VM244
VM244
Modal Analysis of a Cyclic Symmetric Annular Plate
Overview
Test Case
The fundamental natural frequency of an annular plate is determined using a mode-frequency analysis. The lower bound is calculated from the natural frequency of the annular plates, which are free on the inner radius and fixed on the outer. The bounds for the plate frequency are compared to the theoretical results.
| Material Properties | Geometric Properties | Loading |
|---|---|---|
E = 7.03 x 105 kg/cm2 ν = 0.3ρ = 2.79 x 10 -9 kg/cm2 γ = 1.415 x 10-6 kg-sec2/cm3 |
Outside Radius (a) = 50 cm Inside Radius (b) = 18.5 cm Thickness (h) = 0.5 cm |
Free modal analysis |
Analysis Assumptions and Modeling Notes
According to Blevins, the lower bound for the fundamental natural frequency of the annular plate is found using the formula presented in Table 11-2:
Where,
| λ2 = 4.80 |
In Mechanical APDL, a 30° symmetric sector of the annular plate is created via CYCLIC expansion with CYCOPT, NODDIA. The outer edge of the model is constrained in all directions and no dampening or loading is applied. The element types SOLID185, SOLID186, SOLID187, SHELL181, SHELL281, and SOLSH190 are used to solve for the lower bound of the fundamental natural frequency (Hz).