| Project/Area Number |
23KF0050
|
|---|
| Research Category |
Grant-in-Aid for JSPS Fellows
|
| Allocation Type | Multi-year Fund |
|---|
| Section | 外国 |
|---|
| Review Section |
Basic Section 23010:Building structures and materials-related
|
|---|
| Research Institution | Osaka University |
|---|
Principal Investigator |
堤 成一郎 大阪大学, 大学院工学研究科, 准教授 (70344702)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
LUO PENGJUN 大阪大学, 大学院工学研究科, 外国人特別研究員
|
|---|
| Project Period (FY) |
2023-04-25 – 2025-03-31
|
| Project Status |
Granted (Fiscal Year 2023)
|
| Budget Amount *help |
¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 2024: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 2023: ¥1,000,000 (Direct Cost: ¥1,000,000)
|
|---|
| Keywords | fatigue / crack / weld / seismic safety / plasticity |
|---|
| Outline of Research at the Start |
溶接構造体の耐震性・疲労性能評価を可能とするデジタルツイン技術の開発を目的とする。特に、多くの不確実性の定量化を可能とするように、変形や破壊のメカニズムを重要して開発を進める。特にこれまで開発を進めている高精度・高校率なFEMシミュレーション技術を活用し、さらに発展させることで、地震荷重に曝される溶接構造体の耐震性・疲労性能評価を可能にする。
|
| Outline of Annual Research Achievements |
Based on the experimental and numerical studies was conducted in this research, It is concluded that the influences of weld toe shape and hardness distribution on the low-cycle fatigue behavior of steel welded joints was identified clearly. Also, due to its outstanding accuracy and robustness in evaluating both the fatigue crack location and fatigue life for the investigated butt-welded joints, the proposed combination of SCF formula with SMF formula is the most recommended method for the one-side full penetration butt-welded joints. These results can provide deep insights into the improvement of low-cycle fatigue life of steel welded joints, which are crucial to ensure the seismic safety of building structures and to mitigate the disastrous effects under long-period ground motions. These results can also help us establish a low-cycle fatigue life evaluation method in capable of considering multiple critical parameters, which will provide a useful tool for evaluating the safety and reliability of welded joints in building structures.
|
| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
The fatigue behavior of butt-welded joints were investigated. Misalignments and weld geometries (including weld toe radius, flank angle, weld reinforcement height, and width) were measured using a 3D optical scanning system and subsequently used for fatigue evaluation. The test results indicate a noticeable decrease in nominal stress fatigue strength as the assembled axial eccentricities increase. Several stress magnification factor (SMF) and stress concentration factor (SCF) formulae available in the literature are employed to characterize the combined effects of misalignment and weld geometries. The investigation results indicate that misalignments and weld geometries both play critical roles in the fatigue behavior of butt-welded joints.
|
| Strategy for Future Research Activity |
Due to its outstanding accuracy and robustness in evaluating both the fatigue crack location and fatigue life for the investigated butt-welded joints, the proposed combination of SCF formula with SMF formula is the most recommended method for the one-side full penetration butt-welded joints. However, the general applicability of the proposed method should be further confirmed through additional test results, as the current study is limited by the number of specimens.
So, the further experimental research is planed under various conditions including geometry and loading effects.
|
