斜裂纹航空液压直管振动特性分析

Vibration Characteristics Analysis of an Aeronautical Hydraulic Straight Pipe with Slant Crack

关键词:  航空液压直管  斜裂纹  振动响应  应力强度因子  有限元法

Key words:  Aero hydraulic straight pipe  Slant crack  Vibration response  Stress intensity factor  Finite element method

摘要:

为了研究含裂纹航空液压直管的振动响应特性，防止液压管路系统出现灾难性失效，针对液压直管可能出现的斜裂纹故障，考虑剪切力以及剪切系数的影响，推导出斜裂纹液压直管的局部柔度系数表达式，从而建立斜裂纹液压直管流固耦合有限元模型。利用Newmark-β积分法求解了液压直管的振动响应，将数值计算结果与试验测试结果对比分析，验证了有限元模型的正确性。利用本文模型分析了裂纹夹角和柱塞泵转速对液压直管系统振动响应特性的影响，结果表明：裂纹夹角的变化会影响液压直管的振动响应，当裂纹夹角趋于0°时，液压直管的振动响应幅值最小，随着裂纹夹角的增加，裂纹对液压直管振动响应的影响更显著；在不同的转速下，横向裂纹液压直管的振动响应幅值均大于斜裂纹液压直管。

Abstract:

In order to study the vibration response features of aero hydraulic straight pipeline with cracks and avoid the catastrophic failure of hydraulic pipeline system， considering about the influence of shear force and shear coefficient， the expression of local flexibility coefficient is derived for hydraulic straight pipe with slant cracks for the latent fault in hydraulic straight pipe， thus building the fluid-structure coupled finite element model for hydraulic straight pipe with slant cracks. Newmark-β integral method is used to solve the vibration response of hydraulic straight pipe. The correctness of finite element model is verified by comparing the results between numerical calculation and experimental test. The model is used to analyze the effects of crack angle and rotation speed of plunger pump on the vibration response of hydraulic straight pipeline system. As shown by results， the vibration response of hydraulic straight pipe is affected by the change of crack angle. The amplitude for vibration response of hydraulic straight pipe is minimum when the crack angle is close to 0°. The larger the crack angle， the more significant the effects of cracks on vibration response of hydraulic straight pipe are. Under different rotation speeds， the amplitude for vibration response of hydraulic straight pipe with straight cracks is larger than that with slant ones.