Can wood break metal ?

[Foxsikes]

Hi guys I just signed up to these forums because I love the science discussions here and I'm pretty big on science myself.

 

Here is my first question and my body and I are arguing non stop about this.

 

Can wood break metal ?

 

I know metal is a lot denser than wood but lets take this scenario:

 

If there was a metal wall about 2 inches thick and it was made out of steel and it is 6 feet high and 3 feet wide, how much wood would have to hit it at what speed to break through the metal ? Is this even possible ? Can wood ever break through metal at all with enough force and speed ? I have hear a theory that states any material at any density can always break something more dense if it is heavy enough and moving at high speeds. Does this apply to this scenario ? Is there truth to this theory ?

[Moontanman]

I personally have used wooden mallets to bend form and sometimes break metal, put a nice seasoned piece of crepe myrtle into a reasonably powerful air cannon and I am sure it could penetrate a significantly thick piece of metal, I'm not sure 2" is a reasonable thickness of metal to do this with but I am quite sure metal in general can be broken by wood....

Edited July 28, 2013 by Moontanman

[EdEarl]

Try a light weight experiment.

 

Materials:

 

Old useless extension cord.

 

Block of wood about 1/2 kg or 1 lb. Any wood will work, for example some from a fallen tree branch. However, if you are willing to spend a few dollars buy a block of balsa wood, which is very soft.

 

 

Remove a fine strand of wire from the extension cord (they are a bit thicker than a human hair).

 

One person will hold the strand of wire taught between their hands.

The other person will drop the block from 1 m (1 yd) on the wire strand.

 

Scale up using two strands, three strands, four strands, etc until you use all the wire or it does not break.

 

If you use balsa, then enough strands of wire may cut into the balsa before breaking, perhaps even one strand. Although, it may depend on whether the balsa hits cross grain or end grain.

 

Enjoy

[Foxsikes]

I personally have used wooden mallets to bend form and sometimes break metal, put a nice seasoned piece of crepe myrtle into a reasonably powerful air cannon and I am sure it could penetrate a significantly thick piece of metal, I'm not sure 2" is a reasonable thickness of metal to do this with but I am quite sure metal in general can be broken by wood....

Fully broken or dented ?

[Moontanman]

Fully broken or dented ?

 

 

Completely broken, in fact high winds can throw wooden objects through metal, I live in a hurricane zone, high speed winds can do some amazing things like drive a piece of wood all the way through the metal sides of an automobile...

And you have to consider that some metals are rather brittle and can be broken easily, all metals are not created equal...

Cast iron comes to mind...

[Danijel Gorupec]

When I was a kid, a was fascinated with the fact that ice broke through Titanic hul. I imagined that Titanic should easily cut through the iceberg.

 

I suppose that by metal you mean steel (steel would be, unlike sodium, a respectful metal). I also suppose that the wood chunk is ball shaped, or half-ball shaped. I also suppose that the metal plate edges are strongly supported.

 

With your thick-but-small-area metal plate I GUESS two scenarios:

- a wooden (half)ball is slowly pushed into metal plate by very large force - I suppose the wood whould break into pieces, but if it is somehow supported from all sides it would compress into something that is not wood and will finally pierce the plate

- a wooden ball hits the plate at high-enough velocity - yes it will go through, but when it exists at the other side, it will not be wood any more.

[Moontanman]

When I was a kid, a was fascinated with the fact that ice broke through Titanic hul. I imagined that Titanic should easily cut through the iceberg.

 

I suppose that by metal you mean steel (steel would be, unlike sodium, a respectful metal). I also suppose that the wood chunk is ball shaped, or half-ball shaped. I also suppose that the metal plate edges are strongly supported.

 

With your thick-but-small-area metal plate I GUESS two scenarios:

- a wooden (half)ball is slowly pushed into metal plate by very large force - I suppose the wood whould break into pieces, but if it is somehow supported from all sides it would compress into something that is not wood and will finally pierce the plate

- a wooden ball hits the plate at high-enough velocity - yes it will go through, but when it exists at the other side, it will not be wood any more.

 

 

Then what would it be?

[Danijel Gorupec]

 

 

Then what would it be?

