Initial/residual stress due to shot peening process

[smyth13]

I am trying to apply some initial compressive stress to the surface of a casting due to the shot peening process. I was wondering if anyone has any experience with this? I am looking to apply this initial stress as a function of depth into the surface. Does anyone know if this is possible using the INISTATE command?

 

[gurmeet2003]

I think this would be really hard to do. Shot peening causes a compressive stress near the surface. But below the compressive level there has to be a tensile stress to create a force field that is in equilibrium. One would have to specify the stress variation with depth and ensure that total is zero. I have also thought about this problem, but so far do not know the solution. If you find a solution I would also like to know.

gurmeet

 

[ifegermany]

why not use a fine graded mesh at the surface, varying E-Modulus according to hardness.

Frank Exius
IFE Deutschland

http://www.ife-ansys.de

Telefon ++49\2642\980409
Germany

Dienstleistung in ANSYS
FEM Berechnung Simulation
Digital/virtual Prototyping

 

[smyth13]

I have been thinking about overlaying some layered shell elements on the solid with each layer containing a certain value of initial stress. I am not sure exactly how to implement this correctly though.....it is just a thought. Not even sure if it is possible.

 

[ifegermany]

I think simulating that effect realistically isn't that transparent (see gurmeet2003), so I sugested a method which just ignores the deeper intrications, caused in the real manufacturing process.

A layer-, element- or integration-point-wise varying INISTRESS seems more like it (again see gurmeet2003), but a varying Modulus may appeal - if you think of calibrating against failure based on admissible strains. I.e. if instead of looking at admissible stresses you use strains as the design criteria.

Frank