Auckland Bioengineering Institute

Biaxial testing rig


The Biaxial Rig was custom built to investigate the mechanical properties of soft tissue membranes, such as skin.

A circular array of 16 displacement actuators (Physik Instruments) and 2D force transducers are used to impose deformations in the tissue sample. Internal displacements are monitored with a CCD camera (Atmel) and measured using a cross-correlation technique.

All data acquired during an experiment are post-processed using a finite element analysis (software CMISS) to allow parameter estimates to be determined for material laws.

The Multiaxial Rig and the corresponding numerical techniques have successfully established a constitutive model for the stress-strain behaviour in human skin. 3-D positioning to sub micron resolution, and automated tissue removal and imaging.