A high-fidelity dynamic model for the Active Rack Isolation System

1998 ◽  
Author(s):  
R. Hampton ◽  
Nagendra Subba Rao ◽  
Young Kim ◽  
William Wagar ◽  
Allen Karchmer
Keyword(s):  
Dynamic Model ◽  
High Fidelity ◽  
Isolation System

Study on Floating Raft Vibration Isolation System for Pumping Unit

2011 ◽  
Vol 383-390 ◽  
pp. 130-135 ◽  
Author(s):  
Fu Mao Wang ◽  
Chang Guo Wang ◽  
Lan Lan Guo ◽  
Bang Chun Wen ◽  
Yong Li
Keyword(s):  
Finite Element ◽  
Dynamic Model ◽  
Vibration Isolation ◽  
Steel Structure ◽  
Elastic Cylinder ◽  
Isolation System ◽  
Vibration Isolation System ◽  
Floating Raft ◽  
Pumping Units ◽  
Important Basis

In this paper, based on the theory of double layered vibration isolation, the finite element dynamic model of floating raft vibration isolation system has been established for the project of vibration and noise control in a heat exchange station. The dynamic model of single pump is simplified an elastic cylinder based on the principle of equivalent parameters, and the elastic raft frame is used of steel structure. The dynamic characteristics of the system is analyzed by used of ANSYS with SOLID45 unit and COMBIN14 spring-damper unit, which provide an important basis for the engineering design of floating raft isolation system with pumping units.

Optimal Design Parameters of Cab’s Isolation System for Vibratory Roller Using a Multi-Objective Genetic Algorithm

2018 ◽  
Vol 875 ◽  
pp. 105-112 ◽  
Author(s):  
Van Quynh Le ◽  
Khac Tuan Nguyen
Keyword(s):  
Genetic Algorithm ◽  
Optimal Design ◽  
Dynamic Model ◽  
Nonlinear Dynamic ◽  
Ride Comfort ◽  
Design Parameters ◽  
Nonlinear Dynamic Model ◽  
Nsga Ii ◽  
Isolation System ◽  
Multi Objective

In order to improve the vibratory roller ride comfort, a multi-objective optimization method based on the improved genetic algorithm NSGA-II is proposed to optimize the design parameters of cab’s isolation system when vehicle operates under the different conditions. To achieve this goal, 3D nonlinear dynamic model of a single drum vibratory roller was developed based on the analysis of the interaction between vibratory roller and soil. The weighted r.m.s acceleration responses of the vertical driver’s seat, pitch and roll angle of the cab are chosen as the objective functions. The optimal design parameters of cab’s isolation system are indentified based on a combination of the vehicle nonlinear dynamic model of Matlab/Simulink and the NSGA - II genetic algorithm method. The results indicate that three objective function values are reduced significantly to improve vehicle ride comfort.

scholarly journals Modeling and Control of a Six Degrees of Freedom Maglev Vibration Isolation System

Sensors ◽  
2019 ◽  
Vol 19 (16) ◽  
pp. 3608 ◽  
Author(s):  
Qianqian Wu ◽  
Ning Cui ◽  
Sifang Zhao ◽  
Hongbo Zhang ◽  
Bilong Liu
Keyword(s):  
Dynamic Model ◽  
Nonlinear Dynamic ◽  
Degrees Of Freedom ◽  
Vibration Isolation ◽  
Nonlinear Dynamic Model ◽  
Isolation System ◽  
Vibration Isolation System ◽  
Modeling And Control ◽  
And Control ◽  
Isolation Performance

