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3D S Parameters - Hybrid Parameters


Ssc (Mean Summit Curvature)

Ssc is the Mean Summit Curvature for the various peak structures. Peaks are found as described above for the summit density. Ssc is given by the following:

(Note that Ssc is not strictly defined in the ISO 25178-2 but was established earlier in the research which contributed to ISO 25178-2. Future sections of ISO 25178-2 may address parameters such as Sds as “Feature Parameters”.)

Ssc definition

Evaluated only over the summit features.

Shot Peened Surface for which  Ssc = 37 mm-1 i.e. mean radius of curvature is 27um
Shot Peened Surface for which Ssc = 37 mm-1 (i.e., mean radius of curvature is 27 µm.)


Ssc is useful in predicting the degree of elastic and plastic deformation of a surface under different loading conditions and thus may be used in predicting friction, wear and real area of contact for thermal/electrical applications.


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