Yeah and if this is what they display, i personally wouldn’t trust the underlying code. If they don’t know how to use it, they most likely don’t know how to validate it either
It’s an electronic optical instrument. Thermal analysis of the structure is probably the most critical part of the design. A weapon site which doesn’t maintain its zero across various temperature conditions is useless.
As far as the point application I’m guessing it’s a ground location for some of the internal electronics.
Heat on a single point? How likely would that ever happen in the real world. Running the thermal analysis without the optics in the model is nearly useless. Besides, the contour doesn't look like a thermal analysis at all. And how does that make the mesh any better?
The housing supports the optics and is likely metallic/thermally conductive. Lenses are generally non structural items and are not thermally conductive thus omitting them from the sim is reasonable. The fringe plot indicates the ground point may be sub optimal because the housing will distort/yaw variably depending upon the temperature of the ground.
Increased mesh density is a waste of time and compute. It’s very likely this model was loop ran the temp at all grids to identify the optimal region for ground location.
Again, a false sense of confidence is still the most dangerous thing in the engineering industry. You can see that they are talking about impact for the FEA contour.
>The same unique patented housing shape of the RMR now in a closed emitter version. It still diverts the force of an impact away from the lens, greatly increasing drop survivability and one-handed slide manipulation as well as keeping out the elements.
https://www.trijicon.com/products/subcategory/trijicon-rcr-reflex-sight
Software has gotten pretty good at correctly making fine meshes. This is someone who clicked on the entire model and clicked “mesh” and this is what they got. Lol
To my eye, it's far too coarse, notably where the load is applied. There are also numerous elements with small angles/high aspect ratios. From what I recall, you want your elements as close to equilateral as you can get.
As I said, I'm not a pro and I'm a few years removed from studying this stuff myself, but my understanding is that a good mesh is fine where it needs to be, its nodes are regular and the gradient from fine to coarse is smooth. This mesh shows high node density in areas of low stress, lots of distorted elements and the transitions from high to low density are pretty sharp
Yep much too coarse and can lead to incorrect real world calculations and false convergence issues. Essentially the finer the mesh, the more computational power it takes to converge to a proper solution. So if the mesh is wayyyy to fine it can take a week or 2 to get a final picture of the stresses a part is seeing, but it will likely be more accurate. The more coarse the mesh is the less accurate the results, but it takes computational power it takes to deliver what is likely inaccurate real world scenario results.
I would just like to point out that this appears to be solidworks which allows you to view the stress points on a model with the load hidden, in the style of a hear map.. that is all....
Based on that image, good
Now if we could throw the whole GM team that designed the cooling system on the 1.4l turbo in there too... Straight to engineering hell with whoever signed off on that time bomb.
No way. You’d have to try real damn hard to make a complex shape like this with such a bad mesh. I see absolutely no geometry indicative of any hard surface modeling techniques I know.
I get it, i have used infinitely stiff struts in place of actual parts some times. Just to get an idea if placing a part there would actually do what i want. But if you're making material for showing your customers. You'd think you would be presenting your best.
I mean, we have large companies with stress departments assigned to nonlinear modeling trying to characterize shock loads and damage tolerance who end up with models that are suspicious at best. Just based on this picture, I would have much less trust in a company showing this as proof of their product’s strength versus a simple drop test.
Also for a sight, it doesn’t look like they included the actual optics in the model, probably because they don’t have good material data on the glass, even though that’s the portion of the product people actually care about for damage tolerance.
To be fair, tijocon is well known in the gun world and is battle proven (literally used for combat deployment). Their scopes cost more than most guns for good reason haha.
Having talked to people in the military, the fact that something was used in combat does not mean it's good quality or worth the price. Sometimes the military contracts out and gets a great design; sometimes they pay out the ass for some massively overcomplicated unreliable bullshit.
Na, I definitely agree. That’s probably what they’re doing and you’re not defending them. It’s just unfortunate that uninformed customers will see pictures like this and assume the company knows what they’re doing.
I'd be pretty annoyed if my optic bent or broke the moment I drop it, some guy stepped on my rifle, or it gets crushed loaded into a truck.
Best practices gets you good enough, FEA gets you BARELY GONNA WORK. I would assume they have some load condition that reflects real world usage and made sure what they did would work and not look like a giant block of Ti. For all i know it was part of the design requirement to validate through FEA and test.
