Residual stress around rail bolt holes after cold-expansion

Focused on rail bolt hole cold-expansion, the theoretical prediction models and results of residual stress analysis on related Problems are summarized. And a stress analyzing method based on both of the strain measurement during the Process of cold expansion and elastoc-plastic theory is developed. By the method proposed and the magneto-elastic method as well as the stress relief measurement detailed experimental study on the residual stress surrounding the cold-expanded tail bolt hole is performed. Relationship between the distribution of residual stress and cold expansion rate are established. The adaptability and limitation of theoretical predichon are also analyzed by comparing the theoreticaland experimental results.