JP

Organization

Research Division

Risk Evaluation and Disaster Mitigation Research Division
Computational Safety Engineering Lab
Assistant Professor
Ph.D.(Enginnering)
Research Subject(s)
I am developing numerical simulation methods that accurately reproduce the extremely large deformation and failure of ground and structures caused by sediment-related disasters. The goal is to clarify multi-stage failure phenomena in such disasters and to advance damage prediction.
Key Words
Comutational mechanics / Material point method / Large deformation / Fracture mechanics / Numerical stabilization
Website
Research Activities

Simulation of crack propagation and fracture in structures
I am developing numerical methods to simulate how cracks initiate and propagate in structures subjected to earthquakes, debris impacts, and other external forces. Conventional methods often require computational meshes to be reconstructed as cracks propagate, making complex fracture process difficult to simulate. To overcome this limitation, I have developed a method combining the crack phase-field model with the material point method (MPM). This approach enables seamless simulation of crack propagation and structural separation without remeshing. I aim to extend this method to better understand structural damage and collapse caused by landslides and debris flows.

Improving numerical accuracy through pressure stabilization
Numerical simulations of large deformations in soils and structures can suffer from artificial pressure oscillations, reducing computational accuracy and stability. This problem is particularly significant for materials that undergo little volume change during deformation. To address this issue, I have developed a stabilized mixed formulation that treats displacement and pressure as independent variables and incorporates the variational multiscale (VMS) method. This approach effectively suppresses artificial pressure oscillations and improves numerical stability. Through this research, I aim to achieve more accurate and reliable simulations of large deformation and failure in soils and structures.

Selected Works

Sugai, R., Hidano, S., Matsubara, S., and Terada, K. (2026). Variational multiscale-stabilized extended B-spline-based mixed implicit material point method for elastoplasticity at finite strains. Computer Methods in Applied Mechanics and Engineering, 459, 119057, doi:10.1016/j.cma.2026.119057

Suzuki, Y., Sugai, R., Hidano, S., Nomura, R., Moriguchi, S., Kodaka, and T., Terada, K. (2026). Multi-patch B-spline-based hybrid MPM-FEM for simulating piping failure. Computational Particle Mechanics, 16, 359-383, doi:10.1016/j.cpms.2026.07.002

Sugai, R., Nomura, R., Moriguchi, S., and Terada, K. (2025). Extended B-spline-based mixed material point method stabilized by the variational multiscale method for compressible and nearly incompressible hyperelastic materials. Advances in Computational Science and Engineering, 4, 85-118, doi:10.3934/acse.2025013

Sugai, R., Han, J., Moriguchi, S., and Terada, K. (2024). Diffusive-discrete crack transition without remeshing achieving by extended B-spline-based implicit material point method. Computer Methods in Applied Mechanics and Engineering, 421, 116771, doi:10.1016/j.cma.2024.116771

Sugai, R., Han, J., Yamaguchi, Y., Moriguchi, S., and Terada, K. (2023). Extended B-spline-based implicit material point method enhanced by F-bar projection method to suppress pressure oscillation. International Journal for Numerical Methods in Engineering, 124(11), 2423-2448, doi:10.1002/nme.7216

Selected Memberships
  • International Association for Computational Mechanics
  • Japan Society of Computational Engineering and Science
  • Japan Society of Civil Engineering
Selected Awards
  • FY2022 Young Researcher Paper Award, Japan Society for Computational Engineering and Science (JSCES)
  • FY2022 Dean's Award, Graduate School of Engineering, Tohoku University
  • Young Fellow Outstanding Presentation Award, the 27th Conference on Computational Engineering and Science (JSCES)