Moment of Inertia of Circular Tube Cross Section at an Angle 13

[dik]

Does anyone have the formula for a circular tube cut at an angle to the axis? I have one for an ellipse, but if I make the major diameter equal to the minor diameter then I get a different number than for a straight circular cross section. They should be similar/exact.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[r6155]

Fillet weld size at base (inclined or not) of post is 0,7 x thickness of pipe post

For design loads See OSHA 1926.502 “Fall protection systems criteria and practices”.

Regards

 

[dik]

Just to clear up a bit of confusion on my part. I don't have access to W59. Is the minimum dihedral angle, for a prequalified fillet weld, 45 degrees or 60 degrees?

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[Enable]

Figure 4.8 equivalency of fillets relative to 90 degree joint (F = 1.0)

The relation between dihedral angle and the effective throat shall be as follows:
(a) 60° to 135°: the effective throat (E) shall be considered equal to the theoretical throat (T) (see Figure 4.8);
(b) 45° to 60°: the effective throat shall equal the theoretical throat reduced by 3 mm (1/8 in), unless a larger effective throat is established through procedure qualification (see Figure 4.8); and
(c) Theta < 45°: the effective throat shall be established through procedure qualification (see Figure 4.8)

 

[dik]

They are for the sngles on the opposite sides... thanks for the clarification, and the weld capacity would be modified by the F factor based on the fillet weld size. For example a fillet weld on a 60 deg angle on the RHS would have 0.71 times the equivalent 90 deg fillet weld. Is that correct?

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[Enable]

It's the other way around. These are equivalency factors for leg length.

For example lets say you need a 6mm weld at 90 degrees. The equivalent leg length on a 60 degree joint would be S = 6mm*0.71 = 4.26mm. If you put a 6mm leg length then your capacity would be 1 / 0.71 (1.41x) as much as for a 6mm weld at a 90 degree joint. For the same leg length the effective throat is greater in a joint with a smaller angle and less in a joint with a larger angle.

https://app.aws.org/mwf/attachments//73/286473/SMAWSKEW1.pdf

 

[dik]

thanks... I would have thought it would be reversed.
Thanks for the link

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[BAretired]

thanks... I would have thought it would be reversed.

I believe the strength of the weld is proportional to the length of the green line shown below. Doesn't seem to be precisely equal to Enable's reference, but his is conservative.

BA

 

[dik]

I realised that looking at the cross section shown that the acute weld was 'stockier'... and more robust... thanks... My inital thought was that the space was limited and the weld capacity would be smaller...

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[r6155]

I cannot understand how something so simple is treated here in something so complicated.
Is this railing for a nuclear power plant?
Even in a nuclear power plant they don't make it that complicated.

Sorry

Regards

 

[dik]

It's all part of a learning process... I often connect HSS tubes on an angle and have just use a circular cross section of the attachment moment; since I write a lot of programs to do my work... I thought I would check to see what sort of overkill there was. I've now got a method shown in the moment of inertia and section modulus program above that gives me a reasonable more exact solution. I do maybe 20 or 30 guardrails a month... In 15 minutes, I can check half a dozen conditions from various spans and cantilevers on various slopes... just making life easier actually. If I have one with a different base, I modify the template to cover it. I've attached a print of the various bases I have so far. The guardrail program is up to about 15 pages of calcs, now...

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik