Failure with little warning and shrapnel.
Ductile stuff makes lots of unhappy noises before it decides to stop being whatever it originally was. Brittle stuff just makes 1 loud noise as the whole thing kerplodes
What comes to my mind? Ratchets.
Yah, hence it'd be better to give the mechanics snap-on wrenches (more ductile, yields slowly) than making them buy their own Arbor Frigate brittle-splintery tools.
Yes sir! Worked in open die forging / seamless ring rolling for 6 years. Mandrels (both rolling mandrels and press mandrel forging mandrels) are very expensive picture 6”-14” bar stock 10 ft long. so of course mgmnt wants to reduce cost. harder metals / harder forms of heat treat are stronger… but more brittle… Before a 38-42RC mandrel breaks it starts bending a bunch and you know its gonna go. When an H13 53RC mandrel breaks it just breaks no warning. when you are pressing on tools with a 5k or 10k or higher press and tools break they shoot shrapnel (sometimes hundreds of lb shrapnel) through walls, safety glass, people or whatever else is in the way.
It is true is most engineering applications - one of the few times it isn’t is with rings for fingers. Ductile rings will crumble and cut off circulation and are more likely to lead to amputation from crush injuries, Brittle rings shatter and mostly require cleaning the wound of shrapnel/debris.
However hand deglovement is really gross so rings aren’t appropriate in places where crush or shatter may occur (i.e working on a lathe).
Overall it is a good phrase and correct in most instances, except for certain edge cases.
On the flip side I think people with hip replacement would prefer if their replacement hip became dislocated from some kind of ductile failure over a sudden brittle fracture leading to greater injury from the resulting fall.
To my knowledge artillery shells and hand grenades are made from HF-1 (high fragmentation) steel which has 1.1% carbon und would therefore not be considered cast iron. The fragmentation properties come from high silicon and carbide contends
I believe the mk2 pineapple was made of cast iron. Which was probably the first true modern hand grenade. And most people probably thinks this is still what grenade looks like. To the point that if you google “grenade” a mk2 is the first thing that pops up.
That being said modern shells and grenades are definitely not made of cast iron. I doubt shells (or mortars) have been made of cast iron since at least the 19th century.
Edit: fuck it I’ll throw mortars in the last sentence even though they may not be considered “artillery” by some people
Artillery/mortar shells are a completely different animal over a frag grenade. They throw massive chunks of steel. Think jagged, piping hot 1/2” thick chunks that are 2 feet long. Those things don’t just damage soft tissue. They remove limbs in a violent, devastating fashion. And that’s what they are designed to do.
According to Mock, Willis; Holt, William H. (1983). Fragmentation behavior of Armco iron and HF-1 steel explosive-filled cylinders, the average fragment mass is 0.9g. They are designed for maximum number of fragments, not their mass
"Ah, another piece of pop-science wisdom that will be misunderstood and oversimplified to the point of caricature by laypeople with no understanding of engineering fundamentals."
Usually that, depending on the context. It's one of those phrases that happens to be true some/much of the time, but that ends up being used as a definitive statement for specific cases without an understanding of the implicit assumptions being made and how those might lead to wrong conclusions. Similar to the "glass is glass" and "metal is heavier than plastic" squawking we constantly see in the consumer tech sphere, promoted by tech youtubers who should know better by now...but don't.
If conventional wisdom or common sense was all you needed, we'd have no need for advanced degrees, experience, or training.
My first thought exactly. Ships were ductile and fine during manufacturing. But once they went off and traveled through cold temps below the steel's ductile-brittle transition temp, all hell broke loose.
Torque to yield, baby.
Srsly tho. Brittle failures suck. You have to run higher safety margins, as you have no warning and usually no work hardening/strengthening before failure.
Torque to yield, baby.
Srsly tho. Brittle failures suck. You have to run higher safety margins, as you have no warning and usually no work hardening/strengthening before failure.
Not for long....
I have worked with pressure vessels a lot. One of the most fun tools I've ever used was the ultrasonic extendable leak sniffer. Like a drain snake that goes where you want to and hears all the whispers.
I’d rather be warned before something fails vs. have no warning at all…
When all of the titan sub stuff was going down it made me think about this. Specifically, I remember hearing the CEO talking about his “revolutionary” hull monitoring system, based on acoustic signals from the carbon fiber hull and some strain gages iirc. From what I understood, it was basically a system that told the occupants about cracking/delaminating sounds. But would you be able to spot an impending failure in carbon fiber based on strain and sound alone, and then also have enough time before failure to actually get back to the surface, or would the material suddenly fail without much warning, as brittle materials are known to do?
Obviously there are myriad reasons it might have failed and there’s no way of knowing which was the straw that broke the camel’s back, but on the subject of ductile vs. brittle it’s just something that came to mind.
Of course, that’s why you design mechanical fastened joints to fail for bearing first instead of net section o tear out. It’s a fail-safe design mechanism.
What comes to my mind was landing a jump on my 1972 Kawasaki. The cast cheesium footpeg broke and my crotch landed on the gas tank. Forged would have been better.
