Structural integrity assessment of glass components in Concentrated Solar Power (CSP) systems

Abstract

Due to the importance of glass components in Concentrated Solar Power (CSP) systems, an integrated assessment procedure conceived to facilitate the design of an intrinsically brittle component, limiting the amount of calculations, is presented. Since the fracture strength of brittle materials depends on the size and distribution of flaws as well as the duration of loading, conventional design approaches are generally very conservative and large safety factors are often used. However, these large safety factors are somewhat arbitrary and not satisfactory, because it is not very clear what the true factor of safety really is. In this paper, it is firstly reviewed and discussed the advanced methods to characterise the strength of glass. Then, based on the Weibull statistical method and the resulting probabilistic theory of the weakest link, a new modelling framework is proposed to consider different possible failure mechanisms (over-loading fracture and stress corrosion induced failure). In this way, the size effect as well as the multi-axial stress effect (including the contact stress between the glass component and the mount assembly) are considered. The integrated assessment procedure for structural glass elements is developed and implemented as a post-process of finite element analysis. The proposed procedure is demonstrated trough an application example: the design of a glass window to be used in a solar furnace reaction chamber.