0
$\begingroup$

how to increase the moment of inertia of a hollow aluminium pipe with external diameter fixed and only allowed to change the shape of internal section for example rectangular hole or extruded section

$\endgroup$

closed as unclear what you're asking by John Rennie, JamalS, Neuneck, Kyle Kanos, ACuriousMind Feb 4 '15 at 14:01

Please clarify your specific problem or add additional details to highlight exactly what you need. As it's currently written, it’s hard to tell exactly what you're asking. See the How to Ask page for help clarifying this question. If this question can be reworded to fit the rules in the help center, please edit the question.

1
$\begingroup$

All things being equal, the contribution of a mass element to the total moment of inertia about a given axis increases as the square of its distance from the axis of rotation. Basically, you want to put as much mass as possible as far away from the rotational axis as possible.

Since your question appears to imply that the axis of rotation is the center axis of the pipe, the answer is simple: an ordinary thick-walled cylindrical shell (aka common pipe) maximizes the moment of inertia. You can find the corresponding formula here. Since the the outer diameter is given, you only need to find the inner radius, which depends on how much aluminium per length of pipe you're allowed.

$\endgroup$

Not the answer you're looking for? Browse other questions tagged or ask your own question.