Abstract
This thesis is devoted to the study of the influence of a thin heterogeneous layer on the linear elastic behavior of a three-dimensional structure. Two types of heterogeneties are considered : cavities and elastic inclusions. For inclusions of high rigidty a further study was performed in the case of a heat conduction problem. A formal analysis using the matched asymptotic expansions method leads to an interface problem which characterizes the macroscopic behavior of the structure. The microscopic behavior of the layer is determined in a basic cell. The asymptotic model obtained is then implemented in a finite element software. A numerical study is used to validate the results of the asymptotic analysis.