| 引用本文: | 李静,李春旺,张忠平.考虑附加强化效应的多轴稳态循环塑性本构模型[J].哈尔滨工业大学学报,2017,49(11):143.DOI:10.11918/j.issn.0367-6234.201612058 |
| LI Jing,LI Chunwang,ZHANG Zhongping.Plastic constitutive model for multiaxial stabilized cyclic stress-strain response considering additional hardening effects[J].Journal of Harbin Institute of Technology,2017,49(11):143.DOI:10.11918/j.issn.0367-6234.201612058 |
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| 摘要: |
| 已有试验结果表明，非比例循环加载下应变主轴连续旋转，导致多滑移系开动，阻碍材料内部形成稳定的位错结构，使非比例加载下的应力－应变曲线高于比例加载下的应力－应变曲线，从而产生非比例附加强化现象.由此，从应力空间表述的塑性增量本构模型一般形式出发，建立一个能够反映非比例附加强化效应的稳态循环塑性本构模型.在Armstrong-Frederick模型背应力演化方程的基础上，新模型通过引入非比例度因子和附加强化系数，构建了一个新的背应力演化方程.然后，通过一致性条件建立塑性模量方程与背应力之间的关系.同时，利用最小法向应变范围，提出一种计算非比例度因子的新方法，并针对一般的多轴加载情形，明确最小法向应变范围的计算步骤.新模型从加载路径和材料本身两个方面来考虑非比例附加强化效应的影响，克服Armstrong-Frederick模型中材料常数确定方法繁琐，且通过单轴疲劳试验数据确定的材料常数不能很好地反映材料非比例附加强化现象的不足.应用新模型时，仅仅需要3个独立的常规力学参量和2个疲劳参数，便于工程应用.利用多种多轴加载路径下S460N钢和304不锈钢的试验结果对模型进行验证，预测结果与试验结果吻合良好.
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| 关键词: 非比例附加强化 稳态循环应力应变响应 塑性本构模型 非比例度因子 附加强化系数 |
| DOI：10.11918/j.issn.0367-6234.201612058 |
| 分类号:O344 |
| 文献标识码:A |
| 基金项目:国家自然科学基金(1,4)； 陕西省自然科学基础研究计划(2015JM5240)； 空军工程大学理学院博士科研启动资金 |
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| Plastic constitutive model for multiaxial stabilized cyclic stress-strain response considering additional hardening effects |
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LI Jing,LI Chunwang,ZHANG Zhongping
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(The Science Institute, Air Force Engineering University, Xi’an 710051, China)
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| Abstract: |
| Existing test results show that the continuous rotation of principal strain axis in cyclic deformation leading to actuation of multi-slip systems which hinders the forming of stable dislocation substructures inside the material, during nonproportional cyclic loading. As a result, the stress response under nonproportional loading will be larger than that under proportional loading. In other words, the material shows additional hardening upon nonproportional cycling. Therefore, a new constitutive model for modeling stabilized cyclic stress-strain response is proposed to consider the effect of nonproportional additional hardening based on the general form of stress-space incremental plasticity relation. In the hardening rule of the proposed model, the evolution of the back stress is simulated by introducing the nonproportionality factor, fnp, and the additional hardening coefficient, αnp, into the basic Armstrong-Frederick model. The consistency condition is enforced to obtain the relationship between the back stress and plastic modulus. Besides, a new algorithm is proposed to calculate the nonproportionality factor on the basis of the minimum normal strain range. Procedures to determine the minimum normal strain range are presented for the general multiaxial loadings. In the proposed model, the effect of nonproportional additional hardening is reflected by introducing fnp and αnp, not only on the shape of the loading path, but also on the material and its microstructure. Meanwhile, the two drawbacks of the Armstrong-Frederick model are overcome. The proposed model requires only five material constants for estimating the stabilized response. Comparisons between test results of S460N steel and 304 stainless steel and model predictions under various loading paths show that the proposed model predicts relatively accurate stress responses under both proportional and nonproportional loading paths.
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| Key words: nonproportional additional hardening stabilized cyclic stress-strain response plastic constitutive model nonproportionality factor additional hardening coefficient |
