The Preisach-Mayergoyz (PM) model describes hysteretic behavior in several fields. For fractured rocks, a discretized version of the PM model successfully models nonlinear hysteretic elasticity under multiple loading cycles. In addition to hysteresis, granular media are subjected to large irreversible (plastic) deformation. To account for plastic deformation, we propose a modification of the PM density matrix, in which we include negative opening pressure. We associate negative opening pressure with rearrangements of the contact network. We apply the model to three sand samples undergoing multiple isotropic loading cycles. Calibrating the model parameters from quasi-static measurements of volumetric deformation, we estimate the quality of prediction of the dynamic bulk modulus. When this elastoplastic PM model is compared to the classic PM model, strong improvements are found both in matching the strain path and in the estimation of the dynamic bulk modulus.Plain Language Summary Hysteresis in the elasticity of a rock is when its elastic properties depend on its history. A classical model of hysteresis is the Preisach-Mayergoyz model. According to this model, after a compression-decompression cycle, the system comes back to its original state. However, granular media are subject not only to hysteresis but also to irreversible deformation. To model it, we propose a modification of the Preisach-Mayergoyz model. In brief, we assume that some units in the rock remain shrunk after decompression. Mathematically, we obtain this result by imposing that these units have negative opening pressure. From a physical point of view, these units represent rearrangements in the grain network. We apply this model to laboratory measurements on beach samples, and we show that this model, given a small number of parameters, describes sufficiently well the volumetric deformation of the samples and the response of the sample to wave propagation. This is important because this modified model improves the classic hysteresis model, including plasticity in the same mathematical framework. Both the static and dynamic behavior of granular media, as well as the strain path, are better explained.