Vibration And Energy Absorption Performance Of Carbon Fiber Circular Tube Reinforced Hyperelastic Porous Structures

Underwater explosions often cause more damage to ships than air explosions,and the protection capability of underwater blast loads is an important indicator that affects the vitality of a ship.It is found that the acoustic impedance of superelastic rubber material is close to water,which is a natural acoustic stealth material for submarines,and the superelastic porous structure will show excellent impact isolation characteristics under the action of underwater blast load due to fluid-solid coupling,which is a structure with both acoustic stealth and underwater blast protection capability.However,hyperelastic porous material will lose its protective effect after densification,especially in the deep sea area with high water pressure or under large shock wave load,which will greatly weaken its protective effect and thus aggravate the damage to the ship.Based on the above background,in order to slow down the densification process of the structure and improve the energy absorption,while taking into account the acoustic stealth and impact isolation characteristics,this paper designs and prepares a carbon fiber circular tube reinforced super-elastic porous polyurethane structure,and systematically investigates the quasi-static compression performance,modal properties,vibration damping performance and nonlinear dynamic mechanical behavior of the structure under the action of underwater blast load.The main research contents include.Firstly,based on the idea of bionic porous gradient structure and hybrid design,a carbon fiber circular tube reinforced superelastic porous structure was designed,and the porous superelastic polyurethane structure specimens were prepared by open-mold casting combined with gluing process.Based on the stress-strain curve of the superelastic polyurethane measured by compression test,the Mooney-Rivilin superelastic ontological parameters were fitted,the viscoelastic properties of the polyurethane were measured by DMA test,and the basic mechanical properties of the carbon fiber round tube were obtained by in-plane compression test,which were combined with the finite element simulation results to verify the accuracy of the parameters and lay the foundation for the subsequent work.Then,quasi-static compression tests are used to study the quasi-static compression mechanical response,deformation damage mode and energy absorption characteristics of the carbon fiber circular tube reinforced superelastic porous structure.A three-dimensional finite element mechanical model of the real structure is established,and the accuracy of the finite element model is verified by the experimental results.The results show that the finite element simulation matches well with the experimental results,the pore wall buckling and interface debonding are the main failure damage modes of the structure,and the addition of carbon fiber round tubes can significantly improve the stiffness and energy absorption capacity of the structure.Then,the inherent modal properties of the structure were analyzed,and the influence law of carbon fiber circular tube reinforcement on the inherent frequency of the structure was given.The acceleration response curve and vibration level dropout(VLD)curve of the structure were obtained by shaker sweep test.It is found that the carbon fiber circular tube reinforced structure has higher inherent frequency and lower VLD curve peak compared with the unreinforced structure,and the vibration damping performance is better.Finally,the dynamic behavior of the structure under the water blast load was investigated by a non-pharmaceutical simulated underwater explosion test device,and the shock wave pulses in the water chamber and the deformation damage process of the specimen were measured during the test.Based on the CEL(Coupled Eulerian-Lagrangian)method combined with the three-dimensional Hashin criterion,the nonlinear response of the structure under the water blast load was simulated by considering the strain rate effect of polyurethane material,and the support reaction force,deformation mode and the maximum velocity response of the backing plate were analyzed.The comparison reveals that the simulated underwater explosion test device has good reliability,and the simulation and test results agree well,which verifies the accuracy of the numerical model.The results show that the structure has excellent impact resistance,and the velocity and deformation of the backing plate of the structure with the addition of carbon fiber round tubes are significantly reduced,among which the asymptotic and asymptotic gradient structures have better underwater blast resistance.The research results can provide theoretical reference and technical support for the selection of new protective structures for ships and enhance the life cycle of ships.