Determination of the Young's modulus of silica aerogels – an analytical–numerical approach

Lei, Jincheng; Yeo, Jingjie; Ng, Teng Yong

doi:10.1039/c3sm51926k

Cited by 41 publications

(27 citation statements)

References 31 publications

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“…Molecular dynamics (MD) simulations are also a powerful tool to investigate these properties. However, past simulations focusing on porous SiO 2 were only carried at the length-scale of a few tenths of nanometers [9,10,11], with too small pore sizes when compared to the 10 nm range observed in experiments. These simulations offer interesting insights in the inner structure and the mechanical properties of secondary particles but cannot fully reproduce their peculiar heterogeneous microstructure.…”

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confidence: 98%

Nanocompression of secondary particles of silica aerogel

et al. 2018

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The compression of highly porous silica nanospheres is investigated using molecular dynamics simulations and modeling. The ligaments network (3-6 nm) of nano-sized silica sustains the load and nanoparticles deform plastically due to highly localized shear events, at the junctions between ligaments. Dangling ligaments are more numerous as the size of the nanosphere decreases, thus impacting the mechanical response. Based on simulation results, we propose a scaling law that describes the particle size effect on the indentation force when applied to silica aerogel secondary nanoparticles under compression.

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confidence: 98%

Nanocompression of secondary particles of silica aerogel

et al. 2018

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“…Appropriate MD models have been formulated by the authors (Ng et al 2012;Lei et al 2013;Yeo et al 2013) across a wide range of densities for fast and reasonable reproduction of the geometrical, mechanical, and thermal properties of bulk experimental porous silica aerogel. It will be demonstrated that differing methods of negative pressure rupturing first introduced by Kieffer and Angell (1988), as well as the heating, expanding, and quenching scheme first proposed by Murillo et al (2010), will result in dramatic variations in thermal conductivities obtained.…”

Section: Numerical Characterization Of Aerogel Structures and Propertiesmentioning

confidence: 99%

Effects of Nanoporosity on the Mechanical Properties and Applications of Aerogels in Composite Structures

Joshi

Yeo

2016

Advances in Nanocomposites

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Aerogels are ultralight solids with nanoporous structure and are one of the world's lightest materials available in the market. It is a dry gel, principally made up of 99.8 % of air and weighing just around three times that of air. The first aerogels were realized in 1931, when Kistler (J Phys Chem 36: [52][53][54][55][56][57][58][59][60][61][62][63][64] 1932) attempted to remove liquid from a wet gel. It started out with the testing of the hypothesis that the liquid in a jelly can be replaced by a gas so as to avoid the collapse of the wet gel. He postulated that it was possible to slowly expand the supercritical fluid within a gel and obtain an air-filled non-collapsed gel structure. He subsequently succeeded in producing silica aerogels with densities in the range 20-100 kg/m 3 , as well as aerogels of alumina, tungsten, ferric, and stannic oxides. Today, silica aerogel is frequently used in nanocomposites for their light weight and excellent thermal insulating properties. In this chapter, we document some of the silica aerogel-filled carbon composite sandwich structures we have recently developed and also numerically examine the underlying mechanisms which enable silica aerogels to possess extreme insulation properties and especially how pore size plays a major role.

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“…Many biopolymer aerogels have qualitatively similar fibrillar structures, making them very different from classical oxide-based aerogels with interconnected nanoparticles. For classical oxide-based aerogels a substantial body of experimental data have been reported and a wide range of modelling methods, including all-atom molecular dynamics, coarse-grained and macroscopic models, have been suggested [9,10,11,12,13,14]. Mechanical tests, primarily axial compression tests, for fibrillar biopolymer aerogels only recently started to appear in the literature [15].…”

Section: Introductionmentioning

confidence: 99%

Modelling of Mechanical Behavior of Biopolymer Alginate Aerogels Using the Bonded-Particle Model

2019

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A novel mesoscale modelling approach for the investigation of mechanical properties of alginate aerogels is proposed. This method is based on the discrete element method and bonded-particle model. The nanostructure of aerogel is not directly considered, instead the highly porous structure of aerogels is represented on the mesoscale as a set of solid particles connected by solid bonds. To describe the rheological material behavior, a new elastic-plastic functional model for the solids bonds has been developed. This model has been derived based on the self-similarity principle for the material behavior on the macro and mesoscales. To analyze the effectiveness of the proposed method, the behavior of alginate aerogels with different crosslinking degrees (calcium content) was analyzed. The comparison between experimental and numerical results has shown that the proposed approach can be effectively used to predict the mechanical behavior of aerogels on the macroscale.

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Determination of the Young's modulus of silica aerogels – an analytical–numerical approach

Cited by 41 publications

References 31 publications

Nanocompression of secondary particles of silica aerogel

Nanocompression of secondary particles of silica aerogel

Effects of Nanoporosity on the Mechanical Properties and Applications of Aerogels in Composite Structures

Modelling of Mechanical Behavior of Biopolymer Alginate Aerogels Using the Bonded-Particle Model

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