Study On Interval Non-probabilistic Reliability Of Nuclear Damaged Rail

In recent years,under the background of "Belt and Road Initiative",the development of China's railway industry has reached an unprecedented height,and with the rapid development of railway,the problem of rail damage,especially rail nuclear damage,has become more and more prominent.In the rail in service,there may be nuclear injuries of different sizes and locations,which pose a great threat to driving safety.Therefore,based on interval mathematics theory and non-probabilistic reliability theory,the finite element model of wheel-rail contact is established to calculate the reliability of nuclear damage at different locations,sizes and angles,and the safety of the nuclear damage rail under different working conditions is evaluated,the main work is as follows:The non-probabilistic reliability model based on interval theory is used to study the reliability of nuclear damaged rail.Taking U78 Cr V rail used in heavy haul railway line as an example,considering train axle load,temperature load,rail residual stress and rail hardness,the finite element analysis of nuclear damaged rail is carried out,and the maximum Mises stress on the crack surface of nuclear damage is extracted as the standard for calculating reliability index.In view of the fact that the relationship between the variables and the effect value is nonlinear,the response surface method is used to construct the limit state function,and the improved global optimal method is used to solve the final reliability index.Through the calculation of the non-probabilistic reliability of the nuclear damage rail under different working conditions,the safety range and failure range of the nuclear damage under different working conditions are obtained,and it is concluded that the closer the nuclear damage is to the rail tread and the inner edge of the rail,the smaller the reliability index is;the smaller the angle between the nuclear damage and the driving direction is,the smaller the reliability index is;the larger the nuclear damage size is,the smaller the reliability index is.According to the reliability calculation results of nuclear damage rail and comparing the safety standards of otherstructures,a set of safety classification standards for nuclear damage rail based on non-probabilistic reliability theory is proposed,and the safety level is divided into three levels.According to the classification standard,the safety levels of nuclear damage of different sizes under different working conditions are evaluated,and the safety levels of nuclear damage of different sizes are obtained.