The environment in space provides favorable conditions for space missions. However, low frequency vibration poses a great challenge to high sensitivity equipment, resulting in performance degradation of sensitive systems. Due to the ever-increasing requirements to protect sensitive payloads, there is a pressing need for micro-vibration suppression. This paper deals with the modeling and control of a maglev vibration isolation system. A high-precision nonlinear dynamic model with six degrees of freedom was derived, which contains the mathematical model of Lorentz actuators and umbilical cables. Regarding the system performance, a double closed-loop control strategy was proposed, and a sliding mode control algorithm was adopted to improve the vibration isolation performance. A simulation program of the system was developed in a MATLAB environment. A vibration isolation performance in the frequency range of 0.01–100 Hz and a tracking performance below 0.01 Hz were obtained. In order to verify the nonlinear dynamic model and the isolation performance, a principle prototype of the maglev isolation system equipped with accelerometers and position sensors was developed for the experiments. By comparing the simulation results and the experiment results, the nonlinear dynamic model of the maglev vibration isolation system was verified and the control strategy of the system was proved to be highly effective.

Development of curved beam periodic structure in broadband resonance suppression for cylindrical shell structure

2015 ◽  
Vol 23 (8) ◽  
pp. 1267-1284 ◽  
Author(s):  
Xiuchang Huang ◽  
Jinpeng Su ◽  
Longlong Ren ◽  
Hongxing Hua
Keyword(s):  
Cylindrical Shell ◽  
Boundary Conditions ◽  
Numerical Simulations ◽  
Band Gap ◽  
Dynamic Model ◽  
Periodic Structure ◽  
Shell Structure ◽  
Curved Beam ◽  
Isolation System ◽  
Vibration Transmission

A dynamic model is developed to incorporate a curved beam periodic structure in the transfer path of an internal isolation system to reduce the resultant vibro-acoustic of the receiving cylindrical shell structure in a passive broadband way. The vibration transmission from the multi-connected internal isolation system with/without the curved beam periodic structure is built by the matrix method. The analytical representation of the curved beam is employed to establish the transfer matrix dynamic model of the proposed multi-layer curved beam periodic structure. Both numerical simulations and experimental investigations are carried out. The numerical simulations demonstrate that the resonances of the internal isolation system will magnify the vibro-acoustic responses notably and the designed curved beam periodic structure is an effective band-stop mechanical filter to minimize the vibration transmission and acoustic radiation responses at resonances in the band gap. The experimental results confirm that the normal acceleration responses on both the bases and the surface of the cylindrical shell are reduced in the band gap of the curved beam periodic structure. An average reduction amount of 9∼12 dB on the bases and 2∼3 dB on the shell is obtained. The vibration transmission in the curved beam periodic structure is tested and found to be influenced by the boundary conditions at the input and output ends, which is different from that under the free boundary conditions.

scholarly journals Dynamics and control of a bio-inspired Stewart platform

2021 ◽  
Vol 39 (2) ◽  
pp. 258-266
Author(s):  
Yuansheng Peng ◽  
Honghua Dai ◽  
Hao Zhang ◽  
Xiaokui Yue
Keyword(s):  
Dynamic Model ◽  
Feedback Linearization ◽  
Vibration Isolation ◽  
Control Method ◽  
Stewart Platform ◽  
The Novel ◽  
Isolation System ◽  
Theoretical Simulation ◽  
Vibration Isolation Performance ◽  
Isolation Performance

Collision and strong impacts take place in mission of the on orbit capture of non-cooperative spacecraft. So, it is necessary to design a vibration isolation system with efficient vibration isolation performance. A Stewart vibration isolation platform based on the bio-inspired isolation system is proposed in this paper. The characteristics of the novel bio-inspired Stewart platform realizes the vibration isolation protection of the serving spacecraft during the capture mission. The dynamic model of the vibration isolation platform is established by Lagrange's equations. The fidelity of the established dynamic model is verified via a comparison of the theoretical simulation and the ADAMS simulation. Comparisons between the presently proposed vibration isolation platform and the traditional spring-mass-damper type Stewart vibration isolation platform demonstrates the advantages of the present platform. The effects of system parameters on the isolation performance of the present platform are thoroughly investigated. The feedback linearization control method is used to control the present platform which overcomes the drift motion that occurs in the passive isolation case. The results show that the novel bio-inspired Stewart platform has excellent vibration isolation performance, which provides a promising way for the vibration isolation of the non-orbit capture mission.

