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Calculating buckling strength of steel pipe for nonaxial load 
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#1
Aug113, 05:23 PM

#2
Aug213, 04:01 PM

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sudnak: Ensure d2/t does not exceed 40, and then your steel pipe will not flexurally buckle, where d2 = pipe outside diameter (OD), and t = pipe wall thickness.
Yes, compute moment of inertia (I). Also compute bending moment (M) on the pipe at the cable. Then compute sigma = M*c/I. Ensure sigma does not exceed 170 MPa. Because you have the cable tensile force, you can compute bending moment M, but you will need the distance from the pivot to the cable attach point, the distance from the pivot to the mass, the mass of the mass, and the angle between a vertical line and the pipe when the cable tensile force is 2800 N. 


#3
Aug213, 06:27 PM

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What is c in your M*c/I?



#4
Aug213, 10:17 PM

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Calculating buckling strength of steel pipe for nonaxial load
c = OD/2, where OD is outside diameter of the pipe.



#5
Aug213, 10:25 PM

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You haven't specified the type of piping material or grade you are using. For ordinary pipe material, the maximum tensile strength is lower than that for ordinary steel (30 ksi for Grade A pipe v 36 ksi for ASTM A36 steel). I would limit the max. bending stress to 120125 MPa (18 ksi) to give yourself a reasonable factor of safety.



#6
Aug213, 10:57 PM

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Awesome, thank you so much for the recommendations, I cannot tell you how much it helps!



#7
Aug813, 09:14 AM

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Hi, i have some annotations:
 In this case, the kind of stress is bending, not buckling.  I recommend you to consult the "Specification for Structural Steel Buildings (ANSI/AISC 36010)": http://www.aisc.org/WorkArea/showcontent.aspx?id=26516 (go to F.8 chapter). 


#8
Aug913, 09:18 AM

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mauchitoq: No, sudnak is correctly referring to flexural buckling, as well as bending stress. This was covered in post 2. Recheck, e.g., the subject title of the thread.



#9
Aug913, 11:18 AM

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nvn: it's true. But in steel structural engineering, buckling usually is about the behavior explained with Euler formula, and not with the stress failure criteria.



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