Characterizing the Material Structure and Deflagration Profile of Additive‐Manufactured Energetic Materials

摘要

Commonly used rocket propellants such as Ammonium Perchlorate Composite Propellant (APCP) are castinto molds with varying internal geometries and set once the liquid binder polymerizes. Since Solid RocketMotors (SRMs) are ignited internally, the amount of exposed internal surface area to the flame boundarydetermines the burn rate and thrust profile of the motor. The mold design in which the SRM is cast intois thus critically important to the performance of the motor. This relationship between surface area anddeflagration rate is paramount to the performance of all types of explosive materials.However, traditional manufacturing techniques for low explosive materials are rudimentary and leavelittle design flexibility. Cross‐sectional grain geometry is constant throughout the material because themold plug must be removable. In contrast, additive manufacturing (3D‐printing) technologies allow thedesign and fabrication of functionally‐graded energetic materials because no mold is required, andmaterials can be careful designed with internal and external geometries previously unattainable throughconventional manufacturing methods.This research was conducted at the Colorado School of Mines to demonstrate the manipulation ofenergetic material deflagration via 3D‐printing with advanced grain geometry. Liquid Deposition Modeling(LDM) 3D‐printing technologies were applied to energetic materials, and the effects of degree of binderpolymerization and material void fraction are compared to experimental deflagration rate data. Thisresearch investigates the relationship between structural qualities of 3D‐printed energetic materials andtheir deflagration rate. These studies further validate the application of additive manufacturingtechnologies to functionally‐graded energetic materials.