Comparison of assessment methods and optimization proposal on railway vehicle material and its joint strength

Standards at home and abroad had different assessment methods for static and fatigue strength of base metal, HAZ and weld. The comparison among these standards were conducted in the article. The comparison result indicated that all standards had shortcomings illustrated as followed. There was no regulation on the fatigue strength of spot welded joint. No mention or correct regulation on strength of cold hardening stainless steel welding joint was given. Actual welded joint was hardly able to correlate to the welded joint listed in fatigue assessment standard.There existed no regulation on fatigue load in connection region between running gear and car shell, which resulted in several crack cases of car shell. The smaller allowable stress of dissimilar metals for groove welded joint was adopted. However, no consideration was given to the actual scenario that one sort of welding wire was generally used for all dissimilar metals. Strength ratio between all weld metal and base metal of each side was diversified. Incomplete penetration weld was often regarded as complete penetration weld to assess. For fillet, plug weld and slot weld,only the principal stress of corresponding node was checked whether it exceeded the allowable stress of weld/HAZ or not, but weld size, shear force and additional bending moment were left out. The optimization proposal was put forward pursuant to project experience.