Theoretical and Experimental Research of Viscoelastic Damping Limb-Like-Structure Device with Coupling Nonlinear Characteristics

2021 ◽  
pp. 2130002
Author(s):  
Zhen-Hua He ◽  
Zhao-Dong Xu ◽  
Jian-Yang Xue ◽  
Xing-Jian Jing ◽  
Yao-Rong Dong ◽  
...  
Keyword(s):  
Vibration Isolation ◽  
Harmonic Balance Method ◽  
Viscoelastic Damping ◽  
Static Stiffness ◽  
Viscoelastic Damper ◽  
Stiffness Analysis ◽  
Nonlinear Dynamic Equation ◽  
New Type ◽  
Geometrical Effects ◽  
Theoretical Results

The nonlinear characteristic of vibration control systems has attracted increasing attention for its advantage in improving structural performance. In this paper, a new type of viscoelastic damping limb-like-structure (VE-LLS) device is proposed by combing the viscoelastic (VE) damper and limb-like-structure (LLS) together, which possesses coupling nonlinearity characteristic caused by geometric and material factors, as well as a remarkable advantage in improving the control performance. First, to explore the nonlinear geometrical effects on the static stiffness of the VE-LLS device, a formula is derived from static stiffness, and the results are discussed. Second, dynamic analysis is performed of the proposed device considering the coupling geometrical and material nonlinearities in frequency domain, with the real-time effect of frequency and temperature on the mechanical properties of the viscoelastic damper considered in solving the nonlinear vibration equation. The harmonic balance method (HBM) is used to solve the nonlinear dynamic equation. Then, the displacement transmissibility of the VE-LLS device is calculated and assessed. The results indicate that the proposed device possesses excellent vibration isolation performance, and the geometric parameters of the viscoelastic damper have significant nonlinear effect on the performance. Finally, an experiment is carried out of the VE-LLS device to verify the accuracy of the static stiffness analysis. The results show that the theoretical results agree well the experimental ones, and that the theoretical results have high accuracy and reliability.

scholarly journals A Variable Parameter Ambient Vibration Control Method Based on Quasi-Zero Stiffness in Robotic Drilling Systems

Machines ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 67
Author(s):  
Laixi Zhang ◽  
Chenming Zhao ◽  
Feng Qian ◽  
Jaspreet Singh Dhupia ◽  
Mingliang Wu
Keyword(s):  
Vibration Control ◽  
Vibration Isolation ◽  
Control Method ◽  
Control Strategies ◽  
Equations Of Motion ◽  
Variable Parameter ◽  
Harmonic Balance Method ◽  
Variable Stiffness ◽  
Ambient Vibration ◽  
Robotic Drilling

Vibrations in the aircraft assembly building will affect the precision of the robotic drilling system. A variable stiffness and damping semiactive vibration control mechanism with quasi-zero stiffness characteristics is developed. The quasi-zero stiffness of the mechanism is realized by the parallel connection of four vertically arranged bearing springs and two symmetrical horizontally arranged negative stiffness elements. Firstly, the quasi-zero stiffness parameters of the mechanism at the static equilibrium position are obtained through analysis. Secondly, the harmonic balance method is used to deal with the differential equations of motion. The effects of every parameter on the displacement transmissibility are analyzed, and the variable parameter control strategies are proposed. Finally, the system responses of the passive and semiactive vibration isolation mechanisms to the segmental variable frequency excitations are compared through virtual prototype experiments. The results show that the frequency range of vibration isolation is widened, and the stability of the vibration control system is effectively improved without resonance through the semiactive vibration control method. It is of innovative significance for ambient vibration control in robotic drilling systems.

