Dear Dan Ko, your request have been registered and saved in the recor......wops, dropped it. We will instead recommend you "This week with John Oliver" and "Mr Tfue" videos with a direct wormhole to both "Keeping up with the Kardashians" and "Instant regret" playlist, Kind regards - Yotbe, probably.

yeah and you will see this video recommended over and over instead of newer video's from same channel:/ i've watched this channel for a long time yet this video only now popped up in the side list after watching some other 3d print related stuff..also on my youtube recommandation page are only video's i've watched or a good 90% of them..epic fail..

You could always subscribe and turn on notifications to this channel and 💥!! DESTROY!!💥 the like button on all of his videos.

Fingerbang that like button, it helps sometimes.

​@@mRcOOL5YO the benefit is 3 years later, you forget you saw the video and get to watch it again🤣

better than your shit channel especially you are full time on it !

Hey drunky, how's your nose?

LOL it's not that he's drunk, it's some actual medical condition as he's mentioned in some Q&A.

Nobock really!!! I bet you are fun at parties, oh wait you don't get invited.

Don't attack this guy in person, just his content, thank you !

Border conditions can be assessed by destructive testing, while taking in account and adding to the database the conditions the 3d printed part was made. Although that testing is not made under any industry standard, it is valuable data though, because it considers the worst case, real life scenario.

There's so much more to FEM than people think. I dare to say it's one of the most underestimated parts of engineering, because people assume that "pretty colorful images" guarantee accurate and realistic results. Even if you choose the right load case and boundary conditions you might still use the wrong element type or solver and get numerical artifacts without even knowing ( if you don't know what to look for).

Im not too familiar with stress analysis, but could you explain what is the issue with the frictionless surface assumption?

@@TheGoodoftheLand The problem with commenters like yourself, is that you don't take time to listen to information in the actual video, and rather bash a comment you don't agree with. Or, in this case, defend a stupid question. Because the reason why "using a friction less surface is bad" , is given directly after he applied it in the video @9:53. Just because you don't know about a topic, doesn't mean no one does.

@@rikdol This is an informative video for the general public. People like myself watch an learn from it. The question I asked may sound stupid from the point of view of someone who is more familiar with the topic, but for me, it is totally reasonable. I watched the entire video and the reference @9:53 still didn't clear my confusion about this point so I was proactive and asked for clarification. If you know better, please go ahead and explain this point.

@haytham hakla a frictionless surface will be unable to move away from the wall. Earlier in the video ( @1:50, look closely to the bottom part) it shows that the part is bending. When a surface is set to be frictionless, it will be unable to move during a stresstest. So a test like this for stress and bending or warping of material under high load, won't be realistic. Another example of the part moving away from the wall is @20:00, circled in red..

@@rikdol Thanks for clarifying

Thanks, your support is highly appreciated!

Well the analysis tell you where to make it thicker and where is not needed.

Victor Forslund hard to print if you want it to remain in the middle

True!

@@CNCKitchen love your channel by the way, especially your methodical but garage-doable testing regiments! Also your video on heat resistance testing of various materials led me to be able to powder coat PLA! More on that another time

Topologie 😊

Hehe ja Autokorrektur hat zugeschlagen 😅

Welcome to the world of CAE (Computer Aided Engineering)

Also thought about that. Might give it a try next time.

Some FEA software like ABAQUS can model shell elements e.g. only modelling elements on the surface of the part, and then you define the thickness with a separate parameter. That and a way to approximate part infill would be really nice in Fusion.

