Air Cleaner Shell Noise Analysis with Plate and Shell Theory

Plate and shell theory is used to determine the force vibration response of large air cleaner surfaces for the air cleaner breathing modes of vibration. Plate equations are small and can be programmed into a hand held calculator for convenience. The eigenfunction method is used to solve the plate equation to obtain the plate vibration response. Surface reinforcements such as ribs, corrugation and surface curvature are included in the plate equation in terms of structural rigidity. Surface stiffness can be modified by simply changing the stiffener moment of inertia or by changing the number of stiffeners.

The approximation technique was used to model a rectangular shallow shell. The predicted shell first natural frequency compared favorably to that of an exact solution to the shallow shell equation. Two air cleaner covers were modeled with the technique. One of the covers was flat and reinforced with ribs while the other was a shallow shell also reinforced with ribs. Forced vibration and frequency predictions of the air cleaner cover breathing mode compared well with experimental data.