Consider the example problem in Section 13.2.3.1 where a planar surface with a residual compressive stress is subjected to cyclic normal indentation without friction. If the equi-biaxial residual compressive stresses at the indented surface were to be
![1293_b092b5b2-5f3c-4316-a3ff-7082bddeee62.png](https://secure.tutorsglobe.com/CMSImages/1293_b092b5b2-5f3c-4316-a3ff-7082bddeee62.png)
is the yield strength of the material, calculate how much higher normal indentation force P can be applied without plastically yielding the surface as compared to the case where the surface has no residual compressive stresses.