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CG & moment of inertia - W.r.to co-ordiante transformation

CG & moment of inertia - W.r.to co-ordiante transformation

CG & moment of inertia - W.r.to co-ordiante transformation

(OP)
Dear all,

   In a automotive vehicle, we got the CG as well moment of inertia of the power train(engine+clutch+gearbox..) about the vehicle co-ordinate system with zero degree of rotation.When the engine is fitted into the vehicle the engine is rotated -3 deg for connecting the propeller shaft with the rear axle.

 We would like to have the revised CG and moment of inertia for this -3 deg rotation with respect to vehicle co-ordinate system.

Kindly let me know the procedure to convert CG and moment of inertia values from zero deg to 3 deg rotation.

Sample data:

CG X =-660 Y=-7 Z=144

Moment of inertia tensor

IXX= 72    IXY= 0.6     IXZ=-55
IYX-55     IYY= 410     IYZ=0.6
IZX=-55    IZY= 1.58    IZZ=385


Rotation of power train about Y-axis w.r.to Vehicle co-ordinate system.

Kindly let us know whether any other info required.... to calculate the new CG and moment of inertia.

I thought it has to be multiplied by below transformation matrix,but not sure

cos(-3)     0    -sin(-3)
0           1      0
sin(-3)     0     cos(-3)

I look forward for your expert comments for determining the new CG and moment of inertia of power train with respect to vehicle co-ordinate system.

Thanks in advance.

Elogesh  
 

RE: CG & moment of inertia - W.r.to co-ordiante transformation

Looks good to me.

 

RE: CG & moment of inertia - W.r.to co-ordiante transformation

On second thought,if the engine is rotated -3 deg then the vehicle frame is rotated +3 degrees with respect to the engine frame, so the transformation should be

cos(+3)     0    -sin(+3)
0           1      0
sin(+3)     0     cos(+3)

 

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