| 王欣,张峰,郭晓光,王远友,滕儒民.门式起重机主梁蚀坑-裂纹模型应力强度因子研究[J].,2024,64(2):164-172 |
| 门式起重机主梁蚀坑-裂纹模型应力强度因子研究 |
| Study of stress intensity factor of corrosion pit-crack model for main girder of portal crane |
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| DOI：10.7511/dllgxb202402007 |
| 中文关键词: 门式起重机 蚀坑 有限元 应力强度因子 |
| 英文关键词: portal crane corrosion pits finite element stress intensity factor |
| 基金项目:辽宁省高校创新团队资助项目(LT2014001). |
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| 中文摘要: |
| 造船门式起重机长期服役在沿海的潮湿盐雾环境中，主梁多处受腐蚀疲劳形成了蚀坑，影响了结构强度．腐蚀疲劳裂纹成核是一个局部损伤演化的过程，应力强度因子准则是判定蚀坑处萌生裂纹的临界条件之一．在门式起重机有限元模型的基础上建立了蚀坑-裂纹模型，并使用ANSYS软件对复杂边界条件下应力强度因子进行了仿真计算．结果显示，预制裂纹深度和蚀坑深径比影响了应力强度因子的取值，随着蚀坑深径比的增大，蚀坑-裂纹模型的应力强度因子明显增大．应力集中现象可能是引起裂纹萌生的主要因素，蚀坑半径的变化对应力强度因子的影响并不明显．根据半椭球点蚀假设，提出了蚀坑处应力强度因子与应力集中系数的关系式，发现蚀坑对应力强度因子的影响与应力集中系数正相关；随着蚀坑深径比的增大，裂纹萌生位置会随着应力集中位置的变化而变化． |
| 英文摘要: |
| Shipbuilding portal cranes have been in long-term service in the coastal humid, salt and mist environment, and corrosion pits caused by corrosion fatigue in many places affect the structural strength of the main girder. Corrosion fatigue crack nucleation is a local damage evolution process, the stress intensity factor criterion is one of the critical conditions to discern the crack initiation at the corrosion pits, a corrosion pit-crack model is established based on the finite element model of the portal crane, and the stress intensity factor under complex boundary conditions is simulated and calculated using ANSYS software. The results show that the precast crack depth and depth to radius ratio of the corrosion pits affect the value of the stress intensity factor, the stress concentration phenomenon may be the main factor causing the crack initiation; and with the increase of the depth to radius ratio of the corrosion pits, the stress intensity factor of the corrosion pit-crack model is significantly increased. The change in the radius of the corrosion pits does not have a significant impact on the stress intensity factor. According to the hypothesis of semi-ellipsoidal pitting, the relationship between the stress intensity factor and the stress concentration coefficient at the corrosion pits is proposed, and it is found that the effect of the corrosion pits on the stress intensity factor is positively related with the stress concentration coefficient. With the increase of the depth to radius ratio of the corrosion pits, the location of crack initiation will change with the change of the stress concentration location. |
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