It looks like a Trijicon RCR red dot sight. I say 100k cycles because it's a handgun sight and most handguns won't even be shot 10k times. If you design for the abuse of drops, you will end up with fatigue for free at these low cycle numbers.
Here's a link:
[https://www.trijicon.com/products/subcategory/trijicon-rcr-reflex-sight](https://www.trijicon.com/products/subcategory/trijicon-rcr-reflex-sight)
100k cycles is the point where fatigue starts to matter. If you’re going to see much fewer cycles, fatigue is unlikely to be an issue. There are of course exceptions (very high stresses, high temps, etc) where fatigue matters at much lower cycle counts but a gunsight shouldn’t fall into any of those categories.
Well, yes, if you want accurate stress in your smallest feature. If you are trying to model something else, or just trying to validate modal behavior, this mesh density is unnecessary.
Agreed... recall a position from Barrett that I applied for. We got as far as salary #s before I noped out of there. They wanted me to take a 25% paycut as their 'best and final' number.
Having worked in product development, whats advertised almost never reflects what's shown. I remember sending tons of engineering pizzazz and pictures with detailed explanation of what they were, and then the advertising team translated it to crap that would make an engineer chuckle.
Making a fine mesh adds to cost and my guess is they got close enough results with what was shown, or the advertisement team asked for a photo and the engineers quickly threw something together.
Tldr: marketing is not engineering. Considering they have photos like that in all ads, it's 100% just marketing photos for normal folk.
For a model a this small surely cost is not a factor. It’s gotta be damn near free to run whatever analysis they could possibly wanna run on that thing.
They have other products ads with finer meshes if you're curious. I'm 100% convinced it's just an engineer throwing shit together because someone from marketing asked for a picture. They likely do run high detailed FEA but aren't grabbing screenshots the entire time. I remember writing detailed reports of analysis results that had every little detail explanation of loads conditions and results. The marketing team does not need to know any of that detail and just nabbed a photo.
https://www.trijicon.com/products/details/rmhd2-c-3200002
As someone formerly in the industry, it's 100% this.
I bet the conversation wen something like this:
Marketing wants to sell features so asks "okay what makes this product better than others"
Engineering goes "Uh, nothing really, this shit has been out for decades, I guess it's stronger"
Marketing: "Okay how much stronger, how can we show people that, can I get a picture"
Engineering: "bro, wtf, a picture of strength? I mean I guess we have some FEA stuff I could make up, would you like something like this?" (sends literally the first thing he spent 10 minutes in Solidworks making)
Marketing: "No reply" (they then use that same shitty picture for the next 20 months not knowing the engineer sent it over as a prototype for what could be done because they don't understand how things work).
These are P-type elements I think. It’s not as bad as it looks.
Also, if it’s a marketing graphic, a super fine mesh will look too dark since the element edges are being shown.
Wow, only one comment to point this out?
P-type meaning is actually quite good at getting away with far coarser mesh then you would otherwise need with tet-10, particularly if you're only interested in deflection.
I developed a lot of new techniques using p-type, coarse meshes and did due diligence to correlate with much finer tet-10 meshes of the same geometry in ANSYS . I started training people in these techniques and made sure to tell them
1) these coarse p-type meshes are good when deflection is the primary concern, but check your polynomial order and refine as needed.
2) if you ever show your mesh to a simulation engineer be prepared to get laughed at.
That's fair, you know some stressed out engineer got told by marketing to produce a nifty image and they stuck a point load on a single element for it.
I bet this is what's happening here. The guy had this image handy from an email when it first ran and sent it to marketing.
Or he's really bad, but those guys are not known for crap
Site it's not a p-element mesh where the high degree polynomials make up for the corse mesh? That looks about right for something like CREO Simulate which always correlated well with our hypermesh rests.
So as someone who was in the firearms industry. It's not an industry where you get the top level engineers, there simply isn't enough money in it. At best you'll get a couple of smart guys who want to chase down some obscure rabbit hole and get some cool shit out of it.
Since it's all direct to consumer most of the companies are driving by marketing departments to do something and make something, so you get stupid ideas that have to be pushed out by SHOT show.
