腐蚀缺陷对桥式起重机主梁疲劳裂纹扩展行为的影响  

Influence of corrosion defects on fatigue crack propagation behaviors of bridge crane girder

作　　者：戴勇 马超 闵广杰 Dai Yong;Ma Chao;Min Guangjie

机构地区：[1]新疆维吾尔自治区特种设备检验研究院,乌鲁木齐830000 [2]北京起重运输机械设计研究院有限公司,北京100007 [3]新疆大学智能制造现代产业学院,乌鲁木齐830017

出　　处：《起重运输机械》2025年第7期52-58,共7页Hoisting and Conveying Machinery

基　　金：自治区市场监督管理科技计划项目(S2023172053)。

摘　　要：桥式起重机主梁在复杂工况下长期承受交变载荷,易发生疲劳裂纹扩展,且腐蚀缺陷会加速这一过程。文中对起重机主梁的主要材料Q235B进行了疲劳裂纹扩展试验,获得了Paris方程的参数,为后续裂纹扩展模拟提供依据;通过有限元静力学分析,确定了主梁的疲劳危险点,结果显示腐蚀缺陷在危险点处引起应力集中,显著加速了裂纹扩展,使结构疲劳寿命较无缺陷条件下缩短约35%;此外,还研究了疲劳危险点处在有(无)腐蚀缺陷情况下的裂纹扩展行为。结果表明:腐蚀缺陷会显著加速疲劳裂纹的萌发和扩展,且裂纹前沿应力强度超过材料的屈服强度,在降载至额定载荷的75%后,仿真表明裂纹尖端的应力集中得以缓解,避免了塑性变形风险,延长了主梁的疲劳寿命。The main beam of a bridge crane is subjected to alternating loads over extended periods under complex working conditions,making it susceptible to fatigue crack propagation.Corrosion defects further exacerbate this process.Fatigue crack growth tests were conducted on Q235B,the primary material used in crane girders,and the parameters for the Paris equation were obtained.These parameters provide a foundation for subsequent crack growth simulations.Finite element static analysis was employed to identify the fatigue-prone points in the main girder.The results indicate that corrosion defects cause significant stress concentration at critical points,which accelerates crack propagation and reduces the structure’s fatigue life by approximately 35%compared to defect-free conditions.Additionally,the crack propagation behavior at fatigue danger points with and without corrosion defects was investigated.The findings show that corrosion defects markedly accelerate the initiation and propagation of fatigue cracks,with the stress intensity at the crack front exceeding the material’s yield strength.When the load was reduced to 70%of the rated load,simulations revealed that stress concentration at the crack tip was alleviated,the risk of plastic deformation was mitigated,and the fatigue life of the main girder was significantly extended.

关 键 词：桥式起重机 主梁 腐蚀缺陷 疲劳裂纹扩展 有限元仿真 疲劳试验 

分 类 号：TH215[机械工程—机械制造及自动化]