| 摘要: |
| 依据BS7448标准对DH36药芯焊丝气保焊接头进行了裂纹尖端张开位移(crack tip opening displacement,CTOD)试验,通过对接头进行组织、断口分析,同时对预制疲劳裂纹过程进行有限元模拟分析,研究不同预制疲劳裂纹最大载荷对CTOD值的影响.结果表明,预制疲劳裂纹最大载荷对CTOD试验结果影响很大.当预制疲劳裂纹最大载荷远小于BS7448标准规定的最大值时,试验过程易出现突跃,即pop-in现象,从而得到较小的CTOD值;反之,当预制疲劳裂纹最大载荷接近或超过BS7448标准规定的最大值时,pop-in现象减弱、延迟或者消失,得到较大的CTOD值.故而为了保证试验结果的可靠性,标准中应对预制疲劳裂纹载荷敏感的接头更严格的规定其最大值. |
| 关键词: 预制疲劳裂纹最大载荷 裂纹尖端张开位移 突跃 |
| DOI： |
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| 基金项目:天津市自然科学基金资助项目(09JCYBJC05100) |
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| Influence of maximum fatigue precracking force on CTOD value of DH36 flux-cored wire CO2 protection welded joints |
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DENG Caiyan1, MENG Qingyu1,2, WANG Dongpo1, GONG Baoming1
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1.Tianjin Key Laboratory of Advanced Joining Technology, Tianjin University, Tianjin 300072, China;2.Xuzhou Construction Machinery Group, Jiangsu Xuzhou Construction Research Institute, Xuzhou 221004, China
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| Abstract: |
| CTOD tests were carried out for flux-cored gas protection welded joints of DH36 according to Standard BS7448. The effect of fatigue precracking force on the CTOD value was investigated by analyzing the microstructure and fracture surface of the joint and finite element simulation on the process of fatigue precracking. The results show that the maximum fatigue precracking force has a tremendous influence on CTOD value. When the maximum fatigue precracking force was less than the specified value in Standard BS7448, the test process was prone to pop-in phenomenon, and smaller CTOD value occurred. Conversely, when the maximum fatigue precracking force was close to or exceeding the specified value, the CTOD value would be larger. Thus the Standard should be strictly limited to the maximum fatigue precracking force to ensure the reliability of test results. |
| Key words: maximum fatigue precracking force crack tip opening displacement pop-in |
