Mode Count and Modal Density of Isotropic Circular Cylindrical Shells Using a Modified Wavenumber Space Integration Method

2014 ◽  
Vol 136 (4) ◽  
Author(s):  
Mohammad H. Farshidianfar ◽  
Anooshiravan Farshidianfar ◽  
Mahdi Mazloom Moghadam
Keyword(s):  
Boundary Condition ◽  
Acoustic Radiation ◽  
Cylindrical Shells ◽  
Exact Equation ◽  
Flat Plates ◽  
Integration Algorithm ◽  
Geometrical Properties ◽  
Acoustical Properties ◽  
Modal Density ◽  
Circular Cylindrical Shells

A new method based on the wavenumber space integration algorithm is proposed in order to obtain mode count and modal density of circular cylindrical shells. Instead of the simplified equation of motion, the exact equation is applied in mode count calculations. Modal plots are changed significantly in the k-space when using the exact equation. Mode repetition in cylindrical shells is represented by additional mode count curves in the k-space. On the other hand, a novel technique is presented in order to implement boundary condition effects in mode count and modal density calculations. Integrating these two significant corrections, a modified wavenumber space integration (MWSI) method is developed. Mode count and modal densities of three shells with different geometrical and acoustical properties are obtained using the MWSI method and conventional WSI. Results are verified using the exact mode count calculations. Moreover, effects of geometrical properties are studied on mode count plots in the k-space. Modal densities are obtained for cylindrical shells of different lengths, radii, and thicknesses. Finally, modal densities of cylindrical shells are compared to flat plates of the same size and boundary condition. Interesting results are obtained which will contribute in calculation of acoustic radiation efficiency and sound transmission in cylindrical shells.

Thick General Shells Under General Loading

1989 ◽  
Vol 56 (2) ◽  
pp. 391-394 ◽  
Author(s):  
Lloyd H. Donnell
Keyword(s):  
Cylindrical Shells ◽  
Small Strain ◽  
Equilibrium Equations ◽  
Flat Plates ◽  
Circular Cylindrical Shells

Three equilibrium equations in terms of three displacements are derived in scalar mathematics form, by linear, small-strain elasticity principles, for the case of general thick-walled shells under general loading. These reduce to well-known forms for the particular cases of flat-plates and thick circular cylindrical shells.

Power flow between circular cylindrical shells and flat plates

1995 ◽  
Vol 98 (5) ◽  
pp. 2929-2929
Author(s):  
Benjamin F. Willis ◽  
Courtney B. Burroughs
Keyword(s):  
Power Flow ◽  
Cylindrical Shells ◽  
Flat Plates ◽  
Circular Cylindrical Shells

Buckling of Circular Cylindrical Shells Using a Displacement Function

1974 ◽  
Vol 96 (4) ◽  
pp. 1322-1327
Author(s):  
Shun Cheng ◽  
C. K. Chang
Keyword(s):  
Boundary Conditions ◽  
Axial Compression ◽  
Cylindrical Shells ◽  
External Pressure ◽  
Displacement Function ◽  
Combined Loading ◽  
Trial Solution ◽  
Governing Differential Equation ◽  
Circular Cylindrical Shells ◽  
The Stability

The buckling problem of circular cylindrical shells under axial compression, external pressure, and torsion is investigated using a displacement function φ. A governing differential equation for the stability of thin cylindrical shells under combined loading of axial compression, external pressure, and torsion is derived. A method for the solutions of this equation is also presented. The advantage in using the present equation over the customary three differential equations for displacements is that only one trial solution is needed in solving the buckling problems as shown in the paper. Four possible combinations of boundary conditions for a simply supported edge are treated. The case of a cylinder under axial compression is carried out in detail. For two types of simple supported boundary conditions, SS1 and SS2, the minimum critical axial buckling stress is found to be 43.5 percent of the well-known classical value Eh/R3(1−ν2) against the 50 percent of the classical value presently known.

scholarly journals Vibration of rotating circular cylindrical shells with distributed springs

2021 ◽  
Vol 37 ◽  
pp. 346-358
Author(s):  
Fuchun Yang ◽  
Xiaofeng Jiang ◽  
Fuxin Du
Keyword(s):  
Boundary Conditions ◽  
Galerkin Method ◽  
Shell Theory ◽  
Rotation Speed ◽  
Cylindrical Shells ◽  
Free Vibrations ◽  
Governing Equations ◽  
Natural Response ◽  
Circular Cylindrical Shells ◽  
The Galerkin Method

Abstract Free vibrations of rotating cylindrical shells with distributed springs were studied. Based on the Flügge shell theory, the governing equations of rotating cylindrical shells with distributed springs were derived under typical boundary conditions. Multicomponent modal functions were used to satisfy the distributed springs around the circumference. The natural responses were analyzed using the Galerkin method. The effects of parameters, rotation speed, stiffness, and ratios of thickness/radius and length/radius, on natural response were also examined.

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