Influence of micro-scale uncertainties on the reliability of fibre-matrix composites

Abstract

This study investigates the effect of micro-scale geometric and material property uncertainties on the elastic properties and reliability of fibre reinforced composite materials. Composite materials are often designed using conservative design factors to account for a limited understanding of how multiscale uncertainties effect reliability. Structural reliability analysis can produce more efficient designs, but requires an understanding of how all sources uncertainty effect probability of failure. Previous studies have not considered micro-scale geometrical uncertainties and their combinations in a multiscale probabilistic-based reliability framework. Thus, this study will investigate the effect of numerous combinations of micro-scale material property and geometric uncertainties on the homogenised elastic properties. Furthermore, to account for the effect in a reliability-based framework, a novel surrogate modelling technique is developed to represent the uncertainties efficiently. The study concluded that the geometrical fibre stacking uncertainty is as influential as the widely investigated constituent material stiffness uncertainties. Consequently, representing the micro-scale geometric uncertainties within the developed multi-scale probabilistic-based framework improves the estimated stiffness. Thus probability of failure is reduced, compared with considering material property uncertainties only. Moreover, the framework clarified and highlighted the importance of representing fibre geometrical stacking uncertainty for a deeper understanding of their effect on composite stiffness properties.

Multiscale surrogate-based framework for reliability analysis of unidirectional FRP composites

“…Thus, a clear understanding of the overall composite properties under all uncertainties can be obtained. Clarifying this could lead to safer designs and more efficient use of composites, which can be achieved using a probabilistic design approach [10,[12][13][14]. Such an approach requires a reliable and accurate analysis method that can analyse the effect of various uncertainties on design performance.…”

“…Rule of Mixtures [16] and Mori-Tanaka [17], and 2) Numerical homogenisation using Finite Element Analysis (FEA). The latter is more flexible and allows analysing a wide range of composite configurations, compared with the analytical methods that are constrained by assumptions and material property limitations [14,18,19].…”

Effect of fibre bundle uncertainty on the tensile and shear behaviour of plain-woven composites

“…Regarding the sensitivity to the loading conditions, studies focus on the uncertainty of the modulus under uniaxial loading [1,7,13] and Omairey et al [12] reports that the uncertainty in fibre architecture, especially the variation in elastic modulus, cannot be ignored. However, the effect of the uncertainty on other mechanical properties of woven composites is still unclear since the work of Omairey et al [12] was dedicated to unidirectional composites. Other mechanical loadings such as shear, which is critical for material design, may also be influenced by the internal architecture of composites.…”

“…Furthermore, the deviation from the theoretical behaviour may be very localised, and it is thus complex to identify these variations simply based on experimental data. Therefore, the development of a numerical model for a virtual testing environment is interesting, and multiscale modelling is one of the most efficient approaches [1,[7][8][9]12]. The multiscale approach may also include the periodicity of the structure and the possibilities of coupling it with statistical method [14].…”

Principles for Uncertainty Assessment in Kernel Smoothing Estimations

“…Selection of some other attempts to evaluate composite reliability and failure occurrence can be found e.g. in [3,4,5,6].…”