Content of the study program

In recent years, a variety of physical phenomena can be visualized on computer screens due to the development of scientific technologies and devices. However, utilization of these technologies is not limited to entertainment such as films and video games. On-site application methods have been explored in educational and medical fields. Nevertheless, recreation of physical phenomena by numerical computations in physical simulation technologies remains immature. One challenge involves “multiple materials and interactions among multiple disparities” (for example, clothing and human skin). The Material Point Method (MPM) has drawn attention as a useful method to handle interaction problems.

MPM applies basic fluid mechanics principles to individual objects. While this allows uniform handling of multiple objects and materials, it is difficult to handle initial formations and conditions of an object (for example, preservation of volume). Therefore, my research aims to improve the loss of volume problem and establish a more general-purpose technology. A major cause of such difficulties is that the local momentum is not preserved during the computation process even if the total energy is conserved. Thereby, my research proposes adding volume-preserving conditions in deformation gradient tensors that control the degree of deformation in a local region. I worked in collaboration with professor Joseph Teran, who researches MPM in Computer Graphics (CG) video production, to realize a sound method.

Study results

I conducted research directly related to my main doctoral research theme “Stabilization of MPM-based simulation of elasticity”. In addition to weekly meetings, my research was conducted through discussions with the overseas collaborators verbally and by emails.

MPM, which has been drawing attention in the CG industry, is a method to handle elastic and elastoplastic materials as expressions of various constitutive equations. For this stay, I mainly worked on a stabilizing simulation of quasi-static elastic conditions, which tend to be naturally unstable. Since MPM assigns physical quantities to both lattices and particles, I researched a method to find a global solution effectively utilizing the physical quantities assigned to lattices. Furthermore, I contributed to the codebase, which is the basis for development in the research laboratory. Specifically, using MPM, I was in charge of elasticity simulations, energy evaluations, and writing test scripts for bug detection. Currently I am summarizing my own research results and collaborating on a research paper for the aforementioned theme.

My experience abroad

For this study abroad program, Ms. Ikeda at SGU was a tremendous help. On my way to the destination, coronavirus began to spread. Everyone in the office actively guided and helped me. I deeply appreciate it.

As the situations changed drastically, the home I initially planned to stay refused my visit. Although I encountered numerous incidents due to coronavirus, somehow I was able to manage these obstacles. Especially, the last half of my stay resulted in numerous worries in terms of living arrangements. Nevertheless, this program safely ended, and I was able to return home. This makes me feel as if I became mentally stronger.

In addition, the members at the research lab were very kind. Overall, this study trip was characterized by help of others. From a place to live to food to eat, I sincerely appreciate all those who looked after me. As significant social issues were unfolding in front of my eyes such as layoffs due to coronavirus and the Black Lives Matter movement, the study trip also affected my views on social values.

Influence on my future career

Although I am unsure about my future, I had many opportunities to discuss career opportunities with people from U.S. companies, which made me want to go in the direction to improve internationally useful skills. In a good sense, I now think about my future from a broader perspective without limiting the national borders of companies.

Overall, this SGU system was an excellent experience. I am filled with gratitude.