Masatoshi Miki

Development of solid–fluid biomimetic composites: Load dispersion effect of controlled hydrostatic pressure

Abstract The purpose of this research project is to apply biomimetic-designed composites to artificial structures. The natural bone is an optimum-designed structural system to support the living body. So, it is very useful in developing original optimum designs of the composite materials to study composite structures of the bone. Looking at the bio-joint mechanism, the solid–fluid composite structure of the cancellous bone has likely important effect in the load transmission. In this study, the solid–fluid composite model of the cancellous bone was made by using honeycomb structure. Static-indentation tests were carried out, and in-plane deformation conditions of the specimens were measured quantitatively. At first, the load dispersion effect of two kinds of fluid was examined by using small cell size Al honeycombs. Air and glycerine were sealed in each hexagonal cell of the specimens with thin films, respectively. But the film adhesion did not affect the deformation of honeycomb structures. Even the hydrostatic pressure of air greatly affects the in-plane deformation condition of the solid phase. Next, the load dispersion effect of the controlled hydrostatic pressure was examined by using large cell size Al honeycombs. The propagation of air hydrostatic pressure in the specimens was controlled by making a small hole in the specific cell walls of the honeycomb structure. Consequently, as for the solid–fluid composite models, the possibility of the optimum control of the compressive load dispersion was expected.

Static Load Dispersion Analysis of Solid-Air Composites-Effect of Adhesive Film on the Load Dispersion-

In order to propose a new movement of the composite material design, the load dispersion of the solid-air composites caused by the hydrostatic pressures is investigated by applying numerical analysis. To simplify the evaluation of the load dispersion, the admissible stress field is supposed, where each stress field of closed cell is independent and that two different fields being in both sides of a cell wall satisfy the equilibrium of forces through the cell wall. The non-linear deformation under indentation was incrementally simulated by using the finite element formulation based on displacement method. The effect of adhesive film on the load dispersion is considered in the numerical model. It was shown that the assumption of admissible stress field on the interfacial load transmission is useful in evaluating the static load dispersion because the numerical results were well in agreement with the experimental ones. And it was clarified that a few structural design parameters become effective for the load dispersion.

Composite Materials. Solid-Air Biomimetic Composites Designed by Load Dispersion Mechanism of Cancellous Bone Structure. The Effect of the Bulk Modulus and the Dimension.

The purpose of this research is likely to apply biomimetic designed composites to artificial structure. Looking at the bio-joint mechanism, the solid-fluid composite structure of cancellous bone is likely to play a great important role in the load transmission. Therefore, the solid-fluid composite structure of the cancellous bone was modeled to the solid-air biomimetic composites with aluminum honeycomb. The numerical analysis was carried out using the FE model, and it was clarified that the bulk modulus of air and the dimensions become effective for load dispersion.Consequently, the bulk modulus and the dimensions are the important parameters in the design of solid-air composite with the excellent load dispersion characteristic.