The relationship between fragmentation landing speed and blast crater´ depth

In order to establish relationship between fragments from failure´ vessels and blast crater in explosive spot of the chemical plant, the resistances of oval-shaped and end-cap fragments were deduced by cavity expansion theory when fragments penetrated into concrete target. On this basis, through Newton´s second law, the formula was determined about relationship of fragment´s velocity and blast crater´s depth. Taking blast crater with 20 miles depth as an example, the initial velocity and kinetic energy of fragment about 20 kilograms was analyzed. Results showed that the initial input speed was about 42.35 m/s and kinetic energy was equal to about 8.76 KJ. Compared with the previous data, those results were reasonable. The above results provide theoretical basis to analyze the cause of vessels´ failure in the view of energy equilibrium.