Multi-scale computational homogenisation to predict the long-term durability of composite structures

Abstract

A coupled hygro-thermo-mechanical computational model is proposed for fibre reinforced polymers, formulated within the framework of Computational Homogenisation (CH). At each macrostructure Gauss point, constitutive matrices for thermal, moisture transport and mechanical responses are calculated from CH of the underlying representative volume element (RVE). A degradation model, developed from experimental data relating evolution of mechanical properties over time for a given exposure temperature and moisture concentration is also developed and incorporated in the proposed computational model. A unified approach is used to impose the RVE boundary conditions, which allows convenient switching between linear Dirichlet, uniform Neumann and periodic boundary conditions. A plain weave textile composite RVE consisting of yarns embedded in a matrix is considered in this case. Matrix and yarns are considered as isotropic and transversely isotropic materials respectively. Furthermore, the computational framework utilises hierarchic basis functions and designed to take advantage of distributed memory high performance computing.

Three-dimensional nonlinear micro/meso-mechanical response of the fibre-reinforced polymer composites

“…In multi-scale CH, a heterogeneous RVE is associated with each Gauss point of the macro-homogeneous structure, the boundary conditions for which are implemented using the generalised procedure proposed in [3,35]. Small displacement and small strain formulations are used within the framework of first order multi-scale CH, the basic concept of which is shown in Figure 3, where Ω ⊂ R 3…”

“…Compared to conventional materials, fibre-reinforced polymer (FRP) composites can offer exceptional physical and chemical properties (including high strength, low specific weight, fatigue and corrosion resistance, low thermal expansion and high dimension stability), making them ideal for a variety of engineering applications, including aerospace, marine, automotive industry, civil structures and prosthetics [1,2,3]. Phenomenological or macro-level models cannot accurately describe the complex behaviour of FRP composites due to their underlying complicated and heterogeneous microstructure.…”

“…Furthermore, nonlinearities associated with the matrix elasto-plasticity and fibre-matrix decohesion make the computational modelling even more challenging. Multi-scale computational homogenisation (CH) provides an accurate modelling framework to simulate the behaviour of FRP composites and determine the macro-scale homogenised (or effective) response, based on the physics of an underlying, microscopically heterogeneous, representative volume element (RVE) [4,5,6,7,8,9,3]. The homogenised properties calculated from the multi-scale CH are subsequently used in the numerical analysis of the macro-level structures.…”

Efficient Techniques for Solution of Complex Computational Tasks in Building Physics

“…Using computational modeling, moistureinduced stresses and drying shrinkage in concrete were predicted by Azenha et al [8], while the obtained results were satisfactorily validated by means of experimental measurements. Other computational models that have been successfully validated were reported, e.g., by Ullah et al [9], Kacmarczyk et al [10], or Bozorgzad et al [11].…”

“…All the mentioned researches, among many others, utilized the finite element or finite volume method for numerical solution of used models to achieve results as precise as possible. On the contrary, such a high level of accuracy is often balanced by high time demands or by extensive requirements on computing power [9,12] because very detailed finite element discretizations usually result in very high numbers of degrees of freedom. Handling such extensive problems may often be beyond the possibilities of many research departments.…”