Having specific shell type mesh and simulations is partly for ease of computation, and partly for accuracy. A shell mesh generally just covers the outside surface of the part, so the mesh is less complex to model the same part, or you can have a finer mesh for the same computational cost. It generalises it a bit using just a surface mesh e.g. it may assume the variation in stress between the inside and outside of the shell is negligible, which it is if the shell thickness is low compared to the size of the overall model. In FEA, it's important to make the mesh variation smooth e.g. for a given element (smallest 3D shapes in the mesh formed between mesh nodes) you don't want the difference in length of the edges to be too much, something like 1:3 (ideally it should be as close to 1 as possible) ratio between any two edges on an element, otherwise the results become quite innacurate. If you modelled the entire 3-dimensional shell, you may have small edges between the inside and outside of the model, but much longer ones on the surfaces of the objects. So in order to get an accurate simulation, all the edges would have to be similar in length to the ones passing through the shell, and that could make the mesh way more complex again, for not much gain in simulation accuracy. Kind of like in the video where Stefan mentions you should have no less than two elements over the thickness of the part in order to accurately model it with this type of mesh. I'm not sure if one element thickness is good enough for a shell assumption (I'm not an expert in FEA), but even so a very fine mesh would be required. This is basically what a shell type mesh property is for, greatly reducing the computational effort (and user effort) to make an accurate model of this type. In terms of the infill, I was only really thinking of having an internal mesh with different material properties to the surface, modelling the infill exactly would be very difficult unless it could be done in a slicer or with the G-code or something. I'm just thinking the internal mesh could have material properties which better models infill e.g. with 10% infill the Youngs modulus is only 10% for the infill (I'm not exactly sure that example is correct as again I'm not an expert in FEA but you get the idea). I suppose overall the mesh may be just as complex as these ones but I think it would be far more representative. Rather than modelling a solid part, modelling the surface to have diferent properties than the infill is essentially what I'm advocating.

I'm assuming the elements in Fusion are solid continuum elements, since there's no way to change the element type from what I can see. The modelling feature in Fusion evidently is simplified for basic simulations and ease of use. Shell elements are solved differently to solid continuum elements and are better suited to that type of structure. Since practically all 3D prints are shell type structures, something built into Fusion which could model that type of structure accurately would be nice. I'm not an expert but have used FEA to an in depth level for a specific application. Perhaps the standard elements are suitable for that type of structure, I don't know. I do know that in ABAQUS which I have used before, there are standard continuum elements and shell continuum elements, so evidently there is a need for them. Reading into it a bit more, the shell continuum elements have a plane stress assumption, so only the stresses along the surface are measured and stresses normal to the surface are assumed to be neglible. The elements can distinguish the stress variation through the thickness of the part however, with more shell element layers giving a more accurate picture, although that's probably not very important since the shells are generally quite thin on 3D prints. I'm not sure if it would be suitable to all types of model actually. For the infill, I don't see how it would see it as an incompressible solid if the infill was represented as a mesh. If you gave the infill mesh different bulk material properties which reflected it's behaviour e.g. such as Stefans video on infill strength. With low infill settings, the lattice structure is large compared to the overall object and could be significant, but low infill doesn't affect part strength much as we all know. Also at higher infill settings, the lattice is more dense and begins to act as a continuum, so a solid mesh should be a fairly accurate model.

In retrospect, I think I was proposing something (using a shell type mesh to possibly model a 3d printed part more accurately) which seemed to make sense at first but actually might not be correct since I'm not an expert in FEA like I've mentioned, but I have used FEA to understand how it works. Ultimately the proposal is that Autodesk adds some feature, to either fusion or another piece of software, which more accurately and efficiently models 3D printed objects. If they could make a tool which generates a mesh for the shell of the object, then generates a mesh on the inside of the part for the infill with one click and simple data e.g. shell thickness, Youngs Modulus etc. A step further would be to model the anisotropic structure of a 3D printed part i.e a 3D printed part has different strength as well as other properties depending on the direction it is printed. If they gave you a little arrow and allowed you to point it in the direction the part will be printed, then it could apply the properties to the model based on that, perhaps even structure the mesh to be in line with the layer lines of the print. You'll never be able to model a 3D printed part perfectly, but each of the things above would bring it one step closer to being accurate. You could defnitely model a 3D printed part using existing FEA software, but it would be time consuming and laborious. If someone could make something that could automate the above, that would be really useful for the 3D printing community. I guess there hasn't really been any incentive for that type of modelling until recently, since 3D printing has mostly been used for prototypes and not fully functioning parts. Maybe this software exists already although I hope it's not behind a high paywall.

Just hit the bell icon and you will be reminded of new videos at the point of release 😉

Hold that thought! Autodesk says Starting on September 6, 2022: The ability to run simulation studies on a local computer will no longer be an option for simulation solving. All simulation study types within the simulation workspace of Fusion 360 will only have the cloud-solving option. And it will probably be a lot slower than an i9.

BTW Meant to mention really like your testing rig. Cheap, simple, and effective, just remember to duck.

😅 I should maybe update the design a little.

Which one?

Had' some help from the guys ;-)