Measuring "Impact Load" in Ft-Lbs
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Re: Measuring "Impact Load" in Ft-Lbs
Re: Measuring "Impact Load" in Ft-Lbs -- themerc	Post Reply	Top of thread	Forum

Posted by: zekeman ® 06/03/2005, 16:19:06 Author Profile Mail author Edit

I would set up a 1:1 linkage so that verical downward motion on one end would produce vertical upward motion on the other. Then drop a weight at some height to be determined as follows. The vert upward force will be transmitted to the rod and the piston. You would have to compute the division of energy absorbed, not very simple problem; then add the amount absorbed in the rod and add it the input energy, so that the energy (potential) in the drop will be the sum of 10 and the energy absorbed in the rod. If you have a relatively soft piston structure, then a short thick rod may be used, assuming no energy absorbption, to simplify the test.Assume the rod has a crossection area =A, and after impact, the max force is F, then the energy absorbed by the rod is F^2L/2EA where L= length,A = crossesctional area of rod,E = modulus of rod and the energy absorbed in the piston will be of the form kF^2, where k is a constant depending on the structure of the piston, which has to be determined. Alternatively, if you have strain gauge or load cell, you can get the force F, for various heights and apply the F^2L/2EA to get the energy absorbed in the rod and subtract this from the potential energy to get the piston absorbtion. Do this until that value is 10.

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