Researchs On Anti-Explosion Properties Of Metal Cylinder Coated By Poly Urea

It has always been the focus of modern national defense and industrial society to improve the antiknock ability of structures.In recent years,light weight polyurea coating materials have been paid more and more attention and applied.In recent years,improving the Anti-explosion performance of structures through polyurea materials has become the focus of research.In this paper,type Q413 m polyurea material provided by the Institute of Functional Materials of Qingdao University of Technology was used to coat the polyurea on the cylinder structure for the antiknock experiment and numerical simulation.The time-frequency analysis of the strain signal measured by the experiment was carried out by HHT method,and the main frequency range of the dynamic response signal of the cylinder structure under explosion was obtained,and the causes of strain growth were explored.In addition,the deformation data obtained from the experiment was compared with the numerical simulation results to verify the rationality of the selection of simulation parameters,and then the numerical simulation was further used to explore the energy absorption state of polyurea material when the structure produced different deformation results.In addition,the governing equation of the elastic dynamic response of polyurea-cylinder composite structure is established and solved by MATLAB.The main conclusions are as follows:(1)The antiknock experimental study shows that the deformation of the cylinder structure coated with type Q413 m polyurea is 18.1% and 21.1% less than that without polyurea layer under the explosion of 75 g TNT and 100 g TNT,respectively.(2)The strain dynamic response signals of the cylinder structure under explosion were analyzed by HHT method.It was found that the main frequencies of the cylinder structure without polyurea layer were all about 1000 Hz,and the energy was most concentrated at 400 Hz,600Hz,910 Hz and 1340 Hz.The main frequency of the cylinder structure coated with polyurea layer is divided into two parts: 200 Hz and 2400 Hz.The results show that the main frequencies of signals without polyurea layer are more concentrated,and the distance between the main frequencies is close enough to lead to the superposition of modes,which results in the phenomenon of strain growth.In the structure with polyurea layer,the signal main frequencies are far apart and the mode superposition is not easy to occur,so there is no obvious strain growth phenomenon.(3)The energy absorption of polyurea layer under different deformation results was investigated by numerical simulation.The results show that the energy absorption effect of Q413 m polyurea material is much better than that of the structure with plastic deformation only.The main reason is that when the polyurea layer is torn and destroyed,a large number of hydrogen bond breaks and the coating and structure will absorb a large amount of impact energy.(4)The governing equations and boundary conditions for the elastic dynamic response of polyurea-metal cylinder composite structures under load impact are established and simplified.Under the impact of 20 g TNT explosion load,the maximum deformation of single-layer cylinder is 0.117(88),and the maximum deformation of the cylinder coated with Q413 m polyuurea material is 0.098(88).oompared with the simulation results,the error is less than 10%.The results show that the equation is basically applicable.