Yao Koutsawa

Taylor meshless method for solving non-linear partial differential equations

A true meshless integration-free method based on Taylor series named Taylor Meshless Method (TMM) has been proposed recently to solve Partial Differential Equations (PDEs), where the shape functions are high degree polynomials and the discretization concerns only the boundary. With high computational efficiency and exponential convergence, the TMM has been confirmed to be very robust in linear problems, including large-scale cases. In this paper, the TMM and the Automatic Differentiation (AD) are combined with the Newton method to solve non-linear elliptic PDEs, where the AD is used to compute shape functions in a fast manner. The numerical results illustrate that the proposed algorithm is very accurate and efficient in solving non-linear elliptic problems.

Static Analysis of Shear Actuated Piezo-Electric Beams via Hierarchical FEM Theories

Several one-dimensional finite elements for the static analysis of shear actuated piezo-electric three-dimensional beams are presented. A generic expression of stiffness and mass matrices is obtained through a Unified Formulation. The derivation is general regardless of the approximation order of the displacements and the electric potential over the cross-section and the number of nodes along the axial direction. A Lagrange’s polynomials based layer-wise approximation is used. Several mechanical boundary conditions and sensor and actuator configurations are investigated. Results are assessed towards three-dimensional finite element solutions. It is demonstrated that the proposed class of finite elements is able to yield very accurate results.

Toward Micromechanics of Coupled Fields Materials Containing Functionally Graded Inhomogeneities: Multi-Coating Approach

This article presents a micromechanics model for predicting the effective properties of coupled fields composite materials containing ellipsoidal multi-coated inhomogeneities. The model is based on Eshelbys theory of inclusion embedded in an equivalent continuum matrix. The main objective of this work is to build some numerical tools that will be useful for estimating the effective properties of composite materials containing functionally graded inhomogeneities. Two applications of the present micromechanics scheme to two-phase composite materials with electro-elastic and magneto-electro-elastic couplings are presented. The results are in a good agreement with experimental data obtained from the literature.

Effective properties of electro-elastic composites with multi-coating inhomogeneities

This work presents a micromechanics-based model to investigate the effective thermo-electric properties of piezoelectric composite materials. The effective thermo-electric properties are derived by considering a multi-coated ellipsoidal inhomogeneity embedded in a host material in the framework of the generalized self-consistent method (GSCM). An incremental scheme, in which the reinforcements are incrementally put in the host material, is implemented. The validation of the micromechanical model is performed with experimental data. The model proposed has a wide range of applications and can be extended to other physical properties.

Miscibility and nanoparticle diffusion in ionic nanocomposites

We investigate the effect of various spherical nanoparticles in a polymer matrix on dispersion, chain dimensions and entanglements for ionic nanocomposites at dilute and high nanoparticle loading by means of molecular dynamics simulations. The nanoparticle dispersion can be achieved in oligomer matrices due to the presence of electrostatic interactions. We show that the overall configuration of ionic oligomer chains, as characterized by their radii of gyration, can be perturbed at dilute nanoparticle loading by the presence of charged nanoparticles. In addition, the nanoparticle’s diffusivity is reduced due to the electrostatic interactions, in comparison to conventional nanocomposites where the electrostatic interaction is absent. The charged nanoparticles are found to move by a hopping mechanism.

Dataset of the use of tannin of néré (parkia-biglobosa) as a solution for the sustainability of the soil constructions in West Africa

Soil is the main material of construction in African rural areas. Sustainability of construction with soil is a thorny problem to any builder. Finding ways to improve the durability of soil is not only essential but also salutary for the African rural community that mostly lives in soil-built houses that are very often short-lived. The present data assessed the resistance to simple compression and the resistance to bad weather by simulating rainfall alternations through a test of cycles of alternate watering and drying of blocks built from four types of different soils without binder, along with blocks built from the same soils.