Extracting the elastic modulus of compliant materials using a novel plate bulge testing technique

The mechanical properties of compliant materials such as biological tissues and biocompatible soft polymers are essential in medical research and engineering applications. These properties are often determined using techniques that require costly instrumentation (e.g. pull test machines). Alternative and more accessible methods can significantly aid the characterization process. The bulge test determines a material elastic modulus by analyzing the pressure-deflection response of thin samples made of this material. The technique has been extensively employed in the characterization of metals and semiconductors (modulus - 100 GPa). By employing plate rather than membrane mechanics, the present study extends bulge testing to characterize materials with a modulus that is five orders of magnitude lower (~ 1 MPa). The novel method is demonstrated analytically using plate theory, numerically using finite element modeling and experimentally by successfully applying it to polydimethylsiloxane (modulus ~ 1.33 MPa). The introduced technique does not require costly equipment, is simple to implement and presents an appealing alternative to current characterization approaches.