石墨烯气凝胶的压缩力学性能研究

In order to explore the potential application of graphene aerogel in the field of protection, different graphene aerogel samples are prepared by a freeze-drying method and controlled freezing temperature variable, and the uniaxial in-plane compressive mechanics experiments are carried out. The deformation pattern and failure mechanism are analyzed by using 3D digital image correlation (DIC) technology and scanning electron microscope (SEM). The results show that the graphene aerogel samples prepared by freeze-drying method have the characteristics of three-dimensional porous network structure, low density (< 33. 93 mg / cm³ ) and high porosity (> 98. 5%), and have the characteristic microstructure affected by freezing temperature. The compressive stress-strain curves of graphene aerogel exhibit the typical three-stage characteristics of porous materials, and its mechanical properties are affected by the freezing temperature. The Young’s modulus of graphene aerogel obtained at - 80 ℃ is increased by 160% compared with that at - 19 ℃, and the energy absorption per unit volumeis increased by 67% . With the expansion of internal dense region during multiple cyclic loading-unloading of graphene aerogel samples, the absorption energy dominated by plastic energy tends to be stable and unchanged, and its states can be described by the exponential decay model. The different compression deformation forms of the transverse and longitudinal lamellas of graphene aerogels are developed into large-scale spring-like tight folding form, which made the graphene aerogels show resilience. This study provides a theoretical and practical basis for the application of graphene aerogels in the field of protection.