scholarly journals Modal Density of Honeycomb Sandwich Composite Cylindrical Shells Considering Transverse Shear Deformation

2018 ◽  
Vol 23 (1) ◽  
Author(s):  
S. Josephine Kelvina Florence ◽  
K. Renji ◽  
K. Subramanian
Keyword(s):  
Shear Deformation ◽  
Transverse Shear ◽  
Cylindrical Shells ◽  
Sandwich Composite ◽  
Transverse Shear Deformation ◽  
Modal Density ◽  
Honeycomb Sandwich ◽  
Honeycomb Sandwich Composite ◽  
Composite Cylindrical Shells

scholarly journals An Experimental Investigation of Modal Densities of Composite Honeycomb Sandwich Cylindrical Shells

2020 ◽  
Vol 25 (1) ◽  
pp. 112-120
Author(s):  
K. Renji ◽  
S. Josephine Kelvina Florence ◽  
Sameer Deshpande
Keyword(s):  
Boundary Conditions ◽  
Cylindrical Shells ◽  
Sandwich Composite ◽  
Modal Density ◽  
Bending Mode ◽  
Honeycomb Sandwich ◽  
Sandwich Type ◽  
The Face ◽  
Honeycomb Sandwich Composite ◽  
Good Agreement

Honeycomb sandwich composite cylindrical shells are widely used in aerospace structures. Experimentally observed modal densities of such shells are not reported. In this work, modal densities of a typical honeycomb sandwich composite cylinder are obtained experimentally by measuring the drive point admittance. The results are in good agreement with those estimated theoretically that incorporated transverse shear deformation. Its limitations at higher frequencies are investigated and the frequency beyond which the estimation is in error is determined. The results provide an example to prove the need for measuring the imaginary part of the driving point admittance and using it in the determination of the modal densities of honeycomb sandwich-type structures. Experiments are carried out with two boundary conditions for the cylinder and the results provide experimental evidence for the fact that the modal densities at high frequencies do not depend on the boundary conditions. At higher frequencies, it is expected that both of the face sheets vibrate independently. This frequency can be approximately estimated as the fundamental bending mode frequency of the wall of the honeycomb core. The modal density determined through the measured driving point admittance will have a sharp reduction at this frequency and this feature can be used in identifying this phenomenon. The experimental results are in very good agreement with the above results.

Modal density and critical frequency of composite panels considering transverse shear deformation and rotary inertia

2020 ◽  
Vol 26 (17-18) ◽  
pp. 1503-1513
Author(s):  
K Renji
Keyword(s):  
Shear Deformation ◽  
Transverse Shear ◽  
Critical Frequency ◽  
Rotary Inertia ◽  
Transverse Shear Deformation ◽  
Bending Waves ◽  
Modal Density ◽  
The Face ◽  
Orthotropic Properties ◽  
Bending Wave

In this work, expressions for estimating the modal density, speed of the bending wave, critical frequency and coincidence frequency of panels are derived considering orthotropic properties of the face sheets, transverse shear deformation and the rotary inertia. Presence of rotary inertia results in an increase in the modal density and a reduction in the speed of the bending waves. The influence is significant at higher frequencies. The critical and coincidence frequencies increase due to rotary inertia. Results for a typical equipment panel of spacecraft are presented and they show the need for incorporating rotary inertia while determining these parameters.

Effects of Anisotropy in Axisymmetric Cylindrical Shells

1967 ◽  
Vol 34 (3) ◽  
pp. 659-666 ◽  
Author(s):  
S. T. Gulati ◽  
F. Essenburg
Keyword(s):  
Cylindrical Shell ◽  
Shear Deformation ◽  
Transverse Shear ◽  
Shell Theory ◽  
Circular Cylindrical Shell ◽  
Cylindrical Shells ◽  
Practical Importance ◽  
Transverse Shear Deformation ◽  
Circumferential Displacement

The solution of the problem of the generally anisotropic axisymmetric circular cylindrical shell is obtained employing a recent shell theory given by Naghdi. The practical importance of the presence of the circumferential displacement components and the twisting couple arising due to the presence of anisotropy, as well as the significance of the inclusion of the coupled effects of transverse shear deformation and anisotropy, are illustrated by a specific example.

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