scholarly journals Dynamics Modelling and Simulation for Deployment Characteristics of Mesh Reflector Antennas

2020 ◽  
Vol 10 (21) ◽  
pp. 7884
Author(s):  
Xin Jiang ◽  
Zhengfeng Bai
Keyword(s):  
Large Deformation ◽  
Mechanical Model ◽  
Numerical Procedure ◽  
Modelling And Simulation ◽  
Governing Equations ◽  
Precise Description ◽  
Reflector Antennas ◽  
Equivalent Mechanical Model ◽  
Dynamics Modelling ◽  
Large Motion

The dynamics of mesh reflectors are characterized by large deformation when antennas undergo a large motion in the deployment process. In this work, absolute node coordinate formulation (ANCF), with the merit of precise description of large deformation, is employed to consider the flexibility of the reflector net. From a practical perspective, the effect of the torsional spring is incorporated into the dynamic governing equations by an equivalent mechanical model. Deployment simulation of the mesh reflector antennas is performed by a numerical procedure. It can be found that with the action of a degenerative driven force caused by the friction effect, the deployed process of antennas exhibits a character of asynchronous deployment. Additionally, a significant increase in tension during the final period of deployment has an intense influence on smooth deployment.

Dynamics of Liquid Sloshing in Upright and Inverted Bladdered Tanks

1987 ◽  
Vol 109 (1) ◽  
pp. 58-63 ◽  
Author(s):  
F. T. Dodge ◽  
D. D. Kana
Keyword(s):  
Structural Dynamics ◽  
Mechanical Model ◽  
The Body ◽  
Liquid Sloshing ◽  
Model Parameters ◽  
Test Results ◽  
Governing Equations ◽  
Low Gravity ◽  
Equivalent Mechanical Model ◽  
Mechanical Models

The sloshing of liquids in tanks that use a flexible, inextensible bladder to contain the liquid is investigated experimentally and theoretically. The bladder affects both the configuration of the liquid in the tank and the sloshing frequencies and motion. The governing equations of liquid sloshing coupled to the structural dynamics of the bladder are formulated and examined to determine the interaction between the body forces of the liquid and the stiffness of the bladder and to show that the slosh dynamics can be represented by equivalent mechanical models. Tests are conducted to establish such mechanical models for normal and low-gravity conditions. For an inverted tank (liquid above the bladder), the sloshing is sufficiently different from conventional sloshing that the form of the equivalent mechanical model as well as the numerical values of the model parameters must be derived from the test results.

The Influence of Tank Orientation Angle on a 2D Structure-Tuned Liquid Damper System

2013 ◽  
Vol 135 (1) ◽  
Author(s):  
J. S. Love ◽  
M. J. Tait
Keyword(s):  
Mechanical Model ◽  
Vibrational Energy ◽  
Equations Of Motion ◽  
Orientation Angle ◽  
Structural Response ◽  
Tuned Liquid Damper ◽  
Lagrange’S Equation ◽  
Equivalent Mechanical Model ◽  
Principal Axes ◽  
2D Structure

Tuned liquid dampers (TLDs) utilize sloshing fluid to absorb and dissipate structural vibrational energy, thereby reducing wind induced dynamic motion. By selecting the appropriate tank length, width, and fluid depth, a rectangular TLD can control two structural sway modes simultaneously if the TLD tank is aligned with the principal axes of the structure. This study considers the influence of the TLD tank orientation on the behavior of a 2D structure-TLD system. The sloshing fluid is represented using a linearized equivalent mechanical model. The mechanical model is coupled to a 2D structure at an angle with respect to the principal axes of the structure. Equations of motion for the system are developed using Lagrange’s equation. If the TLD and structure are not aligned, the system responds as a coupled four degree of freedom system. The proposed model is validated by conducting structure-TLD system tests. The predicted and experimental structural displacements and fluid response are in agreement. An approximate method is developed to provide an initial estimate of the structural response based on an effective mass ratio. The results of this study show that for small TLD orientation angles, the performance of the TLD is insensitive to TLD orientation.

Transient Response of Inductrack Systems for Maglev Transport: Part II—Solution and Dynamic Analysis

2020 ◽  
Vol 142 (3) ◽  
Author(s):  
Ruiyang Wang ◽  
Bingen Yang
Keyword(s):  
Steady State ◽  
Dynamic Analysis ◽  
Transient Response ◽  
Numerical Procedure ◽  
Steady State Response ◽  
Governing Equations ◽  
Transient Model ◽  
State Response ◽  
Proposed Model ◽  
Non Linear

Abstract In Part I of this two-part paper, a new benchmark transient model of Inductrack systems is developed. In this Part II, the proposed model, which is governed by a set of non-linear integro-differential governing equations, is used to predict the dynamic response of Inductrack systems. In the development, a state-space representation of the non-linear governing equations is established and a numerical procedure with a specific moving circuit window for transient solutions is designed. The dynamic analysis of Inductrack systems with the proposed model has two major tasks. First, the proposed model is validated through comparison with the noted steady-state results in the literature. Second, the transient response of an Inductrack system is simulated and analyzed in several typical dynamic scenarios. The steady-state response results predicted by the new model agree with those obtained in the previous studies. On the other hand, the transient response simulation results reveal that an ideal steady-state response can hardly exist in those investigated dynamic scenarios. It is believed that the newly developed transient model provides a useful tool for dynamic analysis of Inductrack systems and for in-depth understanding of the complicated electro-magneto-mechanical interactions in this type of dynamic systems.

Sign in / Sign up

Export Citation Format

Share Document