Thaum cov hlau hlau tau kos, vim kev sib txhuam ntawm cov hlau thiab cov pwm, nws yooj yim los qhia lub xeev nyuaj ntawm kev ntxhov siab, uas ua rau faib tsis sib xws ntawm cov deformation sab hauv ntawm cov hlau hlau. Qhov kev faib khoom tsis sib luag no tau pom los ntawm lub tshuab kev pom, uas pom tau tias yog kev faib tawm kev ntxhov siab tsis sib luag. Nws nce qhov tsis kam ua kom deformation ntawm cov khoom, ua rau nws nyuaj rau deform cov khoom, ua rau nws nyuaj rau cov khoom tsim, thiab nce qhov nyuaj ntawm kev tsim khoom; thib ob, qhov kev nyuab siab ntxiv uas tsim tau yooj yim, tom qab lub zog sab nraud raug tshem tawm, tseem muaj qee qhov kev nyuab siab nyob hauv cov hlau. Cov kev nyuab siab uas seem, cov vectors ntawm cov kev nyuaj siab seem no muaj ntau txoj kev qhia, feem ntau muab faib ua ob pawg:
Ib qho yog lub zog tensile ntawm cov hlau saum npoo;
Qhov thib ob yog qhov kev nyuab siab hauv cov xaim.
Nyob rau hauv qhov xwm txheej ntawm kev nkag siab, ob hom kev ntxhov siab no sib npaug nrog ib leeg, uas tau tshwm sim hauv kev ncaj ncees ntawm cov hlau hlau thiab qhov ua tau zoo ntawm cov khoom siv dag zog. Thaum cov hlau hlau tau sib tw, nyob rau hauv hom kev nyuab siab no, cov txiaj ntsig sib txawv yuav tshwm sim, pom nyob rau hauv cov lej sib tw thiab seb qhov sib tw tau faib los yog tsis.
