49 citations · 104 across the 7 of their papers we have counts for
7 papers
A frequency-stable Nyström method for two-dimensional diffraction by periodic gratings at and near Wood anomalies
Kei Matsushima, Hiroshi Isakari
We propose and analyze a frequency-stable boundary integral equation method for scalar wave scattering by periodic diffraction gratings in two dimensions. The standard quasi-period…
Orientation Optimization Based on Topological Derivatives in Cooperation with Multi-Material Topology Optimization Based on Extended Level Set Method
Masaki Noda, Kei Matsushima, Takayuki Yamada
This paper provides an orientation angle optimization method for the design of fiber-reinforced composite materials using topology optimization. The orientation angle optimization…
Level set-based multiscale topology optimization for a thermal cloak design problem using the homogenization method
Makoto Nakagawa, Yuki Noguchi, Kei Matsushima +1
Artificially designed composite materials consist of microstructures, that exhibit various thermal properties depending on their shapes, such as anisotropic thermal conductivity. O…
Two-Phase Topology Optimization for Metamaterials with Negative Poisson's Ratio
Daichi Akamatsu, Yuki Noguchi, Kei Matsushima +3
Although recent developments in 3D printing technology have made it possible to fabricate metamaterials with characteristic mechanical properties, it is not easy to fabricate compl…
Exceptional points in cylindrical elastic media with radiation loss
Kei Matsushima, Yuki Noguchi, Takayuki Yamada
Exceptional points (EPs) are singular points on a parameter space at which some eigenvalues (scattering poles) and their corresponding eigenmodes coalesce. This study shows the exi…
A coupled-mode theory for two-dimensional exterior Helmholtz problems based on the Neumann and Dirichlet normal mode expansion
Kei Matsushima, Yuki Noguchi, Takayuki Yamada
This study proposes a novel coupled-mode theory for two-dimensional exterior Helmholtz problems. The proposed approach is based on the separation of the entire space R2 into a fict…
A topology optimization of open acoustic waveguides based on a scattering matrix method
Kei Matsushima, Hiroshi Isakari, Toru Takahashi +1
This study presents a topology optimization scheme for realizing a bound state in the continuum along an open acoustic waveguide comprising a periodic array of elastic materials. F…