A study of loading history effect for thermoviscoelastic solid propellant grains

The results of an investigation on solid propellant grains considering load ing history effect are presented. Traditionally, the thermal loading histor y effect of solid propellant grains was not considered for simplifying the analytical task, and a higher safety factor was inevitable for structural i ntegrity. But this does not mean that the thermal loading history effect is not useful and could be neglected arbitrarily, and this effect usually pla ys a very important role for some critical design. In order to simulate the time-temperature-dependent behavior of thermoviscoelastic and incompressib le polymer materials, concepts of time-temperature shift principle, cumulat ive damage theory and reduced integration were used. In addition, five diff erent types of thermal loading history assumption were performed using the finite element method for discussing the thermal loading history effect. Re sults show that the thermal loading history effect is important for structu ral integrity of solid propellant grains, and improper negligence may cause structural failure of missile systems. (C) 2000 Elsevier Science Ltd. All rights reserved.