Making your own impact tester

So, a bit of a story...

I was watching this video on trying to build 3d printed objects by using half layer offsets...

...and got halfway through when I saw the YouTuber test his products with what seemed to be a homemade Charpy-esque impact tester.

5:38 in the above video

That homemade impact tester is something we've been talking about in our summer camps as a hypothetically simple thing to build, but our discussions tend to be fairly abstract and general - not at all specific as to plans that could be followed. This, however, looks to be something fairly specific and even branded by CNC Kitchen's blue and white logo.

So I went searching and came upon this video by CNC Kitchen that shows a homemade tensile/compression tester at about 8:15, a three-point bend tester at 10:45, and the same impact tester at 12:10.

So onward I went to find plans for the various testers.

I did find a video showing how to make the tensile/compression tester.

...and another for the 3-point bend tester.

...but I wasn't able to find a video for how to make CNC Kitchen's impact tester. Luckily, the impact tester's plans are available online.

Three-point bend test fixture - with plans

3 Point Bend Test Report by phschemguy on Scribd

In the spring of 2015, Bob Hanlin, one of the ASM master teachers and a professor at University of Missouri-Kansas City, came to our spring training with a project that some of his students had developed. It was a three-point beam tester made on the cheap and designed to be cheaply made by high school teachers to more accurately and repeatedly test the cement composite beams that we make as part of the material science curriculum.

Bob had tasked his students with the following requirements, as found on page three of their final report - embedded above...

• Repeatable testing
• The new fixture and method of breaking the cement has to be able to be repeatable and provide similar results.
• Portable
• The fixture has to be compact and easy to transport since high school teachers will have to take the fixture to school and carry it around.
• Accurate
• The testing mechanism hast o prove similar test results when in use.
• Easy to make
• The new fixture design has to be simple and easy to make since high school teacher[s] will be building it to teach the students the importance of material science.
• Inexpensive
• The fixture has to be as low-cost as reasonably achievable since high school teachers have to function on a meager budget and sometimes [are] forced to spend their own money out-of-pocket.

Man, that's a set of requirements that screams understanding of the high school science/engineering teacher world. Cheap, easy to make, portable (storable, too), accurate, and repeatable...that's pretty spot on perfect for our world.

Bob showed off his students' creation at the training, and we were all amazed at the results. No, it's not a commercial beam tester, and the accuracy doesn't approach that level of precision and repeatability, but for $30, it's a brilliant bit of engineering.

I finally got permission from Bob (who actually had to get permission from the university) to publish the tester's plans here on my blog. The one stipulation was that credit had to be given to the students - Gabriella Baptistella, Zach Kellogg, Vincent Nolan, and Lee Seela - and to the University of Missouri-Kansas City. I'm happy to credit all of those folks because their product is just brilliant.

The students explored two fixtures and two methods of testing for each fixture. In the end, the best choice is the one they labeled fixture 2 - method 3. The exact plans for 2-3 can be found in the embedded document above in appendix B (p17). The fish scale that Bob used when he showed us was - I think - this one from Amazon. Everything else would be a Home Depot/Lowe's/local hardware store purchase.

Here are pics of the final product - along with Bob in the dark blue plaid.

 

By the way, in explaining how he'd gotten students to help design the tester, Bob mentioned that the funds for the design project came from the tuition that our ASM summer camp teachers have been paying for grad hours related to the teacher summer camps over the past few years. So it you - like I - have taken the grad hours, thank you for your contribution to this project.

So, go, make yourself some beams and get to testing them.

Oh, and if you want to see our old method for testing the beams, here's a pic from the UMKC website showing our pre-these-plans method from their ASM teacher summer camp.

Source - UMKC website

Why do Baseball Bats Break?

Oh, hey, Grady. Good to see you.

In this video - about why major league baseball saw a sharp uptick in broken bats (and subsequently an uptick of injuries caused by flying bat shards) in the early and mid-2000's - Grady gets into the differences in ash (the wood used to make almost every pre-2000 bat) and maple (a wood that became popular - not poplar - with ball players in the early 2000's after Barry Bonds used one to break the HR record).

He then goes into the non-isotropic nature of wood and how ash and maple are very different. I guess the lessons learned in making ash bats didn't translate cleanly into making maple bats. It doesn't mean that maple bats are inherently less safe, just that they need to be made - and particularly marked - differently than do ash bats.

Really, changing the material requires changing the production and use strategies for that object?

Who would've guessed it?

How Weed Eaters Work (at 62,000 FRAMES PER SECOND) - Smarter Every Day 236

I've spoken of my love of Destin before. One of the things that I love most about him is his scientific curiosity. He's willing to point a slow-mo camera at just about anything and set up some experiments to teach himself more about whatever that camera points at. It's kind of awesome.

In this one, Destin points his Phantom high-speed at weed eater string to see how the string cuts blades of glass (cut or rip? delaminate or clean slice?) and breaks against various wire fencing materials.