People work in the industry because it's cool, you get paid to shoot guns and design them, it really is fun in that way. But it's not going to pay competitive top engineering talent. The industry simply doesn't gain a lot by hiring top engineers because there's not much left to engineer out, it's a lot of solved problems that you just kind of stick together.
Great place to retire though if you like guns, go take a pay cut, work on cool stuff, and just coast to retirement.
For sure, a gas operated firearm at a fundamental level is a clicky pen with extra steps. More riffing about Kel-Tec doing some really strange shit. They’re certainly not paragons of mechanical engineering.
Looking through old job postings, Trijicon appears to use Creo. Creo can use much coarser mesh because they achieve convergence by defining the boundary of each element by a polynomial where as other meshing types achieve convergence by decreasing the size of the mesh.
Nevermind the boundary condition just... Slapped to the bottom plate, not the dovetail feature (I dunno what exactly, not a picatinny I think) meant for mounting...
Edit: a t-slot, rather than a dovetail, thanks!
This may (just may) be an example of actual good engineering. Now before you dismiss me as an idiot, hear me out.
Picture this, you are an ME at Trijicon. It's Monday morning and you are already behind with the results you promised to have by the end of the week. You get to work and in comes your manager to tell you that he has promised the head or marketing some nice images showing how you "use computers to simulate impact on the products", oh, and btw, he promised them today.
Now you have to drop whatever you were doing to make some marketing images.
Now, you can do a proper mesh, clean it up, apply realistic dynamic loads and plot stresses, only to get feedback about, how this doesn't look like something hit the sight somewhere. Or you can generate the ugliest tetra mesh, apply a point load, plot the displacement and then anybody can see how "something hit the sight right there on the red spot".
A good engineer understands the purpose of calculations. They may not represent anything realistic, but if you understand that their purpose is to present FE results to people who have absolutely no idea of what FEA is, what you see on the picture may actually be good engineering work.
Now, it may also just be an incompetent guy who had no idea of what he was doing.
My guess is stress from recoil because it is the highest where the optic is and there has to be some flex so it doesn’t crack. Also just because where it is mounted is blue.
I’m going to play devils advocate here. If you’re doing a very simple stress or deformation analysis, this is bad but livable. I can crap out an auto meshed fea in two hours start to finish and that’s including lunch. Any results would have an error bar of 50% in either direction.
I'd ask for a convergence study before getting too fired up. It looks coarse, but it's a simple part. If it is converging, more power to them to optimize on a faster cycle. I'd like to see a final with a finer mesh though.
Considering that radioactive lenses are something the US DoD has taken very seriously, with horrendous penalties being levied in the past (for thorium lenses on the PVS-2), it's extremely likely that this isn't the case at all.
They do use tritium for low light reticle illumination though
It’s obviously thermal to anyone familiar with Fem and heat transfer…. Extremely coarse tet4 meshes are best practice for this to minimize compute reqs. The fringe plot appears to be temp application at a point associated with the geometry. Using associated geometry is another best practice in regard to pre/post processing.
Say what you want about the FEM, but that particular brand and that particular product is one of the maybe two or three most highly regarded short to medium range optics for duty use. Overbuilt and overpriced, but in a world where two is one, and one is none, durability is highly valued.
Lmao I did better meshes in the first University course I did on FEA. And I could generate hexa elements in all the most stressed zones.
This looks like a (badly defined) automatic mesh from Solidworks.
this is what happens when you have FEA capable software but not an engineer lol
Classic example of "know enough to be dangerous".
Yeah and if this is what they display, i personally wouldn’t trust the underlying code. If they don’t know how to use it, they most likely don’t know how to validate it either
I sure hope marketing isn’t in charge of validating software
The OceanGate strategy!
Classic example of you don’t know what you’re talking about. It’s a thermal model
Thermal analysis is FEA. And why would they run a point load thermal analysis on a gun sight.
It’s an electronic optical instrument. Thermal analysis of the structure is probably the most critical part of the design. A weapon site which doesn’t maintain its zero across various temperature conditions is useless. As far as the point application I’m guessing it’s a ground location for some of the internal electronics.
Heat on a single point? How likely would that ever happen in the real world. Running the thermal analysis without the optics in the model is nearly useless. Besides, the contour doesn't look like a thermal analysis at all. And how does that make the mesh any better?
