Abstract: A review of mass measurement devices developed by the author is presented. According to the measurement principles, the treated devices are classified into two types. The first type uses a dynamic vibration absorber as a device for both mass measurement and vibration control. The main advantage is no vibration transmitted into the surrounding structures during measurement. The second type uses relay feedback. The advantages are simpler mechanism and robustness against disturbances. In this article, the principles of measurement of each type are presented.
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Authors: Shi Liang Jiang, Tie Jun Yang, Jing Tao Du, Yin Yin Hu
Abstract: A frequency-tuned dynamic vibration absorber by tuning stiffness to reduce vibration at some troubled resonance frequencies of a simply supported beam structure is designed in this paper. Both theoretical and simulation analysis of vibration absorption are conducted. On the basis of analyzing bending vibration of the simply supported beam structure, inherent characteristics and frequency response characteristics of the simply supported beam system before and after being fixed dynamic vibration absorber are obtained by using the energy method with Rayleigh-Ritz procedure of flexible structure. Simulation model of the whole system, which is established by code written, is compared with the model established by finite element analysis software. Results are presented to show the efficiency of the vibration absorber, and then the effect of damping of the dynamic vibration absorber on vibration absorption is studied.
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Authors: Chang Rong Liao, J.H. Hao, D.X. Zhao, K.L. Wang
Abstract: The flow differential equation for Magneto-rheological (MR) fluids in annular channels of MR fluid shock absorber is set up and several rational simplifications are made. Analytical shear stress profiles of MR fluids through annular channels are obtained via solution of the flow differential equation. An analytical study on MR fluid shock absorber is present employing shear stress profiles. Both boundary conditions and compatible conditions are established. Both flow velocity profiles and total volumetric flow rate are developed by integration by parts and numerical integration. The prediction method for damping force of MR fluid shock absorber is developed via simultaneous equations. The analytical study on MR fluid shock absorber is validated by means of reformative Herschel–Bulkley constitutive model, in which flow velocity profiles and flow regions boundary radii are drawed. A MR fluid shock absorber, which is designed and fabricated in Chongqing University, is tested by electro-hydraulic servo vibrator in National Center for Test and Supervision of Coach Quality. The experimental results reveal that the methodology is able to predict damping force of MR fluid shock absorber via shear rate profiles and experimental damping forces are in good agreement with analytical those.
1095
Authors: Zhi Xing Li, Li Hua Yang, Qing Chao Yang
Abstract: In this paper, the dynamic characteristics of Duffing strong nonlinear vibration absorber system with additional hard spring is analysed qualitatively. Based on synovial variable structure algorithm, the active control system model of the nonlinear dynamic vibration absorber is designed, and the effectiveness of the control model is verified by elevant examples. It’s found that with the additional hard spring Duffing strong nonlinear vibration absorber, the control effect of active absorption is superior to the passive absorber, so which has has important guiding significance to the design of actual engineering nonlinear vibration absorber.
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Authors: Kazuhide Watanabe, Naoki Miyashita, Du Hong Bin, Kyohei Irisa, Akihiro Takita, Takao Yamaguchi, Edwin Carcasona, Somsak Mitatha, Yusaku Fujii
Abstract: Impact response of contact lenses is measured using the Levitation Mass Method (LMM). In the LMM, a small mass collides with contact lenses and the impact force is measured with high accuracy as the inertial force of the moving part. A pneumatic linear bearing is used to achieve linear motion with sufficiently small friction acting on the moving part. Hysteresis loop and consumed energy as mechanical characteristics of contact lenses are also calculated.
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