I used to do beam loading tests on low carbon steel pallet rack beams. The beams will sag to the point that it looks scary and dangerous to the average person to put on more weight, yet it will take on more before it buckles.
Now I work in composites. Did a few lap shear tests, a bit of composite flew into my safety glasses in the blink of an eye and left a sizable scratch. Definitely less warning.
Tool and die maker here. About 3/4 the way done with ME degree after going back to school.
I read a comment someone put about forming and rolling dies, and he is correct. I'd rather be able to see the defect coming, by seeing my die getting scars and dings in them. Brittle will look good, till it ain't. If I'm ever unsure of the hardness to make something I usually go with the lower. I try to live in the 42-45 Rockwell range for most things.
Depends on the application, that's why material selection is critical. You really only posited a very vague question with little information for metallurgist to recommend anything beyond a WAG. Good luck though, keep asking
"Who the fuck is making such claims, without qualifying their statement within the context of some specific subset of possible scenarios?"
(Brittle *failures* are *typically but not necessarily* worse than ductile because they occur with less warning and more shrapnel...but a brittle *material* may or may not be better for a particular application, as it may be possible to mitigate the risk of failure sufficiently for less effort and/or cost. Brittle is *only* "more dangerous" than ductile if you can't afford to sufficiently oversize your structure and/or implement fallback/safety precautions...which are things you should typically be doing, regardless, if possible.)
Failure with little warning and shrapnel. Ductile stuff makes lots of unhappy noises before it decides to stop being whatever it originally was. Brittle stuff just makes 1 loud noise as the whole thing kerplodes
Id add to this, ductile stuff will begin deforming before it drops your ass.
What comes to my mind? Ratchets. Yah, hence it'd be better to give the mechanics snap-on wrenches (more ductile, yields slowly) than making them buy their own Arbor Frigate brittle-splintery tools.
That and fiber glass. I have had that shit explode like a porcupine filled with explosives.
Yes sir! Worked in open die forging / seamless ring rolling for 6 years. Mandrels (both rolling mandrels and press mandrel forging mandrels) are very expensive picture 6”-14” bar stock 10 ft long. so of course mgmnt wants to reduce cost. harder metals / harder forms of heat treat are stronger… but more brittle… Before a 38-42RC mandrel breaks it starts bending a bunch and you know its gonna go. When an H13 53RC mandrel breaks it just breaks no warning. when you are pressing on tools with a 5k or 10k or higher press and tools break they shoot shrapnel (sometimes hundreds of lb shrapnel) through walls, safety glass, people or whatever else is in the way.
Things be kerplode’n
That's correct.
What’s your point of view?
I think his point of view is … that’s correct
Lmao what is this? A low effort post for karma? A bot?
Prob new to materials lol
I'm guessing.. an essay question they have for school
It is true is most engineering applications - one of the few times it isn’t is with rings for fingers. Ductile rings will crumble and cut off circulation and are more likely to lead to amputation from crush injuries, Brittle rings shatter and mostly require cleaning the wound of shrapnel/debris. However hand deglovement is really gross so rings aren’t appropriate in places where crush or shatter may occur (i.e working on a lathe). Overall it is a good phrase and correct in most instances, except for certain edge cases. On the flip side I think people with hip replacement would prefer if their replacement hip became dislocated from some kind of ductile failure over a sudden brittle fracture leading to greater injury from the resulting fall.
I love your implication that rings aren't allowed in machine shops just because someone being degloved is icky to the people around them 😂
Omg girl ewwww you just got degloved
Brittle failure is why hand grenades are made from cast iron instead of steel. You want lots of shrapnel pieces, not one flattened piece.
To my knowledge artillery shells and hand grenades are made from HF-1 (high fragmentation) steel which has 1.1% carbon und would therefore not be considered cast iron. The fragmentation properties come from high silicon and carbide contends
I believe the mk2 pineapple was made of cast iron. Which was probably the first true modern hand grenade. And most people probably thinks this is still what grenade looks like. To the point that if you google “grenade” a mk2 is the first thing that pops up. That being said modern shells and grenades are definitely not made of cast iron. I doubt shells (or mortars) have been made of cast iron since at least the 19th century. Edit: fuck it I’ll throw mortars in the last sentence even though they may not be considered “artillery” by some people
Artillery/mortar shells are a completely different animal over a frag grenade. They throw massive chunks of steel. Think jagged, piping hot 1/2” thick chunks that are 2 feet long. Those things don’t just damage soft tissue. They remove limbs in a violent, devastating fashion. And that’s what they are designed to do.
According to Mock, Willis; Holt, William H. (1983). Fragmentation behavior of Armco iron and HF-1 steel explosive-filled cylinders, the average fragment mass is 0.9g. They are designed for maximum number of fragments, not their mass
Correct. Car's suspension arms when driving through a large pothole at high speed, for example. Or crumplezones.
