Abstract
Pipe flange connections have been widely used in mechanical structures such as power, chemical plants and so on. Sometimes leakage accidents occur from the connections. In assembling the pipe flange connections, the bolt preloads are scattered and then the connections are subjected to external bending moment due to earthquakes as well as internal pressure. In the present paper, the changes in the axial bolt forces are measured in assembling. The bolts are tightened with torque wrench. Using the history of the axial bolt force changes and FEM calculation the gasket stress distribution is estimated. The amount of leakage of the connection was measured. It is found that the effect of the scatter of bolt preload is substantial on the sealing performance of the connections. And it is found that the effect of the scatter of bolt preload and the effect of bending moment can be added. The changes in axial bolt forces obtained from experimental result are in a fairly good agreement with FEM result.
