| 基于局部应变法的焊接微区低周疲劳性能 |
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| 引用本文： | 徐甄真,张建勋. 基于局部应变法的焊接微区低周疲劳性能[J]. 焊接学报, 2023, 44(2): 10-15+31+129. DOI: 10.12073/j.hjxb.20220309001 |
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| 作者姓名： | 徐甄真 张建勋 |
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| 作者单位： | 西安交通大学, 金属材料强度国家重点实验室, 西安, 710049 |
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| 基金项目： | 国家自然科学基金面上资助项目(51875442) |
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| 摘 要： | 针对忽略焊接力学不均匀性的名义应变法评价焊接接头低周疲劳性能不准确的问题，提出一种考虑焊接接头力学不均匀性、基于弹塑性有限元计算的局部应变法，对焊接接头的低周疲劳性能进行准确评价.通过耐热钢电弧焊接头光滑试样和焊缝光滑试样的低周疲劳试验，以及焊接接头光滑试样在加载过程中的弹塑性有限元计算，采用名义应变法和局部应变法分别对耐热钢电弧焊接头光滑试样进行低周疲劳性能评价.结果表明，耐热钢电弧焊接头在低周疲劳载荷下断裂于焊缝区域.采用名义应变法评价该焊接接头时，结果偏保守.由于局部应变法考虑了焊接接头的力学不均匀性，基于断裂微区的局部应变进行疲劳性能评价，发现采用局部应变法得到的焊接接头应变—寿命曲线与断裂微区焊缝的应变—寿命曲线一致.
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| 关 键 词： | 局部应变法 焊接力学不均匀性 低周疲劳性能 弹塑性有限元计算 |
| 收稿时间： | 2022-03-09 |
Low-cycle fatigue properties of welded microzones based on the local strain approach |
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| Affiliation: | State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, 710049, China |
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| Abstract: | Due to the inaccuracy of the nominal strain approach in evaluating the low-cycle fatigue (LCF) properties of welded joints, a local strain approach considering mechanical heterogeneity of welded joints and based on elastic-plastic finite element analysis was proposed to evaluate the LCF properties of welded joints accurately. The LCF tests of smooth specimens of the welded joint of heat-resistant steel and the weld metal were conducted. The elastic-plastic finite element analysis of the smooth specimens of the welded joints during loading was calculated. The LCF properties of the welded joint were evaluated using the nominal and local strain approach. The results showed that the smooth specimens of the welded joint fractured at the softened weld zone. The LCF properties evaluated by the nominal strain approach were conservative. Since the mechanical heterogeneity of the welded joint was considered by the local strain approach, the LCF properties were evaluated based on the local strain in the fractured microzone. Therefore, the strain?life curve of the welded joint obtained by the local strain approach was close to the strain?life curve of the material of the fractured microzone. |
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