Applied Mechanics and Mechanical Engineering II

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Authors: Z.C. Su, Yan Xia Xue, Cheng Bin Du
Abstract: The stability of a cantilever column subjected to a subtangential follower force and a vertical force is discussed for investigating the effects of these factors on the critical force. The governing differential equation of the system and the corresponding boundary conditions are established, and the exact solution is found out by integrating the differential equation. Based on the exact solution, the effects of the parameters relating to the subtangential follower force and the vertical force on the critical force are analyzed, and discussions for these results are performed, the influence curves of the subtangential follower force parameter and the vertical force parameter to the critical force are plotted. The results show that the parameter of a subtangential follower force can be bigger than 1/2, even equal to 1.0, with taking into account of the effect of the vertical force.
Authors: Hui Feng Zhang, Li Wen Guan, Tie Min Li
Abstract: The structure of an automatic tape-laying (ATL) machine for cylinder components is introduced. The FEM model is established and static stiffness, modal, harmonic response analysis are performed. The improvement scheme is given based on the above analysis result, with better static and dynamic characteristics by increasing cross-sectional area.
Authors: Ming Cong, Tong Zhan Liu, Hai Ying Wen, Zhan Bo Chang
Abstract: In this paper, a life-sized jaw mechanism is proposed on the basis of biological masticatory structure. Its actual parameters are defined in Solidworks according to human masticatory systems, the trajectory and position error of masticatory robot is performed via ADAMS and Matlab. The simulation results have shown that the robotic jaw is able to reproduce the human behavior. However, because the mechanism is a highly coupled and nonlinear system, the position error cannot be eliminated completely, and more sophisticated control system is required in future study.
Authors: Shou Wu Hou, Ying Hou Jiao, Xin Wang, Zhao Bo Chen, Yong Bo Fan
Abstract: To efficiently reduce vibration and noise of a plate, an optimization of passive constrained layer damping (CLD) is presented. The dynamic equation of a sandwich plate with CLD treatment is derived using Lagrange’s method. The assumed modes method is employed to solve the equation and obtain the vibrational energy and sound power, which are used as the objective of optimal design. A genetic algorithm of big mutation is employed to search for the optimum of the location of CLD treatment, the thicknesses of both the constraining layer and the viscoelastic layer and the shear modulus of the viscoelastic material with the restriction of added mass of the total CLD treatment. Numerical results show that for a simply-supported plate with a transverse force (1Hz~200Hz) applied at (0.8La, 0.8Lb), the optimized CLD significantly reduce the vibrational energy and sound power.
Authors: Jian Wang, Li Ming Hu
Abstract: A 2D numerical model is used to modeling the movement of air during air sparging process for groundwater remediation. The zone of influence (ZOI) and the water saturation distribution can be obtained from the calculations. The results agree well with the centrifuge test data, indicating the two-phase flow model is reasonable for numerical simulation of air sparging process. It was also shown that air compressibility has a significant influence on the extent of ZOI.
Authors: Jian Hua Wang, Da Shuai Xi, Shuai Zhao, Shi Chao Wang
Abstract: According to the rule of China Student Formula SAE Competition, This paper discussed and designed the structure. It then chose aluminum-honeycomb and aluminum sheet to make the impact attenuator. Then static and dynamic experiments were carried out to test its performance. It finally drew a conclusion that the design could provide good protection for the driver and racecar. It could also be used on other similar vehicles.
Authors: Hui Xin Yang, Xi Xiang Yang, Wei Hua Zhang
Abstract: Distributed control based on the cyclic pursuit strategies has been of much interest recently. This paper presents distributed control policies based on the simple idea of cyclic pursuit which only require relative measurements of position and velocity of neighbors. First, we study the mathematical theory of cyclic pursuit algorithm. Second, we present Virtual Beacon Guidance is integrated to improve the existing cyclic pursuit strategies to deduce a method of Cyclic Pursuit & Beacon Guidance. Finally, we assume two space missions to prove that the control laws can meet with satellites formation autonomous reconfiguration in various patterns. To this end, the formation can get reconfiguration and reorientation simultaneously. In particular, the mission of convergence to cyclic trajectory with the radius extended is proven by analysis and simulation results.
Authors: Ke Chen, Xue Feng Tong
Abstract: To study on the breaking mechanism of an ice sheet under moving load, have need for researching the displacement responses of ice sheet. From viscoelastic vibration differential equation of ice sheet, dynamic equation of ice sheet was established under moving load in the cylindrical coordinate system, and the boundary conditions were given for solving differential equations. Used Hankel transform and Laplace transform to solve Green function of ice sheet vibration responses under loading, and derived the displacement response of ice sheet on the base of Green function. The example calculation shows that the displacement responses of ice sheet of 0.5m thickness is got under moving load at different time, the peak position of gravity wave propagation lags behind the loading point.
Authors: Fábio Roverto Chavarette
Abstract: In this work, we use a nonlinear control based on Optimal Linear Control. We used as mathematical model a Duffing equation to model a supporting structure for an unbalanced rotating machine with limited power (non-ideal motor). Numerical simulations are performed for a set control parameter (depending on the voltage of the motor, that is, in the static and dynamic characteristic of the motor) The interaction of the non-ideal excitation with the structure may lead to the occurrence of interesting phenomena during the forward passage through the several resonance states of the system. Chaotic behavior is obtained for values of the parameters. Then, the proposed control strategy is applied in order to regulate the chaotic behavior, in order to obtain a periodic orbit and to decrease its amplitude. Both methodologies were used in complete agreement between them. The purpose of the paper is to give suggestions and recommendations to designers and engineers on how to drive this kind of system through resonance.

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