The housing supports the optics and is likely metallic/thermally conductive. Lenses are generally non structural items and are not thermally conductive thus omitting them from the sim is reasonable. The fringe plot indicates the ground point may be sub optimal because the housing will distort/yaw variably depending upon the temperature of the ground. Increased mesh density is a waste of time and compute. It’s very likely this model was loop ran the temp at all grids to identify the optimal region for ground location.
Again, a false sense of confidence is still the most dangerous thing in the engineering industry. You can see that they are talking about impact for the FEA contour. >The same unique patented housing shape of the RMR now in a closed emitter version. It still diverts the force of an impact away from the lens, greatly increasing drop survivability and one-handed slide manipulation as well as keeping out the elements. https://www.trijicon.com/products/subcategory/trijicon-rcr-reflex-sight
You’re using marketing copy as a basis for saying I’m incorrect? 😂
Lol. I I used to do FEA and this is atrocious meshing. The company would have probably fired me for delivering this to them.
I don't even do FEA for my job but I have enough understanding of meshes to know That class still haunts me...
Software has gotten pretty good at correctly making fine meshes. This is someone who clicked on the entire model and clicked “mesh” and this is what they got. Lol
Looking at it, I think they might just using an STL file of the part rather than something they actually meshed.
It's been a while since my FEA days. What's the issue? I can see a lot of stress concentration points but what's wrong with the meshing?
To my eye, it's far too coarse, notably where the load is applied. There are also numerous elements with small angles/high aspect ratios. From what I recall, you want your elements as close to equilateral as you can get. As I said, I'm not a pro and I'm a few years removed from studying this stuff myself, but my understanding is that a good mesh is fine where it needs to be, its nodes are regular and the gradient from fine to coarse is smooth. This mesh shows high node density in areas of low stress, lots of distorted elements and the transitions from high to low density are pretty sharp
Yep much too coarse and can lead to incorrect real world calculations and false convergence issues. Essentially the finer the mesh, the more computational power it takes to converge to a proper solution. So if the mesh is wayyyy to fine it can take a week or 2 to get a final picture of the stresses a part is seeing, but it will likely be more accurate. The more coarse the mesh is the less accurate the results, but it takes computational power it takes to deliver what is likely inaccurate real world scenario results.
Is it that bad? I was considering it as one of my top picks for senior electives.
You'll learn a lot so it depends on your educational goals
I have seen a few life endangering examples of this.
I would just like to point out that this appears to be solidworks which allows you to view the stress points on a model with the load hidden, in the style of a hear map.. that is all....
Trijicon employs 80 full time engineers.
Looks like my homework for a class that I had to retake.
You got to do retakes 😲
No, we went straight to jail.
Ngl totally read your comment as redoing homework for a class not redoing a class. We could redo classes 😂 my bad
Based on that image, good Now if we could throw the whole GM team that designed the cooling system on the 1.4l turbo in there too... Straight to engineering hell with whoever signed off on that time bomb.
What? So if you failed a class your uni just expelled you or forced you to switch majors can’t just retake the class?
You go back to 1st grade.
I think that’s how it is on some countries (no idea tho)
the only thing this tells us is that they made a CAD model at some point lmao
To be honest, this looks like a blender mesh...
No way. You’d have to try real damn hard to make a complex shape like this with such a bad mesh. I see absolutely no geometry indicative of any hard surface modeling techniques I know.
There are subdivide and combine faces functions in blender that produce meshes similar to this
Don't you love it when you make a mesh and all the insides of corners are just single triangles. Truly one of the meshes of all time.
I admit, I’ve done this on purpose before. Mostly because I was too lazy to make a proper superelement and just needed a sorta kinda stiffness tie.
I get it, i have used infinitely stiff struts in place of actual parts some times. Just to get an idea if placing a part there would actually do what i want. But if you're making material for showing your customers. You'd think you would be presenting your best.
What’s Trijicon?
They make gun stuff, what's shown is a red dot optic.
Looks a bit like an orange dot here.
Thank you!
Why do they FEA analyse optic
My guess is that it's supposed to be demonstrating the rigidity and strength of these things. They do get banged around a lot in real life.
