TEST CASE 2.5 NATURAL FREQUENCIES OF THE ROUND PLATE HINGE-SUPPORTED ALONG THE CONTOUR
Reference:
V.N. Chelomey, Vibration in technics, Handbook in six volumes; V.V. Bolotin, Volume 1, The vibrations of linear systems, Moscow, Mechanical Engineering, 1978, p. 207
Problem description:
Determine the natural frequencies of a round plate, hinge-supported along the contour.
Problem sketch:
Type of created problem:
Flat plate or grillage (Z, UX, UY).
Geometric characteristics:
r = 0.5 m; t = 0.01 m.
Material properties:
Elastic modulus: E = 2.06·1011 Pa;
Poisson’s ratio: μ = 0.3;
Density: γ = 7850 kg/m3.
Boundary conditions:
On the perimeter: Z = 0.
Loads:
Dead load.
Model description:
The system is modeled using 1152 finite elements of thin plate (FE type is 19), splitting in the radial direction with a step of 0.03125 m and in the tangential with a step of 5°. To solve the problem, a modal analysis was performed.
Calculation results:
Form № |
Frequency, rad/sec |
Deviation, % |
|
Analytical solution |
LIRA 10 |
||
1 |
306.0 |
306.0 |
0.00 |
2, 3 |
861.8 |
861.8 |
0.00 |
4, 5 |
1588.2 |
1589.4 |
0.08 |
6 |
1842.9 |
1843.1 |
0.01 |
7, 8 |
2477.7 |
2481.4 |
0.15 |
9, 10 |
3006.1 |
3008.1 |
0.07 |
11, 12 |
3524.6 |
3531.6 |
0.20 |
13, 14 |
4347.8 |
4362.0 |
0.33 |
15 |
4598.3 |
4597.0 |
0.03 |