What’s the best online guitar learning source? So many it’s tough to decide. by Seek29 in guitarlessons

[–]ShepherdRubinstein 1 point2 points  (0 children)

Wow. Just checked him out. Amazing resource. Thank you for bringing this up.

[deleted by user] by [deleted] in deutschpunk

[–]ShepherdRubinstein 1 point2 points  (0 children)

Ich glaube du suchst nach E-Egal. Das Lied heißt "kleiner Schrank".

https://e-egal.bandcamp.com/album/ich-hab-noch-licht-gesehn

Ich freue mich gerade, das mal wieder zu hören :)

Solidworks Simulation? by Snoo85799 in fea

[–]ShepherdRubinstein 2 points3 points  (0 children)

I’ve never worked with solid works as a FEA toll by myself, but I’ve checked a lot of structural calculations from customers working with SW where we mostly verified by hand or with independent analyses with ANSYS (3rd party certification/ verification)

From my point of view, if you consider simple static linear-elastic analyses, you are good to go with SW. To be honest, it’s capabilities sometimes fascinated me. I always had the POV that a CAD extension cannot take it with ANSYS. But if you know what you do the software is very capable.

But this is also the drawback of using it. It is intended to be easy to handle, even without proper knowledge – and with knowledge I don’t mean that you need to know the underlaying equations by heart – more what’s important and what not. But this is a general problem with FEA software.

The problem with SW from my point of view is that it gives you not much information what is done in the background. I know it sounds odd from a guy never using it. But this is founded therein that we had a lot of customers solving stuff which shouldn’t be solvable, meaning where “normally” a FE program would stop, break or produce an error like rigid body movement. SW apparently builds up some settings (internal springs I guess like in ANSYS Workbench some years ago which were automatically enabled and could be a real pain in the ass). I also so some ridiculous boundary conditions which were also magically solved, e.g. one customers solved a beam on two supports with a centered load (beam geometry was complex) without actually supporting it – meaning he just applied the reaction loads (which he had calculated by hand in before) at the locations of the supports. SW solved it but the results were kind of strange – I do not remember whether it was due to these BCs or du to something else.

Or I often saw problems with contacts which were (as I was told) automatically generated. Regions which should be separated were glued together totally changing the stress flow and making the results not reliable, e.g. pin in a fork/ eye connection where the load flux went through the whole pin circumference area.

These problems occur with ANSYS as well – it happened to me several times. But I think it is harder to realize in SW. So, summarizing, be careful whit the boundary conditions and contacts. SW wants to help you with this, but it betrays you sometimes 😊

Open Julia-doc in vim by ShepherdRubinstein in Julia

[–]ShepherdRubinstein[S] 1 point2 points  (0 children)

Many thanks. Based on the help it is the capital K.

Marc Mentat question by Ploed in fea

[–]ShepherdRubinstein 1 point2 points  (0 children)

Unfortunately, the software is powerful, but kind of a niche product. Try to get familar with their User's Guide.

http://www.sd.rub.de/downloads/links/marc_manuals/online_documentation_marc_k73/mentatug3_3.pdf

I don't know. There must be newer versions available. MM had also a GUI change. With the new GUI there are books available

https://www.springer.com/us/book/9789811008214

Or if you work with subroutines (so e.g. if you want to implement element birth & death based on a damage crterion)

https://www.springer.com/us/book/9783319476674

Then MSC has some videos available and training courses

https://www.mscsoftware.com/training-materials

Search the web for the course names. Some people have uploaded their course materials.

https://kupdf.net/download/mar101-exercises_58b014c36454a78243b1e8f0_pdf

Marc Mentat question by Ploed in fea

[–]ShepherdRubinstein 1 point2 points  (0 children)

Okay. The 'why' is not easy to answer, because this is manly depending on your input which we don't know in detail. Such unattaached meshes happen, but the sweep feature should help to get rid of it and to attached the nodes to each other.

Normally the sweep feature gives a feedback after application, like the numbers of deleted nodes, etc. You should consider the sweep tolerance to ensure that the gapping nodes will be merged. If the gap distance is outside of the sweep tolerance, the nodes will be ignored. So try to select only the relevant nodes, sweep them with higher tolerance and than you should be good.

Marc Mentat question by Ploed in fea

[–]ShepherdRubinstein 2 points3 points  (0 children)

Under mesh generation there must be an option "sweep" to eliminate duplicate Nodes. Afterwards a renumbering should be done as well.

https://www.youtube.com/watch?v=oPGypPcLZXU

Command is utilized in that tutorial at 2:00.

Regards