We could do a lot worse than show this when talking about destructive testing in class.

There's also a second video that tries to figure out which shape or string is best. He comes to a conclusion, but I'm not sure he does nearly enough experimenting and variable isolation to actually justify the conclusion he comes to.

Touching plasma - Smarter Every Day 193

Let's get this out of the way first. The video isn't remotely about 'touching plasma'. Yes, somebody touches plasma at 9:30, but it's not elaborated on or explained in the least. The title is oddly useless, something I haven't seen from Destin before.

On the other hand, the video does have three minutes of high quality material science content early. From 1:05 through 4:20, Destin goes to Dr. Kavan Hazeli's lab and shows some of the testing of '3d lattice structures printed by NASA.' They're looking at ridiculously lightweight materials, trying to see how much metal they can take away (though it's created via additive manufacturing) while still leaving the 'material strong enough to withstand a space environment.'

We get to see an impact test as the researchers explore the difference in 'quasistatic' pressure and impact pressure tests to the materials. The sample we see tested in nearly pulverized and comes out 'perfectly flat' and hot.

It's like energy is transferred or something.

The rest of the video sees Destin visit two more labs - testing ion thrusters and exploring the fluid dynamics around a butterfly's wing - but they aren't nearly as material science interesting. Watch 'em or don't. Admittedly, at 4:55, Destin announces, 'are you not entertained,' and I'll admit that I'm not. Meh...

It's probably because I don't really understand what's happening with the ion thruster.

How tough is the new Gorilla Glass 6?

Wait, Gorilla Glass 5 has been improved upon?

Fine, but I'm sure nothing will ever surpass Gorilla Glass 6.

In all honesty, I did like seeing the various tests that the glass designers undertake when they're developing a new glass. I haven't had the issues described with the purse, but I'm assuming those are real issues.

In the video below, we get a brief glimpse into the manufacturing and prototyping of the various glass compositions on the way toward a final product.

MAKING A BOWIE KNIFE WITH REAL ENGINEERING!!! PART 2 - WHY we heat treat steel!

Finally, the testing...

The first part of the video is more making a knife - grinding the blade, drilling to attach the handle.

Then, at 5:50, the actual materials testing comes in. Alec Steele takes a steel bar and heat treats it different ways (not on camera, sadly) and gives each piece a few solid wacks with a sledge hammer.

These two videos (Alec's and Real Engineering - whatever that guy's name is) really balance the two sides of material science. Alec shows a lot of a practical knowledge. Real Engineering shows a lot of academic knowledge. Together they're pretty awesome.

Oh, and the testing wraps up around 12:25. Then it's back to finishing off the handle of the Bowie knife.

Snapping a Steel Rod 1000x slower - The Slow Mo Guys

The...

slow...

mo...

guys...

do some neat stuff, and they at least explain some of the science of what's happening along the way...usually...

Just so you know, the actual break happens around 2:30.

We don't actually get much of a science explanation this time, though.

But we do get the braking of a like one (or maybe two-)-inch-diameter rebar rod.

Hydraulic Press | Prince Rupert Drops | Remake | Safe Tails

When it comes to hydraulic press YouTube channels, I'm more of a Hydraulic Press Channel guy than I am a PressTube guy. I'm particularly fond of the destruction of a hockey puck and of the vicious clay creatures that are stopped from wanton murder at the end of each video.

But I am willing to watch the derivative PressTube when they come up with something creative to destroy. In today's video, the PressTube folks destroy a Prince Rupert drop...or two...or ten. And, in the process, they also make some pretty big dents in a chunk of lead.

How to Escape from a Car Window (slow motion) - Smarter Every Day 144

I think I've run out of ways to say that Destin is awesome.

It's like he's put together a video to perfectly explain the differences between tempered glass (like in the side windows of a car) and annealed glass (like what's laminated on the windshield of a car).

And he does it all in super slow motion.

I wanna buy his shirt even though I'm a pudgy XL, and his website says his shirts run small. Hence the largest size available - the XL - still worries me.

Pinkbike vists the Santa Cruz Test Lab Video

Edit: Looks like the video has been taken down from YouTube. It's still available (but not embedable sadly) on this webpage which includes a lot of analysis of the tests.

break it!

Break it!

BREAK IT!

Joe Graney might want to talk to somebody about how to look like he's actually enjoying his hosting duties, because he's lucky enough to be standing there and breaking the snot out of both aluminum and carbon fiber bike frames (with a screw drive at 0:47 and then with dropped weights at 2:45).

Interestingly, the sudden breaks (from dropped weights) don't look all that different, but the slow breaks look very different.

Thanks, by the way, to Frank Marks, Director of Engineering for Utah Test and Training Range, who showed this at our graduation in Salt Lake City last week.

