Mechanical structure–property relations in flexible silica-aerogels

Flexible aerogels exhibit unique mechanical properties, yet standardisation in their testing methodologies remains limited. This study investigates the tensile and compressive behaviour of flexible aerogels through experimental and computational approaches. Cyclic compression tests are performed to assess damage evolution, while digital image correlation is utilised to measure lateral strain and evaluate the influence of different spraying patterns on strain measurement accuracy. Challenges associated with tensile and compressive testing are critically analysed, highlighting inconsistencies in current practices. Finite element modelling is employed to examine the role of friction in inducing the barreling effect under compressive loads. The findings underscore the necessity for standardised mechanical testing protocols for flexible aerogels and provide insights into their deformation behaviour under various loading conditions. • Methodology using moulding devices is shown to synthesise reproducible flexible silica aerogel geometries. • A two-camera setup for conducting digital image correlation for investigating the mechanics of the aerogels is presented. An overspray pattern method is studied against a simplified 9-Dot pattern method. • It is recommended to apply the 9-Dot pattern method as it yielded more precise results for the stress–strain curves under compression. • Finite element method was applied to give insights into the role of friction between the aerogel and testing plates on the resulting constitutive behaviour of flexible silica aerogels.