2007 Fiscal Year Final Research Report Summary
Risk Assessment and Design Criteria ofAged Piping System under Seismir Load
| Project/Area Number |
18360055
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (B)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Materials/Mechanics of materials
|
|---|
| Research Institution | Yokohama National University |
|---|
Principal Investigator |
SHIRATARI Masaki Yokohama National University, Division of System Research, Professor (60017986)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
YU Qjang Yokohama National University, Division of System Research, Associate Professor (80242379)
SHIBUTANI Tadahiro Ykohama National University, Division of System Research, Research Associate (10332644)
|
|---|
| Project Period (FY) |
2006 – 2007
|
| Keywords | Aged Piping System / Risk Assessment to Seismic Load / Low-cycle Fatigue / Wall Thinning / Ratchet / Life to Failure / Finite Element Method / Elasto-plastic Analysis |
|---|
| Research Abstract |
This report presents failure mechanism and dynamic behavior of aged piping system subjected to seismic loads. Computational and experimental approach was performed in this study. This report also presents design criteria for aged piping system. Elasto-plastic response of piping system with wall thinning was examined by using proposed model. Then, we carried out comparison study of failure modes for piping system subjected to in-plane, out-plane, and mixed-mode bending loads. Based on experimental and computational results, we established a fundamental methodology of assessment of the aged piping system. The proposed method consists of simplified dynamic analysis and elasto-plastic analysis. In simplified three-dimensional dynamic analysis, piping system was modeled by piping element which can express oval deformation of the cross-section of the pipes. Displacements were measured by using dynamic finite element analysis. Elasto-plastic analysis was performed to extract detail behaviors such as ratcheting, oval deformation and so on with wall thinning. Miner's rule and Asada's experimental formula were used to estimate fatigue lives of the piping system. Computational estimation agrees with experimental data. Finally, a fundamental approach to estimate a safety margin of aged piping system was verified.
|
