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gravity121

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I know most of the formula's but I'm trying to get a conceptual understanding of everything and finding it very hard to get concise information about everything all in one place especially when there are so many names for the same thing. Most resources just rehash the formulas without explaining what's going on. Please help. I'm looking for the physical understanding of what's going on and clarity on the formulas. Please fill in and correct any mistakes below or confirm if I'm understanding correctly. Thank you

1st moment of area - used to predict resistance to shear stress

Qx - area distribution around x-axis and resistance to shear stress about x-axis? = int yda

Qy - area distribution around y-axis and resistance to shear stress about x-axis? = int xda

Qz - area distribution around z-axis and resistance to shear stress about z-axis? = ?

is this the polar ist moment of area, is there such a thing? Is this correct??

Is there a product 1st area moment? If so, what is it for? = ?

2nd moment of area - a cross sectional resitance to bending

Ixx - resistance to bending about x-axis due moment about x-axis = int y^2 da

Iyy - resistance to bending about y-axis due to moment about y-axis = int x^2 da

Ixy - resistance to bending about x-axis due to moment about y-axis (assuming moment is not applied on through the centroid or this would be zero) = int yx da

Iyx - as above

Iz - resistance to torsion (polar 2nd moment of area) = = int (x^2 + y^2 da) = Ixx + Iyy

Moment of Inertia

Ixx - resistance to rotation about x-axis due moment about x-axis = int y^2 dm

Iyy - resistance to rotation about y-axis due to moment about y-axis = int x^2 dm

Ixy - resistance to rotation about x-axis due to moment about y-axis (assuming moment is not applied on through the center of gravity or this would be zero) = int xy dm

Iyx - as above

Iz - resistance to resistance to rotation about z-axis due to moment about z-axis. Is this also called the polar moment of inertia. = int (x^2 + y^2) dm ?

Is there any other moments of something out there, like volume or whatever?

1st moment of area - used to predict resistance to shear stress

Qx - area distribution around x-axis and resistance to shear stress about x-axis? = int yda

Qy - area distribution around y-axis and resistance to shear stress about x-axis? = int xda

Qz - area distribution around z-axis and resistance to shear stress about z-axis? = ?

is this the polar ist moment of area, is there such a thing? Is this correct??

Is there a product 1st area moment? If so, what is it for? = ?

2nd moment of area - a cross sectional resitance to bending

Ixx - resistance to bending about x-axis due moment about x-axis = int y^2 da

Iyy - resistance to bending about y-axis due to moment about y-axis = int x^2 da

Ixy - resistance to bending about x-axis due to moment about y-axis (assuming moment is not applied on through the centroid or this would be zero) = int yx da

Iyx - as above

Iz - resistance to torsion (polar 2nd moment of area) = = int (x^2 + y^2 da) = Ixx + Iyy

Moment of Inertia

Ixx - resistance to rotation about x-axis due moment about x-axis = int y^2 dm

Iyy - resistance to rotation about y-axis due to moment about y-axis = int x^2 dm

Ixy - resistance to rotation about x-axis due to moment about y-axis (assuming moment is not applied on through the center of gravity or this would be zero) = int xy dm

Iyx - as above

Iz - resistance to resistance to rotation about z-axis due to moment about z-axis. Is this also called the polar moment of inertia. = int (x^2 + y^2) dm ?

Is there any other moments of something out there, like volume or whatever?

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