Defining residual stress direction(+/-), gradient

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Hi,

this is not possible,

heat treatment without any other plastic deformation can be modeled if yield strength over temperature is known (not very likely).

You need to make a model of temperature distribution in your part and derive the shear deformation from temperature induced growth/shrinkage. With this and the yield strength you derive the plastic strain and by this the residual stress after cooling down (heating up).

If you think about milling, turning, grinding this is more complicated as there is a lengthwise deformation and a crosswise deformation and a down deformation.

All of these may generate (x,y,z) plastic strain and related residual stress.

As at the surface there cannot be a down-component (z) of residual stress, the down plastic deformation will generate x and y components of residual stress.

This is further complicated by tool sharpness. Sharp tool generate fast decaying residual stress (with depth). Rounded (cutting edge) tools at turning and milling often generate compressive residual stress as the z-component of deformation induces x and y components of compressive stress.

Grinding in contrary often is generating tensile residual stress (in the direction of grinding) as the individual (undefined) cutting edge is smearing some of the material length wise.

Further advice available - complicated situation.

Subsurface shear stress is one issue but some others add to yield a complicated pattern of failure. Think about micro-creep and form instability.

RHABE