考虑冰桨作用动力效应的桨叶疲劳强度预报方法研究

Blade fatigue strength forecasting method considering dynamic effects of ice propeller action

  • 摘要: 【目的】:针对冰体冲击下桨叶疲劳损伤问题,提出了一种针对冰桨铣削过程的桨叶疲劳强度预报方法。【方法】:基于PD-FEM耦合算法建立冰-桨铣削相互作用数值模型,通过整合基于修正S-N曲线的疲劳强度评估方法和Miner线性累积损伤理论,提出了一种合理且可行的冰区螺旋桨动态接触冰载荷的疲劳强度预报方法,并基于Python并行计算架构实现算法加速,成功实现了动态冰载荷作用下螺旋桨三维疲劳损伤云图的可视化表征。【结果】:研究发现在铣削工况下,叶面的疲劳损伤集中区域主要集中在离桨毂边缘0.1R处靠近随边区域,而叶背的疲劳损伤集中区域则主要分布在离桨毂边缘0.3R左右处的导边区域和叶根弦向中部区域和叶稍部位。此外,随着叶稍受压,叶根受拉的影响,桨叶中部区域的应力幅值会较大,这导致用于S-N曲线的等效应力幅值也随之增大,进而导致桨叶中部也会有较大的疲劳损伤。【结论】:研究结果表明,所提出的疲劳强度预报方法能够精准评估冰区螺旋桨在复杂工况下的疲劳寿命,为冰区船舶螺旋桨的设计与优化提供了更好的理论支撑。

     

    Abstract: Abstract: Objective: Aiming at the fatigue damage problem of propeller blades under ice impact, a global rapid forecasting method for propeller blade fatigue strength in the ice - screw milling process is proposed.Method: A numerical model of ice - screw milling interaction was established based on the PD - FEM coupled algorithm. By integrating the fatigue strength evaluation method based on the modified S - N curve and Miner’s linear cumulative damage theory, a reasonable and feasible fatigue strength forecasting method for the dynamic contact ice load of ice - area propellers was proposed. And the algorithm acceleration was realized based on the Python parallel computing architecture, successfully achieving the visual representation of the three - dimensional fatigue damage cloud map of the propeller under the action of dynamic ice load.Results: It was found that under the milling condition, the fatigue strength concentration area of the blade surface was mainly concentrated in the area near the trailing edge about 0.1R, while the fatigue strength concentration area of the blade back was mainly distributed in the leading edge area about 0.3R, the middle part of the blade root chord and the blade tip part. In addition, for different propeller blades, even in the same position, due to the different sizes of ice load, the stress and amplitude are also different, resulting in significant differences in the fatigue strength of the propeller blades when milling ice blocks. Conclusions: The research results show that the proposed fatigue strength forecasting method can accurately assess the fatigue life of ice - area propellers under complex working conditions, and provides a strong theoretical support for the design and optimization of ice - area ship propellers.

     

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