The Vibration Isolation Effect Research of the Floating Raft Isolation System Based on the Adjustable Flexibility of Foundation

2013 ◽  
Vol 819 ◽  
pp. 115-119 ◽  
Author(s):  
Hui Wang ◽  
Ze Yu Weng ◽  
Gan Xiang ◽  
Bo Lu ◽  
Hong Gang Ding ◽  
...  
Keyword(s):  
Vibration Isolation ◽  
Test System ◽  
Isolation Effect ◽  
Isolation System ◽  
Elastic Beams ◽  
Floating Raft ◽  
Marine Engineering ◽  
Flexible Foundation ◽  
The Relationship ◽  
Theoretical Results

The floating raft isolation system is widely used in the field of marine engineering for its vibration isolation effect. Along with the application of light thinning structure of the ship, the flexibility of foundation of floating raft isolation system makes the vibration isolation effect vary widely between the practical floating raft isolation system and its theoretical results. In order to research the vibration isolation effect of the floating raft isolation system on different flexibility of foundation, the floating raft isolation system with flexible foundation is designed in this paper, and the adjustable flexibility of foundation is achieved by using elastic beams. With simulation and analysis of test system in ADAMS, the results of the relationship between flexibility and vibration isolation effect are obtained.

Efficient (Tube) Settling Tanks

1991 ◽  
Vol 24 (7) ◽  
pp. 223-228 ◽  
Author(s):  
Lazar Ignjatović
Keyword(s):  
Surface Area ◽  
Continuous Flow ◽  
Settling Tank ◽  
Design Flow ◽  
Flowing Water ◽  
Vertical Flow ◽  
Settling Basin ◽  
New Type ◽  
Theoretical Results ◽  
Maximum Design

This paper discusses design principles and theoretical results for a new type of settling tank. Within the settling zone of the tank, sedimentation takes place in tube, as in a quiescent container of equal (3-5 cm) depth. The inlet, sludge and outlet zone are arranged for a continuous-flow rectangular (or circular) basin. A particle that enters the sludge zone is and stays removed, and the sludge can be removed by gravity or pumped from the sludge zone. Hydraulically, the process can be formulated in terms of horizontal-vertical-flow without short-circuiting. Tank loadings are 0.5 L/s per m2 to 1.5 L/s per m2 of tank surface area. The detention period of 15-20 minutes offers the same overall removal efficiency as 4-5 hours for classical one. Variations in flow are of little concern, provided that the maximum design flow is not exceeded. Scum is removed without difficulty from the tank as well as the sludge, and the sludge removal device will also act as a flocculator. This type of settling basin is suitable where sludge volumes are large or where putrefaction of sludge in contact with the flowing water is to be avoided.

scholarly journals Theoretical and experimental investigation of a 1:3 internal resonance in a beam with piezoelectric patches

2020 ◽  
Vol 26 (13-14) ◽  
pp. 1119-1132 ◽  
Author(s):  
Vinciane Guillot ◽  
Arthur Givois ◽  
Mathieu Colin ◽  
Olivier Thomas ◽  
Alireza Ture Savadkoohi ◽  
...  
Keyword(s):  
Harmonic Balance ◽  
Internal Resonance ◽  
Harmonic Balance Method ◽  
Mode Shapes ◽  
Governing Equations ◽  
Internal Resonances ◽  
Thin Beam ◽  
Beam Focusing ◽  
Theoretical Results ◽  
Theoretical Developments

Experimental and theoretical results on the nonlinear dynamics of a homogeneous thin beam equipped with piezoelectric patches, presenting internal resonances, are provided. Two configurations are considered: a unimorph configuration composed of a beam with a single piezoelectric patch and a bimorph configuration with two collocated piezoelectric patches symmetrically glued on the two faces of the beam. The natural frequencies and mode shapes are measured and compared with those obtained by theoretical developments. Ratios of frequencies highlight the realization of 1:2 and 1:3 internal resonances, for both configurations, depending on the position of the piezoelectric patches on the length of the beam. Focusing on the 1:3 internal resonance, the governing equations are solved via a numerical harmonic balance method to find the periodic solutions of the system under harmonic forcing. A homodyne detection method is used experimentally to extract the harmonics of the measured vibration signals, on both configurations, and exchanges of energy between the modes in the 1:3 internal resonance are observed. A qualitative agreement is obtained with the model.

