| High-strength steel cable,as the main stress member of modern prestressed steel structure,not only has extremely high tensile strength,but also has good toughness.Its lightweight and high strength make it widely used in long-span space structures and bridge structures.However,in recent years,with the development of transportation rail technology and the automobile industry,car collision incidents have occurred from time to time.At the same time,public places such as large-span spatial structures are likely to become targets of explosions and collision terrorist attacks.Steel cables are often the key force-bearing components of long-span space cable structures.Under impact and explosion loads,their failure and damage will easily cause the continuity of the structure to collapse.Therefore,it is necessary to study the impact resistance of steel cables,which is of great significance to the safety of prestressed steel structures and the continuous collapse resistance of large-span spatial structures.The High-strength steel cable is made of multiple strands of high-strength steel wire twisted according to a specific process.It is often in a state of high temperature,high pressure,and high strain rate under explosion and impact loads.The constitutive relationship of the material is very different from that in the static state.Compared with ordinary steel,it is very different.In this paper,1670 and 1860 high-strength cables are selected as the experimental research objects,and the mechanical properties of their materials are studied through static tensile test,high strain rate Hopkinson compression bar test,and high temperature static tensile test.A Johnson-Cook constitutive model suitable for grade 1670 and grade 1860 high-strength cables is established.On this basis,a numerical simulation method was used to carry out the research on the resistance to lateral impact of high-strength steel cables.Finally,an equivalent simplified "steel rod" model of steel cables is proposed,which provides a reference for the impact design and numerical simulation of prestressed steel structures.The main research content and conclusions of this paper are as follows:(1)Carried out the material property tests of 1670 and 1860 cable materials,and obtained the relevant mechanical performance parameters of the material under static,high strain rate,and high temperature,including elastic modulus,yield strength,ultimate strength,fracture failure strain,etc.At the same time,the Johnson-Cook constitutive model parameters of grade 1670 and grade 1860 cables were calibrated based on the test data.(2)Based on ANSYS/LS-DYNA,the finite element model of 1670 grade single steel wire and high-strength steel cable is established,and the Johnson-Cook constitutive model obtained from the experiment is used as the material model of the cable body to carry out the numerical simulation study of lateral impact resistance.Calculation examples of different impact conditions are carried out,the impact response is analyzed,and the different failure modes of steel cables are summarized.At the same time,the influence of prestress level,steel cable length,impact material quality,impact speed,impact position,impact angle on the impact resistance of steel cables is analyzed.(3)Taking the simplified model to have the same mechanical behavior and dynamic response as the refined model under impact load,the refined steel cable model is simplified to a single homogeneous "steel rod" model.After verification of accuracy,it is found that the simplified model can be applied to the finite element simulation of lateral impact of steel cables and has high computational efficiency. |
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