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Breechblock operating force is one of the key test parameters of the shock test bed for gun breechblock system. With the design principle determined, the dynamics principle model of the shock test bed is established based on the virtual prototype technology. The kinetic energy theorem is used to calculate the minimum theoretical force F, a standard value for shock test bed to open breechblock. As both the mass of breechblock operating cam and the breechblock operating distance are fixed, the simulation experiment is performed based on the principle model when the breechblock operating force is F.. The results show that the test bed fails to open breechblock under the working condition for energy loss during the impact. By the research, it is better to grasp the dynamics characteristics of test bed before the physical entity experiments, which is benefit to choose a suitable breechblock operating force.

It is necessary to install a damping energy absorbing structure for a certain type of naval gun test shell without projectile belt. Applicable high-performance dampers currently include viscoelastic colloidal damper and magnetorheological damper, and two kinds of special dampers for test shells have been designed and manufactured. In order to evaluate the mechanical properties of these two dampers under dynamic impact, a one-way coupling numerical method was proposed for simulation and analysis. Quasistatic experiments were used to verify the model based on magnetic field finite element (FE) and computational fluid dynamics (CFD). The model is also characterized by passive dynamic mesh and userdefined functions (UDF) based on C language. The results showed that the CFD models of both dampers were accurate. Though the colloidal damper is simpler in structure and lower in the cost, the MR damper has more significant damping and higher energy absorption ratio under impact. Compared with colloidal damper, MR damper is characterized by long working time, multiple vortices, chaotic streamlines and more uniform temperature distribution. When the power was continuously applied, the velocity of the impacted MR damper dropped to zero within 80ms, and the piston finally stopped at a stroke of 1.3mm. The colloidal damper reset within 8ms, and the reset velocity was 1.1m/s. In this study, the performance evaluation results of the two dampers were obtained, and the latest numerical methods for the mechanical performance analysis of colloidal dampers and MR dampers under dynamic impact were provided.

Machining parameters are essential factors affecting the machining efficiency and tool life. Tool reliability varies with the process. Tool reliability affects the life of the tool, and then impacts the processing quality and manufacturing cost. Therefore, machining parameters optimization considering tool reliability is essential and scientific. In this paper, firstly the reliability model of tool life was solved by Markov Chain Monte Carlo (MCMC) method. Then taking the average tool life as the constrain condition, a multi-objective optimization algorithm that integrates the gray correlation analysis (GRA), radial basis neural network(RBF) and particle swarm optimization(PSO) algorithm (GRA-RBF-PSO) was used to search for optimal machining parameters of blisk-tunnel processing. At last, experiments were carried out to validate optimized results. The experimental results indicated that the reliability-based optimization of machining parameters can effectively improve the tool life and as well as ensure smaller cutting force and larger material removal rate during blisk-tunnel processing.

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