Sapphire vs Gorilla Glass - Bending and Impact

At 1:27, we get the straight-up answer: "sapphire is marginally stronger than Gorilla Glass, about 25% stronger, to be exact. In other words, it would take 25% more force to break sapphire glass than Gorilla."

But then things get more complicated, as Gorilla Glass is far more flexible meaning that the Gorilla Glass will likely be better.

I do wish I had a four-point bend tester like that. My guess, though, is that I would probably get in some pretty unpleasant trouble with just trying to test anything lying around.

Gorilla glass tests (2, 3, 4)

Admittedly, this is an advertisement, but at least it's an advertisement with some hard data.

Gorilla Glass was impressive, but Gorilla Glass 2 is light years ahead of it. I'm sure they'll never come out with anything more impressive.



Ok, color me corrected. Gorilla Glass 3 is stunning. That's the best I will ever see. It'll never be topped.

The Glass Age (parts 1 & 2)

Yeah, it's a shill for Corning, but I'm okay with that because corning makes some pretty frickin' cool materials, and the Mythbusters guys - Adam Savage and Jamie Hyneman - are pretty solidly entertaining.

We get some history of glass developments, a look at modern developments in Corning glass (optical fiber, willow glass - check 7:00 for the phenomenally flexible willow glass), and then...well, an end.

Luckily there is also The Glass Age (part 2) from the same folks. Here we get a few destructive tests with older cell phones, an explanation of Prince Rupert's drops, and a windshield glass explanation.

For Gorilla Glass testers, every day is a grind (and scratch and drop...)

Glass isn't supposed to do that, the bending thing that the Gorilla Glass in the photo there is doing.

See, glass shatters.

It's inflexible and rigid.

Yeah, it's tough, but it's not gonna bend like that without a catastrophic failure.

Unless it's Gorilla Glass being bent in Corning Lab's testing lab as chronicled in a cnet article recently. In the article (and included video, check below for the embed) we get to hear why sapphire might not be the material destined to replace Gorilla Glass on all of our smartphone fronts anytime soon.

I particularly enjoy this quote...

We put on safety glasses, walked into a restricted corridor and soon entered one of the main labs, which -- despite all the secretiveness -- looks a lot like shop class. 

I can't tell whether I'm entertained more by the thought that anything that's 'just' a shop class can't do any real science or whether I expect the quote to be followed up with photos of guys with three and a half fingers.

MaterialsScience2000

I love seeing the crystal grains develop as the acid etches the metal surface. It's just gorgeous.

The eight-and-a-half-minute video above shows the preparation of a few different samples, some of which show crystals large enough to be seen by the human eye as well as a few samples that have been etched through natural processes over time.

MaterialsScience2000 has ten total videos posted, and many of them are worth a watch, including a thorough explanation of the tests being preformed. Check out these, too...

A36 Steel Tensile Test

At about eight seconds in, I can start to see the necking which causes the force to concentrate on that area which causes further necking which causes force concentration...back and forth until catastrophic failure nearly at the end of the video.

Not much else to say here but that it's a nice video of a tensile test being performed. I just wish we could get a concurrent graph of the stress/strain curve being generated.

Here's another tensile test from a bit further away...

Concrete Stress Strain Curve (early age 4 days)

We're working on understanding the stress-strain curves today at master teacher training at the ASM dome (love this place), so I'm searching for examples of a tensile test being performed at the same time that a stress-strain curve is being generated.

First find...a concrete pillar being tested.

Cement Reinforce with Steel Bar for Super Gas Rig Supporting Structure

Flexible concrete - an obvious oxymoron, right?

The video opens with an historical background to the improvements on concrete as well as a base recipe for making concrete - 3 parts aggregate, 2 parts sand, 1 part cement. That's a wonderful mixture for a great material - in (repeat after me) compression.

That's not a mixture for a great support structure for a North Sea oil rig that needs to have enough give to flex with the waves.

Add a few reinforcing bars, though, and the concrete becomes a radically different product.

Steel - great under tension...concrete - great under compression...reinforced steel - the dog's nuts.

British accents - also brilliant all around. Only they can give you that kind of...science.

(Warning, the linked videos there - the Brainiac video - show bad science, faked demonstrations, they should be watched only to show what doesn't really happen unless you lie to your audience. Here's my evidence.)

Crash Test 1959 Cheverolet Bel Air VS 2009 Cheverolet Malibu (Frontal Offset)

Gimme a great, old, heavy car if you're going to whomp me with another car.

Obviously that heavier car will have worse gas mileage, but the mass of the old car will mean that I'll be that much safer.

I swear that my dad said something like this when I was getting my first car. He wanted his boy to be safe, gas mileage be damned.

Turns out that maybe Dad was wrong. Yes, the old cars had more mass, but they also had old engineering. New cars are much, much safer because of great new materials and because of great safety engineering...and Ralph Nader.