A New Compression Intermediate Strain Rate Testing Apparatus

A new apparatus for testing in compression at intermediate strain rates is introduced. The apparatus consists of a loading hydraulic actuator and a very long (40 m) transmitter bar. The specimen is placed with one end touching the end surface of the long bar and the other end free. The specimen is loaded by the actuator that impacts the specimen's free end directly. Once loaded, the specimen deforms between the actuator and the transmitter bar. As the specimen is loaded and deformed, a compression wave propagates into the transmitter bar. The amplitude of this wave is measured with strain gages that are placed on the transmitter bar at a distance of about five diameters from the specimen. The wave in the transmitter bar propagates all the way to the end of the bar and then reflects back toward the specimen. The experiment can continue until the reflected wave reaches the strain gages (milliseconds). The strain in the specimen (full field) is measured directly on the specimen using Digital Image Correlation with high speed cameras.