航空发动机用金属橡胶隔振器动静态性能的研究

以某型号航空发动机阻尼减振需求为背景,对开发研制的金属橡胶隔振器与现用的橡胶隔振器进行了动、静态实验研究。研究结果表明:金属橡胶隔振器的能量耗散性能、静态承载能力、过临界的能力及提供振动防护的区域都远远大于橡胶隔振器,而且通过改变金属橡胶隔振器的结构参数和预压缩量可以优化其隔振效果。研究结果为利用金属橡胶隔振器来改善航空发动机的振动状况提供了依据。     

Mathematical models of high temperature flow in gas ducts of rocket engines

Results are given on certain dynamic properties of a high temperature and pressure gas flow. The investigation concerns the effect of sonic processes on the transfer of external signals by the flow and of the gas nonidealities on the properties of a linear and a nonlinear mathematical model of the jet nozzle. The investigation was conducted by the method of small parameters for differential equations of the dynamics of the gas flow, with the help of invariants of these equations, and estimates of solutions with arbitrary signals of a specific class. The results lead to estimates of errors due to usual simplifications of gas flow models such as linearization of jet nozzle equations and neglect of sonic processes. The errors of the latter kind are shown to depend on the Mach number and smoothness of signals. Accurate and approximate models of nozzle flow are obtained useful for controllability analysis of rocket engines. Some computation examples are given.     

From the President

Methods of underwater glider navigation (Russian name - vesoplan) in a nonhomogenous current are proposed. Existing methods are described and problems of positioning of the vesoplan in a nonhomogenous current is stated. Use of method of dead-reckoning and its peculiarities are justified. Conclusion is made that, in this case, dead-reckoning is impossible without current field identification. Principles of current field identification and the algorithms based on them are described.     

Finite element analysis of elastic-hysteretic systems with regard to damping

As applied to calculations of all-metal vibration isolators with dry friction, the use of the finite element software is considered. For simulation of friction forces on the contacts based on the analysis of simple dry friction systems, the distributed moment of resistance to curvature variations is proposed. Also presented are an example of the hysteresis loop calculation for the ring-like vibration isolator and comparison with the experimental data.