塑性域締結におけるねじ締結体の挙動

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抄録

The allowable load on bolted joints tightened in the plastic region is studied experimentally. Behavior of the joints are investigated in different tightening region of the bolt such as elastic region, yield point and plastic region, varying stiffness of clamped parts and the strength grade of the bolt. As a result, it is shown that the additional elastic increase in the axial tension of the bolt under external load is independent of the joints stiffness or the elongation of the bolt at tightening. Load capacity of the joints tightened in plastic region is higher than that in elastic region by 5-10%. Permitting the decrease of initial clamping force by 10%, the allowable load is 90% of the yield strength of the bolt for the joint having lower stiffness, and is equal to the yield strength for one having higher stiffness. The allowable load estimated in the joint (load cell) whose stiffness is lower than actual condition is in safety zone.