relative strength of materials

[FSB1]

What are the properties that define if an arrow can pierce through a wall?

I guess the material properties, as ultimate strength
and the geometry - thickness of the wall, sharpness of the arrow

but given particular examples
arrow of steel
wall of titanium, 10mm thick,

how can we theoretically estimate if the arrow will pierce through or not?

 

[FEA way]

It depends on the impact strength of the wall. It would be very hard (if not impossible) to calculate this analytically. But one can use Finite Element Analysis to simulate the impact with high enough accuracy without the need for physical experiment.

 

[GregLocock]

There are various calculations that can be done for penetration of metals by hard projectiles. This was a matter of great interest to designers of tanks and battleships and the like, so they had budgets. Mr Okun has put a lot of work into this

http://www.navweaps.com/index_nathan/index_nathan.php

I'd add that FEA would be no more accurate since the unknown is the material properties at high strain rates, not the physics.


Cheers

Greg Locock


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[FSB1]

Thanks GregLocock
I agree that weapon/bullet makers would have some approach to this instead of just testing

 

[rb1957]

yes, FEA simulations of impacts (like for birdstrike, using LS-Dyna).

Agree with Greg, these simulatations need to be well grounded/validated by tests.

another day in paradise, or is paradise one day closer ?

 

[drawoh]

leo16,

When I first took an FEA course, we were shown the predicted behaviour of an artillery shell upon impact, and then a photograph of it. It either was a very good analysis, or it was good cherry picking. If the geometry of your arrow and the angle of impact do not conform precisely to your model, there will be a massive effect on the outcome.

--
JHG

 

[rb1957]

even if the arrow geometry and trajectory are correct, the modelling can still "lie" or mislead you … without a good test basis.

another day in paradise, or is paradise one day closer ?

 

[mfgenggear]

I would take stab and say higher density and hardness

 

[IRstuff]

Supersonic arrow, say, about 800 m/s, see

https://www.pewpewtactical.com/30-06-m2-ap-armor-piercing-penetration-tests/

MIL-STD-662F TEST METHOD STANDARD V50 BALLISTIC TEST FOR ARMOR

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[IRstuff]

Also
Effect of Annealing Temperature on the Ballistic Limit Velocity of Ti-6A1-4V ELI

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