Dear Dr. Ronald Wagner, thank you very much for the video, it is very informative. Could you please model a local fattening at some degrees off-axis, let say 15 degrees? Thank you for your cooperation.
I have added here a repository for the excel file with all the equation for spherical shell buckling from the video: github.com/hnrwagner/Sphere_Pressure/blob/main/Shell_Buckling_002.xlsx
Thank you Doctor for your effort. But my question is for the terminated analysis of GNA and GMNA with eigen imperfection. If there is any fixation and completing the analysis.
you want that the analysis complets and not abourt at the buckling pressure? you can reduce the applied loading or adjust the solver settings for better convergence near the buckling pressure
Dr. Wanger, thank you for this video. I have a question about the input of the geometry with imperfection in Abaqus. First, I create my own mesh for the sphere. I have coordinates (X, Y, and Z) for each node. How can I create a new part in Abaqus using my new coordinates? I don't want to create a perfect shell and then change the coordinates in the .inp file. Can I immediately import my new imperfect geometry in Parts in Abaqus? Thank you so much!
Hi Sir..Your content is extremely helpful.. I want to conduct the reduced stiffness method analysis on HDPE made elliptical shell but Firstly, I am unable to get the stiffness matrix coefficients to be inserted in material properties and secondly, I am unable to find the critical buckling pressure theoretical formula for elliptical heads to calculate knockdown factor.. Any suggestion in this regard will be helpful please
@@hnrwagner I use the same Abaqus software..By using the sphere formula with inputting major axis radii of ellipse..I got the pressure of 0.83 MPa but with 1st eigen mode, I got 0.42 MPa.. I found a paper where they have used sphere formula for torispherical. I was wondering If i can use this first eigen value pressure as analytical to calculate knockdown factor after introducing imperfections.
In LRSM, reduction in A matrix led to reduction in buckling load for shell subjected to axial compression. As axial compression is in-plane loading so reduction in A matrix led to reduction in buckling load. For shell subjected to external pressure should we not reduce D matrix instead of A as external pressure is out of plane loading?? Thank you
the idea of the reduced stiffness method is that any from of imperfection reduces the membran stiffness of a shell. However, i never looked into it for external pressure and reducing the d matrix. That could be a nice student or phd topic :)
any imperfection study out there, you want to see in detail ? comment below !
Dear Prof. Wagner, is it possible to have some tutorials for the FE theory of shell elements used in ABAQUS?, e.g. Matrix Formulation, etc.
Its really a high quality and useful video, get a lot from this video and ur papers, thanks.
Dear Dr. Ronald Wagner, thank you very much for the video, it is very informative.
Could you please model a local fattening at some degrees off-axis, let say 15 degrees?
Thank you for your cooperation.
I have added here a repository for the excel file with all the equation for spherical shell buckling from the video:
github.com/hnrwagner/Sphere_Pressure/blob/main/Shell_Buckling_002.xlsx
Thank you Doctor for your effort. But my question is for the terminated analysis of GNA and GMNA with
eigen imperfection. If there is any fixation and completing the analysis.
you want that the analysis complets and not abourt at the buckling pressure? you can reduce the applied loading or adjust the solver settings for better convergence near the buckling pressure
Dr. Wanger, thank you for this video. I have a question about the input of the geometry with imperfection in Abaqus. First, I create my own mesh for the sphere. I have coordinates (X, Y, and Z) for each node. How can I create a new part in Abaqus using my new coordinates?
I don't want to create a perfect shell and then change the coordinates in the .inp file. Can I immediately import my new imperfect geometry in Parts in Abaqus? Thank you so much!
Hi Sir..Your content is extremely helpful.. I want to conduct the reduced stiffness method analysis on HDPE made elliptical shell but Firstly, I am unable to get the stiffness matrix coefficients to be inserted in material properties and secondly, I am unable to find the critical buckling pressure theoretical formula for elliptical heads to calculate knockdown factor.. Any suggestion in this regard will be helpful please
Which software do you use? Also would try analytical solution of ordinary sphere and then introduce elliptical form slowly and check the difference
@@hnrwagner I use the same Abaqus software..By using the sphere formula with inputting major axis radii of ellipse..I got the pressure of 0.83 MPa but with 1st eigen mode, I got 0.42 MPa.. I found a paper where they have used sphere formula for torispherical. I was wondering If i can use this first eigen value pressure as analytical to calculate knockdown factor after introducing imperfections.
In LRSM, reduction in A matrix led to reduction in buckling load for shell subjected to axial compression. As axial compression is in-plane loading so reduction in A matrix led to reduction in buckling load. For shell subjected to external pressure should we not reduce D matrix instead of A as external pressure is out of plane loading??
Thank you
the idea of the reduced stiffness method is that any from of imperfection reduces the membran stiffness of a shell. However, i never looked into it for external pressure and reducing the d matrix. That could be a nice student or phd topic :)
@@hnrwagner Thank you