Internal ballistic simulation (IBS) method of multi-burning-rate solid rocket motor (SRM) was developed based on 3-D burning regression method by parameterized feature CAD model (PFCADM) and lumped parameter

in consideration of time-dependent

erosive-burning-effect from internal ballistic numerical algorithm. By driving multi-parameter CAD model based on PFCADM

the approach is capable of conducting the geometric regression simulation of various grain combinations of complex configurations with different burning rates. Through suitably simplifying the internal ballistic numerical algorithm

the problems of coupling geometric regression simulation of sub-grains of different burning rates and high computational consumption of internal ballistic calculation were solved. One tri-burning-rate grain motor

which had been firing-tested

was used as the validation case of simulation. The results show that

with the 3-D grain regression model and sufficient accurate internal ballistic algorithm

the method realizes IBS of the case in low computational-consumption prediction of its performance within the accuracy of 2% during 1h clock-time. The application of the method provides a practical approach to aid SRM design of multi-burning-rate grain.