ボルト締付け時に発生する応力の評価

抄録

The stress distribution in threaded portions of bolt and nut being fastened by applying torque to nut is analysed by FEM. The object of analysis is composed of a bolt, a nut and a fastened plate, which are all treated as axi-symmetric bodies. Two methods of analysis are proposed. The first method is composed of the axi-symmetric analysis for the state generated by applying tension to bolt and the analysis of torsion for the state generated by applying distributed torque at the contact surfaces. The distributed torque is approximately estimated from the distribution of the normal stress generated at the contact surfaces by the axial tension. The second method is a three-dimensional analysis, where effects of lead angle are considered only through the relationships of forces acting on the pressure flank. From some calculations by the above two methods, effects of the torque applied during fastening on the stress distribution is estimated.