| In the world,bomb terrorist attacks occur frequently.Explosion shock wave and the blasting fragments pose a grave threat to personal safety.Therefore,it is significant to improve the shock resistance performance of the structure in the field of blast mitigation.Polyurea elastomer has excellent mechanical properties,moreover,it combines the low density,large energy absorption and convenient construction,the blast mitigation and shock resistance performance of structural members can be improved greatly.In this paper,the conventional properties of Q190 s spray high strength polyurea elastomer(hereinafter referred to as Q190 s polyurea elastomer)and the influence of different protection methods of polyurea on the shock resistance performance of steel were discussed by experimental research and finite element analysis simulation.Firstly,the conventional properties and thermodynamic performance of Q190 s polyurea elastomer were characterized,the inherent properties and thermal stability of Q190 s polyurea elastomer were analyzed.Secondly,sprayed the polyurea to the surface of the steel substrate by the polyurea spraying equipment,different protective types of polyurea-steel composite structures are made.Study the shock resistance performance of polyurea-steel composite structures by falling ball impact test.Finally,the corresponding structural model was simulated by using the finite element software ANSYS/LS-DYNA,different ways on reinforced steel plate to resist against the steel ball impacts was investigated.Through the above experimental method and simulation study,the following results are obtained:(1)The convention mechanics performance test results of the Q190 s polyurea elastomer were as follows: The tensile strength of polyurea elastomer is 22.47 MPa,the elongation at break is 559.72% and the tear strength is 82.03KN/m;It’s Shore D hardness of 93,the coating has high hardness;The density of test material is 1.19g/cm3;The gel time of the 190 polyurea elastomer is 5s and the drying time is 36s;The solid content is 96.34% and the Akron abrasion loss is 0.194cm3.From the above experiment we can arrive at the conclusion that the material has the property of rapid gelation and higher solid content.Hence,Q190 s polyurea elastomer has the advantages of rapid curing rate,less pollution and less volatilization,besides,quick speed in construction and good mechanical property,it’s a kind of green and environmentally friendly material.(2)Sprayed the Q190 s polyurea elastomer to the surface of the steel,study the shock resistance performance by falling ball impact test,the free-fall velocity of steel ball is 9.9m/s,the dynamic stress acquisition instrument was used to collect and analyze the data,this study indicates,the peak strain of pure steel plate,polyurea-steel composite structure,steel-polyurea composite structure,steel-polyurea-steel sandwich composite structure,polyurea-steel-polyurea-steel composite structure and steel-polyurea-steel-polyurea composite structure was 2372.9,1293.95,1235.36,1082.09,1586.94,1619.38,by comparing the pure steel plate with the back plate coated with polyurea,we can noticed that Q190 s polyurea elastomer has good ability to resist the impact deformation.By comparing the coating structure with the sandwich structure,we can noticed that reinforced in different mode have different effects on shock resistance performance of steel.(3)Through the finite element simulation software of ANSYS/LS-DYNA program,the falling ball impact experiment of polyurea-steel composite structure has been simulated by the finite element method,the results show the simulation result was highly consistent with the experimental data.Through stretching and springback,polyurea consumes the energy applied to the surface of the steel plate thereby reducing transformation of steel plate by numerical simulation.In conclusion,the Q190 s polyurea elastomer has excellent mechanical properties and shock resistance,has a wide prospects in the field of blast mitigation and shock resistance. |
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