Effect of constrained layers on vibrational characteristics of a composite sandwich system—A finite element based critical investigation

2011 ◽  
Vol 7 (4) ◽  
pp. 291-298 ◽  
Author(s):  
R. Venkatachalam ◽  
S. Balasivanandha Prabu ◽  
K. Venkatesh Raja
2019 ◽  
pp. 5-10
Author(s):  
S.E. Martinez Choy ◽  
J. Lenz ◽  
K. Schweizerhof ◽  
H.J. Schindler

Author(s):  
A. S. Sekhar ◽  
N. Ravi Kumar

Abstract The present study aims in performing eigenvalue analysis and unbalance response for a rotor system having a composite shaft, modelled based on first order shear deformation theory using finite element method with shell elements. Different materials such as boron epoxy, carbon epoxy and graphite epoxy have been tried for various stacking sequences. From the study it is clear that the stacking sequence and material have great influence on the vibrational characteristics of composite shafts.


2007 ◽  
Vol 16 (2) ◽  
pp. 096369350701600 ◽  
Author(s):  
Buket Okutan Baba ◽  
Ronald F. Gibson

The aim of this study is to report the effect of delamination on the vibration characteristics of composite sandwich beams. The natural frequencies and corresponding vibration modes of a free-free sandwich beam with delamination of various sizes and locations are predicted using a two-dimensional finite element analysis (FEA). The presence of delamination affects the stiffness of the delaminated beam and results in differences on the natural frequencies of the beam. Assessment of the differences light the way for the existence, size and location of the delaminated region and can be used for a non-destructive evaluation of the damage characteristics of the delaminated beams. Vibration tests are conducted on fully bonded sandwich beams with carbon/epoxy laminated composite faces and foam core to verify the finite element results. Agreement between predictions of the model and experimental observations is good.


2012 ◽  
Vol 201-202 ◽  
pp. 549-552
Author(s):  
Shu Zhang ◽  
Lei Meng

we have used the metaphor of ant colonies to define "the Ant system", a class of distributed algorithms for combinatorial optimization. In this paper we analyze some properties of Ant-cycle, the up to now best performing of the ant algorithms we have tested. We report many results regarding its performance when varying the values of control parameters and we compare it with some FEM algorithms. And in accordance with treatment principles, the microstructure of the alloy is simulated. First modal analyses of microstructure defects are performed in ANSYS. Second the genetic algorithm is implemented in MATLAB to Calculate the Value of b and p. The last, The FEM analysis results are imported in ANSYS about the Stress distribution. The result presented in this paper is obtained using the Genetic Algorithm Optimization Toolbox.


2014 ◽  
Vol 14 (03) ◽  
pp. 1350075 ◽  
Author(s):  
S. K. Sarangi ◽  
B. Basa

This paper deals with the nonlinear dynamic analysis of smart laminated composite sandwich plates. A three dimensional energy based finite element (FE) model has been developed for the composite sandwich plates integrated with the patches of active constrained layer damping (ACLD) treatment. Von Kármán type nonlinear strain–displacement relations and the first-order shear deformation theory (FSDT) are adopted individually for each layer of the sandwich plate in developing the FE model. The constraining layer of the ACLD treatment is considered to be made of active fiber composite (AFC) material. The Golla–Hughes–McTavish (GHM) method is used to model the constrained viscoelastic layer of the ACLD treatment in the time domain. Sandwich plates with symmetric and antisymmetric laminated faces separated by HEREX core are considered for evaluation of the numerical results. The numerical results indicate that the ACLD patches significantly improve the damping characteristics of the composite sandwich plates for suppressing their geometrically nonlinear transient vibrations. The effect of variation of piezoelectric fiber orientation angle in the AFC material on the control authority of the ACLD patches is also investigated.


2015 ◽  
Vol 1095 ◽  
pp. 751-755
Author(s):  
Hai Yan Wang ◽  
Yi Jiang ◽  
Yuan Peng Xia ◽  
Yun Li Zhou

Plasma torch is one of the most important parts for plasma arc generating system. A design of orifices in a nozzle would decide the properties of plasma arc. However, mechanisms of orifice to plasma arc are seldom discussed. In this paper, the plasma arc with two assistant orifices were analyzed by finite element method. It was concluded that the plasma arc would be further compressed in the direction parallel to two assistant orifices, but expand perpendicular to assistant orifices. Through the constriction of two assistant orifices, the shape of the plasma arc would be elliptical other than circular of the oridinary plasma arc. The torch design with two assistant orifices could be available to many fields such as plasma arc welding, especially to a welding torch with a large pressure chamber.


2015 ◽  
Vol 77 (17) ◽  
Author(s):  
Yasmin Abdul Wahab ◽  
Ruzairi Abdul Rahim ◽  
Mohd Hafiz Fazalul Rahiman ◽  
Leow Pei Ling ◽  
Suzzana Ridzuan Aw ◽  
...  

The non-invasive sensing technique is one of the favourite sensing techniques applied in the process tomography because it has not a direct contact with the medium of interest. The objective of this paper is to analyse the simulation of the non-homogenous system of the non-invasive ERT using finite element software; COMSOL Multiphysics. In this simulation, the liquid-air medium is chosen as the non-homogenous system. A different analysis of the non-homogenous system in term of the different position of the single air, different size of the single air and the multiple air inside the vessel were investigated in this paper. As a result, the location, size and multiple air inside the pipe will influence the output of the non-invasive ERT system. A liquid-gas medium of non-homogenous ERT system will have a good response if the air is located near the source, the size of the air is large enough and it has multiple air locations inside the pipe.


Author(s):  
Özgün Şener ◽  
Oğuzhan Dede ◽  
Oğuz Atalay ◽  
Mert Atasoy ◽  
Altan Kayran

Transverse shear moduli of the sandwich core and flexural stiffness of all-composite sandwich constructions are determined with three-point beam bending tests, and compared with the analytical and finite element analysis solutions. Additionally, Digital Image Correlation (DIC) system is employed to validate the experimental results by monitoring the displacements. The effect of orientation of the composite core material with respect to the beam axis on the shear modulus of the core material itself, flexural stiffness of the sandwich beam, maximum loading, and the maximum stresses on the sandwich panel are also examined. Comparable results are achieved through experiments, finite element and analytical analyses.


2013 ◽  
Vol 22 (6) ◽  
pp. 096369351302200
Author(s):  
S.K. Jalan ◽  
B. Nageswara Rao ◽  
S. Gopalakrishnan

Finite element analysis has been performed to study vibrational characteristics of cantilever single walled carbon nanotubes. Finite element models are generated by specifying the C-C bond rigidities, which are estimated by equating energies from molecular mechanics and continuum mechanics. Bending, torsion, and axial modes are identified based on effective mass for armchair, zigzag and chiral cantilever single walled carbon nanotubes, whose Young's modulus is evaluated from the bending frequency. Empirical relations are provided for frequencies of bending, torsion, and axial modes.


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