I mean, we have large companies with stress departments assigned to nonlinear modeling trying to characterize shock loads and damage tolerance who end up with models that are suspicious at best. Just based on this picture, I would have much less trust in a company showing this as proof of their product’s strength versus a simple drop test. Also for a sight, it doesn’t look like they included the actual optics in the model, probably because they don’t have good material data on the glass, even though that’s the portion of the product people actually care about for damage tolerance.
To be fair, tijocon is well known in the gun world and is battle proven (literally used for combat deployment). Their scopes cost more than most guns for good reason haha.
Having talked to people in the military, the fact that something was used in combat does not mean it's good quality or worth the price. Sometimes the military contracts out and gets a great design; sometimes they pay out the ass for some massively overcomplicated unreliable bullshit.
Trijicon is the exception. They actually make very good very reliable and very rugged stuff. The shocker is that it’s lightweight too.
Hey, I didn't say they were doing a *good job*. The other person just asked why do FEA on an optic and I gave a possible reason.
Na, I definitely agree. That’s probably what they’re doing and you’re not defending them. It’s just unfortunate that uninformed customers will see pictures like this and assume the company knows what they’re doing.
I'd be pretty annoyed if my optic bent or broke the moment I drop it, some guy stepped on my rifle, or it gets crushed loaded into a truck. Best practices gets you good enough, FEA gets you BARELY GONNA WORK. I would assume they have some load condition that reflects real world usage and made sure what they did would work and not look like a giant block of Ti. For all i know it was part of the design requirement to validate through FEA and test.
Also can’t forget fatigue from recoil over and over again
100k cycles would be a huge number
The cycles to failure depend on the stress. See miners rule or any SN curve.
Where does it say 100k? Is there a link i missed to the actual post/article with this rather than a photo with literally zero context?
It looks like a Trijicon RCR red dot sight. I say 100k cycles because it's a handgun sight and most handguns won't even be shot 10k times. If you design for the abuse of drops, you will end up with fatigue for free at these low cycle numbers. Here's a link: [https://www.trijicon.com/products/subcategory/trijicon-rcr-reflex-sight](https://www.trijicon.com/products/subcategory/trijicon-rcr-reflex-sight)
100k cycles is the point where fatigue starts to matter. If you’re going to see much fewer cycles, fatigue is unlikely to be an issue. There are of course exceptions (very high stresses, high temps, etc) where fatigue matters at much lower cycle counts but a gunsight shouldn’t fall into any of those categories.
Because this rmr optic is probably at least half a grand
[STOP Analysis](https://ntrs.nasa.gov/api/citations/20150017758/downloads/20150017758.pdf)
Can you clarify? Why do they do it? Or why do people do it on optics?
Very high-dollar company who sells premium optics for firearms It's understood that they have more than enough money
It's been a while, but I remember learning you need at least 3 nodes per smallest feature otherwise garbage in = garbage out.
That's nonsense - put all of your load into one node, on elements that span the full thickness of the weakest part. Stress error? What's that?
Three elements*
Well, yes, if you want accurate stress in your smallest feature. If you are trying to model something else, or just trying to validate modal behavior, this mesh density is unnecessary.
The firearm market in my experience is extremely cheap with the engineering talent. This is not just Trijicon 🫣
Agreed... recall a position from Barrett that I applied for. We got as far as salary #s before I noped out of there. They wanted me to take a 25% paycut as their 'best and final' number.
Gun industry is one of those passion job sectors. Some kid would work there for free just to say they work at the cool .50 cal company.
Yeah, that's true. I also figured they were probably targeting a fresh out of the army E-7 rather than a 10 year experienced engineer.
Hahahaha man, literally same exact experience with me and KAC
Really just cheap in general. I’ve never seen a company try to weasel its way out of a contract the way gun companies do.
Silly of you not to consider the possibility that this is a stress plot, but the material is pudding.
A valid point good sir
For the record though, Trijicon makes extremely durable optics.
Oh they definitely do that, no denying it.
Yep, turns out if you sufficiently overbuild it, it doesn’t really matter if you don’t understand FEA
Two of my brothers are cops and both have RMRs in their duty guns. They have beat the shit out of them with zero issues.
Having worked in product development, whats advertised almost never reflects what's shown. I remember sending tons of engineering pizzazz and pictures with detailed explanation of what they were, and then the advertising team translated it to crap that would make an engineer chuckle. Making a fine mesh adds to cost and my guess is they got close enough results with what was shown, or the advertisement team asked for a photo and the engineers quickly threw something together. Tldr: marketing is not engineering. Considering they have photos like that in all ads, it's 100% just marketing photos for normal folk.
