Development of a simplified analytical viscoelastic formulation for the analysis of laminated composites

Andressa da Nóbrega Lira¹; Romildo dos Santos Escarpini Filho¹

¹ Universidade Federal de Alagoas

doi:10.20906/CPS/CILAMCE2017-0837

Resumo

Currently several projects pursue the study, modeling and execution of structures with high degree of complexity and in order to be considered all micromechanical characteristics of the materials. In this context the advanced materials known as composites appear, which are formed by the joining of distinct materials, looking for the best characteristics of each phase. For the study of these materials, some formulations and theories are applied, such as analytical models of micromechanics and classical laminate and numerical theories, such as the finite element method. In addition to the microstructural configuration of the reinforcements of the composite material (geometry, position, volumetric fraction), there is a need to consider other physical properties, such as: thermal and / or electrical conductivity, plasticity, viscoelasticity, among others. In classical laminate theory (CLT) the laminate is composed of stacked thin laminas with perfect bonding, which has a constant thickness and is composed by a matrix and unidirectional fibers. Therefore, in this work, it is intended to develop a linear viscoelastic formulation based on CLT, originally developed for elastic materials. The linear viscoelastic properties will be modeled using the Standard model and will be included in the matrix material of some laminas. This inclusion was made through the application of the Laplace transform in the constitutive relation of the lamina (Hooke's Law) which allows evaluating viscoelastic expressions in the elastic form inside the Laplace domain. In this way, it is aimed to obtain the CLT expressions with viscoelastic constituents, allowing the evaluation of tensions, deformations or displacements in the time domain. The results obtained are compared with those found in the literature.

Palavras-chave: Linear viscoelasticity; Laminated composites; Laplace transform