Strengthening and damaging under low-amplitude loads below the fatigue limit

The strengthening and damaging of low-amplitude loads below the fatigue limit are investigated by single tooth bending for the transmission cylindrical gear under constant low-amplitude loading and program loading. The experimental results show that the strengthening effects of low-amplitude loads are very obvious under constant low-amplitude loading, while are weakened under program loading. The strengthening loads under constant low-amplitude loading maybe have not the strengthening effects for the influence of overload in program loading, but the less low-amplitude loads could exhibit the strengthening effects. The strengthening effects of low-amplitude loads in program loading are influenced remarkably by the cycles of low-amplitude loads.