Integrated Thermo-Structural Viscoelastic Multiphysics Framework for KNSU Solid Rocket Motor
£5.00
Sebastian Valencia, Jaime Enrique Orduy
2025.078.0298
DOI https://doi.org/10.59332/jbis-078-09-0298
Solid rocket motors (SRMs) are a mainstay of academic propulsion research, yet most studies focus narrowly on either internal ballistics or structural integrity in isolation. This work addresses the critical gap in integrated multiphysics modelling of potassium nitrate–sucrose (KNSU) propellant SRMs at a cost-effective scale, where safe, repeatable design practices are urgently needed to support hands-on aerospace education. We present a unified simulation framework that couples Saint-Robert’s burn-rate law and one-dimensional thermochemical modelling with transient, viscoelastic finite-element analysis of both grain and steel casing (AISI 1020 for the shell, AISI 4140 for the nozzle). Key novelties include (1) a Prony-seriesbased constitutive model calibrated against dynamic-mechanical-analysis data to capture rapid ignition transients in sugarbased propellants, and (2) a comparative benchmark against industrial design criteria to pinpoint pathways for performance enhancement. Transient simulations reveal a 0.1 s ignition spike to 8.6 MPa, stabilizing at 4.8 MPa, while peak von Mises stresses of 172 MPa (casing) and 210 MPa (nozzle throat) remain below allowable limits. The computed 1.3 kN thrust aligns with academic benchmarks, validating the model’s fidelity. We further identify that modifying grain geometry and substituting higher-strength alloys could raise safety factors from 1.9 toward industry-standard ≥2.5, and boost thrust toward >5 kN. By explicitly bridging internal ballistics, thermal–structural coupling, and viscoelastic grain behaviour, this study offers the first comprehensive computational toolkit for safe, scalable KNSU SRM design in academic settings—and lays the groundwork for future experimental validation and optimization.
Keywords: Solid Rocket Motor, KNSU Propellant, Combustion Chamber Pressure, Structural Analysis, Aerospace Propulsion
