Decomposes complex vibration into independent modes.
Modal analysis decomposes response into modes using eigenvectors: x=Σφᵢqᵢ(t). Experimental modal analysis excites structures with hammers or shakers and measures frequency response functions. Used for troubleshooting and model validation.
Hammer-testing a car body finds its first bending frequency.
Modal analysis breaks a complex vibration into simple modes, which makes response prediction and testing far more manageable.
Decomposes complex vibration into independent modes.
Modal analysis breaks a complex vibration into simple modes, which makes response prediction and testing far more manageable.
It measures frequency response functions by exciting a structure and recording its response, from which natural frequencies, damping and mode shapes are extracted.
It shows which modes are critical for a load, so stiffness or mass changes can target the right mode.
Typical applications include identifying the modes of an aircraft wing from ground vibration tests, simplifying the response of a machine foundation for design and finding which mode is excited by a known machine speed.
Study "Multi-degree-of-freedom systems" first (topic 79 of 106 in Engineering Mechanics). It covers the groundwork this topic builds on.
Frequencies, damping and shapes. Truncation to a few modes. Mode shape visualisation.
Hammer-testing a car body finds its first bending frequency.
The next topic is "Balancing rotating machinery", which builds directly on this one.
It is classed as Advanced in Engineering Mechanics (topic 80 of 106). It is an advanced topic. It assumes you are comfortable with the intermediate topics in Engineering Mechanics.
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