Luo C.,Beihang University |
Luo C.,China Airborne Missile Academy |
Xiong J.,Beihang University
Chinese Journal of Aeronautics | Year: 2012
This paper deals with static pull and push bending tests on two-dimensional (2D) orthogonal EW220/5284 twill weave fabric (TWF) composite tee-joints processed with the resin transfer moulding (RTM) technique. Static pull and push bending properties are determined and failure initiation mechanism is deduced from experimental observations. The experiments show that the failure initiation load, on average, is greater for push bending than for pull bending, whereas the scatter is smaller for push bending than for pull bending. The failure mode of RTM-made tee-joints in pull bending tests can be reckoned to be characteristic of debonding of resin matrix at the interface between the triangular resin-rich zone and the curved web of tee-joint until complete separation of the curved web from the bottom plate. In contrast, as distinct from the products subject to pull bending loading, the RTM tee-joints in push bending tests experience matrix cracking and fibre fracture from outer layers to inner layers of the bottom plate until catastrophic collapse resulting from the bending. Three-dimensional finite element (FE) models are presented to simulate the load transfer path and failure initiation mechanism of RTM-made TWF composite tee-joint based on the maximum stress criterion. Good correlation between experimental and numerical results is achieved. © 2012 Chinese Journal of Aeronautics.
Hao Y.,Shenyang Ligong University |
Dong F.,Shenyang Ligong University |
Zhang J.,Shenyang Ligong University |
Bao L.,China Airborne Missile Academy
Zhongguo Jixie Gongcheng/China Mechanical Engineering | Year: 2014
Micro-gripper as end devices, directly determined the efficiency of the micro-assembly. MEMS mechanism contained many tiny moving parts and functional elements, so as to achieve the stabally gripping and automatic assembly of these tiny devices. A micro-gripper with two grade displacement amplification was designed, which was actuated by piezoelectric ceramics and based on flexible hinges. The micro-gripper node stress, stiffness and maximum deformation, etc. were analyzed and calculated, and the micro-gripper prototype was produced. The experimental results show that the maximum deformation levels of the gripper is as 245μm, the magnification is about 12.3 times, that meets the requirements of MEMS micro-assembly. On this basis of above, the deformation and gripping force were focused on, and a formula of 99.99% reliability drive voltage was derived by nonlinear regression of the test data, and the precise control of the micro-gripper is achieved.
Jin Q.,China Airborne Missile Academy
Journal of Applied Optics | Year: 2014
For the wide use of micro-spectrometer in diverse applications, its core device, torsion-type micromachined scanning gratings, were designed, fabricated and characterized. In order to obtain large scanning range and low resonant frequency at low driving voltage, the structure without additional starting electrodes was designed and studied by silicon-on-insulator (SOI) fabrication technology. The micromachined scanning gratings fabricated by SOI wafers were characterized, which prove that the micromachined scanning gratings has good modulation performances. The maximum deflection angles can reach ±4.8°, corresponding to a total optical scanning range of 19.2°at a driving voltage of 25 V.
Li J.-X.,China Airborne Missile Academy
Xi Tong Gong Cheng Yu Dian Zi Ji Shu/Systems Engineering and Electronics | Year: 2011
The one-dimensional clustering range resolution algorithm is a common stable ambiguity resolution in radar detection. The one-dimensional algorithm can acquire the unambiguous range by optimizing the least cost error. Based on the idea of reducing the range error step-by-step, a three-step-search algorithm is presented to solve the range ambiguity. First three different range errors are given corresponding to the radar system parameters, then the cost error is demanded to reduce gradually, meanwhile the ambiguity region is shrunk compared with the preceding region until the ambiguous range is acquired. The experimental results show that the three-step-search algorithm is efficient for range ambiguity resolution.
Wang J.,China Airborne Missile Academy
Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering | Year: 2010
The time performance of region labeling algorithm is very important for precision guidance based on image. However, common region labeling algorithms can not meet the requirements of real-time image processing. By analyzing the current image labeling technologies, a technique using segment to record the connective area was proposed in this paper, connective closure and information related to the target could be computed during a one-time image scan. The coordinates of target edge pixels were recorded to computer target's features such as centroid, area, track and grey etc. as labeling. Then, the algorithm's conceptions and realization step were presented. Experimental results show that the proposed algorithm is capable of labeling targets in the image of 128 × 128 size in 0.4 ms with TMS320C6414 600 MHz simulator, and is more efficient, correct and stable compared with the other algorithm. It can well meet the timer performance requirements of real-time processing, and is applicable in high speed target capture and tracking.