The paper by Lee et al. (2009) applies the original version of the MPS (Moving Particle Semi-implicit) method (Koshizuka and Oka, 1996) to the simulation of slamming-induced impact pressure. Based on a simulation-experiment (Chung et al., 2007) comparison, the authors conclude that the original MPS method is able to accurately simulate the impact loads and pressures. However, a number of previous papers have clearly shown the drawbacks of the original MPS method that would make it practically inapplicable to the prediction of impact pressures. Therefore, the main conclusions of this paper are in clear contrast to those in previous papers. Further, the experimental data reported by the authors and used for comparison and validation are not consistent with those by Chung et al. (2007). The inconsistencies between the reported and original experimental data would add more doubts to the statements/conclusions by the authors (Lee et al., 2009).
In this discussion, we firstly highlight some controversial statements/conclusions of this paper by referring to some earlier works on impact pressure calculations using the original MPS method. The inconsistencies between the reported and original experimental data are pointed out in the second section. Finally, in the third section, we will present a brief review on the major shortcomings of the original MPS method as well as a concise description of the state-of-the-art of the improved MPS methods. From the viewpoint of discussants, the third section is essential to avoid any misunderstanding for the readers of the journal and to provide a better insight on particle-based simulations of impact pressures.