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Pressure at knee joint

Please see the attached.

If the attached drawing represented a very crude design of a theoretical and artifical leg ---- and if I know the force applied is 100 kg, how would I go about calculating the pressure applied to the knee joint and foot that I show.

I have not provided a dimension for the knee joint but could I assume that since a knee joint is smaller than a foot, that the pressure on the knee joint would be slightly higher than on the foot? And, can I assume that the pressure exerted on the foot is merely the 100 kg divided by the area of the foot in contact with the floor surface?

Then I heard a lab instructor say something that confused me and I believe is wrong ----- it was said (in English units) that a 1 lb reduction in force would equal a 4 psi reduction in pressure on the knee joint or foot ----- this doesn't compute and it seems that this wrong?

Can you comment and show me some simple analysis?

Thank you


Solution Preview

Please see the attached.

100 kg - If a 100 kg force was applied to the structure noted with the intention
that the force would be transmitted vertically through an incompressible
joint and then to 20 cm long x 9 cm wide x 3 cm thick plate as shown:

1) Is the pressure theoretically the same at the incompressible joint vs.
the plate on the ...

Solution Summary

The vertical force on a structure is given and the pressure is calculated.