航空柱塞泵缸体疲劳分析及寿命预测方法

Fatigue analysis and life prediction method for cylinder block of aviation piston pump

缸体是航空柱塞泵核心部件之一,其直接影响航空柱塞泵的功能。针对目前缸体寿命研究的实验周期长、缺乏理论分析方法的不足,提出了基于有限元分析和线性累积损伤理论的缸体疲劳分析和寿命预测方法。首先,基于理论力学和材料力学建立缸体的力学模型,在MATLAB平台上进行仿真分析,计算缸体受力;其次,建立缸体的有限元模型,在ANSYS平台上计算缸体的应力和应变;然后,将缸体应力、应变等结果导入nCode中,基于线性累积损伤理论,探究缸体的薄弱部位及影响缸体疲劳寿命的因素;最后,进行实验验证。结果表明,靠近配流盘一侧的柱塞腔外壁较为薄弱,容易出现疲劳破坏,与仿真结果基本吻合,验证了所提的缸体疲劳分析和寿命预测方法的正确性,为结构紧凑型柱塞泵缸体的设计提供参考。

The cylinder block is the crucial part of the aviation piston pump, which can directly affect the function of aviation piston pump. In view of the drawbacks of long test period and lacking theoretical approaches, a method for fatigue analysis and life prediction of the cylinder block is proposed based on finite element method and linear cumulative damage theory. Firstly, the mechanical model of the cylinder block is established using theoretical mechanics and material mechanics, and the force analysis calculation is implemented on MATLAB. Then, the finite element model of the cylinder block is established on ANSYS platform in order to simulate the stress and strain. Further, the results of stress and strain are imported into nCode to find out the weak parts of the cylinder block and investigate the affecting factors of the fatigue life based on linear cumulative damage theory. Finally, the verification test is carried out. The result shows that the outer wall of the piston chamber near the side of the distribution plate is weak and prone to fatigue damage, and the damage part of the experimental pump is approximately coincident with the simulation, which can validate the correctness of method for the fatigue analysis and life prediction of the cylinder block. The study findings of this paper can provide guidelines for designing the cylinder block of compact piston pumps.