Dziękuję. W tym przykładzie po prostu wybrałem sensowną skalę po serii testów. Ale zwykle amplitudę imperfekcji przyjmuje się m.in. na podstawie rekomendacji z norm. Jest to generalnie ułamek grubości powłoki. Tu akurat ok. 20%. Ale powłoki są zazwyczaj bardzo wrażliwe na imperfekcje, więc warto sprawdzić wpływ innych wartości na wyniki.
Brilliant tutorial. Thank you for uploading it I just wish to know if there is any reason behind the scale factor 200. I know it is used to obtain the intial imperfection but why specifically the factor 200. In general, how should we decide which scale factor to use for any unknown geometry
Thanks. In this case, I just selected a reasonable value after a bunch of tests. But normally, imperfection amplitude is selected following the recommendations from engineering codes, among the others. It's a fraction of the shell thickness. Here, it was around 20%. But shells are usually very sensitive to imperfections so it's good to check different values.
It’s possible with dynamic implicit or (better) explicit analysis procedure. It may not be easy because of the limitations of CalculiX but should be doable. Dynamic analysis will be available in the next release of PrePoMax, for now it can be defined using keywords.
@@McHumaty Geometric imperfection is applied this way in PrePoMax - perfect mesh of the cylinder is replaced with deformed mesh from linear buckling analysis.
@@McHumaty Yes, it’s crucial in nonlinear buckling analyses to introduce imperfections so that the bifurcation problem is turned into a problem with continuous response.
I'd like to request some tutorials on how to best work with .inp files within PrePoMax, and especially in relation to using not yet implemented CalculiX functionality within PrePoMax.
There is one tutorial showing the usage of a built-in keyword editor for creep analysis. For now, I omit other examples like that because they may soon become obsolete once new CalculiX features are implemented in PrePoMax (like dynamic analyses). Perhaps I could show something requiring export and external editing of the input file but then the analysis would have to be submitted from the command line and only the results could be opened in PrePoMax.
@@FEAnalyst I understand, and I suspected this would be your reply. I think your suggestion is good, and relevant. It could be many years before all CalculiX features are implemented into PrePoMax.
@@wgmg7746 Dodałem automatyczne angielskie napisy do wszystkich filmów. Oglądając można włączyć tłumaczenie na polski. W wolnej chwili postaram się poprawić błędy w tych auto napisach.
Super cool! Love these. You're doing the community a great service with these videos. Can't wait to follow the tuorial in the coming days
As always; well explained and detailed tutorial. Excellent. Thank you.
Really, really usefull. Very interesting and many thanks for your work.
Wonderful, sensational. thanks for the class.
Thank you very much, very useful
Świetny film. Czy wartość faktora 200 przy skalowaniu przyjmuje Pan z doświadczenia?
Dziękuję. W tym przykładzie po prostu wybrałem sensowną skalę po serii testów. Ale zwykle amplitudę imperfekcji przyjmuje się m.in. na podstawie rekomendacji z norm. Jest to generalnie ułamek grubości powłoki. Tu akurat ok. 20%. Ale powłoki są zazwyczaj bardzo wrażliwe na imperfekcje, więc warto sprawdzić wpływ innych wartości na wyniki.
so intresting. can i ask how you select the entity of the imperfection (200in this case)
Thanks. Please check my reply to the recent comment by rishabhbhatt3840, I explained it there.
Brilliant tutorial. Thank you for uploading it
I just wish to know if there is any reason behind the scale factor 200. I know it is used to obtain the intial imperfection but why specifically the factor 200. In general, how should we decide which scale factor to use for any unknown geometry
Thanks. In this case, I just selected a reasonable value after a bunch of tests. But normally, imperfection amplitude is selected following the recommendations from engineering codes, among the others. It's a fraction of the shell thickness. Here, it was around 20%. But shells are usually very sensitive to imperfections so it's good to check different values.
@@FEAnalyst thank you for the information
sir we are not able to access ur website
Great tutorial, as always, thank you! Do you know if with PrePoMax (or CalculiX) it is possible to do a dynamic crushing simulation of a tube?
It’s possible with dynamic implicit or (better) explicit analysis procedure. It may not be easy because of the limitations of CalculiX but should be doable. Dynamic analysis will be available in the next release of PrePoMax, for now it can be defined using keywords.
@@FEAnalyst Very interesting, thanks
Is it possible to also evaluate the Mohr-Coulomb theory in the software?
CalculiX doesn't have built-in Mohr-Coulomb material model but it can be implemented using UMAT subroutine.
@@FEAnalyst I didn't understand why you imported the file (12:14), can you explain? What is the proposal?
@@McHumaty Geometric imperfection is applied this way in PrePoMax - perfect mesh of the cylinder is replaced with deformed mesh from linear buckling analysis.
@@FEAnalyst I understand, so you took into account that the evaluated geometry had imperfections... I like it!
@@McHumaty Yes, it’s crucial in nonlinear buckling analyses to introduce imperfections so that the bifurcation problem is turned into a problem with continuous response.
I'd like to request some tutorials on how to best work with .inp files within PrePoMax, and especially in relation to using not yet implemented CalculiX functionality within PrePoMax.
There is one tutorial showing the usage of a built-in keyword editor for creep analysis. For now, I omit other examples like that because they may soon become obsolete once new CalculiX features are implemented in PrePoMax (like dynamic analyses). Perhaps I could show something requiring export and external editing of the input file but then the analysis would have to be submitted from the command line and only the results could be opened in PrePoMax.
@@FEAnalyst I understand, and I suspected this would be your reply. I think your suggestion is good, and relevant. It could be many years before all CalculiX features are implemented into PrePoMax.
Thanks you
Jak zwykle świetne. Szkoda, że nie ma napisów po polsku.
Brak czasu, może kiedyś dorobię.
@@FEAnalyst Nie ma funkcji włączania automatycznych napisów dla angielskiego?
@@wgmg7746 Sprawdzę, ale nawet jeśli to pewnie będzie to strasznie koślawe tłumaczenie.
@@FEAnalyst Będę wdzięczny. Niemiec ma to świetnie zrobione. :-)
@@wgmg7746 Dodałem automatyczne angielskie napisy do wszystkich filmów. Oglądając można włączyć tłumaczenie na polski. W wolnej chwili postaram się poprawić błędy w tych auto napisach.