Abstract: Ballistic gelatin is used as a stimulant for human tissue in the experimental study of temporary cavity which is an important factor of ballistic injury. To study the motion of temporary cavities, the steel spheres with diameters of 3 mm, 4 mm and 4. 8 mm are fired into the gelatin blocks at 650 ~1 000 m/ s in the experiments. The movement of temporary cavity is recorded by a high speed camera. The sine motion of the cavity wall is deducted based on the displacement field assumption and the elastic deformation assumption of gelatin. The empirical relations between amplitude and energy, and frequency and energy are established using the experimental data while a penetration model of spherical fragments in gelatin is built. The model is used to predict the temporary cavity for a 5. 2 mm tungsten sphere penetrating into gelatin at 800 m/ s. The predicted results are in good agreement with the experimental data.

Key words: ordnance science and technology, temporary cavity, sine motion, ballistic gelatin, spherical fragment