Projectile Impact + Plate Stress Check
Projectile Impact + Plate Stress Check
(OP)
We have a projectile of mass m travelling at a velocity of v impacting in elastically to 1/2" plate. Assuming there is no local perforation of projectile, how do I determine that the global response of the plate is acceptable (i.e. some plate yielding is acceptable as long as it does not form a mechanism and fold/crumble under impact force). Also how do i determine the impact force.
Any pointers will be greatly appreciated.
Thanks
Any pointers will be greatly appreciated.
Thanks





RE: Projectile Impact + Plate Stress Check
Impact force can be monitored via accelerometers; I'm surprised your company is not up on this.
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RE: Projectile Impact + Plate Stress Check
RE: Projectile Impact + Plate Stress Check
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RE: Projectile Impact + Plate Stress Check
Your "problem statement" of mass "m" BEGINS with too little information! Do you have a BB pellet hitting a matchbox car? Or a 16 inch cannonshell hitting a battleship?
How much mass?
How much mass is the target?
What shape impacting mass?
How is the target plate supported?
How thick is its maximum?
How many impactors? (As mentioned above).
What angle of impact?
What is your "success" criteria? One impact + "not too badly damaged"? Or "many machine gun bullets at close range" + "None get through even if plate is bent"?
RE: Projectile Impact + Plate Stress Check
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: Projectile Impact + Plate Stress Check
It is better to have enough ideas for some of them to be wrong, than to be always right by having no ideas at all.
RE: Projectile Impact + Plate Stress Check
Rob Stupplebeen
www.optimaldevice.com
RE: Projectile Impact + Plate Stress Check
Can you assume that the projectile is fairly soft?
--
JHG
RE: Projectile Impact + Plate Stress Check
Can you assume that one projectile only hits the centre of your plate?
If all these conditions are valid, you can look up some plate equations in Roark, work out the spring rate, and work out the deflection when all of your kinetic energy is converted to strain energy.
Then, you can work out the stress on your plate and verify that you are within the yield stress of your material.
If my assumptions above are not valid, then this problems is as complicated as everybody says it is.
--
JHG
RE: Projectile Impact + Plate Stress Check
IMPACT EFFECT OF FRAGMENTS STRIKING STRUCTURAL ELEMENTS (http://www.osti.gov/scitech/servlets/purl/4315907)
The force calculated by using equation 13 is way less then that calculated using an elastic energy conservation approach. The force obtained using equation 13 seems reasonable.
Any comments ?
RE: Projectile Impact + Plate Stress Check
The force obtained in the paper is probably going to be way less than what will really happen, because the model is so simple. Note that calculators weren't even around then, so the level of verisimilitude is going to be relatively low. The model makes MANY assumptions that I don't think are true in a real impact.
TTFN

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RE: Projectile Impact + Plate Stress Check
It is better to have enough ideas for some of them to be wrong, than to be always right by having no ideas at all.
RE: Projectile Impact + Plate Stress Check
RE: Projectile Impact + Plate Stress Check