 The various branches of the DEM family are the distinct element method proposed by Peter A. Cundall in 1971, the generalized discrete element method , the discontinuous deformation analysis (DDA) and the finite-discrete element method concurrently developed by several groups (e.g., Munjiza and Owen).The general method was originally developed by Cundall in 1971 to problems in rock mechanics.The theoretical basis of the method was established by Sir Isaac Newton in 1697. showed that DEM could be viewed as a generalized finite element method.