基于弹塑性理论的低压级组动叶叶根承载能力研究

为提高低压级组动叶叶根承载能力,基于弹塑性理论,考虑了材料非线性应力应变关系,用非线性有限元方法定量分析了某级动叶叶根在离心力作用下的应力分布.经数值模拟发现,在叶根和叶根槽的原角应力集中区域已经进入强化阶段或者塑性变形区域,但是尚未到发生破坏的强度极限.这种定量结果可以很好地解释某些汽轮机叶片应力为什么可以超出屈服极限,并作为设计新型叶片的参照指标.因此,基于弹塑性理论的有限元方法可以作为叶片设计的一种重要的辅助工具.

Investigation of Bearing Capacity of LP Stage Moving Blade Root Based on Elasto-Plastic Theory

In order to improve the bearing capacity of moving blade root in low pressure （LP） stage, a numerical computation based on the nonlinear FEM is performed by utilizing elasto-plastic theory with consideration of nonlinear constitutive relation to obtain the stress distribution of a blade root. It can be observed that the peak stresses of the root and the bladed disk slot are beyond yield, but under failure limit. The results can be utilized to interpret the reason why the peak stress of practical blades can be beyond yield. Thus, the results can be used as references and the finite element method based on elasto-plastic theory can be considered as an important auxiliary method for blade design.