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Toni Arndt
10-12-2005, 11:18 PM
Dear all,

We have been validating a strain gauge based, custom made force plate against a Kistler plate. One of the tests we performed was to place (fixed with double sided tape) the custom made plate on top of the Kistler and drop a weight on it. We also dropped the same weight, from exactly the same height onto only the Kistler. The weight was a 20 kg standard gym free weight made of solid rubber (therefore slightly deformable).

The results showed a far higher force (17000 N) with a steeper loading rate when the was dropped onto the custom plate on top of the Kistler than when the weight was dropped straight onto the Kistler (11000 N).

Why? Shouldn't the custom plate act as a low pass filter, therefore reducing the peak force? It would be exciting if somebody could educate me on this! I can't work it out.

Cheers,

Toni Arndt
Karolinska Institute
Stockholm
Sweden