inertia moment of a truck axle

[pietro82]

Hi all,

I have to model the brake system of a 12 ton traler with two axles, and to do it I need the the axle inertia moment along the its rotational axis. Does anyone have a reasonable guess of it?

Thanks

 

[IRstuff]

you can't find weights for 4 wheels + axle?

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[pietro82]

Hi,

unfortunately I don't have the axle and rims at my workplace and manunfactures don't claim their masses. I thought to assume the axle as a beam with two circular plates, but I don't have the weight of both of them.

Where could I get them?

 

[IRstuff]

Have you used Google?

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[pietro82]

Yes I do..I found only axle inertia moment in roll and yaw direction.

 

[IRstuff]

Is this for school?

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[MintJulep]

A wheel and tire can be simulated using easy-to-calculate primitive shapes.

 

[pietro82]

I'm not a student, unfortunately . I have to design a brake system and the controller for a trailer to reproduce a specific trailer dynamics. To model the wheel dynamics I need the axle inertia moment. I don't work for a trailer manunfacturer.

 

[GregLocock]

MintJ's approach is sensible, otherwise guess r=.4 and I=m.r.r



Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376

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[pietro82]

What could it be the axle shaft diameter for an axle with a rated load of about 6 tons?

 

[LionelHutz]

Truck trailers don't have axles that rotate.

 

[pietro82]

Hi Lionel,

Thanks I didn't know it, it helped me a lot.

Cheers

Pietro

 

[DHambley]

If the analysis is for a brake system, it seems you'd want the total inertia as seen by the axle which would include the 12 ton truck mass converted into a rotational inertia along the axis. Much higher than just the inertia of the axle alone.

 

[pietro82]

Hi hgldr,

you're right, infact on Limpert book it is written that approx the 5% of the total inertia is due to the rotational components. In case of a traler it's even lower.

Cheers