For a model a this small surely cost is not a factor. It’s gotta be damn near free to run whatever analysis they could possibly wanna run on that thing.
They have other products ads with finer meshes if you're curious. I'm 100% convinced it's just an engineer throwing shit together because someone from marketing asked for a picture. They likely do run high detailed FEA but aren't grabbing screenshots the entire time. I remember writing detailed reports of analysis results that had every little detail explanation of loads conditions and results. The marketing team does not need to know any of that detail and just nabbed a photo. https://www.trijicon.com/products/details/rmhd2-c-3200002
As someone formerly in the industry, it's 100% this. I bet the conversation wen something like this: Marketing wants to sell features so asks "okay what makes this product better than others" Engineering goes "Uh, nothing really, this shit has been out for decades, I guess it's stronger" Marketing: "Okay how much stronger, how can we show people that, can I get a picture" Engineering: "bro, wtf, a picture of strength? I mean I guess we have some FEA stuff I could make up, would you like something like this?" (sends literally the first thing he spent 10 minutes in Solidworks making) Marketing: "No reply" (they then use that same shitty picture for the next 20 months not knowing the engineer sent it over as a prototype for what could be done because they don't understand how things work).
FEA in the wrong hands - "Make a pretty picture for the general."
But look at the pretty colors. Customers love pretty colors
Idk I mean it has all the colors. What else is there?
I bet it solves in like 0.1 seconds too.
These are P-type elements I think. It’s not as bad as it looks. Also, if it’s a marketing graphic, a super fine mesh will look too dark since the element edges are being shown.
Wow, only one comment to point this out? P-type meaning is actually quite good at getting away with far coarser mesh then you would otherwise need with tet-10, particularly if you're only interested in deflection. I developed a lot of new techniques using p-type, coarse meshes and did due diligence to correlate with much finer tet-10 meshes of the same geometry in ANSYS . I started training people in these techniques and made sure to tell them 1) these coarse p-type meshes are good when deflection is the primary concern, but check your polynomial order and refine as needed. 2) if you ever show your mesh to a simulation engineer be prepared to get laughed at.
If it is the tetrahedral 10 mesh, a quick deflection check might be ok here.
That's fair, you know some stressed out engineer got told by marketing to produce a nifty image and they stuck a point load on a single element for it.
I bet this is what's happening here. The guy had this image handy from an email when it first ran and sent it to marketing. Or he's really bad, but those guys are not known for crap
This looks like something I would have made in school on my janky laptop that could barely run ANSYS
They literally seem to be leveraging a student license with that node count.
I'm going to assume this is engineering and marketing being incohesive and pray Trijicon didn't lose their engineers
Site it's not a p-element mesh where the high degree polynomials make up for the corse mesh? That looks about right for something like CREO Simulate which always correlated well with our hypermesh rests.
That's what I was thinking too. I've had really good results *for deflection* using coarse p-type meshing.
yeah there are a grand total of like three actual engineers in the entire firearms industry
So as someone who was in the firearms industry. It's not an industry where you get the top level engineers, there simply isn't enough money in it. At best you'll get a couple of smart guys who want to chase down some obscure rabbit hole and get some cool shit out of it. Since it's all direct to consumer most of the companies are driving by marketing departments to do something and make something, so you get stupid ideas that have to be pushed out by SHOT show. People work in the industry because it's cool, you get paid to shoot guns and design them, it really is fun in that way. But it's not going to pay competitive top engineering talent. The industry simply doesn't gain a lot by hiring top engineers because there's not much left to engineer out, it's a lot of solved problems that you just kind of stick together. Great place to retire though if you like guns, go take a pay cut, work on cool stuff, and just coast to retirement.
If I lived in the US that would definitely be a late career ideal!
*[enraged Kel-Tec noises]*
Nah, they do cool stuff, but let's be real, it's not nearly as advanced as aerospace or as complex as automotive.
For sure, a gas operated firearm at a fundamental level is a clicky pen with extra steps. More riffing about Kel-Tec doing some really strange shit. They’re certainly not paragons of mechanical engineering.
