衝撃荷重を受けるねじ締結体の軸力挙動に及ぼす初期締付け力の影響 [in Japanese] Influence of Tightening force on Behavior of Axial force of Bolted Joints by Impact Load [in Japanese]
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As the requirements for the safety and the reliability of mechanical structures have grown more and more demanding,the properties of the bolt joints, which are the indispensable component of mechanical structures, have also fallenunder greater and greater scrutiny. Thus the awareness on importance of the bolt parts has been increasing. To determinethe properties of the impact strength for bolted joints when subjected to impact loads, this paper examines howthe property-class of the bolt as well as the force exerted by tightening (in both the elastic range tightening and in theyield point tightening) influence the axial-force behavior of the bolt joints. To achieve this, we have experimentally determinedthe following three parameters: i) the additional axial force; ii) the internal/external force ratio; and iii) thedecrement of the axial force. From the experimental results, we then discern the influences of the property-class of thebolt and the initial tightening force on the axial force behavior of the bolt joints subjected to the external impact force.Thus we come to our central findings, namely that: (1) By increasing the initial tightening force the internal/externalforce ratio of the bolted joint subjected to an impact load can be decreased. (2) When the impact load is applied continuously,the value of the internal/external force ratio tends to decrease as the bolt strength increases. Also, the ratio tendsto increase as the residual axis force decreases. (3) By increasing the bolt strength, the decrement of the residual axisforce of the bolt joint can be diminished. (4) While the internal/external force ratio decreases as the initial tighteningforce is increased, since the yielding of the bolt furthers the elastic elongation, when a relatively large external force isapplied to the bolt joint the residual axis-force decreases significantly.
- Research reports of the Kogakuin University
Research reports of the Kogakuin University (118), 45-52, 2015-04