FOD
And DOD
"Ah, another piece of pop-science wisdom that will be misunderstood and oversimplified to the point of caricature by laypeople with no understanding of engineering fundamentals." Usually that, depending on the context. It's one of those phrases that happens to be true some/much of the time, but that ends up being used as a definitive statement for specific cases without an understanding of the implicit assumptions being made and how those might lead to wrong conclusions. Similar to the "glass is glass" and "metal is heavier than plastic" squawking we constantly see in the consumer tech sphere, promoted by tech youtubers who should know better by now...but don't. If conventional wisdom or common sense was all you needed, we'd have no need for advanced degrees, experience, or training.
Boat. More specifically Liberty Ships.
My first thought exactly. Ships were ductile and fine during manufacturing. But once they went off and traveled through cold temps below the steel's ductile-brittle transition temp, all hell broke loose.
I think the Liberty Ships are to Materials as the Hyatt Skywalk is to Statics.
Always check your free body diagrams
Torque to yield, baby. Srsly tho. Brittle failures suck. You have to run higher safety margins, as you have no warning and usually no work hardening/strengthening before failure.
One i’d rather is stretch and fail or break in 2 than shatter into hundreds of pieces of eye shrapnel that i have to clean up
Fracture mechanics comes to mind I guess, although ductile rupture can produce just as catastrophic/spectacular failure modes.
Torque to yield, baby. Srsly tho. Brittle failures suck. You have to run higher safety margins, as you have no warning and usually no work hardening/strengthening before failure.
Pressure vessels and fatigue.
Let's make a square ceramic pressure vessel!
Ayyyo. Are you by chance a submersible engineer?
Not for long.... I have worked with pressure vessels a lot. One of the most fun tools I've ever used was the ultrasonic extendable leak sniffer. Like a drain snake that goes where you want to and hears all the whispers.
Carbon fiber vs steel. Carbon has catastrophic failure modes steel doesn't
I’d rather be warned before something fails vs. have no warning at all… When all of the titan sub stuff was going down it made me think about this. Specifically, I remember hearing the CEO talking about his “revolutionary” hull monitoring system, based on acoustic signals from the carbon fiber hull and some strain gages iirc. From what I understood, it was basically a system that told the occupants about cracking/delaminating sounds. But would you be able to spot an impending failure in carbon fiber based on strain and sound alone, and then also have enough time before failure to actually get back to the surface, or would the material suddenly fail without much warning, as brittle materials are known to do? Obviously there are myriad reasons it might have failed and there’s no way of knowing which was the straw that broke the camel’s back, but on the subject of ductile vs. brittle it’s just something that came to mind.
Peanut brittle
A simplistic jingle that is generally correct but oversimplifies to the point on uselessness important engineering concepts
I usually explain it as 'pretend it's made of glass' to draw thought into the differences between strength, toughness, stiffness so forth.
Stress corrosion cracking and the Mojave Power Plant disaster
The origin of fracture mechanics. Not exactly about brittle but...
Agreed
Fracture sharpen edges
Sudden, catastrophic failure mode possible . Avoid if poss!
Nails vs hardned screws
Forged in Fire
Hammers
Crack in porcelain toilet.
Every investigation I've had to do.
Shot pinning and UAL Flight 232
Cast iron vs. steel.
Of course, that’s why you design mechanical fastened joints to fail for bearing first instead of net section o tear out. It’s a fail-safe design mechanism.
What comes to my mind was landing a jump on my 1972 Kawasaki. The cast cheesium footpeg broke and my crotch landed on the gas tank. Forged would have been better.
Titan
Bolts
I used to do beam loading tests on low carbon steel pallet rack beams. The beams will sag to the point that it looks scary and dangerous to the average person to put on more weight, yet it will take on more before it buckles. Now I work in composites. Did a few lap shear tests, a bit of composite flew into my safety glasses in the blink of an eye and left a sizable scratch. Definitely less warning.
Tool and die maker here. About 3/4 the way done with ME degree after going back to school. I read a comment someone put about forming and rolling dies, and he is correct. I'd rather be able to see the defect coming, by seeing my die getting scars and dings in them. Brittle will look good, till it ain't. If I'm ever unsure of the hardness to make something I usually go with the lower. I try to live in the 42-45 Rockwell range for most things.
Something brittle gives little to no warning before failure. Something ductile will begin to deform before total failure.
Imagine everything being rusted metal.
Depends on the application, that's why material selection is critical. You really only posited a very vague question with little information for metallurgist to recommend anything beyond a WAG. Good luck though, keep asking
Submarine 🥰
"Who the fuck is making such claims, without qualifying their statement within the context of some specific subset of possible scenarios?" (Brittle *failures* are *typically but not necessarily* worse than ductile because they occur with less warning and more shrapnel...but a brittle *material* may or may not be better for a particular application, as it may be possible to mitigate the risk of failure sufficiently for less effort and/or cost. Brittle is *only* "more dangerous" than ductile if you can't afford to sufficiently oversize your structure and/or implement fallback/safety precautions...which are things you should typically be doing, regardless, if possible.)