1.

論文
論文
1. Estimation of Thermal Shock Resistance of Al_2O_3 Ceramics by Laser Irradiation
Akiyama, Shigeru ; Amada, Shigeyasu ; Yoshii, Tokuharu
出版情報: JSME international journal. Ser. A, Mechanics and material engineering.  38  pp.594-600,  1995-10-15.  社団法人日本機械学会
概要: application/pdf<br />Journal Article<br />Various structural ceramics have been developed as heat-resistant materials. In some applications it is anticipated that they will be exposed to very-high-temperature environments of the order of … thousands of degrees. Moreover, these ceramics are subjected to thermal loadings which change rapidly with time. Therefore, it is very important to investigate their thermal shock characteristics. In this report, the distributions of temperatures and thermal stresses of cylindrical-shaped Al_2O_3 ceramics under irradiation by laser beams are analyzed using the finite element method. Critical fracture curves are obtained from the relationships between spot diameters of laser beams and maximum values of thermal stresses for various power densities of laser beams. The irradiation experiments yield these critical fracture curves, and theoretical and experimental curves are in good agreement. 続きを見る
2.

論文
論文
2. Estimation of Fracture Conditions of Ceramics by Thermal Shock with Laser Beams based on the Maximum Compressive Stress Criterion
AKIYAMA, Shigeru ; AMADA, Shigeyasu
出版情報: JSME international journal. Ser. 1, Solid mechanics, strength of materials.  35  pp.94-95,  1995-01-15.  社団法人日本機械学会
概要: application/pdf<br />Journal Article<br />Structural ceramics are attracting attention in the development of space planes, aircraft and nuclear fusion reactors because they have excellent wear-resistant and heat-resistant … characteristics. However, in some applications it is anticipated that they will be exposed to very-high-temperature environments of the order of thousands of degrees. Therefore, it is very important to investigate their thermal shock characteristics. In this report, the distributions of temperatures and thermal stresses of cylindrically shaped ceramics under irradiation by laser beams are discussed using the finite-element computer code (MARC) with arbitrary quadrilateral axisymmetric ring elements. The relationships between spot diameters of laser beams and maximum values of compressive thermal stresses are derived for various power densities. From these relationships, a critical fracture curve is obtained, and it is compared with the experimental results. 続きを見る