[Example] Rotating Dynamics Eigenvalue Analysis

We conducted a modal complex eigenvalue analysis at the specified rotational speeds to investigate the whirling modes caused by rotation, changes in damping, and critical speeds.

**Case Summary** ■Product Name: NX Nastran ■Analysis: Eigenvalue Analysis ■Industry: Other The vibration characteristics of rotating bodies exhibit whirl motion due to centrifugal force, tilt vibrations, and gyroscopic effects as the axis rotates, causing changes in eigenvalues. When the direction of rotation and whirl coincide, it is referred to as forward whirl, and when they are opposite, it is called backward whirl. When the rotational speed matches the eigenvalue of the axis, the amplitude of the whirl increases, leading to instability in the rotating system and potential damage to components. The speed at this point is referred to as the critical speed. In this analysis, modal complex eigenvalue analysis was conducted for specified rotational speeds to investigate the whirl modes induced by rotation, changes in damping, and critical speeds. □ For other features and details, please refer to the catalog.

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