Hot Spot Stress Analysis Of Column-base Weld In H-cantilever Under Complex Stresses

In recent years,the high-speed railway has been developing rapidly in China.H-section steel poles of OCS?overhead contact system?are widely used in high-speed railway.H-section steel poles of OCS?overhead contact system?with fixed-Base and disengaged Capital can be regarded as cantilever member.The geometric catastrophe of Welding Connection will seriously result in the stress concentration and weak the fatigue performance of the weld.Up to today,there isn't any domestic code or standard to specify the fatigue behavior of the welded joints.The column-base-weld fatigue behavior of H-cantilever column affects the whole column's life.In this paper,the theoretical analysis and numerical calculation of weld's fatigue behavior of H-section steel poles of OCS was made.A type of numerical model was established and analysis on hot spot stress of weld's fatigue behavior was made based on surface extrapolation method under bending,torsion and combined bending and torsion.The type of numerical model including weld was established with a high-precision element.The results show that the location of hot-spot stress and main influence factors of the hot spot stress concentration factor.Parametric analysis was carried out by changing the ratio of flange thickness to baseplate thickness?t₁/t2?,the ratio of flange thickness to web thickness?t₁/t₃?,the web thickness?t₃?and the depth of the H-section?h?.The results show that the hot spot stress concentration factor(SCF_mhs)decreases with?t₁/t₃?and?t₃?,but has little relationship with?t₁/t2?and increases with?h?,the suggested value can be taken as 1.44,under bending moment;(SCF_ths)decreases with?t₁/t2?and?t₃?,but has little relationship with?t₁/t₃?and increases with?h?,the suggested value can be taken as 1.22,under torsion;?SCFmths?decreases with?M/T?,the suggested value can be taken as 1.05 SCF_ths.Finally,the method of IIW recommended was used to predict weld fatigue life of weld of H-section steel poles of OCS under complex stresses.The H-section steel poles of OCS used in some high-speed rail were introduced to calculate the fatigue life of column-base-weld.The results show that the location of hot spot stress is constant,fatigue life increases with the increment of the section of H-section steel poles of OCS by 2.19% to 13.03%.