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Ozen

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Been researching armor piercing mechanics but I can't seem to find a reliable model for hand calculations. What makes matters worse is I don't know the correct value for the design I am studying. Only 3 formulas gave me similar results: NAVY 1940's "Universal" Formula, Original F-Formula, and NAVY 1930s "Thompson F-Formula". The Lambert-Zukas formula yielded ~1/2 the penetration depths of those three. Wijk's Penetration Model yielded ~3/4th depth of the first three. And Pol's Model yielded ~5/6th the depth of the first three. So my results are scattered all over the place, and this is only the models that were in the ballpark, some gave back at ~0.1% of the depth computed.

How do I know which model is correct for my case? My case specifically is a small rifle bullet (0.224in diameter) of tungsten vs AR500 steel plate, velocity = 2800 ft/s, and mass = 1.1004774e-02 pounds. Length for the ones that need it is 0.924in.

The only model I haven't been able to figure out is "FURTHER RESULTS IN THE THEORY OF LONG ROD PENETRATION*" by A. Tate, which they use a long rod penetration model. What gets me is the Yp and Rt values for my case. Yp is the pressure at which the penetrator material acts like a liquid; and Rt is the pressure when the target material acts like a liquid.

I would just toss this into ANSYS AutoDyn but I can't afford the commercial version and the student version can't handle it (I tried..).

Making a couple test pieces isn't feasible since equipment needed to produce it is in the thousands.

Anyone have any ideas on what to do here?

How do I know which model is correct for my case? My case specifically is a small rifle bullet (0.224in diameter) of tungsten vs AR500 steel plate, velocity = 2800 ft/s, and mass = 1.1004774e-02 pounds. Length for the ones that need it is 0.924in.

The only model I haven't been able to figure out is "FURTHER RESULTS IN THE THEORY OF LONG ROD PENETRATION*" by A. Tate, which they use a long rod penetration model. What gets me is the Yp and Rt values for my case. Yp is the pressure at which the penetrator material acts like a liquid; and Rt is the pressure when the target material acts like a liquid.

I would just toss this into ANSYS AutoDyn but I can't afford the commercial version and the student version can't handle it (I tried..).

Making a couple test pieces isn't feasible since equipment needed to produce it is in the thousands.

Anyone have any ideas on what to do here?

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