Denial,Klaus,
Mx is indeed torsion.
I attached a link for the derivation of the shown equation for completeness. Thx.
reference:
http://www.public.iastate.edu/~e_m.424/unsymm%20bending.pdf
Dear fellow engineers,
I am looking for a closed form solution for the axial stress Sx for an unsymmetrical cross section loaded by Mx, My and Mz. I expect it will be a more generic equation than the equation for the special case for when Mx=0 as shown in the attached figure. Thank you for...
Hello All,
Yes I have looked through the NACA Structural Stability Handbook by Gerard (NACA-TN-3781 series)but none contain this figure.
The closest I found was the wrinkling equation in NACA-TN-3431 (eq. 7) which is based on Timoshenko's "Theory of Elasticity" column on an elastic foundation...
Dear Engineers,
The Grumman Structures Manual (page B6.11.2-7) shows attached figure 4, with the title "Short wave Buckling of Stiffened Sheet" and refers to "St. Mech. Note 15.". Does anybody know the full citation for this reference? I like to buy a copy. Thx.
Grumman Structures Manual...
Hello Denial,
I attached a copy of Timoshenko's original book which matches your reference.
Timoshenko:
http://files.engineering.com/getfile.aspx?folder=31b1f9d4-5c02-4356-952c-a34bd992d09a&file=Timo.pdf
Dear Engineers,
The Grumman Structures Manual (page B6.11.2-7) shows attached figure 4, with the title "Short wave Buckling of Stiffened Sheet" and refers to "St. Mech. Note 15.". Does anybody know the full citation for this reference? I like to buy a copy. Thx.
Grumman Structures Manual...
Hello Ingenuity,
Thank you for your reply. I appreciate your help.
Can you clarify what should change in the EI = Ds equation.
Are you able to update the derivation so it matches the NACA equation? Thx.
Dear Fellow Engineers,
NACA-TN-3431 shows on page 9 equation 5 the stability criterion for a plate to fail in short wave failure mode (aka. skin wrinkling failure). Mentioned NACA Technical Note refers for this equation to Timoshenko's 1936 book "Theory of Elastic Stability" and states that the...
I recommend to follow the F&DT Class provided by Dr. Patrick Safarian (http://fdtcourse.com/index.php/instructors/). He is the FAA Specialist on Fatigue and Damage Tolerance analysis.
I attended Patrick's class and learned a lot.
If you work at an OEM you might want to have Patrick give the...
Hello All,
Thank you all again for your great posts.
Hello BAretired,
Thank you for posting the scan of your hand analysis.
Your notes are easy to follow and the outcome matches the numbers I posted earlier.
I think the small difference is caused by the detail of the corners in the idealization...
Thank you all for your responses.
BAretired,
I tried the method you described and even rotated the cross section to its principal axis first but was not able to match the solution I got from my FEM (x= -0.32743, y= -0.19332 if a=1.000" and t=0.100"). I used Timoshenko's integration method where...
Hello Ukbridge,
I added the picture attachment. Can you give an the example calculation using the first moment of area of all the bt3/3s?
I have been able to find a solution with FEM but like to understand the theory better. Thank you for your help.
Dear fellow engineers,
I am requesting your help figuring out the best way to calculate the shear center of an unsymmetrical cross section as shown in the attachment. I am familiar with the theoretical solutions of Timoshenko for cross sections with at least one axis of symmetry.
I appreciate...
