Units to be used in structural analysis

[coolniks37]

Hi

I am confused with units in a structural analysis. I have modelled the geometry in mm (keypoints selected assuming mm dimensions).
It is a tube subjected to internal pressure.

I need to apply the following loads and get deflection in mm? What are the units I should follow?

1) Youngs Modulus
2) Density
3) Gravity (Unit of acceleration)
4) Internal pressure
5) External force.
6) Thermal expansion
7) Thermal conductivity

Pls help

 

[0rel]

Hi,

If you work in mm, just be sure you units are consistent, i.e :
1) MPa
2) kg.mm-3
3) kg.mm.s-2
4) MPa
5) N

For thermal units, I don't remember them, but as for structural ones, check that they are consistent.

 

[coolniks37]

Thanks Orel for a quick reply.

But, i think , for point 3, the unit is wrong..
Should i specify gravity in 9.81m/s2 or 9810 mm/s2
Pls confirm

Can you also specify why density needs to be in kg/mm3 where as all other items are in N, MPa etc.
Or is it shall be in N/mm3

Reply pls.

Thanks a lot.

 

[0rel]

Yeah, you are right for point 3, 9.81 m/s2 = 9810 mm/s2.

For density, simply because a density is in kg/mm3, so that if you multiply it by the volume of your body you get your mass.