Dynamic Model of Elastically Mounted Machinery with Cylindrical Shell

2013 ◽  
Vol 419 ◽  
pp. 423-431
Author(s):  
Wei Xu ◽  
Chang Geng Shuai ◽  
Zhi Qiang Lv
Keyword(s):  
Cylindrical Shell ◽  
System Design ◽  
Dynamic Model ◽  
Reaction Force ◽  
Thin Wall ◽  
Electric Motors ◽  
Isolation System ◽  
Vibration Excitation ◽  
Shell Motion ◽  
Shell Equation

Mounting machinery by isolators can reduce vibration transmitted to the base and attenuated environmental noise. In this paper the machine having cylindrical shell such as electric motors is modeled by thin-wall cylindrical shell motion equation. The reaction force exerted by isolator is considered as point force and integrated in the shell equation. The typical vibration excitation of machinery is represented by point and line excitations. The forces transmitted to the base through isolators are then calculated under different excitations. Conclusions with respect to machinery and isolation system design are presented based on numerical results.

A method for developing a high fidelity test-corrected dynamic model

1998 ◽  
Author(s):  
J. Lollock ◽  
T. Cole ◽  
M. Ankrom ◽  
W. Cooley
Keyword(s):  
Dynamic Model ◽  
High Fidelity

scholarly journals The Influence of the Friction-Sliding Coefficient of Support Structures and Parameters of Seismic Actions on Reactions and Reliability of Structures with Seismic Protection

2021 ◽  
pp. 12-23
Author(s):  
A. D Abakarov ◽  
H. R Zainulabidova
Keyword(s):  
Differential Equations ◽  
Dynamic Model ◽  
Seismic Isolation ◽  
Statistical Characteristics ◽  
Optimal Parameters ◽  
System Of Differential Equations ◽  
Isolation System ◽  
Reliability Indicators ◽  
Cantilever Rod ◽  
Seismic Impact

The study is focused on a structure represented by a multimass elastic cantilever rod with dry friction seismic isolation elements in the support part under a horizontal random impact of a seismic type. The paper aims at investigating the seismic reaction and selecting optimal parameters of the seismic isolation system involving random impact characteristics, limit parameters of the structure, and the seismic isolation system. The researches are based on dynamic computations; the impacts and fluctuations of the system are random processes. The dynamic model of the structure with the considered seismic isolation is presented in the form of a cantilever rod with concentrated masses; a system of differential equations describing the displacement of the structure with the seismic-isolating sliding elements at the level of the top of the foundations is compiled; and a seismic impact is modeled in the form of a nonstationary random process. An algorithm is developed to integrate the system of differential equations of motion and to determine the statistical characteristics of the seismic reaction and reliability indicators of the structures with the seismic isolation. A method aimed at evaluating effectiveness of the seismic isolation system and selecting its rational parameters is suggested. We developed the computational dynamic model of the structure with the seismic-isolating sliding elements installed at the top level of the foundations, and elastic and rigid limiters for the movement of the sliding supports. This model is made in the form of a multimass cantilever rod that takes into account the relative movements of the masses and the stops of the system on the movement limiters. The structure’s movement under a seismic impact is described by a system of differential equations that takes into account the conditions of transitions of the structure from the state of sticking to the state of sliding and vice versa. The statistical characteristics of the seismic reaction and the reliability indicators of the structure in the process of vibrations are determined for different values of the maximum acceleration of the ground vibration, the prevailing period of impact, the number of masses in the calculated model and the coefficient of friction-sliding of the support elements. The influence of the impact parameters and the system on the efficiency of the seismic isolation of the structures with sliding elements is estimated. The proposed approach to selecting the optimal parameters of the seismic isolation system can be used as a research method aimed at improving efficiency of systems with different design options for seismic isolation of structures.

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