Tadashi Ishida

Fluid dynamic analysis of lubrication mechanism of hydrogel at the nanoscale

Grant No.：JPMJPR2191

Researcher

Tadashi Ishida

Outline

I assume that high lubrication of hydrogels is driven by fluid flow field in not only water film but also water absorbed in crosslinked polymer mesh structure at three dimension. To experimentally verify this model, I will develop an electron microscope technique for dynamics of water and mesh structure, and a friction test device of hydrogels under electron microscope observation. With these, the friction interface of hydrogels will be in-situ observed by scanning electron microscope. Friction force will be measured by the device, and shear force will be calculated by water flow. Through the comparison between them, the lubrication mechanism will be analyzed hydrodynamically.

Yuichi Otsuka

Multi-modal measurement to scale up mechanism of fatigue wear

Grant No.：JPMJPR2192

Researcher

Yuichi Otsuka

Outline

This study aims at revealing the effect of plastic deformation on wear mechanism using multi-modal measurement combined by friction force microscope and raman spectroscopy. Revealed nano scale wear mechanism will be integrated into molecular dynamics simulation and coarse-grained scale up model of macro scale wear and then compared with that derived from experimental results of fretting fatigue

Kazuaki Kato

Toughening of polymer resins by loose constraints

Grant No.：JPMJPR2193

Researcher

Kazuaki Kato

Outline

Control of topological constraints between different molecules is necessary to realize unique properties and functions that no conventional materials have. A new class of polymer resins that consist of polymers and threading ring molecules have unique large motions of the polymers within the topological constraints by the glassy framework of the rings and have a unique strain-induced intercomponent phase-separation. These unique features arise from the high degree of independence between different components. In this research, I aim to establish a new guideline for controlling the degree of topological constraints that directly influence the unique dynamics and the strain-induced functions. Through this, I shall realize hard and tough resins, though the rigidity and the toughness are generally incompatible in conventional polymers.

Ken Kojio

Molecular Aggregation Structure and Deformation Mechanism of Glassy Polymer under Biaxial Elongation Deformation Using Multi-scale Structure Analyses

Grant No.：JPMJPR2194

Researcher

Ken Kojio

Outline

A real aggregation structure and relationship between a nanoscale structure and mechanical properties of glassy poymers under biaxial elongation deformation will be elucidated based on in situ multi-scale structure analyses including evaluation of molecular chain distance, dense-sparse structure, void/crack by synchrotron X-ray scattering measurement and orientation of functional groups and molecular chains by birefringence measurenet

Kazuki Shibanuma

Multiscale physics of creep damage at high temperature

Grant No.：JPMJPR2195

Researcher

Kazuki Shibanuma

Outline

An “integrated model of multi-mechanism” is developed for simulating creep damage at high temperature. The integrated model is composed of (i) the model of finite element analysis, (ii) the model of microstructure, (iii) the model of relative velocities of grain boundaries, (iv) the model of void nucleation and growth, and (v) the model of grain boundary energy. “Non-destruction techniques for time-series measurements” are also developed for identifying thermo mechanical properties of the target materials. The techniques are composed of (a) in-situ measurement of grain boundaries deformation, and (b) X-ray CT measurement of voids.

Ryota Tamate

Development of soft materials based on ultra-high molecular weight polymers and expolaration of their novel functions

Grant No.：JPMJPR2196

Researcher

Ryota Tamate

Outline

In this project, the novel functions of ion gels formed by in situ polymerization of ultra-high molecular weight polymers in ionic liquids, such as high toughness, stretchability and self-healing ability are investigated from the molecular scale viewpoints including entanglement of polymer chains, solvent-polymer interaction, and interfacial dynamics of polymer chains. Based on the molecular mechanism, we will expand the concept of ultra-high molecular weight polymers to various polymer systems such as hydrogels, organogels, and elastomers. Finally, we will systematically establish the functional polymeric materials based on entanglement of ultrahigh-molecular weight polymers.

Daisuke Matsunaka

Elucidation of mechanical properties of nano-scale interfaces by first-principles machine learning calculations

Grant No.：JPMJPR2197

Researcher

Daisuke Matsunaka

Outline

In this study, dynamical defect behaviors at nano scale near interfaces between dissimilar materials are elucidated. The development scheme of interatomic potentials for the nano-scale interfaces based on first-principles calculation data is constructed employing machine learning techniques and molecular dynamics analyses with the interatomic potentials including information on interface bonds and catalytical effects are carried out. Trough systematically investigating various types of the nano-scale interfaces and interpreting electronic states near the interfaces, this study aims to clarify key factors which determine mechanical propterties of the interfaces.

Emi Minamitani

Construction of a Machine Learning Force Field by Applying Topologcal Data Analysis

Grant No.：JPMJPR2198

Researcher

Emi Minamitani

Outline

Focusing on amorphous materials, we will develop topology-based structural descriptors to accurately predict thermal conductivity and stiffness. In addition, we will extract correlations and relationships between these properties and nanostructures. The goal is to elucidate the common nature of nanostructures that govern different physical properties and to specify the creation process that has a desirable relationship between these properties. Furthermore, we will build a machine learning force field that is robust to disordered structures by applying topological structure descriptors, and establish a basis for multi-scale simulations.

XiaoWen Lei

Material functional design by disclination control based on fusion of geometry and mechanics

Grant No.：JPMJPR2199

Researcher

XiaoWen Lei

Outline

Focusing on the establishment of disclination elasticity theory, we construct deformation mechanics theory on the basis of the lattice curvature of low-dimensional structures based on the fusion of geometry and nanomechanics. We aim to enable the creation of high-strength and high-ductility structural materials that overturn the common sense of materials science. Specifically: Establishment of discrete curved surface design principle in nanostructures → Formulation of new disclination theory by fusion of geometry and mechanics → Elucidation of the deformation / strengthening principle of the bundle structure by disclination control. We conduct this series of unique studies.

Masato Wakeda

Control of deformation transmission at crystalline boundaries with various degrees of freedom for mechanical property design

Grant No.：JPMJPR219A

Researcher

Masato Wakeda

Outline

Crystalline boundaries such as grain boundaries and phase boundaries in metal have complex local structures, and they have various effects on the strength and fracture properties via nanoscale phenomena of deformation transmission and generation at the crystalline boundaries. Based on the atomistic simulation methods, this study will directly reveal the effects of various geometrical and chemical degrees of freedom on the dislocation transmission and generation behaviors at the crystalline boundaries for the purpose of the improvement of mechanical properties utilizing the crystalline boundary structures.