Deflection of pipe
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Posted by: johng ® 07/11/2007, 16:25:25 Author Profile eMail author Edit

We are hoisting pipes, diameter 2700 mm, wall thickness varies from 50mm to 75mm, length about 80.000 mm. Weights about 300 metric tonnes. We pick the pipe at two point several meters from top and bottom of the pipe. Can the calculation for deflection be made by simple deflection calculation and super position principle. Has anyone an example? Grz John

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Re: Deflection of pipe
Re: Deflection of pipe -- johng	Post Reply	Top of thread	Forum

Posted by: rconner ® 07/16/2007, 14:23:16 Author Profile eMail author Edit

Do you mean "80 meters" for "length" (instead of "mm" that was typed)?

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Re: Re: Deflection of pipe
Re: Re: Deflection of pipe -- rconner	Post Reply	Top of thread	Forum

Posted by: johng ® 07/16/2007, 14:32:55 Author Profile eMail author Edit

80 meters = 80.000 mm. grz John Grz John

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Re: Deflection of pipe
Re: Deflection of pipe -- johng	Post Reply	Top of thread	Forum

Posted by: andrewjmorin ® 07/12/2007, 16:32:23 Author Profile eMail author Edit

how is this?

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Re: Re: Deflection of pipe
Re: Re: Deflection of pipe -- andrewjmorin	Post Reply	Top of thread	Forum

Posted by: johng ® 07/16/2007, 14:11:25 Author Profile eMail author Edit

What programm did you calculate this? grz John Grz John

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Re: Re: Re: Deflection of pipe
Re: Re: Re: Deflection of pipe -- johng	Post Reply	Top of thread	Forum

Posted by: andrewjmorin ® 07/17/2007, 17:18:55 Author Profile eMail author Edit

that was done in ansys

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Re: Re: Deflection of pipe -- andrewjmorin	Post Reply	Top of thread	Forum

Posted by: johng ® 07/16/2007, 14:01:07 Author Profile eMail author Edit

This is great, but I already made an Excel sheet to calculate the centre of gravity or a long pipe. In this Excel sheet I would like to implement the deflection and stresses. I know that with FEM you can calculate the stresses, but thanks anyway. Grz John Grz John

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Re: Re: Re: Deflection of pipe
Re: Re: Re: Deflection of pipe -- johng	Post Reply	Top of thread	Forum

Posted by: andrewjmorin ® 07/17/2007, 17:29:13 Author Profile eMail author Edit

Actually, that plot is the vertical deflection in mm. If it is a spreadsheet solution that you want, you will have your hands quite full even if you restrict your calculations to 1-dimensional beam-deflection analysis. This page has some good info, and the basic formula for beam deflection under it's own weight: https://www.efunda.com/formulae/solid_mechanics/beams/casestudy_display.cfm?case=simple_uniformload The problem is that you'll need a different solution, with different support conditions and loads, for each of your pipe's different segments. Are you trained as an engineer? If so I apologize for the applied mechanics lesson.

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Re: Deflection of pipe
Re: Deflection of pipe -- johng	Post Reply	Top of thread	Forum

Posted by: Kelly Bramble ® 07/11/2007, 17:45:15 Author Profile eMail author Edit

Perhaps to estimate the mass of the pipe. Then apply stress, strain and deflection calculations.

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Re: Re: Deflection of pipe
Re: Re: Deflection of pipe -- Kelly Bramble	Post Reply	Top of thread	Forum

Posted by: johng ® 07/16/2007, 14:09:47 Author Profile eMail author Edit

The mass, length etc are known. But what kind of calculation can I use. The pipe is hoisted with two cranes, which have different lifting capacity. Therefore the distance to the centre of gravity is different. The pipe is build from several smaller pipes with different wall thickness. For deflection to the lift point I can use f=5/384*ql^4/EI. What happens next. Below schematic the pipe. L1 L2 _____|_____________| ___________|_______ | Weight in C of G | Grz John Modified by johng at Mon, Jul 16, 2007, 14:35:14

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