Modeling of Solid Propellants Viscoplastic Behavior
Using Evolutionary Algorithms


Robert ZALEWSKI, Mariusz PYRZ

Institute of Machines Design Fundamentals, Warsaw University
of Technology, 84 Narbutta St., 02-524 Warsaw, Poland

Institute of Vehicles, Warsaw University of Technology,
1 Politechniki Sq., 00-661 Warsaw, Poland

Institute of Industrial Organic Chemistry,
Annopol 6, 03-236 Warsaw, Poland

Abstract: In the paper an initial attempt to the experimental analysis of viscous
effects, characteristic for homogeneous solid rocket fuels is proposed. For this
reason uniaxial tensile experiments, carried out on dumbbell homogeneous solid
propellants have been chosen. Laboratory tests have been carried out on INSTRON
tensile testing machine. Research schedule involved destructive tensile tests with
various strain rates. Three different values of strain rates have been taken into
consideration. Experimentally obtained hardening curves are presented in suitable
Basing on obtained results, authors confrm the viscoplastic behavior of studied
materials. Essential impact of the applied strain rate on the position of experimental
hardening curves is observed. Acquired results are the base for the further stage of
investigations of homogeneous solid propellants – the modeling of their physical
Additionally, numerical modeling of studied phenomena, using the viscoplastic
Chaboche’s model, identifed on the basis of experimental data, is presented. The
material parameters of the constitutive law are determined numerically using an
evolutionary algorithm procedure. The effciency of the model and the identifcation
approach are discussed.

Keywords: solid rocket fuel, experimental studies, modeling, constitutive
law, evolutionary algorithms, numerical simulation