Diffrence Between Pressure and stress

[Badri07]

Hi All,
I am trying to analyse a clamp pad,i was told that the pressure on surface of the clamp pad should not exceed say 100 kpa,i would like to know how do plot the pressure distribution on the pad,and i am using Ansyswb V11.i know that we can get stress distribution on the pads

Finally,i would like to know is pressure and stress are same?

regards
Badri.

 

[corus]

Pressure and stress have the same units though you could say that internal stress is caused by an external pressure load.
On a free surface with an applied pressure load then the stress component normal to that surface should be the pressure you applied.

corus

 

[prost]

Don't most people use the convention that pressure is a normal compressive traction? (Tractions are stresses applied on the external surfaces of the body).

In your FE solution, then, the pressure would be the stress at the surface, normal to that surface, and compressive to that surface. If that surface is circular, then the pressure is the radial stress at the surface, and is negative.

 

[cbrn]

Hi,
if you are using Ansys WB, then select the pad's loaded surface only as the scope, then select the appropriate normal stress (the best you can do is setup an appropriate CSYS to refer this stress to).
Regards

 

[Badri07]

Hi All,
Thank all you for your post,i am still having some problem with the way normal stress is plotted,the pad is a curved plate with uniform thickness.

The normal stress plot reads positive in some areas of the pad and negative in some areas of the pad,could somebody explain me why is this happening.

Thank you

Badri07

 

[feaplastic]

Just a suggestion:

If you use surface elements, can you check element normal and make it uniform.