Yasutomo Uetsuji

Hierarchical modelling of textile composite materials and structures by the homogenization method

For the simulation of mechanical behaviours of textile composite materials and structures, a novel hierarchical modelling technique is proposed. Not only the global deformation but also the stresses at multiscales are analysed precisely. Four-level hierarchy is defined for the textile composites such as woven and knitted fabric composites. The stresses at the mesostructure, which is a periodic unit cell of textile composite materials consisting of fibre bundles and matrix, can be evaluated accurately by the homogenization method and finite-element mesh superposition technique. The latter technique makes it possible to overlay arbitrary local fine mesh on the global rough mesh. Anisotropic damage mechanics is also utilized for strength evaluation at the mesoscale. Three-dimensional modelling of the mesostructure of woven and knitted fabric composite materials is shown. Localization analysis has been carried out within practical computational time and cost by the proposed hierarchical modelling.

Piezoelectric-fluid interaction finite element analysis of a valve-less piezoelectric pump

In this paper, a new composite actuator, which consists of a bimorph piezoelectric plate and a metal cap, was proposed for micro-TAS (Total Analysis Systems) which is widely used for chemical, biological and medical devises. The main objective of this work is to verify the displacement amplification introduced by a new design of composite actuator. At first, the proposed disc-shaped composite actuator was modeled and the static deflection was compared with conventional ones which are monomorph, bimorph actuators and a composite actuator called Moonie. Additionally, the proposed composite actuator was applied to a valve-less pump in a Y-shaped fluid channel and a piezoelectric-fluid interaction finite element simulation was performed. Computations demonstrated the superior performance of the new composite actuator compared with conventional ones.