 

I wonder... In first scenario, some dense matter that does not exist as wood. In the second scenario, plasma maybe. I am only guessing, sure.

 

(If the plate is much larger area, say 1km x 1km, then I beleive wood might have the chance to go through in the first scenario - without significant compression)

Edited July 28, 2013 by Danijel Gorupec

[Moontanman]

The cast iron reference comes with a serious memory for me, I once hit one of my grandma's cast iron cook pots with a ball bat and it shattered, later that day my ass experienced the feel of wood as well...

Edited July 28, 2013 by Moontanman

[John Cuthber]

Moontanman,

I would vote that up, but you forgot the apostrophe.

Anyway, water is strong enough to break metal.

http://en.wikipedia.org/wiki/Water_jet_cutter

[Foxsikes]

Wow you guys are great , I love this site. Thank you everyone for your answers but I have one more question, if a a 100 ton piece of wood fell 1 mile down onto a tank, say an Abraham's tank, would the tank completely break

And explode?

[arc]

When I was a kid, a was fascinated with the fact that ice broke through Titanic hul. I imagined that Titanic should easily cut through the iceberg.

 

 

I thought the same thing when I was a kid, I even tried to break or cut steel with ice. Titanic would have resisted the ice burg if its mass would not have been spread out so thin. Its hull was, in scale to its mass and volume, incredibly thin. It really just broke itself against the ice that had not only a greater mass, but more important, a solid interior structure.

 

Titanic's hull plate's thickness varied from 2.5 cm (1 inch) to 3.8 cm (1.5 inches) which for a structure that was 269.06 m (882.75 ft) long with a maximum breadth of 28.19 m (92.5 ft) and weighed 46,328 gross register tons is quite thin. Its total height from the base of the keel to the top of the bridge was 32 M (104 ft). It displaced 52,310 tons. During construction a ship of this scale could be damaged by its own weight, not having the ocean around it for even support and stability. It looks like some of the ship's over three million iron and steel rivets are what actually failed and allowed the steel plate to re-position and fracture under the extreme loads applied to them.

 

Can wood break metal ?

 

I know metal is a lot denser than wood but lets take this scenario:

 

If there was a metal wall about 2 inches thick and it was made out of steel and it is 6 feet high and 3 feet wide, how much wood would have to hit it at what speed to break through the metal ? Is this even possible ? Can wood ever break through metal at all with enough force and speed ? I have hear a theory that states any material at any density can always break something more dense if it is heavy enough and moving at high speeds. Does this apply to this scenario ? Is there truth to this theory ?

 

. Here is my guess on this, it depends on how malleable the steel is for one. Steel is so widely used because of is ability to absorb kinetic energy and retain a reasonable amount of its original structural shape, like in car bodies. It could respond like a catchers mitt. The wood may possible grind itself up against the target material. And there is a wide variety of wood out there. You would need a piece of wood that could carry enough energy to overcome the steel's hardness.

 

I have a board out in my shop my dad gave me, It is a tropical hardwood that he called iron wood. There are as many as 30 varieties of this wood, I am sure this material would have the best chance to penetrate the steel. You cannot drive a nail into it. I think with a point and enough velocity, a shaft of this stuff could do the job. It is almost as heavy as steel.

Edited July 29, 2013 by arc

[Foxsikes]

Is the wood a little dark or grayish ? Because I've seen black wood that is incredibly dense.

[arc]

Black and brown and unbelievably dense, it might not even float.

 

It would need to hit the target perfectly square at 90 degrees. Anything less would deflect off the steel's surface. The wood will compress and then bend. You need the projectile to have enough mass energy to penetrate. But increasing length increases compression bending on impact which leads to deflection.

 

I think the shape of the penetrator is extremely important. Most of the mass forward behind the point.

 

 

The sharp point may work against it, simply absorbing energy without displacing steel in return.

 

A blunt end would probably be the best, sudden loading in a small area, like a hole punch. An circular shock fracture is what we want.

 

Cool the penetrator to harden it but avoid causing brittleness. Fire out of air cannon at point blank range or if a rifled barrel at a short range. (Difficult to maintain 90 degree contact.)

Edited July 29, 2013 by arc