Abstract: The uni-axial ratcheting experiments of two materials under different mean stress and stress amplitude are carried out, and the plastic flow characteristics of experiment results are also analyzed. Both features of the uni-axial ratcheting and different evolution rules of plastic modulus at the symmetric loading points are presented. The nature that the current two?? surface constitutive model fails to describe the ratcheting is also revealed. On the basis mentioned above, a new plastic modulus formula is introduced; meanwhile, the numerical simulation is also carried out. Through the comparative tests carried out between the simulation and the experiment, it is discovered that simulation results matches well with experiment results. So the reasonability of the plastic modulus formula is verified.

Key words: ratcheting, two-surface constitutive model, plastic modulus

摘要： 开展了两种材料在不同应力水平和不同应力幅值下的单轴棘轮效应实验,进行了实验结果的塑性流动特性 分析;揭示了单轴应力循环下的棘轮效应特征和塑性模量在正、反向加载时所遵循的不同演化规律,分析并指出了 现有双曲面本构模型无法正常描述棘轮效应的实质。在此基础上,引入了新的塑性模量演化公式,并开展了数值 模拟,通过与实验结果比较发现,两者吻合较好,从而验证了塑性模量演化公式的合理性。

关键词: 棘轮效应, 双曲面本构模型, 塑性模量