Kev kos duab yog ahlau ua haujlwmtxheej txheem uas sivtensilequab yuam kom ncabhlau. Raws li cov hlau tau kos (rub), nws stretches thinner, mus rau hauv ib qho kev xav thiab thickness. Kev kos duab yog muab faib ua ob hom:daim hlaudaim duab thiabhlau, bar, thiabcevdaim duab. Cov ntsiab lus tshwj xeeb rau daim ntawv hlau kos duab yog tias nws cuam tshuam nrog cov yas deformation hla lub axis nkhaus. Rau hlau, bar, thiab raj kos duab pib Tshuag yog kos los ntawm atuagtxo nws txoj kab uas hla thiab nce nws qhov ntev. Kev kos duab feem ntau yog ua nyob rau hauv chav tsev kub, yog li cais aua haujlwm txiastxheej txheem, txawm li cas los xij nws tuaj yeem ua tiav ntawm qhov kub siab rauua haujlwm kubcov xov hlau loj, rods los yog hollow seem kom txo tau lub zog.
Kev kos duab txawv ntawmdovhauv qhov ntawdsiabntawm kev kos duab tsis yog kis los ntawm kev tig ntawm lub zeb tab sis es tsis txhob nyob ntawm kev quab yuam siv hauv zos ze ntawm thaj tsam ntawmcompression. Qhov no txhais tau hais tias tus nqi ntawm kev kos duab tuaj yeem raug txwv los ntawm lub zog tensile ntawm cov khoom, qhov tseeb tshwj xeeb tshaj yog thaum kos cov xov hlau nyias.
Kev vam meej ntawm kev tsim yog nyob rau hauv kev sib raug zoo rau ob yam, ntws thiab stretch ntawm cov khoom. Raws li kev tuag tsim cov duab los ntawm cov ntawv tiaj tus hlau, yuav tsum muaj cov khoom siv txav mus rau hauv cov duab ntawm qhov tuag. Cov dej ntws ntawm cov khoom yog tswj los ntawm kev siv siab rau qhov khoob thiab lubrication thov rau qhov tuag lossis qhov khoob. Yog tias daim ntawv txav tau yooj yim heev, wrinkles yuav tshwm sim hauv ib feem. Txhawm rau kho qhov no, lub siab ntau dua los yog tsawg dua lubrication yog siv rau qhov khoob kom txwv cov khoom ntws thiab ua rau cov khoom ncab lossis teeb nyias. Yog tias siv ntau dhau, qhov yuav dhau los ua nyias thiab tawg. Kev kos duab hlau yuav tsum tau nrhiav qhov tseeb qhov sib npaug ntawm wrinkles thiab tawg kom ua tiav qhov ua tiav.
