"Contact Pressure" in AutoCAD Inventor Stress Analysis ?

[kevinyucc]

There are Contact Pressure results in the Stress Analysis.
But I could not any expressions about the definintion of Contact Pressure in the help.

Could any one help me to get the definitions about the contact pressure in AutoCAD Inventor Stress Analysis?

[henderh]

Hi kevinyucc,

I searched the help, but couldn't find the definition either. It is logged as 1241348 and forwarded on to Technical Publications.

At the risk of sounding redundant, contact pressure is the pressure at the contact interface. In the image, I have a bonded contact between the stacked cubes. The bottom face of the bottom cube has a frictionless constraint. I solved using the "Detect and Eliminate Rigid Body Modes (movement)". This is so we don't create stress concentrations at a fixed bottom face (it wouldn't be able to "expand out").

Since I'm applying a pressure of 1 MPa to the top face of the top cube, the stress throughout both cubes is 1 MPa. That 1 MPa load is being transferred from the top cube to the bottom cube through the bonded contact. Thus, the bonded contact pressure is ~1 MPa as shown by the Maximum label.

I realize the value is a little off, and is computed as 1.0562 MPa (using default mesh settings). This is because the mesh is not fine enough in the area of interface between the cubes. If we refine the mesh we can get closer to the theoretical 1.000 MPa contact pressure. By simply changing the average element size from the default 0.1 to 0.075 we can calculate 1.0111 MPa (within 1.1% of theoretical)

I hope this helps!

Best regards,

Hugh Henderson (Autodesk)
Simulation SQA Engineer

[jasonrecords]

What are your results showing if you hav a negative contact pressure?