scholarly journals Proposal of an Equal-Stiffness and Equal-Stroke 2D Micro-Positioning Platform Driven by Piezoelectric Actuators

Actuators ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 47
Author(s):  
Feng Sun ◽  
Yansong Hao ◽  
Fangchao Xu ◽  
Junjie Jin ◽  
Qiang Li ◽  
...  
Keyword(s):  
Simulation Analysis ◽  
Structural Parameters ◽  
Piezoelectric Actuators ◽  
Static Stiffness ◽  
Coupling Ratio ◽  
Stiffness Analysis ◽  
Magnification Ratio ◽  
Measurement Experiment ◽  
Nested Structure ◽  
Long Stroke

Micro-positioning platform plays an important role in the field of precision positioning such as microelectronics, robotics and biomedicine. This paper proposes an equal-stiffness and equal-stroke 2D micro-positioning platform, which is driven by piezoelectric actuators. The overall structure of the 2D micro-positioning platform adopts a nested structure and the displacement magnification mechanism adopts two hourglass displacement magnification mechanisms. The displacement magnification ratio of the hourglass displacement magnification mechanism was studied, and its structural parameters were optimized. Static stiffness analysis and simulation analysis of the micro-positioning platform were carried out. The simulation stiffness of the micro-positioning platform in the XY direction is 46873 N/m and 46832 N/m respectively. The experimental prototype of the micro-positioning platform was built. Through the measurement experiment with the prototype, the maximum stroke of the micro-positioning platform in the XY direction is 489 μm and 493 μm respectively; the maximum coupling ratio in the XY direction is 2.38% and 2.70% respectively. The research indicates that the micro-positioning platform had the characteristics of small size, equal long stroke, equal stiffness and low coupling ratio in the XY direction.

Analysis and Optimal Design for the Static Stiffness of a 2UPS-UPR Parallel Machine Tool

2009 ◽  
Vol 626-627 ◽  
pp. 429-434 ◽  
Author(s):  
Liang Zhao ◽  
Ya Dong Gong ◽  
Guang Qi Cai
Keyword(s):  
Machine Tool ◽  
Structural Design ◽  
Machine Tools ◽  
Structural Parameters ◽  
Parallel Machine ◽  
Static Stiffness ◽  
Stiffness Analysis ◽  
Stiffness Model ◽  
Parallel Machine Tool ◽  
Stiffness Distribution

The stiffness model of the parallel machine tool is established by static analysis, the static stiffness analysis is carried out through numerical Simulation and the stiffness distribution is given. On the basis of this, the optimal objective is given which is the average of 729 values of -axis stiffness and -axis stiffness corresponding to 729 positions in the workspace. With MATLAB software, the effects are simulated which the structural parameters of the parallel machine tool have on their stiffness, their change rules are gained, and this provides a basis for the structural design of this type of machine tools.

Nonlinear Vibration Analysis of Viscoelastic Isolator

2012 ◽  
Vol 160 ◽  
pp. 140-144
Author(s):  
Chao Zhou ◽  
Cai Mao Zhong
Keyword(s):  
Dynamic Response ◽  
Fractional Derivative ◽  
Nonlinear Dynamic ◽  
Harmonic Balance Method ◽  
Nonlinear Damping ◽  
Vibration Isolator ◽  
Response Characteristics ◽  
Nonlinear Dynamic Equation ◽  
The Stability ◽  
Stiffness And Damping

Research on nonlinear dynamic response of passive vibration isolator, which was excited by foundation vibration and isolated by viscoelastic material was done. Nonlinear stiffness was expressed by the cubic polynomial function of deformation and nonlinear damping was characterized by viscoelastic fractional derivative operator. Then the fractional derivative nonlinear dynamic equation of passive vibration isolator was established. The dynamic response characteristics were analyzed by harmonic balance method and the frequency response equation and amplitude-frequency curve were obtained, and furthermore, the influence of nonlinearity on system was analyzed. Finally, the stability and the stable interval of the periodic solution were argued by the Floquet theory. The result s indicates that the proposed equation can precisely describe the dynamic characteristics of viscoelastic vibration isolator. The ignorance of nonlinearity of stiffness and damping will result in obvious error. The proposed method provides theoretic reference for design of viscoelastic isolator and the evaluation of its effect.

