防振用天然ゴムの疲労特性:　第2報，一軸変動荷重下における疲労寿命予測方法に関する一考察

摘要

自動車のエンジンマウントや鉄道車両の車軸支rn持などの防振ゴムには複雑な実働荷重が負荷されrnる．機械の長期安全を保障するには，実働荷重下にrnおいて防振ゴムの疲労寿命を予測することが重要rnである．%In order to investigate fatigue characteristics of vulcanized natural rubber (NR), fatigue tests are carried out under various stress ratios R and variable loading. In this paper, fatigue crack propagation life is predicted depending on fatigue crack propagation behavior, because the fatigue life is almost the fatigue crack propagation life. Two essential assumptions for the application of Miner's rule are satisfied. It is considered that Miner's rule can predict the fatigue life safely under two-step loading, because the fatigue damage location is depending on R. Under complex variable loading, it is considered that the crack growth rate under 0 < R < 1 condition is accelerated because of disappearance of crystallization effect. So, it is necessary to make up the modified constant life diagram. The fatigue crack propagation life can be predicted using the modified constant life diagram and Miner's rule.