A Novel Electromechanical Apparatus for Intermediate Strain-Rate Testing and Validation on Polycarbonate

The characterization of material behavior under intermediate deformation rates remains a major challenge, since conventional testing devices are mainly developed for either quasi-static or high strain-rate conditions. Nonetheless, understanding material response in this regime is essential in several applications, such as crashworthiness, bird strike resistance, or metal forming, as well as for the development of reliable constitutive models. In this work, the design and validation of a novel electromechanical apparatus for intermediate strain-rate testing (∼1–102 s−1) of various materials is presented. One of the novelties of the proposed system is the integration of high-performance electromechanical actuators capable of reaching velocities up to 3 m/s, with 16,000 m/s2 acceleration, and impact forces up to 24 kN. During testing, one specimen end is impacted by a striker while the other is in contact with a 14.5 m transmitter bar. Upon impact, the sample deforms, and a compressive stress wave propagates in the transmitter bar. Strain gauges are employed to measure its deformation and, therefore, the force transmitted to the sample. The velocity and displacement of the impact head are instead recorded with high temporal resolution and accuracy by integrating Photon Doppler Velocimetry (PDV) into the system. Validation tests performed on polycarbonate confirmed the accuracy, repeatability, and overall effectiveness of the apparatus.