Grant-in-Aid for Scientific Research (C).
Materials/Mechanics of materials
|Research Institution||Shizuoka University|
NODA Naotake Shizuoka University, Faculty of Engineering, Professor, 工学部, 教授 (20022238)
ISHIHARA Masayuki Shizuoka University, Faculty of Engineering, Reasearch Associate, 工学部, 助手 (60283339)
TSUJI Tomoaki Shizuoka University, Faculty of Engineering, Associate Professor, 工学部, 助教授 (80188531)
|Project Fiscal Year
1998 – 2000
Completed(Fiscal Year 2000)
|Budget Amount *help
¥3,200,000 (Direct Cost : ¥3,200,000)
Fiscal Year 2000 : ¥700,000 (Direct Cost : ¥700,000)
Fiscal Year 1999 : ¥800,000 (Direct Cost : ¥800,000)
Fiscal Year 1998 : ¥1,700,000 (Direct Cost : ¥1,700,000)
|Keywords||Crack propagation paths / Thermal stresses / Functionally gradient material plates / Fracture mechanics / stress intensity factor / Finite element method / Unsteady state / Cracks / き裂進展挙動 / 熱応力 / 傾斜機能材料 / 破壊力学 / 応力拡大係数 / 有限要素法 / 非定常 / き裂 / 弾性 / 熱衝撃 / き裂伝播 / 亀裂伝播|
This research project consists of two parts :  Study of thermal stress intensity factors in the functionally graded material plates (FGPs) with cracks under thermal load,  A study of crack propagation paths in FGPs under thermal load by Finite Element Methods (FEM).
PART  : Study of constitutional equations of the functionally graded materials (FGMs) under thermal loading.
(1) We proposed a laminated composite model to study FGMs with arbitrary compositional profile subjected to thermal loading.
(2) Multiple crack problems could be treated by the proposed a laminated composite model.
(3) When FGPs with collinear crack are subjected thermal loading, stress intensity factor at an inner edge of collinear crack is larger than one at outer edge and increases with decreasing the distance of each crack.
PART  : A study of crack propagation paths in FGPs under thermal load by Finite Element Methods (FEM).
(1) We could develop a program with automatically production of mesh of FEM.
For the single crack growth simulation, the straight or curved cracks are obtained for several conditions of the thermal shock and the compositional profiles. Some cracks curve sharply and grow in the direction parallel to the surface. Such cracks cause delamination of the surface. The other cracks are arrested in the middle of the plate.
(3) As two crack growths is one of the basic forms of the multiple thermal cracking, the interaction between the two cracks are discussed. The cracks grow in curve and away from each other, when the cracks exist in short distance. For spalling cracks that come close to each other from a long distance, the cracks curve in the direction normal to the surface as the crack tips come closer. Then the cracks are arrested in the middle of the plate.
* 平板表面から二個の垂直き裂が進展する場合、(a)二つのき裂は互いにとうざかる方向に屈曲して進展する。(b)二個の垂直き裂が十分離れているとき、互いにき裂が近づく方向にき裂が進展しても、ある程度まで近づくとき裂は再び屈曲し、き裂は合体しない。 Less