Design and application of a comprehensive experimental system for real imaging-virtual imaging of dynamic caustics.

On the basis of the principle of caustics, a comprehensive experimental system for real imaging-virtual imaging was designed and established and then applied to dynamic fracture mechanics experiments. An explosion load experimental system was used to investigate the interaction between blast stress waves and prefabricated cracks. The virtual image information of the caustic spot of the crack tip under the radial compressive stress of the explosive load was captured and quantified. Combined with the experimental data obtained by the real imaging system, the entire interaction process of the blast stress wave and prefabricated cracks was quantitatively characterized. The impact load test system was used to carry out three-point bending impact testing on a unilateral offset crack specimen. In the experiment, the load applied to the upper boundary and the stress intensity factor of the crack tip were simultaneously obtained. The comprehensive experimental system had a simple light path and could simultaneously obtain two sets of experimental information for the real and virtual images, respectively. Thereby, abundant and reliable data were obtained for experimental research. In summary, the experimental systems were effectively used in the investigation of impact and explosion dynamics.