Advanced Materials Research Vols. 712-715

Abstract: Based on the research of wave loads calculation methods for the submarine and ship, compared the date of wave loads obtained by strip theory with that obtained by linear-simplified calculation method, we proved the engineering feasibility of linear-simplified calculation method of wave loads on underwater vehicles cabin when sailing on the water surface and near the water surface, the linear-simplified calculation method shorten the calculation cycle and guarantee the engineering accuracy.

Abstract: In order to reduce the recoil of High Initial Velocity Grenade Launcher (HIVGL) and obtain better firing precision, two reduction recoil structures - short recoil barrel structure and laval nozzle structure were used for HIVGL. Virtual prototype simulation model of HIVGL were established, the dynamics curves of automatic mechanism of HIVGL and human shoulder force curves were obtained when HIVGL was launched by dynamic simulation software - ADAMS. The motion characteristics of automatic mechanism and the variation regulation of the maximum shoulder force were analyzed with different combinations of HIVGL structures and nozzle chamber charge amount. The barrel floating spring stiffness, pre-pressure and the effect of barrel stroke on spring energy storage were also analyzed. As proved by the research results, the maximum recoil of HIVGL can be greatly reduced by introducing short recoil barrel structure and laval nozzle structure. This result provides a beneficial reference for structure design and optimization of HIVGL.

Abstract: Technology of reducing the recoil force by jet gas is a new effective technology to reduce recoil in recent years. In order to understand deeply the influence of Laval nozzles structure to achieve low recoil force on auto-weapon, two-phase flow model was developed and a machine gun as the experiment object was used for numerical analogy, analogy the influence of the efficiency of recoil reduction about nozzle angle and nozzle length, etc.

Abstract: To improve the firing stability of Galtling gun by installing an arc-shaped support plate on a light tripod,a firing dynamic model of Gatling gun shooting on light tripod which has a arc-shaped support plate fixed on the different positions established based on rigid-flexible multi-body dynamic theory. The muzzles vibration and tripods deformation obtained through dynamic simulation. The results show that while the arc-shaped support plate fixed close to the bracket, the supporting effect to Galting gun decreased, tripods deformation and muzzles vibration increased. On the contrary, it reduced muzzles vibration and enhanced the firing stability. The analytic results provide a reference to improve the arc-shaped support plate in tripod.

Abstract: In order to reduce the recoil energy of the chain gun, this paper put forward a high-efficiency recoil-reducing way with new-style high-efficiency muzzle brake and buffer parameter combined by studying the modeling and simulation of low recoil firing of chain gun. This paper studied the variation rules of gun recoil movement and recoil force of muzzle brake on three states. The results show the recoil of chain gun can be reduced significantly by using high-efficiency muzzle brake and selecting suitable parameters for buffer compared with that of only using muzzle brake and buffer. The research results put forward theoretical basis and application reference for studying high power low recoil chain gun.

Abstract: Vehicle drivability is now one of the keystones of product quality, and is refined aggressively to achieve vehicle brand differentiation and market position. This paper starts with an illustrating of drivabilitys definition, and then the objective measure metrics and model-based approach for vehicle drivability development during advanced vehicle and powertrain system development process are analyzed. The accelerator pedal aggressing and pedal-acceleration response characteristic as drivability critical factors are investigated emphatically at last.

Abstract: The reliability data of nuclear power CNC wheel groove milling machine is so few that the reliability can not be predicted by traditional reliability prediction method;or the reliability prediction error is large. A reliability prediction method of nuclear power CNC wheel groove milling machine based on the gray theory is proposed in this paper. Establishing the reliability model of gray theory, the reliability of machine subsystem is determined. Then the relationship between the corresponding average fault-free time and system reliability is realized. The gray comprehensive correlation between theoretical output of the model and the actual system reliability is established, the overall reliability of the nuclear power CNC wheel groove milling machine is determined. For system reliability analysis and system maintenance decision research puts forward a new thinking path, have a good applied foreground. Key words: the nuclear power CNC wheel groove milling machine; gray theory; average fault-free time; system reliability; reliability analysis.

Abstract: Machine working environment was simulated by using ANSYS software for analysis and calculation. Modal analysis results indicated that machine tools didn't produce resonance during the machine working. Harmonic response analysis result shew the displacement response frequency was 42Hz along the Y, Z two directions on the bottom of ram, and X direction's response frequency was 43 Hz. The conclusion given by this paper has guiding significance to use the machine safely in the future.

Abstract: The paper uses the finite element software ANSYS to establish a 1.5 MW horizontal-axis wind turbine tower model as an example and works on the modal analysis. The modal analysis takes into account the totalmass of wind rotor and nacelle and assumes the bottom of the wind turbine tower is fully constrained. The result shows that the natural frequency of the 1.5MW wind turbine tower is not coincident with the excitation frequency of the wind turbine, and the wind turbine can operate stably at the design condition.

Abstract: A structural non-probabilistic reliability analysis model based on the imperialist competitive algorithm (ICA) is proposed. In practical engineering, the independent variables of the limit state function are usually the structural responses, which, together with the gradients, need to be resolved. The proposed model could find out the global optimum solution through the competition among the empires, without any additional gradient information, showing a good feasibility in many kinds of optimization problems. When utilizing the penalty function method, the constraint domain is enlarged to the failure domain, overcome the difficulties of searching the optimum due to the former narrower constraint domain. A numerical example verifies the high precision and good feasibility of the model.