At the 1998 International Appliance Technology Conference, a mechanical engineer named Sven-Olof Emanuelsson of SKF in Göteborg, Sweden, gave a fascinating presentation on a simple, mechanical autobalancing mechanisms for hand-held grinders.During his presentation, Sven used the following diagram, which he referred to as “Sven Jr.”, to show the various mechanical resonances in the human body (click on the picture for a detailed diagram – 32k):
For us electrical engineers, it’s important to note that the things that look like resistors in the diagram are actually springs in the mechanical engineering world, and the things that look like polarized capacitors are dampers. Sven didn’t provide any information on the Q and the damping factors of the various resonances – I imagine it would vary substantially from person to person.
I’ve seen the human body modelled as a collection of weights in aeronautical engineering, as a collection of capacitors and resistors in static discharge studies, and now as a collection of springs in mechanical engineering. Are there other human body models out there in other branches of engineering? Let me know… Alex McEachern
Ed Russo of Dranetz-BMI points out that, in ballistic testing, gelatin is used as a model of the human body. The caption to the picture at right (from American Guardian’s 10/97 issue) refers to “ten percent ballistic gelatin”, but it isn’t clear what the “ten percent” measures.
Power Standards Lab
980 Atlantic Ave.
Alameda, California 94501
US: 1.888.SEMI.F47 or 1.888.736.4347