Assessment of grain damping models for finite element analysis of solid rocket motors

The accurate and efficient computational modeling of highly damped structures in transient simulations is critical for design and certification of spacecraft. An important step in the process is indeed the coupled loads analysis of the payload-launcher system subject to time-domain excitations. In order to accurately predict the satellite dynamic mechanical environment, the system damping properties must be correctly taken into account in the numerical models used for transient simulations. Additionally, the damping models must be tailored toward dynamic condensation techniques and efficient solution algorithms in order to allow analysing multiple designs and operating conditions in limited times. This paper reviews existing approaches to damping modeling applied to the transient analysis of highly damped structures described in terms of finite element models. The performance of the examined methods is discussed by correlating numerical and experimental results for a scaled-down test article dynamically representative of a slender launch vehicle with a solid rocket motor stage.