Non-linear elasticity experiment and analysis of acrylic material used for human occupied vehicle

Acrylic is an ideal material for some components in underwater engineerings, such as observation windows and fully-transparent hulls of Human-Occupied Vehicle (HOV). The safety of these acrylic structures is quite essential for the integrity of the underwater facility and the research on the acrylic performance used in the deep sea is not very systematic. To capture the accurate properties of the acrylic used for these structures, several compression experiments are carried out to identify the compressive elasticity of acrylic under different loading rates, including the elastic region, upper yield point and lower yield point. Non-linear performance and rate-dependent characteristics are found in the experiments. Based on the experimental data, polynomial form of hyper-elasticity is well-matched to describe the non-linear stress and strain diagram. Numerical analysis of acrylic specimen and observation window are conducted based on the hyper-elastic model. The results show good consistency between simulations and experiments. The illustrated material model provides a basis for establishing a more accurate design-by-analysis-methodology for acrylic structures used in underwater facilities.