Relationship between mass moment of inertia and second moment of area?

AI Thread Summary
The discussion centers on the relationship between mass moment of inertia and second moment of area while modeling a damped frame in SimMechanics. The user is transitioning from theoretical concepts in "Dynamics of Structures" to practical application in Simscape, which requires mass and inertia tensor inputs. A key point raised is the dependency between area moment of inertia and mass moment of inertia, which can be expressed through the equation Imass = ρarea * Iarea, where ρarea is the area density. The conversation highlights the need for clarity on this relationship to ensure accurate modeling and verification against textbook examples. Understanding this connection is crucial for successfully creating and validating the model in SimMechanics.
Fat Ryan
Messages
48
Reaction score
0
I am trying to create a model in SimMechanics of a simple damped frame. I am very new to this software and structural dynamics as well. I have a copy of "Dynamics of Structures" 3ed by Chopra. In the textbook, the author uses the standard geometric and material properties that I am familiar with to obtain stiffnesses (modulus of elasticity, E & second moment of area, I). Simscape, however, asks for mass and inertia tensor. The latter of which has units of mass*length^2. Is there some sort of relationship between the area moment of inertia and mass moment of inertia? The reason it of importance is because I need to create this model and verify it somehow. If I replicate an example in the textbook, then obviously I'll know if I'm doing things correctly. Unfortunately, the textbook only provides area moment of inertia in it's examples.
 
Engineering news on Phys.org
Sorry, the two are totally independent of each other.
 
viscousflow said:
Sorry, the two are totally independent of each other.

hmm, does anyone know why there's a difference between the book and simscape then?
 
viscousflow said:
Sorry, the two are totally independent of each other.

This isn't really true...

They are different, but still dependent/related to each other...
I've never found this in a book,
but one can show the relation between them by using balance of linear momentum...

The relation is the following:

Imass = \rhoarea * Iarea

where

Imass : Mass Moment of Inertia
Iarea : Area Moment of Inertia
\rhoarea : area density (kg/m²)
 
Assuming constant density...
 
enigma said:
Assuming constant density...
Yes, I forgot to mention that. Thanks!
 
Thread 'Turbocharging carbureted petrol 2 stroke engines'
Hi everyone, online I ve seen some images about 2 stroke carbureted turbo (motorcycle derivation engine). Now.. In the past in this forum some members spoke about turbocharging 2 stroke but not in sufficient detail. The intake and the exhaust are open at the same time and there are no valves like a 4 stroke. But if you search online you can find carbureted 2stroke turbo sled or the Am6 turbo. The question is: Is really possible turbocharge a 2 stroke carburated(NOT EFI)petrol engine and...
I need some assistance with calculating hp requirements for moving a load. - The 4000lb load is resting on ball bearing rails so friction is effectively zero and will be covered by my added power contingencies. Load: 4000lbs Distance to travel: 10 meters. Time to Travel: 7.5 seconds Need to accelerate the load from a stop to a nominal speed then decelerate coming to a stop. My power delivery method will be a gearmotor driving a gear rack. - I suspect the pinion gear to be about 3-4in in...
Back
Top