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为了研究Q235低碳素钢平板对接焊接试件以及十字型承载V型坡口焊接试件的低周疲劳行为,采用等幅应变控制法对24个试件在不同塑性应变幅下的超低周疲劳性能进行了测试,拟合得到了两类焊接构造细节试件的疲劳寿命S-N曲线,并将测试结果与国际焊接协会发布的疲劳设计规程中同类焊接构造细节的S-N曲线进行对比.结果表明:平板对接焊接试件与十字型承载V型坡口焊接试件的裂纹起源不相同;在超低周疲劳范围内,两类焊接材料的损伤破坏主要包括材料延性损伤和循环疲劳损伤,比国际焊接协会中相同疲劳构造细节的高周疲劳寿命S-N曲线预期的疲劳强度更低,表现出更低的疲劳寿命.
In order to study the low cycle fatigue behavior of Q235 low carbon steel flat butt welded specimens and cross-shaped V-grooved welded specimens, the effect of constant strain control on the ultra-low cycle of 24 specimens with different plastic strain amplitude The fatigue life is tested and the SN curve of fatigue life of two kinds of welded structural details is obtained and compared with the SN curves of the details of similar welding structure in the fatigue design rules issued by the International Welding Society.The results show that: The crack origin of the flat butt welded specimens and the cross-shaped V-grooved welded specimens is not the same. Within the range of ultra-low cycle fatigue, the damage of the two types of welding materials mainly includes ductile damage and cyclic fatigue damage, The high-cycle fatigue life SN curve of the same fatigue-structural detail in the association is expected to have a lower fatigue strength and exhibit a lower fatigue life.