Solid oxide fuel cells (SOFCs) are one of the most promising energy sources in the next generation due to their high efficiency. This study targets anode materials for SOFCs and performs classical molecular dynamics simulations and first-principles calculations to reveal the mechanisms of reduction in triple phase boundary (TPB) density by sintering and chemical reaction at TPB.
Molecular dynamics simulation of NiO reduction using ReaxFF.
As the application of plastic composite materials to automobiles and airplanes
is getting more and more accelerated these days, it is urged to establish
guidelines for designing polymer materials possessing both high strength
and toughness. We perform a 'bottom-up type' multi-scale simulation aided
by the coarse-grained molecular dynamics method with the aim to obtain
constitutive laws of materials by numerical simulations. We also carry
out finite-element method (FEM) simulations of crack propagation problems
to build a model that reproduce experimental results and to clarify the
mechanism of crack propagation.
FEM simulation of crack propagation in rubbers. So-called velocity jump phenomenon is successfully reproduced.
Molecular dynamics simulation of tension of polymer.
Experiments have demonstrated peculiar lubrication properties of steel
having hetero-nano structures (i.e., ultrafine grain structures). With
the aim to eucidate its mechanism, we perform coarse-grained molecular
dynamics simulations of the system consisting of hetero-nano structured
metal surfaces and lubricant molecules. We are tackling this problem from
the viewpoint of polymer brush structures formed on the metal surfaces
and their relation to grain structures.
Coarse-grained molecular dynamics simulation of lubricants in between metal surfaces mimicking hetero-nano structures.
We perform finite element method (FEM) simulations of environmental barrier
coating (EBC) for SiC-based ceramics used in aircraft engines. We calculate
energy release rates of crack propagation under practical mechanical and
thermal conditions in order to evaluate the reliability of EBC.
The ideal strength is defined as the maximum stress that a perfect crystal can attain when the crystal undergoes uniform (ideal) deformation. While macroscopic materials possess far smaller strength than the ideal strength due to defects being sources of fracture, nano-scale materials with few or no defects can be closer the ideal strength. The ideal strength is also a key index to understand elementary process of plastic deformation in crystals. For example, the critical shear stress for dislocation nulcreation in pristine crystals is close to the ideal shear strength. Our group has been evaluating ideal strengths of various crystals by means of density functional method calculations with the aim to reveal fundamental mechanical properties of crystals.