Identification of Bimodular Material Parameters via a Semi-Closed Form Solution of the Brazilian Test

Background

Digital Image Correlation (DIC) is an advanced measurement technique capable of capturing full-field surface displacements in a non-invasive manner. However, the application of such measurements in the identification of bimodular materials remains insufficiently exploited.

Objective

Recalibration with Analytic Solution Updating (RAU) has been proposed for the identification of mechanical elastic parameters of asymmetric constitutive law behavior using the Brazilian test. This method accomplishes identification by minimizing the gap between the measurements and the semi-closed form solution.

Methods

Two types of data are employed: the first derived from the semi-closed form solution and the second measured on a 42-day aged mortar specimen using DIC. In the RAU method, three distinct cases are implemented to identify mechanical elastic parameters. These cases are determined by the nature of the data utilized, which can be categorized into axial displacement field, strains at the center, and full-field surface displacement measured on a given specimen area.

Results

The RAU method successfully identified the compressive, tensile Young’s modulus, and the compressive Poisson’s ratio from the surface data provided. The identification with full-field surface displacement presented the highest level of accuracy in the RAU method using the identified results of synthetic data.

Conclusion

The RAU method demonstrates significant accuracy and practicality in identifying the mechanical elastic parameters of bimodular materials.