Study On Dynamic Constitutive Model And Impact Resistance Of 1770 Grade Steel Wire

High strength steel cable is an important component in modern long-span spatial structure and bridge structure.Its damage often leads to the continuous collapse of the structure,and its safety is very important.As the component material of cable components,high-strength steel wire is often in the state of high strain rate under the impact,explosion and other loads.The stress-strain relationship of the material is very different from that under quasi-static state.In order to obtain the constitutive relation of high-strength steel wire material under this high strain rate,1770 grade high-strength steel wire is selected as the research object in this paper.Based on Johnson cook model,a series of material property tests are carried out to realize the calibration of all relevant parameters in Johnson cook model,and a Johnson cook model suitable for this kind of steel wire is established.On this basis,a single 1770 grade high strength steel wire was tested by gravity drop hammer to observe the response of steel wire under different impact conditions.The Johnson cook dynamic constitutive model is applied to the numerical simulation,and the numerical simulation results are compared with the test data to verify the reliability of the Johnson cook model in the numerical simulation.Finally,the numerical simulation of single steel wire under impact load with different parameters is carried out to study the influence of impactor height,impactor mass,steel wire length,impact position and prestress grade in steel wire on the impact resistance of steel wire.The main contents and conclusions of this paper are as foll ows:(1)The quasi-static tensile test of 1770 grade high strength steel wire,Hopkinson compression bar test and quasi-static tensile test at high temperature were carried out.The static mechanical parameters,mechanical properties at high strain rate and mechanical properties at high temperature were obtained.The relevant parameters in Johnson cook model were calibrated and the Johnson cook model suitable for the material was obtained.(2)Based on the gravity drop hammer impact test system and transien t acquisition system,a single steel wire gravity drop hammer impact test was carried out under different impact object height,different steel wire length and different impact position,and the response of 1770 grade steel wire under different impact conditions was obtained.(3)Johnson cook model is applied to numerical simulation,and the reliability of Johnson cook dynamic constitutive model in numerical simulation is verified by comparing the test and simulation results.Numerical simulation is carrie d out to study the influence of different factors on the impact resistance of 1770 grade high-strength steel wire.It can be concluded that: the increase of impact material speed,the increase of steel wire length and the impact position close to the restr aint end will reduce the impact resistance of steel wire;the increase of impact material quality has no significant effect on the impact resistance of steel wire;the application of a certain amount of prestress in steel wire can improve the impact resistance to a certain extent However,too high prestress will reduce its impact resistance.