Annotation: This paper describes the firing rig test of the solid rocket motor, fastened to the rig in order to measure the thrust level. It is shown that when the motor enters the steady-state mode, the rig with solid rocket motor starts experiencing mechanical oscillations due to the sudden thrust build-up. Motion of the oscillating system is studied under the impact of the linearly or suddenly increasing impulse load. Mechanical oscillations damping is considered on the basis of the viscous friction model. Procedure of the analytical modeling of the damped oscillations is suggested for the complex pattern of the loading variations, based on the fundamental principle of superposition, according to which the motor displacement during the oscillating motion is considered as sum of displacements due to the impact of the impulsive, sudden and linearly increasing loadings. This procedure simulates different time variations of thrust as motor enters the steady-state mode. Oscillating motion with parameters of the oscillating system and thrust change with time option have been simulated as they were realized during the firing rig tests of one of the solid rocket motors. Simulated and experimental (thrust sensor readings) curves of the elastic force were compared, which showed the qualitative and quantitative conformity of the suggested model of oscillations to the actual oscillations of the solid rocket motor, installed in the rig during the firing rig test. Values of the initial thrust, initial impulse and other simulation parameters were updated, adjusting the simulated curve of the elastic force to the experimental one. It was concluded that simulation of the elastic oscillations of the solid rocket motor in the rig using the suggested analytical model will enable more reliable definition of the initial thrust of the motor and its time behavior, impulse loading due to the separation of the plug and used elements that separate with it. Application of the suggested procedure of motor oscillations simulation in the phase of rig design will enable more detailed prediction of the occurring processes as well as the estimation of parameters of the individual elements, units and rig as a whole.

Annotation: The information on Yuzhnoye SDO experience in designing and operation of special equipment for testing of SRM of various classes is presented, the description and analysis of results of this equipment operation are given.

Annotation: The results of experimental verification of solid rocket motors warranty periods are presented. Some peculiarities and methods of tests with simulation of rocket motor operational mechanical and environmental loads are considered.

Annotation: The solid rocket motors thrust is measured according to the developed measurement procedure; fulfilment of its requirements guarantees obtaining the results with required accuracy parameters. Compliance of this procedure with the measurement accuracy requirements is confirmed by way of its validation that can be performed according to different algorithms. The proposed article deals with two validation algorithms of measurement procedure for solid rocket motor thrust up to 30 tf – end-to-end and link-by-link validation methods. The composition of measurement channel, the experimental works performed at each validation algorithm are described, the calculation formulas to evaluate the limits of absolute measurement error and the obtained numerical values of the latter are presented. The comparative analysis of the results of validation procedure of solid rocket motor thrust measurement procedure obtained during metrological investigations of thrust measurement channel by end-to-end and link-by-link validation methods shows that to ensure the required measurement accuracy, the algorithms of end-to-end method is preferable, at which the lower values of reduced error can be obtained as compared with the algorithm of link-by-link validation.

Annotation: This article dwells on results of firing bench testing of the solid-propellant rocket engine (SPRE), fastened to the thrust-measuring assembly stand. It is shown that when engine enters the steady-state mode of operation, plane (forward and rotation) vibrations of the SPRE can take place in the assembly stand due to the sudden pattern of thrust generation and displacement of the center of mass of the vibrating system from the engine axis. These vibrations distort measured values of engine thrust and pattern of its change versus time. The purpose of this work is to simulate the oscillating processes of the engine atop the assembly stand to single out in the distorted values of the measured thrust the components related to the processes in the engine and components, which are introduced into the thrust measurement by the oscillating processes in the system “assembly stand – engine”. Model of vibrating system is suggested, which consists of two rigidly connected bodies, containing elastic links, enabling forward and rotary motion and limited by the rigidity of the links. Mathematical model of the vibrating system is developed. Internal forces and moments acting in oscillatory system are defined. Method of numerical simulation of plane vibrations within the limits of the developed model is suggested. Plane vibrating motion and elastic force curve (curve based on force sensor readings) were simulated in thrust-measuring system for different cases of thrust curve and values of vibrating system parameters. Resonance condition was simulated and mutual influence of elastic parametrical link between forward and rotary vibrations was established. Impact of thrust-measuring system rigidity on peak values of force sensor readings was found out. Elastic force vibrations in thrust-measuring system with vibrating system parameters were simulated including variant of thrust change versus time, implemented during firing bench tests of one of the SPRE. It is shown that registered simulation results recreate thrust measurement results in pattern and values obtained by the force sensor during the firing bench tests, and owing to this, it was concluded that oscillating process parameters, assumed in the model, meet the actual ones. It is concluded that simulation provides objective interpretation of the thrust curve, reliable and comprehensive analysis of engine run during firing bench tests, more detailed and exact design of the assembly stand.