抄録
Pressure vessel such as compressor and pump operated in various plants is demanded to be tightened by bolt with high axial tension, and bolt tensioner is frequently adopted for the tightening. Bolt tensioner is able to load high axial tension to the bolt by hydraulic pressure, and axial tension variation caused by contact friction among tightening parts is small. However, initial tension loaded by hydraulic pressure decreases, because of stiffness changing and transferring of tightening parts after nut seating and unloading. The ratio of residual axial tension to initial tension is the most important factor to load with high accuracy by bolt tensioner. In this study, estimating equation of the ratio was formulated by considering plastic deformation of tightening parts and re-loading of hydraulic pressure. Compliance of tightened parts is derived from elastic analysis, and plastic deformation value is derived from elastic-plastic analysis. Finally, bolt tightening with bolt tensioner was experimented, and estimation accuracy of the estimating equation is examined.
