An approach for constituting double/multi wall BLE by single wall BLE of spacecraft shield

Ballistic limit equation (BLE) is an important tool for spacecraft shield design. An approach for constituting dual/multi wall BLE by single wall BLE is proposed. A new single wall BLE is built first based on the current BLE form analysis. A total of 100 experimental test data collected from the literature are introduced for verifications and comparisons. The new single wall BLE has obtained a better correct prediction rate of 83% than other tested BLEs. Secondly, the new Whipple shield (double wall) BLE is constituted of the new single wall BLE. In the low velocity regime the projectile isn't completely fragmented behind the bumper, the Whipple shield BLE is therefore obtained just by the summation of the single wall BLEs of the bumper and the rear wall. While in the hypervelocity regime, the expansion effect of the completely fragmented debris cloud is taken into consideration. The single wall BLE of the rear wall is multiplied by a correction term of the spacing between the two walls before the summation. The shatter regime BLE is obtained by the linear interpolation of the endpoints. A total of 268 experimental test data collected from the literature are introduced for verifications and comparisons. The new Whipple shield BLE has obtained a better correct prediction rate of 72% than other tested BLEs. Finally, the new multi-shock shield BLE is preliminarily constituted of the new single wall BLE and the Whipple shield BLE. The new multi-shock BLE is used to predict 5 experimental test cases and all of which are correct.