| 種別 | paper |
| 主題 | AE Application to Fracture Mechanics |
| 副題 | |
| 筆頭著者 | Masayasu OHTSU （Kumamoto University） |
| 連名者1 | |
| 連名者2 | |
| 連名者3 | |
| 連名者4 | |
| 連名者5 | |
| キーワード | |
| 巻 | 11 |
| 号 | 2 |
| 先頭ページ | 673 |
| 末尾ページ | 678 |
| 年度 | 1989 |
| 要旨 | INTRODUCTION The application of fracture mechanics to concrete materials is actively investigated to study the tensile and shear failure of concrete structures(1).The fracture mechanics is also of practical use far clarifying fundamental mechanisms of cracking. A critical stress intensity factor K was originally introduced as a fracture toughness parameter based on the linear elastic fracture mechanics (LEFM),whereas the applicability of LEFM to concrete is in debate. A major drawback of LEFM results from the presence of fracture process zone(2).To take into account the process zone, a cohesive crack model and a smeared crack model are proposed in the finite element method (FEM). In the previous paper(3),the application of the boundary element method (BEM) to an analysis of crack propagation was studied,based on LEFM. Although crack traces predicted were in reasonable agreement with experimental findings,no care was taken with respect to the effect of the process zone. To confirm the feasibility of the previous procedure and to elucidate the length of the process zone ,AE observation in a four-point-bending test of relatively small specimens is performed and plausible KIc values applicable to the prediction analysis of crack traces are investigated . CONCLUSION The scope of the research is to estimate the critical value KIc for the initiation of the process zone,because the procedure for the prediction of crack traces is under development. The feasibility of the values is investigated in respect to the characteristic length,which is determined from the value KIc by AE observation and the tensile strength. Results show that for high toughness materials,the present procedure based on AE observation and LEFM is available. |
| PDFファイル名 | 011-01-2113.pdf |