Design of a versatile liquid-fluorineliquid- hydrogen upper stage

Abstract

obtained have been checked against known solutions and a limited number of photoelastic and experimental test models. In all instances adequate correlation was achieved. In the particular case of environmental conditioning propellant grains, maximum stresses and strains invariably occur at the initial or final steady-state condition. This does not eliminate these systems from consideration, however, because not all loadings are maintained until steady-state temperatures are achieved as in the first example problem. Although the failure criteria used in this analysis do not include timeor path-dependent characteristics, some propellants possibly may exhibit such properties. If such phenomena are anticipated, a critical condition could exist at an intermediate temperature, and a transient analysis would be required. This study has been oriented specifically toward propellantgrain problems, but no such limitation is inherent in the techniques described. The computer program can be applied without modification to other axisymmetric components such as nozzles, nose cones, and turbine rotors. Loads other than thermal stresses can also be analyzed because the formulation includes surface pressure, shears, and body forces generated by either axial or rotational accelerations. Experimental data for these problems are not very extensive, however, and the analysis must be used with caution until adequate substantiating data become available.