1999 Fiscal Year Final Research Report Summary
Research on the Propagation of Thermal and Thermal Stress Waves in FGMs
| Project/Area Number |
09650094
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Materials/Mechanics of materials
|
|---|
| Research Institution | Shizuoka University |
|---|
Principal Investigator |
SUMI Naobumi Shizuoka University Fac. of Education Professor, 教育学部, 教授 (20022189)
|
|---|
| Project Period (FY) |
1997 – 1999
|
| Keywords | Thermal Stress Waves / FGM / Characteristic Method / Generalized Thermoelasticity / Relaxation Time / Coupling Parameter |
|---|
| Research Abstract |
The Functionally Graded Materials (FGMs) for high-temperature applications have special composition distributions in which two different base materials, such as ceramics and metals, are compound with gradually changing composition in order to display functions such as the reduction of the thermal stresses and the shielding of the heal flow. Information about the behavior of FGMs is important in understanding the response to a dynamic thermal input of composite materials and materials with impurities.
This research deals with the propagation of thermal and mechanical waves in FGMs under impulsive heat addition. The development of the analysis is based on the generalized theory of thermoelasticity, a coupling between thermal and mechanical fields is taken into account and the classical Fourie's law is also modified by adding a thermal relaxation term to the heat conduction equation. In this research, a set of unified equations is presented, which is applicable to plane, cylindrical, and spherical waves in FGMs. The solutions are obtained by using the method of characteristics.
The numerical data are obtained for ceramic/metal FGMs subjected to two types of temperature-change input : one is the ramp-type heating on the surface of the FGMs and the other is the internal heat generation by the absorption of laser-pulses. The material parameters of the FGM are determined from the volume fraction of the inclusion phase by assuming the FGM as a spherical inclusion-matrix material system.
The influences of the magnitude of the relaxation time and the volume fractions of the constituents of the FGMs on the profile of the thermal and mechanical waves are found.
|
