Load of an automatic feed mechanism is composed of the stretching force of feed belt at the entrance to lower flexible guidance and the friction force between feed belt and flexible guidance. A mathematical model for computing the load was presented. An optimization problem was formulated to determine the attitude of the flexible guidance based on the principle that the potential energy stored in the system was the minimum at the equilibrium. Then the friction force was obtained according to the attitude of guide leaves and the moving velocity of the feed belt and the friction factor. Consequently, the load of the automatic feed mechanism can be calculated. Finally, an example was given to compute the load when the horizontal and elevating firing angles of the automation were respectively 45˚ and 30˚. The computing result can be a criterion to determine the designing parameters of automat.
The choosing of overall parameters, in the conceptual design stage, has been shown decisive, for developing efficient and reliable final gun and bullet products. Aimed at the feature that multidisciplinary knowledge will be related in the overall parameters design process, and in order to meet the various design requirement and aim, a multidisciplinary design optimization system is proposed to automatically acquire the optimized overall design parameters in this paper. Based on the empirical methods of individual disciplines including mechanics, ballistics, dynamics, the analyzing procedures for each discipline are developed, the coupling relations between disciplines are analyzed, and the integral analytic and optimized model of overall parameters are presented, then an integrated multidisciplinary design optimization system is built through integrating each analyzing procedure as well as the optimization software iSIGHT. Taking the 7.62mm semi-automatic gun and bullet system as a verification example, the gun's firing rate and the bullet's destination kinetic energy are obviously improved compared to the initial values , which proves the feasibility and effectiveness of the proposed integration system in overall parameter design and optimization for gun and bullet system. Index Terms-Gun and bullet system, integration system, multidisciplinary design optimization, overall parameters. Zhifang Wei was born in China and obtained her PhD degree in artillery, automatic gun and ammunition engineering in North University of China in 2008. She joined the College of Mechatronic Engineering, North University of China in 1997 and now is an associate professor. Her research interests are focused on virtual design in arms engineering. Fang Wang was born in China and obtained his master's degree in artillery, automatic gun and ammunition engineering in North University of China in 2014. His research interests are focused on simulation technology in arms engineering.
The article introduces the basic features of a VR training system for Computer Numerical Control (CNC). The system is designed and implemented based on the World ToolKit (WTK) software to support the interactive training for workpiece machining.
Recoil spring is a key part in automatic or semi-automatic weapons re-entry mechanism. Because the stranded wire helical spring (SWHS) has longer fatigue life than an ordinary single-wire cylindrically helical spring, it is often used as a recoil spring in various weapons. Due to the lack of in-depth research on the dynamic characteristics of the current multi-wire recoil spring in recoil and re-entry processes, the fatigue life analysis of the current multi-wire recoil spring usually only considers uniform loading and does not consider dynamic impact loads, which cannot meet modern design requirements. Therefore, this paper proposes a research method for fatigue life prediction analysis of multi-wire recoil spring. Firstly, based on the secondary development of UG, a three-wire recoil spring parameterized model for a gun is established. Secondly, ABAQUS is used to carry out a finite element analysis of its dynamic response characteristics under impact, and experimental verification is performed. Then, based on the stress-time history curve of the dangerous position obtained by finite element analysis, the rain flow counting method is used to obtain the fatigue stress spectrum of recoil spring. Finally, according to the Miner fatigue cumulative damage theory, the fatigue life prediction of the recoil spring based on the S-N curve of the material is compared with experimental results. The research results show that the recoil spring has obvious transient characteristics during the impact of the bolt carrier. The impact velocity is far greater than the propagation speed of the stress wave in the recoil spring, which easily causes the spring coils to squeeze each other. The maximum stress occurs at the fixed end of the spring. And the mean fatigue curve (50% survival rate) is used to predict the life of the recoil spring. The calculation result is 8.6% different from the experiment value, which proves that the method has certain reliability.
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