When a structure experiences large seismic motions in the past or is subjected to material degradation over time, there is no appropriate methodologies for estimating how it bring out the load bearing ability and, if the excitation is beyond it, for predicting how it fails and reaches the final state. In this study, "multistage failure" is defined as the progressive failure process involving material degradation, histories of damage experiences, change of stress transmission mechanism, collapse, catastrophic failure, etc. With a view to improving risk evaluation for disaster prevention, we are developing numerical analysis methods capable of seamlessly simulating this series of complex failure phenomena.
In Japan, heavy rainfalls have caused a lot of damage. One of the biggest disaster triggered by rainfalls is a ground disaster with large difference in height and complex geometries. Therefore, a reliable prediction method of these damages is needed to make appropriate countermeasures against these ground disasters and construct some protective structures. In this study, a new solid-liquid coupled Material Point Method (MPM) is developed to accurately predict a collapse process of ground structures such as slopes and embankments subjected to excess pore pressure during a heavy rainfall, which involves a transition process from a soil structure to flowing mixture.
The use of coastal trees has widely been accepted as an ecosystem-based disaster risk reduction (Eco-DRR) system. With a view to evaluating the effect of such systems, we develop a two-scale approach. By reference to the principle of macrohomogeneity in homogenization theory, the modeling strategy is based on the idea that the total work done by the resistance at each point in the global shallow-water flow domain is identical to the space-time average of the energy dissipation of the 3D Navier-Stokes flow over the local domain.
Y. Yamaguchi, S. Takase, S. Moriguchi and K. Terada: Solid–liquid coupled material point method for simulation of ground collapse with fluidization, Comp. Part. Mech., Vol. 7, No. 2, pp. 209-223, 2020. doi: 10.1007/s40571-019-00249-w
5. T. Kotani, K. Tozato, S. Takase, S. Moriguchi, K. Terada, Y. Fukutani, Y. Otake, K. Nojima, M. Sakuraba, Y. Choe
Probabilistic tsunami hazard assessment with simulation-based response surface, Coastal Engineering, Volume 160, September 2020, 103719. doi: 10.1016/j.coastaleng.2020.103719
K. Terada, N. Hirayama, K. Yamamoto, M. Muramatsu, S. Matsubara and S. Nishi: Numerical plate testing for linear two-scale analyses of composite plates with in-plane periodicity, Int. J. Numer. Methods Eng., Vol. 105, No. 2, pp. 111-137, 2016, doi: 10.1002/nme.4970
K. Terada, J. Kato, N. Hirayama, T. Inugai and K. Yamamoto: A method of two-scale analysis with micro-macro decoupling scheme: application to hyperelastic composite materials, Comput. Mech., Vol. 52, No. 5, pp. 1199-1219, 2013, doi: 10.1007/s00466-013-0872-5
K. Terada and N. Kikuchi: A class of general algorithms for multi-scale analyses of heterogeneous media, Comput. Methods Appl. Mech. Eng., Vol. 190, No. 40, pp. 5427-5464, 2001, doi: 10.1016/S0045-7825(01)00179-7