scholarly journals Dynamic analysis of detumbling a rotating satellite using flexible deceleration rod

Author(s):  
Honghua Dai ◽  
Hao Chen ◽  
Xiaokui Yue

Abstract Malfunctioning satellites are generally non-cooperative tumbling objects. Due to their complex tumbling motion, it is essential to stabilize the target within an acceptable rotating range in the pre-capture phase. In contrast to contactless methods, contact methods based on flexible devices are efficient and can generate sufficient operating torque through flexible contact. However, accurate dynamic analysis of the operation is challenging because of two limitations. It is difficult to obtain a high-efficiency description of the large deformation arising from the operating process. Moreover, the contact between a flexible device and a tumbling object is hard to detect efficiently. This paper proposes a method for detumbling a free-floating rotating satellite; it uses a flexible rod to contact the solar array of the target. The absolute nodal coordinate formulation is first applied to a rod-contact detumbling model in simulation to describe the large deformation of the rod precisely with a low computational burden. Next, a two-step method to detect the contact is employed to pinpoint the contact point and speed up the simulation: coarse detection in the contactless phase and fine detection in the contact phase. Finally, the feasibility of the contact detumbling method is verified. In addition, through the further analysis of the contact process, some characteristics of this kind of strategy are studied for the first time.

2015 ◽  
Vol 744-746 ◽  
pp. 1949-1952 ◽  
Author(s):  
Hai Bin Li ◽  
Jiang Jiang Li

Based on the coupling of PC-Crash program and MADYMO software, thekinematics laws of pedestrian in the contact process for automobile-pedestrian collision are analyzed through modeling and simulation by establishing vehicle model and pedestrian model, and selecting main influencing factors on contact phase as independent variables for simulation tests.


2011 ◽  
Vol 199-200 ◽  
pp. 251-256
Author(s):  
Kai An Yu ◽  
Ke Yu Chen

Based on requirements of pipe transport systems on deepwater pipelaying vessel, a new pipe lifting mechanism was designed. It was composed of crank-rocker and rocker-slider mechanism with good lifting capacity and high efficiency. When the slider went to the upper limit position, the mechanism could approximatively dwell, meeting the requirement for transverse conveyor operation. According to the theory of dynamics, numerical analysis method was used to the dynamic analysis of the mechanism. The results showed the maximum counterforce was at the joint between the rocker and ground, and this calculation could be a guideline for the kinematic pair structure designing.


Author(s):  
Jun Shen ◽  
Yunlong Wu ◽  
Heng Peng ◽  
Yinghua Liu

Coal gasification is a key technology for clean coal conversion with high efficiency. During the past decade, more than twenty Shell Key Gasification Equipments (SKGE) used in the Shell Coal Gasification Process (SCGP) have been built in coal-to-chemicals industry in China. SKGE is composed of Gasifier and Syngas cooler which are connected by Transfer duct. The support skirt of the Gasifier base is fixed, while the Syngas cooler side is supported by a constant hanger (floating support). In this paper, a FE model of the largest 2000-ton SKGE system in China is established by using ANSYS. The global dynamic response under the seismic load is simulated. In order to verify the correction of the calculation, the results are also compared with that by using ABAQUS. Compared to the traditional static analysis, it can be found that the deformation and stress distribution, the force and moment on several specified cross sections of SKGE change over time under seismic load based on the transient dynamic analysis. As the result of the seismic analysis is the prerequisite and foundation for accurate calculation of each key part (e.g. connection between Transfer duct and Gas reversal chamber), the seismic analysis is one of the most important analyses in the Gasification design, which will ensure the essential safety of SKGE system.


2014 ◽  
Vol 496-500 ◽  
pp. 1535-1538
Author(s):  
Yan Cao ◽  
Zhi Jie Wang ◽  
Yu Bai

Aiming at the low machining accuracy, low efficiency, cumbersome programming process, strong empirism and great programming difficulty of special shape blades, a new NC spiral milling method of high-quality and high-efficiency is put forward to process aviation blades. Three methods of constructing spiral tool path are studied, i.e., constructing the spiral using interpolation in parametric domain, constructing the spiral based on a driving surface and projection technology, and segmentally constructing the spiral by plane intersection. By comparison and analysis, their advantages and disadvantages are presented. According to the characteristics of spiral milling, the principles and algorithms of interference-free cutter location calculation for space free-form curved surface are introduced and the focus is put on cutter contact point calculation algorithms.


2013 ◽  
Vol 28 (6) ◽  
pp. 3039-3046 ◽  
Author(s):  
Chien-Hsuan Chang ◽  
En-Chih Chang ◽  
Hung-Liang Cheng
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