrog lub hnub nyoog ntawm cov ntaub ntawv. Piv txwv li, lub modulus ntawm elasticity ntawm qhob B25, yuav tsum muaj ntau ib xyoo dua nws yog chiv, tab sis tom qab 10 lub xyoo nws yuav loj hlob ntau heev tshaj dua. Yuav kom txiav txim seb qhov ciaj ciam ntawm elasticity muaj ib tug tshwj xeeb lub rooj, uas qhia tau hais tias cov approximate thawj zaug modulus ntawm cov khoom ntawm txhua hom.