The influence of out-of-plane motion on the deformation measurement of planar biaxial tests on biological soft tissue

Abstract

Planar biaxial testing is a popular technique to characterize a wide range of biological soft tissues. Nevertheless, a lot of variability exists between experimental setups. One particularly important variation relates to the difference in strain measuring techniques to characterize the deformation during the test: digital image correlation using one camera (measuring the out-of-plane motion as false strain), or two cameras (providing a stereo view). This study aimed to compare the two methods and provide practical guidelines for their use. A planar biaxial experiment was performed on ovine arterial samples on which both methods produced similar results in terms of strain measurements and material properties. The two-dimensional approach using a single camera is an appropriate and less time-consuming alternative to measure the deformation of soft biological tissue during planar biaxial loading conditions for similar setups.