Thickness from Moment of Inertia

[Mechanical-909]

Hi guys... I am creating a parametric spreadsheet to predict the behaviour of a sign post when subject to a specified wind speed for a uni assignment . Currently half way through creating the spreadsheet and one of the questions requires me to calculate a wall thickness of the pipe using the moment of inertia.. is this possible? if so how? please help guys all solutions are welcome :)!

Thanks

 

[PhanthomJay]

The moment of inertia of the pipe depends upon its wall thickness and diameter. The larger the diameter, the smaller the required thickness. Once you determine I, you may have to choose amongst available sizes and strengths, with economics also in mind, amongst other considerations.

 

[Mechanical-909]

The moment of inertia of the pipe depends upon its wall thickness and diameter. The larger the diameter, the smaller the required thickness. Once you determine I, you may have to choose amongst available sizes and strengths, with economics also in mind, amongst other considerations.

Okay thank you. Guess my question is that, is possible from the equation: PI/64*(Od^4 - Id^4) Od being outside Diameter and Id being the inside diameter.

 

[PhanthomJay]

Okay thank you. Guess my question is that, is possible from the equation: PI/64*(Od^4 - Id^4) Od being outside Diameter and Id being the inside diameter.

that equation is correct for the moment of inertia, but you have two unknowns, the outside and inside diameters, so you can't solve for either without assuming one of the variables or choosing the lowest weight available tube that will support the load.