Computation of stress field in a polymer scaffold from optically measured deformation field using particle images

Abstract

Different mechanical stimuli are applied to the substrate of a microchip and a cellular scaffold to simulate in vivo biomechanical environment, but few studies have been performed to measure the stress inside the substrate and the scaffold. In this study, a novel technique of computing the stress field inside a scaffold using optically measured deformation field has been developed. The effectiveness of our proposed technique is evaluated using a polymer block undergoing indentation deformation. The deformation field in the cross section of a block under indentation loading was measured using a particle image analysis method, and the accuracy of the displacement measurement method was verified. The measured displacement fields were mapped into the cross sectional surface of a block model, and FE analysis was performed to compute the stress fields. The stress field estimated from the inverse analysis using the measured displacement fields agree with that of the direct force loading simulation, and the relative error of maximum stress was less than 3%. The indentation forces also agreed well with those in the direct force loading FE analysis, and the errors were less than 8%.