Numerical Study On Impact Resistance Of Honeycomb And Sandwish Panels With Different Poisson’s Ratio

With the improvement of ship technology,the hull type and speed are gradually improved.At the same time,the probability of hull being impacted by various loads is greatly increased,such as ice block impact,bullet impact and explosive impact.Traditional protective structures can no longer meet the impact requirements.In order to improve the impact resistance of hull structures,many researchers focus on honeycomb structures.Honeycomb structure has become the leader of many new protective structures due to its mechanical characteristics,and as a light material,it can reduce the weight of the ship to a large extent.In order to study the honeycomb structure with the best impact resistance under the same weight,different t/l(wall thickness/wall length)and θ By structural design(cell angle),the honeycomb structures with different Poisson’s ratio(positive/negative/zero)are obtained,with values of-2.76～3.63.The designed honeycomb structures are used for uniform load impact,ball impact test and underwater explosion test.The main research contents are as follows:(1)Study on Dynamic Compression Performance of Honeycomb Structure under Uniform Impact Load.Deformation modes,platform stress,compact strain and energy absorption of three honeycomb structures were compared,and advantages were found in different honeycomb structures.The negative poisson’s ratio honeycomb with larger t/l and smaller θ has larger plateau stress,the positive poisson’s ratio honeycomb with smaller t/l and θ has larger EA(energy absorption),and the zero poisson’s ratio honeycomb has the best stability.(2)Study on Compression Performance of Honeycomb Sandwich Structure under Small Ball Impact Load.The impact force,the displacement of the back panel,the energy absorption and the energy absorption ratio of each portion of the three honeycombs are compared.It is found that the hexagonal honeycomb has the strongest cushioning performance,and the EA of the sandwich structure and the displacement of the back panel are conflicting.Therefore,the choice of the displacement of the back panel and the EA should be fully considered in the shock resistance design of the honeycomb structure.(3)Study on Compression Performance of Honeycomb Sandwich Structure under Underwater Explosion Load.The backplane displacement and energy absorption index of three kinds of honeycombs are compared.It is found that the half concave hexagonal honeycomb structure has the strongest cushioning performance.The increase of t/l and θ reduces the number of honeycomb cells and dense strain,which is beneficial to reduce the backplane dis placement.(4)The hexagonal honeycomb was improved to obtain the double-cell hexagonal honeycomb.The stiffness of the structure is reduced so as to improve the deformation capacity of the core layer of the sandwich s tructure.Under the low and medium local impact load,the displacement of the back plate of the d ouble-cell hexagonal honeycomb structure is greatly reduced.A new type of multi-concave SILICOMB structure is designed.The honeycomb structure has good stability and stiffness.Under underwater explosion load,the center point displacement of the back plate of the multi-concave SILICOMB sandwich structure decreases.