Abstract
The bodies of steam turbine casings used at power plants are divided into top and bottom, in order to facilitate maintenance such as replacements and repairs. The two parts (top and bottom) are joined together with bolts in order to maintain internal pressure. As the structure is not a single unite, it is not an ideal pressure container. Analysis of contact stress at the flange contact surface of pressure containers is, therefore, especially important in terms of both safety and efficiently. This study investigated the safety of casings using the three-dimensional photoelastic stress freezing method and the Finite Element Method. We investigated safety aspects from the viewpoint of contact stress distribution, which is affected by, the distance between bolt holes, flange outside diameter, and changes in the position of bolt holes.
