Investigation On Mechanical Behaviors Of Carbon Fiber Reinforced Composite Sandwich Structures With Y-shaped Cores

Investigation on the composite sandwich structures can benefit the design of the lightweight ship structures,which will eventually improve the safety of ship operation and increase the economic benefits of the marine trade.The carbon fiber reinforced composite sandwich structure with Y-shaped cores possesses high strength to weight ratio and high stiffness to weight ratio,high quality of resisting to the seawater erosion,and its maintenance cost is low.Hence,it is plausible for the composite sandwich structure with Y-shaped cores to be used in ship building industry.However,the studies on fabrication method and mechanical properties of the composite sandwich structure with Y-shaped cores are limited at present,especially for the mechanical behavior and failure mechanisms.In order to understand the mechanical behavior and failure mechanisms,and contribute to the application of the composite sandwich structure with Y-shaped cores in ship building industry,it is necessary to investigate the mechanical behavior of the carbon fiber reinforced composite sandwich structure with Y-shaped cores.Firstly,the carbon fiber reinforced composite sandwich structure with three different relative densities(RD)were fabricated by hot-press molding method.The compressive experiments were conducted according to ASTM.The failure mode and compressive stress-strain curves of the composite sandwich structure with different relative densities were recorded.The effects of the relative density on the mechanical properties of the composite sandwich structures were analyzed and discussed.By force analysis,the analytical model of the composite sandwich structure with Y-shaped cores was derived to predict the mechanical properties.At the same time,the carbon fiber reinforced composite laminates were fabricated to measure the compressive modulus and strength.The progressive damage model was applied to numerically simulate the mechanical behavior of the composite sandwich structure with Y-shaped cores.The numerical results and analytical results were compared with the experimental results.Secondly,the shear experiments of the composite sandwich structure with three different relative densities were carried out.The failure mode and shear stress-strain curves of the composite sandwich structure with different relative densities were documented.The influence of the relative density on the shear mechanical properties of the composite sandwich structures were analyzed and discussed.By force analysis of the composite sandwich structure with Y-shaped cores,the analytical model was derived to predict the shear mechanical properties.In order to obtain the prediction of the shear mechanical properties of the composite sandwich structure with Y-shaped cores,the specimens with I-shaped profile were fabricated to measure the shear strength.The analytical predictions were compared with the experimental results.Finally,the three-point bending experiments were performed on the composite sandwich structure with three different relative densities.The failure mode and bending load-displacement curves of the composite sandwich structure with different relative densities were documented.The influence of the relative density on the bending mechanical properties of the composite sandwich structures were analyzed and discussed.By force analysis of the composite sandwich structure with Y-shaped cores,the analytical model was derived to predict the bending mechanical properties.The analytical predictions were compared with the experimental results.