Fatigue properties and fracture mechanism of load carrying type fillet joints with one-sided welding
Fatigue properties and fracture mechanism of load carrying type fillet joints with one-sided welding
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DOI：
10.3221/igf-esis.35.23
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发表时间：
2015-12
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影响因子：
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通讯作者：
Takamasa Abe;H. Akebono;Masahiko Kato;A. Sugeta
中科院分区：
文献类型：
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作者：
Takamasa Abe;H. Akebono;Masahiko Kato;A. Sugeta
液压挖掘机和起重机的结构具有大量的单侧焊接接头。然而，具有盒状结构的附件难以在两侧焊接。因此，需要高精度的评价方法。为了更准确地评估单面焊承载角接头的疲劳损伤，对单面焊承载角接头的疲劳性能和断裂机理进行了试验研究。结果，试件中的疲劳裂纹从未焊接部分的尖端开始并扩展到焊接材料中。在未焊接部分观察到多个焊接缺陷，但似乎不是裂纹源。虽然这些焊接缺陷影响裂纹扩展的方向，但它们的影响很小。三维观察表明，疲劳裂纹开始在疲劳发展的早期阶段。我们推断，疲劳寿命主要取决于裂纹扩展寿命。裂纹在试样的多个部位开始。随着循环次数的增加，这些裂纹扩展并结合。因此，考虑多裂纹源的裂纹组合对于精确评估疲劳损伤是非常重要的。
The structures of the hydraulic excavator and the crane have numerous one-sided welded joints. However, attachments with box like structures are difficult to weld at both sides. Therefore, high accurate evaluation method is needed. In this study, the fatigue properties and the fracture mechanism of the load carrying type fillet joints with one-sided welding were investigated experimentally to evaluate its fatigue damage with high accuracy based on the experimental results. As the results, fatigue cracks in the test piece initiated from the tip of the unwelded portion and propagated into the welding materials. Multiple welding defects were observed in the unwelded portion, but did not appear to be crack origins. Although these welding defects affected the direction of crack propagation they exerted minimal influence. The three-dimensional observations revealed that fatigue cracks initiate at an early stage of the fatigue development. We infer that the fatigue lifetime is chiefly governed by the crack propagation lifetime. Cracks were initiated at multiple sites in the test piece. As the number of cycles increased, these cracks propagated and combined. So considering the combination of cracks from multiple crack origins is important for a precise evaluation of fatigue damage.