Experimental System and Validation for Energy-Based Characterization

This paper presents the experimental system and experimental validation of an energy-based characterization for the identification of elastic constants. Unlike the standard uniaxial testing machine, which uses a contact strain sensor such as extensometer, the developed system uses a non-contact optic sensor as an advantage to measure and derive external work and strain measurements for characterizing the elastic constants. To investigate the validity of the energy-based characterization, a graphical user interface and the experimental system were developed for the tensile tests of aluminum open-hole specimens. During the validation, the means and variances of the characterization results were analyzed. The reliability of its recursive estimation was further investigated by the convergence of covariance at every new measurement. Results showed that the recursive estimation allows identification of elastic constants of a test coupon at every acquisition of sensor data in an online manner. The identification of all the constants during deformation thus demonstrated the overall validity and efficiency of the energy-based characterization.