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Xun Wang,Xiaoting Rui 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.6
For analyzing the influence of the clearance between trunnion and bearing on vibration characteristics of a tracked armored vehicle during marching firing, the rigid-flexible coupling multibody dynamics model of a tracked armored vehicle is established according to the transfer matrix method for multibody systems, in which the clearance trunnion-bearing is considered. The coupling interaction between gun and projectile is also considered by applying launch dynamics theory. The interaction of trunnion-bearing is described by two planar clearance revolute joints, and its contact collision model and friction model are described by Lankarani-Nikravesh theory and modified Coulomb friction theory, respectively. According to the automatic deduction theorem, the overall transfer equations and overall transfer matrices of the tracked armored vehicle are derived. A typical planar four-bar mechanism with a clearance revolute joint is used as an illustrative example to validate the proposed method. Numerical simulations under the situations of the trunnion-bearing modeled as an ideal revolute joint and unideal revolute joints with different clearance sizes are performed to obtain the dynamics response of the muzzle and the projectile’s motion in bore. The influence of clearance trunnionbearing on vibration characteristics of tracked armored vehicle is analyzed.
Jianpeng Wu,Xumin Zhang,Kuan Jiang,Hongbing Jia,Xiaoting Rui,Fufeng Yang 한국섬유공학회 2020 Fibers and polymers Vol.21 No.8
In this work, a distinguished hydrothermal treatment succeeded in modifying aramid nanofibers (ANFs) with thehelp of mixed acid, and the hydrothermal-treated ANFs (hANFs) were regarded as a reinforcement agent to be introducedinto styrene-butadiene rubber (SBR) via latex co-agglutination treatment. The enhanced comprehensive behaviour of SBR/hANFs composites induced by π-π stacking interaction between hANFs and polymer chains were investigated in details. With respect to virgin SBR, it was found that the temperature at maximum rate of degradation, tear strength and tensilestrength of composites with adding 7 phr (parts per hundred rubber) hANFs significantly improved by 14 oC, 148 % and215 %, respectively. The incorporation of hANFs also endowed SBR with greatly enhanced solvent resistance.
Dynamics Modelling and Simulating of Ultra-precision Fly-Cutting Machine Tool
Hanjing Lu,Yuanyuan Ding,Yu Chang,Gangli Chen,Xiaoting Rui 한국정밀공학회 2020 International Journal of Precision Engineering and Vol.21 No.2
Dynamics modelling and simulating are the significant process to improve the machining accuracy of the machine tool. This paper is aimed to model and simulate the ultra-precision fly-cutting machine tool (UFMT) and find the relations between structure parameters and machined surface. In this paper, the multi-rigid-flexible-body dynamics model of the UFMT is firstly built by using transfer matrix method for multibody systems. After deducing overall transfer equation, overall transfer matrix, eigenfrequency equation and dynamics equations, the vibration characteristics and dynamics response of tool-tip are simulated and validated by tests. The machined surface is simulated by transferring displacement between the fly-cutting tool-tip and the workpiece into 3D curve. According to the simulation results, both the air-bearing stiffness of the flying-cutting head and cutting process parameters have effects on the machined surface.