The response of materials to impact shock loads.

The response of a variety of materials subject to impact shock loads was investigated with a 38mm diameter Kolsky bar. Strain rates up to approximately 4000 strain/second were achieved by using a 4.5g SX2 explosive charge to initiate an incident stress pulse of max1mum amplitude, 560 N/mm2.
The errors associated with the apparatus (ie magnetostr1ct1ve electricity, electromagnetically induced signals, dispersion, attenuation, and specimen geometry> were examined, and evaluated.
The rod velocities for the materials were determined by analysis of the pressure bar traces and by a dynamic photoelastic technique.
Axial and radial strains were measured in both pressure bar and specimens. This investigation was to find the delay in development of radial strain under dynamic loading conditions, and to assess Po1ssons ratio for small specimens of explosive. The method was also used to detect shear waves in the pressure bar.
Specimen behaviour was examined in four ways: 1. Pressure bar data was analysed using Lindholm and Yeakley's (1968) method to determine stress/strain for the specimen. The pressure bar data was corrected for dispersion using a FFT and Bancrofts (1941) data 2. Hugoniots were produced for the explosives. The strain time I relationship was differentiated to find the average particle velocity for the specimen, which was compared to the theoretical particle velocity at the shock wave front. 3. Fracture planes in the Perspex specimens were subjected· to examination with an electron scanning microscope. 4. Acoustic emissions were recorded for explosive specimens in the Kolsky bar, and compared to ERSG response.