Concentration Dependence of Tensile Behavior in Agarose Gel Using Digital Image Correlation

Abstract

Tensile testing of soft, slippery biological materials is a challenging task due to the difficulties associated with the gripping method and accurate measurement of axial and lateral strains. In this manuscript, the above issues were effectively resolved by using a shoulder-supported tensile specimen and digital image correlation (DIC) technique, respectively. The tensile response of agarose gel with concentration ranging from 1.5 to 4.0 wt% was determined using the above method. Unlike the previous literature where the tensile strain was obtained from machine crosshead displacement, the DIC technique utilized a speckle pattern introduced into the gage area to obtain full-field maps of axial and lateral strains. It is found that the tensile strength and modulus of agarose gel increases linearly with an increase in agarose concentration. The Poisson’s ratio was determined to be around 0.5 for virgin specimens and it decreased slightly with axial strain, possibly due to the loss of water during deformation.