Experimental Study on the Performance of the Laminated Steel Isolators

2013 ◽  
Vol 423-426 ◽  
pp. 1603-1607
Author(s):  
Yao Guo Xie ◽  
Ping He ◽  
Xian Qiang Qu ◽  
Hong Bin Cui
Keyword(s):  
Experimental Study ◽  
Vibration Isolation ◽  
Dynamic Stiffness ◽  
Damping Ratio ◽  
Dynamic Performance ◽  
Performance Testing ◽  
Stiffness Ratio ◽  
Static Stiffness ◽  
Comparison Of The Results

Through the analysis and comparison of the results of static and dynamic performance testing of a series of laminated steel pieces isolators used in the vibration isolation of warships, in the number and thickness of laminated steel pieces of the same circumstances, laminated steel arc and preload of test samples had a certain impact on the values ​​of static stiffness, dynamic stiffness, damping ratio as well as dynamic and static stiffness ratio.

Dynamic Response Analysis for the Solar-Powered Aircraft Composite Wing Panel with Viscoelastic Damping Layer

2011 ◽  
Vol 105-107 ◽  
pp. 491-494
Author(s):  
Tie Jun Liu ◽  
Yong Zhang ◽  
Gang Li ◽  
Feng Hui Wang
Keyword(s):  
Dynamic Response ◽  
Vibration Isolation ◽  
Viscoelastic Damping ◽  
Response Analysis ◽  
Aircraft Wing ◽  
Maximum Displacement ◽  
Displacement Response ◽  
Stiffened Structures ◽  
Solar Powered ◽  
Wing Panel

In design of solar powered aircraft wing panel, vibration properties of wing panel should be considered, especially for the peak value of dynamic response. In this research, a viscoelastic damping layer is built for vibration isolation, wing panel finite element models of stiffened and no-stiffened structures base on fiber-reinforced laminates with damping layer in the middle are built. Natural frequency and displacement response are analyzed with different thickness of damping layer and structures. Result shows natural frequencies decrease as thickness increased, and that of laminates are lower than stiffened structure. The maximum displacement response value decreased when thickness increased and that of laminates is higher than structured with stiffer. The presented work is helpful for type selection and designing of solar powered aircraft wing panel.

Wind-Induced Vibration Control for Transmission System Using Steel-Lead Viscoelastic Damper

2014 ◽  
Vol 597 ◽  
pp. 376-379 ◽  
Author(s):  
Feng Lin Gan ◽  
Hai Long Jiang
Keyword(s):  
Time History ◽  
Element Model ◽  
Transmission Tower ◽  
Viscoelastic Damper ◽  
Line System ◽  
Type Steel ◽  
New Type ◽  
Auto Regressive ◽  
Working Principle ◽  
Wind Induced Vibration

For wind-induced vibration of transmission tower-line system, the vibration reduction effects are studied based on a new type steel-lead viscoelastic damper. Firstly, Calculate damped coefficient basing on the test of the new type steel-lead viscoelastic damper under slow reversed cyclic horizontal loads. Then, a finite element model of transmission tower was built by using ANSYS. And the time history samples of random fluctuating wind load is obtained with the linear auto-regressive filter law principle. Next, three installation plans of dampers on tower were proposed based on analyzing the working principle damper and the structure of tower. Finally, a wind-induced vibration transient response simulation was performed respectively for the different plans. The influences of SLVD dampers on the displacement and on the acceleration of the controlled nodes were compared. SLVD damper can reduce the top node displacement by about 37.89%. The results indicated that the SLVD damper can suppress the wind-induced vibration. And through comparison, the optimal installation scheme of SLVD dampers is obtained.

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