J.C. López-Realpozo

Characterization of piezoelectric composites with mechanical and electrical imperfect contacts

The aim of the present work is to study the influence of the mechanical and electrical imperfections in reinforced piezoelectric composite materials with unidirectional cylindrical fibers periodically distributed in rhombic cells under mechanical and electrical imperfect contacts. The behavior of the composites is studied through two approaches: the two-scale asymptotic homogenization method and the finite element method. The asymptotic homogenization method is applied to a two-phase composite with mechanical and electrical imperfect contacts and to a three-phase composite with perfect contact in the interphase. The constituents of the composite are homogeneous piezoelectric materials with transversely isotropic properties. The local problems are formulated for the spring-capacitor and three-phase models by the asymptotic homogenization method. The solution of each plane local problem is found using potential methods of a complex variable and the properties of doubly periodic Weierstrass elliptic functions. Closed-form formulae are obtained for the effective properties of the composites with both types of imperfect contacts and different configuration of the cells. The finite element method is implemented for analysis of piezoelectric composite materials with unidirectional cylindrical fibers periodically distributed in rhombic cells under mechanical and electrical imperfect contacts. Some numerical examples are given under the presence of both imperfect contacts and different arrangement of the cells. Comparisons between the numerical results reported by asymptotic homogenization method and finite element method are provided.

Effective Properties of Non-Linear Elastic Laminated Composites with Perfect and Imperfect Contact Conditions

In the present work, the asymptotic homogenization method is applied to investigate the global behavior of non-linear elastic laminated composites exhibiting a periodic structure. The periodic cell can be formed by any finite number of layers. Two different types of non-linear composites are studied: a physically “weakly non-linear” situation given by a third-order polynomial energy, and a “strongly non-linear” situation corresponding to a piece-wise linear constitutive equation (linear hardening). Analytical expressions of the effective laws are derived from the solution of the local problems for three types of different conditions at interface. The influence of two types of imperfect contact conditions at interface is shown by means of numerical examples that involve the measured second-order elastic constant.

Micro-Macro Characterization of Effective Properties for Fibrous Composites With Parallelogram Cells and Imperfect Contact Condition

In this work, two-phase parallel fiber-reinforced periodic piezoelectric composites are considered wherein the constituents exhibit transverse isotropy and the cells have different configurations. Two types of imperfect contact at the interface of the composites are studied: a) imperfect contact via spring model, b) three phase model. Simple closed-form formulae are obtained for the effective properties of the composites with both types of contact and different parallelogram cells by means of the asymptotic homogenization method (AHM). Some numerical examples and comparisons with other theoretical results illustrate that the model is efficient for the analysis of composites with presence of parallelogram cells and imperfect contacts.Copyright