Project 07

Modal analysis of an airfoil.

A modal analysis in Ansys to find the first five natural frequencies and mode shapes of an airfoil fixed at its root. Then the same analysis on a plain rectangular plate of equal volume, to see if the simpler shape gives the same answer.

Ansys contour plot of the airfoil first bending mode at 853 Hz — Mode 1, 853.36 Hz — first bending.

Modes

The next four

Bending first, then twisting, then combinations of the two.

Ansys contour plot of airfoil mode 2 at 3826.9 Hz — Mode 2, 3826.9 Hz.

Ansys contour plot of airfoil mode 3 at 4228.6 Hz — Mode 3, 4228.6 Hz.

Ansys contour plot of airfoil mode 4 at 5213.1 Hz — Mode 4, 5213.1 Hz.

Ansys contour plot of airfoil mode 5 at 11385 Hz — Mode 5, 11385 Hz.

Plate check

Does a flat plate work instead?

The same study was run on a rectangular plate with the same volume as the airfoil, which works out to a thickness of 5.371 mm.

Ansys contour plot of the rectangular plate first mode at 623.91 Hz — Plate, mode 1, 623.91 Hz.

Mode	Airfoil	Plate
1	853.36 Hz	623.91 Hz
2	3826.9 Hz	2873.1 Hz
3	4228.6 Hz	3850.4 Hz
4	5213.1 Hz	4595 Hz
5	11385 Hz	9134.7 Hz

The plate frequencies are close to the airfoil's and follow the same pattern, so the plate is a reasonable stand-in for a first estimate.

Ansys 2023 R2. Coursework for ME 5139 at Ohio State, autumn 2024.