Influence of equivalent continuum model based on the Eshelby-Mori-Tanaka scheme on the vibrational response of elastically supported thick continuously graded carbon nanotube-reinforced annular plates

2013 ◽  
Vol 35 (8) ◽  
pp. 1644-1661 ◽  
Author(s):  
V. Tahouneh ◽  
M.H. Yas
Keyword(s):  
Carbon Nanotube ◽  
Continuum Model ◽  
Vibrational Response ◽  
Annular Plates ◽  
Model Based ◽  
Equivalent Continuum Model ◽  
Elastically Supported ◽  
Equivalent Continuum

Continuum Modeling of a Slewing ISAT (Innovative Space Antenna Technology)

2005 ◽  
Author(s):  
Armaghan Salehian ◽  
Eugene M. Cliff ◽  
Daniel J. Inman
Keyword(s):  
Continuum Model ◽  
Degrees Of Freedom ◽  
Natural Frequencies ◽  
Space Antenna ◽  
Geometrical Properties ◽  
Strain Components ◽  
Equivalent Continuum Model ◽  
Equivalent Continuum ◽  
Very High ◽  
The Continuum

A simple approach is presented herein for obtaining the equivalent continuum model of an ISAT (Innovative Space Antenna Technology) truss structure in order to find the free vibration solutions for different coordinates of vibration. Kinetic and potential energy expressions are written in terms of the strain components of the elements and the nodal velocities. The Lagrangian approach is employed to find the governing partial differential equations of the structure which for the bending degrees of freedom lead to an equivalent Timoshenko beam. Finally, the physical characteristics of the continuum model are written in terms of the material and geometrical properties of the truss, which provide a simple tool for comparing dynamic characteristics of lattices with different properties. The natural frequencies are found for each of the bending, longitudinal, and torsional coordinates of vibration and are compared to those of a FEM solution for the purpose of validation. The analytical model shows very high accuracy in prediction of the natural frequencies of the original truss.

Vibration Modelling of String-Harnessed Beam Structures Using Homogenization Techniques

2014 ◽  
Author(s):  
Blake Martin ◽  
Armaghan Salehian
Keyword(s):  
Continuum Model ◽  
Dynamic Behaviour ◽  
Natural Frequencies ◽  
Strain Tensor ◽  
Space Structures ◽  
Power Cables ◽  
Structural Elements ◽  
Equivalent Continuum Model ◽  
Lagrange Strain ◽  
Equivalent Continuum

Harnessing structural elements with strings, power cables, and signal cables increases the complexity in modelling the dynamic behaviour of such structures. Developing models capable of accurately predicting the dynamic behaviour of these systems is of great importance for space structures that cannot be tested prior to launch. The focus of this work is obtaining an equivalent continuum model for string-harnessed beam-like structures with periodic wrapping patterns. The tension in the string is assumed to vary as the beam deflects. The displacement field with second-order terms is determined and from which the Green-Lagrange strain tensor is obtained. After finding kinetic and potential energy expressions Hamilton’s principle is used to obtain the partial differential equation and boundary conditions. Numerical results for the shift in the natural frequencies are presented for various string properties to investigate their effects on the structure.

Dynamic Analysis and Experiment of Beamlike Space Deployable Lattice Truss

2011 ◽  
Vol 199-200 ◽  
pp. 1273-1280
Author(s):  
Hong Wei Guo ◽  
Rong Qiang Liu ◽  
Zong Quan Deng
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Continuum Model ◽  
Model Simulation ◽  
Element Model ◽  
Mode Shapes ◽  
Equivalent Continuum Model ◽  
Simulation Results ◽  
Equivalent Continuum ◽  
The Finite Element Model

The dynamic equivalent continuum model of beamlike space deployable lattice truss which is repetition of the basic truss bay is established based on the energy equivalence. The finite element model of the lattice truss is also developed. Free vibration frequencies and mode shapes are calculated and simulated based on equivalent continuum model and discrete finite element model. The analytical solutions calculated by equivalent continuum model match well with the finite element model simulation results. A prototype of deployable lattice truss consist of 20 truss bays is manufactured. The dynamic response of lattice truss with different truss bays are tested by dynamic vibration experiment, and natural frequencies of lattice truss with different length are obtained from acceleration response curves. The experiment results are compared with simulation results which verifies that the correctness of finite element model, which also validate the effectiveness of equivalent continuum model indirectly.

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