Impact response for sensor-less speckle-less elastic and viscoelastic material properties of flexible polymer composites

Measuring the global dynamic response without sensors of flexible polymer composite can be achieved with only high-speed camera images. We apply a non-contact, speckle-less, custom Matlab script to isolate composite specimens filmed under uniaxial low velocity impacts via Vision Research Phantom UHS V2640 and measure the displacement time history. A custom fitting curve is applied to this data and two derivatives with respect to time are performed to provide the acceleration time history. Since the impactor mass is known, we can solve for the contact force without sensors. Comparison with a dynamic load sensor and using our previous efforts with extracting the hyper-elastic and visco-elastic material constants from a single impact test, we compare the dynamic impact response of the flexible polymer composites; the non-contact, speckle-less method matches the force response within 1% peak value and 2% in pulse duration and the overall finite element validation model also matches within a small error for magnitude and duration.