Modeling and Vibration Analysis of Deployable Space Boom Structures

2005 ◽  
Author(s):  
Bingen Yang ◽  
Hongli Ding ◽  
Houfei Fang ◽  
Michael Lou
Keyword(s):  
Equilibrium Equation ◽  
Analytical Modeling ◽  
Transfer Functions ◽  
Dynamic Equilibrium ◽  
Space Structures ◽  
Solution Technique ◽  
Transfer Function Method ◽  
Global Dynamic ◽  
Global Equilibrium ◽  
Distributed Transfer Function

Lightweight booms are being developed as a basic building element of deployable space structures for future NASA missions. This paper presents an analytical modeling and solution technique, namely the Distributed Transfer Function Method (DTFM), for synthesis and design of deployable boom structures. A space boom structure in consideration is modeled as a space frame that is enhanced by springs. In the DTFM, the distributed transfer functions describing the bending, torsion, and longitudinal deformations of frame members are first derived. A global dynamic equilibrium equation of the boom structure is assembled from the member transfer functions. Solution of the global equilibrium equation leads to free vibration solution and frequency response of the boom structure. The accuracy and efficiency of DTFM is demonstrated in a numerical example.

Modeling of Gossamer Space Structures with Distributed Transfer Function Method

2003 ◽  
Vol 40 (4) ◽  
pp. 548-552 ◽  
Author(s):  
Houfei Fang ◽  
Michael Lou ◽  
Bingen Yang ◽  
Yaubin Yang
Keyword(s):  
Transfer Function ◽  
Function Method ◽  
Space Structures ◽  
Transfer Function Method ◽  
Distributed Transfer Function

SEMI-ANALYTICAL SOLUTION OF TWO-DIMENSIONAL ELASTICITY PROBLEMS BY FINITE DIFFERENCE–DISTRIBUTED TRANSFER FUNCTION METHOD

2010 ◽  
Vol 10 (02) ◽  
pp. 315-334 ◽  
Author(s):  
YAUBIN YANG ◽  
BINGEN YANG
Keyword(s):  
Transfer Function ◽  
Finite Difference ◽  
Analytical Solution ◽  
Function Method ◽  
Transfer Functions ◽  
Two Dimensional ◽  
Dynamic Problems ◽  
Arbitrary Boundary ◽  
Transfer Function Method ◽  
Distributed Transfer Function

A semi-analytical solution method, called the Finite Difference–Distributed Transfer Function Method, is developed for static and dynamic problems of two-dimensional elastic bodies composed of multiple rectangular subregions. In the development, the original two-dimensional elasticity problem is first reduced into a one-dimensional boundary-value problem by finite difference; the exact solution of the reduced problem is then obtained by using the distributed transfer functions of the elastic continuum. The proposed technique, which combines the simplicity of finite difference and the closed form of analytical solutions, is capable of handling arbitrary boundary conditions, delivers highly accurate solutions for static and dynamic problems, and is computationally efficient. The proposed method is illustrated on a square region and an L-shaped region.

scholarly journals Dynamic Equilibrium Equations in Unified Mechanics Theory

2021 ◽  
Vol 2 (1) ◽  
pp. 63-80
Author(s):  
Noushad Bin Jamal Bin Jamal M ◽  
Hsiao Wei Lee ◽  
Chebolu Lakshmana Rao ◽  
Cemal Basaran
Keyword(s):  
Energy Loss ◽  
Entropy Generation ◽  
Equilibrium Equation ◽  
Dynamic Equilibrium ◽  
Free Vibration Analysis ◽  
Newtonian Mechanics ◽  
Equilibrium Equations ◽  
Time Coordinate ◽  
Proposed Model ◽  
Laws Of Thermodynamics

Traditionally dynamic analysis is done using Newton’s universal laws of the equation of motion. According to the laws of Newtonian mechanics, the x, y, z, space-time coordinate system does not include a term for energy loss, an empirical damping term “C” is used in the dynamic equilibrium equation. Energy loss in any system is governed by the laws of thermodynamics. Unified Mechanics Theory (UMT) unifies the universal laws of motion of Newton and the laws of thermodynamics at ab-initio level. As a result, the energy loss [entropy generation] is automatically included in the laws of the Unified Mechanics Theory (UMT). Using unified mechanics theory, the dynamic equilibrium equation is derived and presented. One-dimensional free vibration analysis with frictional dissipation is used to compare the results of the proposed model with that of a Newtonian mechanics equation. For the proposed entropy generation equation in the system, the trend of predictions is comparable with the reported experimental results and Newtonian mechanics-based predictions.

