TEMPER simulations of bullet impact and fragment impact tests of 155 mm shell filled with MCX-6100 composition

IM classification of munitions requires testing according to STANAG 4439 (1). All tests have to be performed unless the Threat Hazard Analysis shows that specific threats in the STANAG do not exist for the life cycle of the specific munition. In some nations a full scale test may be replaced by small scale testing accompanied with simulations. In this report results from small scale testing of the explosive composition MCX-6100 have been used as input for simulations of Bullet Impact (BI) and Fragment Impact (FI) tests with the MSIAC TEMPER software. The munitions we have studied are 155 mm shells. MCX-6100 is a melt-cast composition to be used in this munition. The TEMPER simulations of BI test with flat end rod on shell filled with MCX-6100 CH 6027/14 compositions show a no reaction response for the three shock sensitivities studied in this report. With TEMPER we have studied impact by only one bullet. The STANAG 4241(2) requires hit by three bullets. Shock properties of damaged explosive are not available for the MCX-6100 compositions. However, nothing in the obtained simulation results indicate problems to achieve a no reaction response in BI tests for a 155 mm shell filled with MCX-6100. The requirement in STANAG 4439 for the BI test to fulfill the IM requirements is a type V reaction, no response more severe than burning. Simulations of FI test with a conical NATO fragment and the test conditions given in STANAG 4496 (3) have been performed on different shell thicknesses of shells filled with MCX-6100 having three different shock sensitivities. With a MCX-6100 filling with a shock sensitivity of 58.5 kbar, a shell thickness of 6 mm or more gives a no reaction response. With a MCX-6100 filling with a shock sensitivity of 47.5 kbar, a shell thickness of 8 mm or more gives a no reaction response. For MCX-6100 fillings with a shock sensitivity of 36.4 kbar, a shell thickness of 11 mm or thicker gives a no reaction response. The requirement in STANAG 4439 for the FI test to fulfill the IM requirements is a type V reaction, no response more severe than burning. The simulations with TEMPER of both bullet and fragment impact tests show that the requirements in STANAG 4439 can be fulfilled. For the fragment impact test, however, the shock sensitivity of the MCX-6100 composition should be 50 kbar or better to obtain a type V response.