An elastoplastic phase transformation model for the formation of kink bands in sedimentary rocks was put forward to reveal its formation mechanism. Considering the discontinuity of deformation gradient and stress across the interface between kink bands and un-kinked areas, the continuity of traction across the interface and Maxwell relation were imposed. Using the elastoplastic constitutive equation for sedimentary rocks based on Drucker-Prager yield criteria, the control equations for the formation of kink bands in sedimentary rocks under plane strain state were deduced. The compressive stres...
