Research On Impact Resistance Of Layered Gradient PVC Foam Sandwich Structure

With the development of anti-ship weapons,ships are facing more and more serious threats,and designing and analyzing the ship protection structure has become a research hot topic for scholars.Therefore,designing a multi-functional protection structure with lightweight,highstrength,high anti explosion performance is far-reaching significant to improve the impact resistance of ships.Polyvinyl chloride(PVC)foam has many outstanding properties,such as high mechanical strength,chemical corrosion resistance,low water absorption and strong energy absorption capability.It is often used as core material of sandwich structure.Therefore,it is important to study the mechanical behavior of PVC foam sandwich structure under dynamic impact loading.In this paper,the mechanical response of PVC foam sandwich structure is studied under dynamic impact loading by a combination of experiment and numerical simulation.First,the compressive strength,elastic modulus and stress-strain curves of PVC foams with different densities were measured by INSTRON universal testing machine.Then,a three-layer density gradient PVC foam sandwich structure was designed and fabricated.The dynamic impact response of the gradient PVC foam sandwich structure was studied by using the large size split Hopkinson pressure bar device(SHPB).The effects of the density gradient strategy on the transfer force,transfer impulse and energy absorption of the structure were analyzed.The SHPB impact test of gradient foam sandwich structure was simulated by ANSYS/LS-DYNA software.The validation of the simulation model is verified by comparing the simulation results with the experimental results.The obtained results showed that LGD configuration with large density gradient has the smallest transfer impulse,and the homogeneous UD configuration has the largest dynamic impact force and the highest energy absorption efficiency.Finally,the dynamic response of multi-layer PVC foam sandwich panels under blast loading was numerically analyzed.The dynamic response of three layers and six layers of PVC foam sandwich structure made of Kevlar composite material under different explosives was analyzed,and the peak back plate deflection,the support reaction on the boundary and the energy absorption were used as the evaluation index of the structure anti-blast properties.The results showed that the influence of the density gradient of the core layer on the LGD configuration with large density gradient is greater than that of the SGD with small density gradient.GD-2 has the optimal anti-blast properties.Increasing the thickness of the back plate can effectively improve the anti-blast properties of the structure.