The numerical analysis for the assembly stress in the local short fault of a vessel girth joint;

The main cause of fatigue origination was excessive assembly stress which was created in the course of heavy repair assembly,and the issue of missed check also existed.

The author analyses the radial displacement of the cylinder wall caused by the internal pressure in hydraulic operating cylinder by means of Lame formula, and taking a composite cylinder as a mechanical model, analyses and derives the assembling stress caused by the shrink range between the cylinder and the beam hole.

Analyses the effect of installation stress on boilers and pressure vessels and establishes the criteria for evaluation of instailation stress under different conditions, which can be used as references for settlement of disputes on quality issues between parties A and B during installation.