9 - Simultaneous full-field strain and temperature measurements in high strain rate testing

Abstract

Recent developments in high-speed infrared imaging have allowed full-field temperature measurements in high strain rate experiments. By combining full-field deformation measurements with infrared imaging at high speeds, researchers have been able to obtain information on the thermomechanical behavior of materials that were previously difficult to obtain. There are many challenges in the integration of these full-field measurements, such as the temporal and spatial synchronization, as well as representing the data in the same frame of reference. The temporal synchronization has been addressed by using waveform generators for synchronized clocking and simultaneous triggering of the cameras. The spatial synchronization has been carried out by using the same camera pinhole model to translate all cameras to the same world coordinate system and applying displacement vector fields on the infrared images to represent the temperature data in a Lagrange frame of reference. Considering the adiabatic nature of high strain rate testing, the combination of strain, temperature, and load has allowed researchers to use the full-field data to investigate how efficiently materials convert mechanical work into heat during deformation. The information obtained from the synchronized full-field strain and temperature measurements improves our understanding of the physical and mechanical behavior of materials. This new knowledge can be used to improve the current material plasticity and failure models and validate numerical simulations.