Pointwise Identification of Elastic Properties in Nonlinear Hyperelastic Membranes-Part II: Experimental Validation

Following the theoretical and computational developments of the pointwise membrane identification method reported in the first part of this paper, we perform a finite inflation test on a rubber balloon to validate the method. The balloon is inflated using a series of pressurized configurations, and a surface mesh that corresponds through all the deformed states is derived using a camera-based three dimensional reconstruction technique. In each configuration, the wall tension is computed by the finite element inverse elastostatic method, and the in-plane stretch relative to a slightly pressurized configuration is computed with the aid of finite element interpolation. Based on the stress-strain characteristics, the Ogden model is employed to describe the material behavior. The elastic parameters at every Gauss point in a selected region are identified simultaneously. To verify the predictive capability of the identified material model, the deformation under a prescribed pressure is predicted using the finite element method and is compared with the physical measurement. The experiment shows that the method can effectively delineate the distributive elastic properties in the balloon wall.