Inverse Design of Additive Manufactured Rocket Propellant Grains with Non-Uniform Properties

This work explores solid rocket motor grain design, leveraging additive manufacturing techniques based on slurry deposition and UV-curing. The objective is to develop an automated design procedure to identify optimal solutions that meet mission requirements, exploiting new geometries and ballistic configurations previously unattainable with the classical mix–cast–cure manufacturing process. The design procedure is based on a stochastic optimization approach coupled with surrogate modeling of the pressure–time response, considering variable geometrical and ballistic parameters. Several surrogate models were tested after the creation of suitable databases through the computation of pressure evolution for different configurations. The most appropriate surrogate model was selected and applied within optimization routines to evaluate individual designs. The optimizer identifies the most suitable configuration to obtain the desired pressure–time response and to meet motor requirements. Different design approaches have been tested to evaluate the ballistic distribution’s influence on performance and how it can be leveraged to meet requirements, even with significant modifications in grain geometry. The results show that the proposed procedure is able to effectively achieve the expressed requirements, successfully handling the novel design environment. Furthermore, they highlight the strong influence of the ballistic distribution on performance and show how it can be successfully exploited to guide grain design.