Contents - Index


MOI_ThinRing

 

 

This procedure returns mass and moments of inertia of a straight thin rod bent into a ring

 

Inputs

r = radius of the ring [m, ft]

A = cross-sectional area of rod [m^2, ft^2]

rho = material density [kg/m^3, lbm/ft^3]

 

Outputs

m=mass [kg, lb_m]

I_x = moment of inertia about the x-axis [kg-m^2 or lbm-ft^2]

I_y= moment of inertia about the y-axis [kg-m^2 or lbm-ft^2]

I_z = moment of inertia about the z-axis [kg-m^2 or lbm-ft^2]

 

Example:  

$Load Mechanical Design

$UnitSystem SI K Pa 

$VarInfo I_x units=kg-m^2

$VarInfo I_y units=kg-m^2

$VarInfo I_z units=kg-m^2

r = 0.25 [m]

A = 1e-4 [m^2]

rho=990 [kg/m^3]

 

Call moi_thinring(A, r, rho: m, I_x, I_y, I_z)

 

 

{Solution:

m = 0.1555 [kg]

I_x= 0.00486 [kg-m^2]

I_y= 0.00486 [kg-m^2]

I_z = 0.009719 [kg-m^2]

}

 

 

Reference:  Gray, G.L, F. Costanzo, R.J. Witt, and M.E. Plesha, Engineering Mechanics: Statics and Dynamics, Third Edition, McGraw Hill, (2023).

 

Moment of Inertia Index