Recent content by Chris31

rb1957, I appreciate all your help. I didn't hold back information on purpose. The stringers do not see this compression for non -pressure cases, which is why I didn't think of this earlier. However, I did mention the high bending moments previously - I just didn't think (or understand) how...

Thank you ieaz123 - I believe you are exactly right. The fuselage sees area ruling at this location as well, which all contribute to very high bending moments. Thank you for your explanation.

Thank you all - I've created a simple model to determine what is going on. I created 2 beam elements surrounded by 4 quad (plate) elements. the left side of the beam and skin is fixed and I apply a shear to the right end in order to cause bending of skin/stringer combination. Interesting -...

rb1957, Please explain - how is the analogy off target. The pressure vessel is "sealed" so if you don't have the empenage there is no difference. The only difference is that the tail won't translate aft as the bulkhead expands aft. aft of the pressure vessel is unpressurized, so there is no...

could it be that the skin is seeing tension at the skin ML and the NA (where beam forces are reported due to offsets)is in compression due to the high bending moments? ie, the imaginary nodes at the NA move close together due to curvature effects of bending?

Thank you for the response btrueblook - The fuselage isn't an open tube though, the pressure bulkheads act as plugs - therefore poisson's effect doesn't hold does it? Aft of the pressure bulkhead should exhibit no loads (or minimal) due to pure pressure cases. If you tape a paper empenage to...

Quick question for anyone that has any insight. Fuselage stringer is modelled as a beam and the skin as a plate. The beams have offsets. When I run a pressure case only, the skin goes into tension and the beam goes into compression. Anyone have any ideas as to how this can happen? GPF...

rb1957, Thanks for the post - The bending freedoms are not released as I am getting high plane1 and 2 bending moments (E+03). I understand what you are saying about stringer bending but will this put the beam into compression? Dan320, Thanks to you as well. As far as the connections, the...

Quick question for anyone that has any insight. Fuselage stringer is modelled as a beam and the skin as a plate. The beams have offsets. When I run a pressure case only, the skin goes into tension and the beam goes into compression. Anyone have any ideas as to how this can happen? GPF...

Quick question for anyone that has any insight. Fuselage stringer is modelled as a beam and the skin as a plate. The beams have offsets. When I run a pressure case only, the skin goes into tension and the beam goes into compression. Anyone have any ideas as to how this can happen? GPF...

Hi all, Relatively new to matlab - I have a question for everyone and would like to hear other opinions on how to get what I am trying to do if you have better ideas. I would like to write a short script that would search a series of nastran output (f06) files, find a given subcase and...

Sorry, The output is NX Nastran Ouput and there are multiple subcases and element types. Thanks for all your help.

Can anyone offer suggestions on where to look for the following: I'm trying to write a script that will search through a Finite Element output file and print axial force values for specific element ID numbers. Any help is greatly appreciated. Thanks, Chris

Sorry, The second to last line should read inx01 = find(X1==bt01); I copied from the wrong part of the script.

X1=7.5:0.0001:70; Y1=interp1(x_1EF,yfit,X1); plot(X1,Y1,'r'); bt01=(Htotal-2*Rbulb-Tflange)/Ttee; inx01 = find(X0==bt01); Z01=Y0(inx01);