Analysis On The Anti-explosion Performance Of Steel-polyurea Composite Structures Subjected To Close-range Air Blast Loading

Because of the good mechanical properties,polyurea has great application value in the anti-explosion protection design of ships.The protective mechanism of polyurea under air blast loading needs to be further studied.In this thesis,the dynamic response characteristics of steel-polyurea composite structures under air explosion load are studied.The main contents of this thesis are as follows:(1)Taking polyurea-coated steel plate structure as the research object,its damage characteristics under close-range air blast loading were studied through experiment.Discussing the effects of the polyurea location and strength matching on anti-explosion performance.The results show that the steel/polyurea structure contributed to the best blast resistance,followed by the steel plate(without polyurea),lower the polyurea/steel structure.When the strength of the steel plate was relatively small,the deformation between the two layers was more compatible.(2)The dynamic response characteristics of steel/polyurea composite structures under close-range air blast loading were numerically investigated.The effects of thickness ratio,strength ratio and interlayer strength on the anti-explosion performance of steel plate/polyurea composite structure were studied.And the rationality and effectiveness of the numerical investigation were verified by related experiments.The results show that the initial deformation speed of the steel/polyurea structure is higher than that of the solid plate,but the final permanent deformation is smaller than that of the solid plate.The polyurea layer had two caving phenomenon under blast loading due to the shear and tensile failure.The protective effect of polyurea on the structure was mainly reflected in the form of collapse.The results show that under the condition of constant overall surface density,the steel/polyurea composite structure had the optimal thickness matching of anti-explosion performance;As the steel strength increased,the polyurea layer was tend to debond and then spall of from the front steel layer;Failure shear stress and failure normal stress had less effect on the maximum plastic deformation of the steel plate and greater effect on the collapse area of the polyurea layer.Among them,failure shear stress had a greater impact.(3)The effects of steel layer thickness ratio and interlayer strength on dynamic response characteristics of the sandwich structure were studied.A multi-layer composite structure was proposed.The difference of the blast resistance capacity was studied from the aspects of energy absorption,velocity and acceleration response.The results show that the sandwich structure has the best anti-explosion performance when the thickness of upper and lower steel layers were the same.The interlayer strength has little influence on the sandwich structure.In the multilayer composite structure,when the thickness of the upper and lower polyurea layer is similar,the structure has the largest plastic deformation and overall energy absorption.Compared with steel/polyurea composite structure,the sandwich panel limits the caving failure of the polyurea core.The polyurea in the sandwich structure consumes less energy and the steel plate has greater deformation.The results of this study can provide a valuable reference for the design and application of steel-polyurea composite structures on anti-explosion engineering.