共查询到16条相似文献,搜索用时 187 毫秒
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304不锈钢室温和高温单轴循环塑性的实验研究 总被引:2,自引:0,他引:2
对304不锈钢进行了室温和高温单轴应变控制和应力控制下的系统循环试验。揭示和分析了循环应变幅值、平均应变及其历史和温度历史对材料应变循环特性的影响以及应力幅值、平均应力及其历史以及温度对循环棘轮行为的影响。也讨论了应变循环和应力循环间交互作用对材料循环塑性行为的影响。研究表明,无益单轴应变循环特性还是非对称单轴应力循环下的棘轮效应不仅取决于当前温度和加载状态,而且强烈依赖于其加载历史。研究得到了一些有助于304不锈钢室温和高温单轴循环行为本构描述的结果。 相似文献
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本文对316L不锈钢进行了单轴与多轴非比例路径下的应力控制棘轮试验,考察了应力幅值、平均应力和加载历程对棘轮特性的影响。同时进行了应变控制循环试验以研究材料的应力松弛特性。试验结果表明轴向棘轮效应在对称剪切荷载下效果明显,同时棘轮应变随应力幅值和平均应力的增加而增加。研究了Chen-Jiao随动强化模型与Jiang-Sehitoglu随动强化模型采用的单轴与多轴参数对背应力分量增量方向的影响,将Chen-Jiao模型中的多轴系数替换为界面饱和率,并在此基础上引入新的参数对塑性模量系数进行修正,计算结果表明修正后的模型能提升应力控制下多轴棘轮的预测精度,并能很好的预测应力松弛现象,表明了新模型的正确性与有效性。 相似文献
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一个考虑循环应变幅值历史效应的粘塑性本构模型 总被引:1,自引:0,他引:1
本文提出了一个考虑材料应变幅值历史效应的粘塑性本构模型。在该模型中,引入了三个具有不同演化速率的背应力演化方程;建立了非弹性应变幅值历史记忆模型,对各向同性变形阻力,引入了具有先前加载历史记忆的演化方程。将本文模型用于1Cr18Ni9Ti不锈钢循环变形行为描述中,其预言结果与实验结果吻合得很好,表明该模型能很好地描述材料的循环应变幅值历史下的循环变形行为。 相似文献
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40钢非比例循环塑性行为研究 总被引:1,自引:0,他引:1
对40钢在拉扭循环复杂应变路径下的硬化特性和流动特性进行了实验研究。研究表明:40钢材料的循环硬/软化不但依赖于应变路径形状,而且依赖于等效应变幅值,还具有路径历史效应;材料的塑性流动几乎不受先前路径历史的影响,仅依赖于当前应变路径形状和等效奕变幅值。 相似文献
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An experimental study was carried out for the cyclic properties of pure aluminium subjected to uniaxial cyclic straining and stressing. For a material of pure aluminium the effects of the cyclic strain amplitude history and mean strain on the cyclic deformation behavior were investigated, and the influences of stress amplitude, mean stress and their histories on cyclic creep (i. e., ratcheting) were analyzed. It is shown that either uniaxial cyclic property under cyclic straining or ratcheting behavior under asymmetric uniaxial loading depends not only on the current loading, but also on the previous loading history. Some significant results were obtained.Financial support from NFSC is acknowledged. 相似文献
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《International Journal of Plasticity》2005,21(1):43-65
Uniaxial and multiaxial ratchetting tests were conducted at temperatures between 200 and 600 °C on modified 9Cr–1Mo steel, which exhibits both viscoplastic and cyclic softening behavior. Anomalous behavior was observed in the stress-controlled uniaxial ratchetting tests; the material exhibited outstanding ratchetting in the tensile direction under zero mean stress. Under the uniaxial conditions, the ratchetting deformation significantly depended on the loading rate and hold time in addition to parameters such as the maximum stress and stress ratio. The uniaxial ratchetting was also accelerated to a great extent when cyclic deformation was given before the ratchetting tests. Under the multiaxial conditions, the ratchetting depended on the steady stress, cyclic strain range and strain rate. The ratchetting progressed faster as the steady stress or strain range became larger, or the strain rate became smaller, as expected. Monotonic compression tests were carried out to investigate the reason for the rachetting under no mean stress. Strain range change tests were also conducted to investigate the effect of strain range on the cyclic softening behavior of the material in detail. 相似文献
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《International Journal of Plasticity》2000,16(3-4):225-240
A new kinematic hardening model useful for simulating the steady-state in ratchetting is developed within the framework of the strain hardening and dynamic recovery format. The model is formulated to have two kinds of dynamic recovery terms, which operate at all times and only in a critical state, respectively. The model is examined on the basis of nonproportional experiments of Modified 9Cr–1Mo steel at 550°C and IN738LC at 850°C. The experiments include multiaxial, as well as uniaxial, ratchetting, multiaxial cyclic stress relaxation, and nonproportional cyclic straining along a butterfly-type strain path. It is shown that the model is successful in simulating the experiments, and that the model is featured by the capability of representing appropriately the steady-state in ratchetting under multiaxial and uniaxial cyclic loading. 相似文献
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《International Journal of Plasticity》2006,22(5):858-894
The time-dependent strain cyclic characteristics and ratchetting behaviours of SS304 stainless steel were investigated by uniaxial/multiaxial cyclic loading tests at room and elevated temperatures (350 and 700 °C). The effects of loading rate, peak/valley strain or stress holds, ambient temperature and non-proportional loading path on the cyclic softening/hardening and ratchetting behaviours of the material were discussed. It is shown that: the cyclic deformation of the material presents remarkable time-dependence at room temperature and 700 °C; the cyclic hardening feature and ratchetting strain depend significantly on straining or stressing rate, hold-time, ambient temperature and the non-proportionality of loading path; the time-dependent ratchetting is resulted from the slight opening of hysteresis loop and visco-plasticity together, and the viscosity is a dominating factor at 700 °C; at 350 °C, abnormal rate-dependence and quick shakedown of ratchetting are observed due to the dynamic strain aging of the material at this temperature. Some significant conclusions are obtained, which are useful to construct a constitutive model to describe the time-dependent ratchetting behaviour of the material. It is also stated that the unified visco-plastic constitutive model discussed here cannot provide reasonable simulation to the time-dependent ratchetting at 700 °C, especially to that with certain peak/valley stress hold, since the effect of the high viscosity on time-dependent ratchetting cannot be properly described by using a unified visco-plastic flow rule. 相似文献
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In this part, the Khan–Huang–Liang (KHL) constitutive model was extended to account for kinematic hardening characteristic behavior of materials. The extended model is then generalized and used to simulate experimental response of oxygen free high conductivity (OFHC) copper under cyclic shear straining and biaxial tension–torsion (multiaxial ratchetting) experiments presented in Part I (Khan et al., 2007). In addition, a new modification for the non-linear kinematic hardening rule of Karim–Ohno (Abdel-Karim and Ohno, 2000) is proposed to simulate multiaxial ratchetting behaviors. Although, the kinematic hardening contributes the most to the response, it is shown that, the loading rate effect, and a coupled isotropic and kinematic hardening effect should also be considered while simulating the multiaxial ratchetting behavior of OFHC copper. Furthermore, the newly modified kinematic hardening rules is able to fairly well simulate the multiaxial ratchetting experiments under different loading conditions, irrespective of the value of applied axial tensile stress, shear strain amplitude, pre-cyclic hardening and/or loading sequence. 相似文献