核电站内压直管道在位移控制下的棘轮效应

研究核电站直管道在恒定内压和循环位移作用下的棘轮效应,分析了内压、循环位移和多步载荷对内压管道棘轮应变的影响.结果表明:最大棘轮应变发生在直管的环向方向,轴向棘轮应变与环向棘轮应变相比小得多.在相同内压下,棘轮应变随着循环位移的增大而增大;在相同位移下,棘轮应变随内压的增大而增大.采用多步加载时,前一步棘轮变形会降低后一步应有的棘轮应变率,尤其前一步具有较大的位移作用下发生棘轮应变后,这种现象十分明显.根据直管试验装置特点,确定了内压直管在位移控制下的棘轮边界.

Ratcheting Effect of Pressurized Straight Pipe Under Displacement Control

The ratcheting effect of pressurized straight pipe was studied for nuclear power plant. The effect of internal pressure， displacement and multistep loading on ratcheting strain was mainly studied. The results indicated that ratcheting strain occurs mainly in hoop direction and it′s not evident in axial direction. Ratcheting strain increases with the increasing of displacement at the same pressure. At the same displacement， ratcheting strain increases with the increasing of internal pressure. For multi-step loading， ratcheting strain rate in the next step would be decreased by ratcheting deformation in the preceding step. The effect of ratcheting history at higher level loading on ratcheting strain is larger than that at lower level loading. According to the quasi-three-point-bending apparatus， ratcheting boundary was determined.