Abstract
To realize a reliable simulation of biological soft tissues, we have to understand its complicated mechanical property, which can be hardly obtained by the conventional material testing. Proposed here is a new method of three-dimensional deformation measurement by integrating the X-ray CT system and the material testing machine. This system provides the three-dimensional images of the specimen in initial and deformed states. By comparing these two images, we identify the displacement field inside the specimen, and consequently obtain the strain field. The basic concept is based on the digital image correlation method. However, the CT image has few patterns to be matched between initial and deformed images, and soft tissues allow intricately distributed large deformation. To overcome such difficulties, we make use of the B-spline functions as the basis functions of displacement field and the Levenberg-Marquardt method as a fast solver for the correlation calculation on the three-dimensional images, which constitutes a large-scale nonlinear programming problem.
