Vincent Pensée

A damage model for ductile porous materials with a spherically anisotropic matrix

In the present study, we investigate the macroscopic strength of ductile porous materials having a Hill-type radial anisotropic matrix. The procedure is based on a limit analysis (LA)-based kinematic approach of a rigid plastic hollow sphere. We first established the exact solution (stress and velocity fields) to the problem of the hollow sphere subjected to an external hydrostatic loading. Then, we propose, for general loadings, an appropriate trial velocity field which allows to implement the kinematic LA procedure. The resulting macroscopic criterion, whose closed-form expression is provided, extends the well-known Gurson criterion to materials with radial anisotropy. Numerical limit analyses are provided by performing standard finite elements computations which validate the new criterion. Finally, the yield criterion is supplemented by a plastic flow rule and evolution equations of the internal parameters, allowing to study the predictions of the complete model for axisymmetric proportional loadings at fixed stress triaxiality. A strong influence of the radial anisotropy is observed on the stress softening and the growth of the porosity.

Domino Effects and Industrial Risks : Integrated Probabilistic Framework - Case of Tsunamis Effects

This paper presents an integrated probabilistic framework that deals with the industrial accidents and domino effects that may occur in an industrial plant. The particular case of tsunamis is detailed in the present paper: simplified models for the inundations depths and run-ups as well as their mechanical effects on industrial tanks.

Digital Image Correlation Analysis of CFRP to Brick Bonded Joints Fastened by Fiber Anchor

In the framework of the reinforcement of masonry structures by FRP sheets (Fiber Reinforced Polymer), the use of “Fiber Anchor” is an innovative performing solution to increase the peak load and the dissipation capability of the strengthened system. To analyze the performance of this new technology an experimental campaign composed by 36 tests has been conducted. Six series of CFRP to brick bonded joint fastened by different configurations of fiber anchor have been tested. To deeply describe the measure fields, the Digital Image Correlation (DIC) has been used. The strain fields obtained in the series not fastened by anchors have permitted to define the bond stress field and the advancement of the stress transfer zone. The DIC appears as a performing methodology to use in a lot of civil engineering experimental problems.

Asymptotic derivation of a curved piezoelectric interface model and homogenization of piezoelectric composites

In this work, we derive a general piezoelectric interface model by using a coordinate-free asymptotic approach. Next, this interface model is applied to the homogenization of fibrous piezoelectric composites. The overall piezoelectric properties are calculated and compared to the ones obtained by using the three-phase model.

Poroelasticity of Fluid-Saturated Nanoporous Media

The purpose of this work is to extend the equations of linear poroelasticity to the case of materials with nanopores. We consider a model of microstructure which corresponds to an assemblage of hollow spheres saturated by a fluid. The solid phase is linearly elastic and isotropic; pores are assumed to be of nanometric size. To account for the pore surface stresses, the Young-Laplace model is used. The nanopore size effects on the effective bulk modulus, Biot’ modulus and coefficient are shown. When pores are sufficiently large, the classical relations of linear poroelasticity are retrieved.