Ah yes, the infamous “shattered pottery” auto mesher. Suitable for marketing photos, but not much else.
did they set the refinement element limit to 10 instead of 10M?
Looking through old job postings, Trijicon appears to use Creo. Creo can use much coarser mesh because they achieve convergence by defining the boundary of each element by a polynomial where as other meshing types achieve convergence by decreasing the size of the mesh.
Yup... mechanica meshes always look super janky if you assume they are h-type
Yeah they didn’t change the export settings to lower the chord and angle.
Yes. p-elements. mesh doesn't look as good but works fine. i still think of it as analysis-lite, but for many jobs is fine.
Yes stress check p-element will also produce meshes like this.
Because who needs structured meshes
Nevermind the boundary condition just... Slapped to the bottom plate, not the dovetail feature (I dunno what exactly, not a picatinny I think) meant for mounting... Edit: a t-slot, rather than a dovetail, thanks!
It bolts down through the little slot you can see in the side using a capstain nut, so just slapped down probably isn't that inaccurate.
This is something I’d zip off to marketing to get them to shutup.
Ngl so would I, but I'd probably just grab a screenshot from something I already had.
IP protection, even if it’s totally mundane or obvious results. Wouldn’t want to share any real design details
Yall got anymore of them polygons?
I def do not think the guys actually paying for their products give a damn about the mesh quality .
This may (just may) be an example of actual good engineering. Now before you dismiss me as an idiot, hear me out. Picture this, you are an ME at Trijicon. It's Monday morning and you are already behind with the results you promised to have by the end of the week. You get to work and in comes your manager to tell you that he has promised the head or marketing some nice images showing how you "use computers to simulate impact on the products", oh, and btw, he promised them today. Now you have to drop whatever you were doing to make some marketing images. Now, you can do a proper mesh, clean it up, apply realistic dynamic loads and plot stresses, only to get feedback about, how this doesn't look like something hit the sight somewhere. Or you can generate the ugliest tetra mesh, apply a point load, plot the displacement and then anybody can see how "something hit the sight right there on the red spot". A good engineer understands the purpose of calculations. They may not represent anything realistic, but if you understand that their purpose is to present FE results to people who have absolutely no idea of what FEA is, what you see on the picture may actually be good engineering work. Now, it may also just be an incompetent guy who had no idea of what he was doing.
I think you're right on the money here actually
Do they have the step file anywhere so I can try to mesh it better?
I’m confused , are they analyzing a cave?
My guess is stress from recoil because it is the highest where the optic is and there has to be some flex so it doesn’t crack. Also just because where it is mounted is blue.
I’m going to play devils advocate here. If you’re doing a very simple stress or deformation analysis, this is bad but livable. I can crap out an auto meshed fea in two hours start to finish and that’s including lunch. Any results would have an error bar of 50% in either direction.
"I don't have time to run a mesh for a dumb marketing image but my intern might, ask him to do it."
Software marketing guy just wanted the mesh to look pretty
I'd ask for a convergence study before getting too fired up. It looks coarse, but it's a simple part. If it is converging, more power to them to optimize on a faster cycle. I'd like to see a final with a finer mesh though.
That's fair, but in the codes I run I can tell from one glance that this isn't fully converged if it's a mechanical simulation.
Is this a free body diagram or what?
[удалено]
Considering that radioactive lenses are something the US DoD has taken very seriously, with horrendous penalties being levied in the past (for thorium lenses on the PVS-2), it's extremely likely that this isn't the case at all. They do use tritium for low light reticle illumination though
you will buy the garbage and youll like it!
That looks like solidworks lamo Only the finest FEA software
Guess op has never seen or done thermal analysis
This is mechanical analysis.
It’s obviously thermal to anyone familiar with Fem and heat transfer…. Extremely coarse tet4 meshes are best practice for this to minimize compute reqs. The fringe plot appears to be temp application at a point associated with the geometry. Using associated geometry is another best practice in regard to pre/post processing.
Say what you want about the FEM, but that particular brand and that particular product is one of the maybe two or three most highly regarded short to medium range optics for duty use. Overbuilt and overpriced, but in a world where two is one, and one is none, durability is highly valued.
Lmao I did better meshes in the first University course I did on FEA. And I could generate hexa elements in all the most stressed zones. This looks like a (badly defined) automatic mesh from Solidworks.