An Experimental Study of Tendon Vibration Control System for Flexible Space Structures

1991 ◽  
Author(s):  
Yoshisada Murotsu ◽  
Hiroshi Okubo ◽  
Kei Senda
Keyword(s):  
Mathematical Model ◽  
Control System ◽  
Vibration Control ◽  
Transfer Functions ◽  
Mimo Systems ◽  
Experimental System ◽  
Space Structures ◽  
Flexible Beam ◽  
Tendon Vibration ◽  
Large Space

Abstract The idea of a tendon vibration control system for a beam-like flexible space structure has been proposed. To verify the feasibility of the concept, an experimental tendon control system has been constructed for the vibration control of a flexible beam simulating Large Space Structures (LSS). This paper discusses modeling, identification, actuator disposition, and controller design for the experimental system. First, a mathematical model of the whole system of the beam and tendon actuator is developed through a finite element method (FEM). Second, to obtain an accurate mathematical model for designing a controller, unknown characteristic parameters are estimated by using an output error method. The validity of the proposed identification scheme is demonstrated by good agreement between the transfer functions of the experimental system and an identified model. Then, disposition of actuators is discussed by using the modal cost analysis. Finally, controllers are designed for SISO and MIMO systems. The feasibility of the proposed controller is verified through numerical simulation and hardware experiments.

Damping Mechanisms in Cable-Harnessed Structures for Space Applications: Analytical Modeling

2020 ◽  
Vol 143 (2) ◽  
Author(s):  
Pranav Agrawal ◽  
Armaghan Salehian
Keyword(s):  
Structural Parameters ◽  
Analytical Models ◽  
Space Structures ◽  
Real Time Control ◽  
Space Applications ◽  
Time Control ◽  
Starting Point ◽  
Recent Developments ◽  
Damping Effects ◽  
Distributed Transfer Function

Abstract Recent developments in the aerospace industry have driven focus toward accurately modeling the effects of the cables and electronic cords on space structures. In the past, researchers have modeled the mass and stiffness effects of these cables but primarily overlooked their damping effects through careful analytical model developments. The objective of the current work is to present analytical models for cable-harnessed structures that also include the damping effects in their vibration response. Obtaining simple, low-order and high-fidelity models are highly advantageous in designing robust vibration real-time control algorithms for structures. Additionally, the analytical models are useful tools in providing insight into and better understanding of the dynamics of space structures as they are often difficult to be tested prior to launch due to their large size and at best only a few components may be tested. Motivated by the space applications, this work considers beam structures wrapped with cables which are modeled using beam and string theory assumptions. Two different damping models namely Kelvin–Voigt and hysteretic damping are considered. The homogenization approach is used as a starting point for structures of periodic wrapping patterns. Using the variational principle, the governing partial differential equation for the transverse coordinate of vibrations is found for three cable patterns and the results are compared to those from the distributed transfer function method (DTFM). Finally, the effects of several structural parameters are studied on the overall system damping.

Application of Transfer Functions to the Thermal Processing of Sweet and Sour Cherries Preserves: Influence of Particle and Container Sizes

2003 ◽  
Vol 9 (2) ◽  
pp. 69-76 ◽  
Author(s):  
C. A. Márquez ◽  
V. O. Salvadori ◽  
R. H. Mascheroni ◽  
A. De Michelis
Keyword(s):  
Thermal Processing ◽  
Transfer Functions ◽  
Sucrose Solution ◽  
Simulation Method ◽  
Point Of View ◽  
Average Error ◽  
Transfer Function Method ◽  
Glass Containers ◽  
Enzyme Degradation

The conditions of thermal processing of fruit preserves packed in transparent glass containers have great importance from the point of view of the final product appearance. Process simulation can allow to predict the quality of the product and its possible degradation. This work applied the transfer function method to simulate the pasteurisation of whole sweet and sour cherries canned in glass containers, with a 25 °Brix sucrose solution as covering liquid, and the predicted results were experimentally tested. The influence of fruit and container diameters on the treatment times was analysed. Kinetic models for enzyme degradation were coupled to the prediction model as examples of the possibilities of optimising the whole pasteurisation process. The accuracy (average error in predicted temperatures: 2.1%) of the simulation method was satisfactory for practical purposes, its use resulted simple and fast, and it allowed adjusting of pasteurisation times, even during the process.

Port-Based Modeling of Distributed-Lumped Parameter Systems

2010 ◽  
Vol 164 ◽  
pp. 183-188
Author(s):  
Cezary Orlikowski ◽  
Rafał Hein
Keyword(s):  
Distributed Systems ◽  
Transfer Function ◽  
Distributed System ◽  
Function Method ◽  
Input Data ◽  
Distributed Parameter ◽  
Transfer Function Method ◽  
Lumped Parameter ◽  
Concise Representation ◽  
Distributed Transfer Function

This paper presents a uniform, port-based approach for modeling of both lumped and distributed parameter systems. Port-based model of the distributed system has been defined by application of bond graph methodology and distributed transfer function method (DTFM). The proposed approach combines versatility of port-based modeling and accuracy of distributed transfer function method. A concise representation of lumped-distributed systems has been obtained. The proposed method of modeling enables to formulate input data for computer analysis by application of DTFM.

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