1997 Fiscal Year Final Research Report Summary
A proposal of mathematical analysis method for a coupled hygrothermoelastic problem in nonhomogeneous bodies and its application to material tailoring of functionally graded material with a function of humidity regulation
| Project/Area Number |
08650084
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Materials/Mechanics of materials
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| Research Institution | lwate University. |
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Principal Investigator |
SUGANO Yoshihiro Iwate Univ., Faculty of Engng., Dept.of Mech.Engng., Professor, 工学部, 教授 (90089160)
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| Project Period (FY) |
1996 – 1997
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| Keywords | Nonhomogeneous Hygrothermoelasticity / Coupled Diffusion Problem / Temperature and Humidity / Hygrothermal Stress / Functionally Graded Materials / Reduction of Thermal Stress / Function of Humidity Regulation / Material Tailoring |
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| Research Abstract |
The purpose of this research is to derive analytical solutions for the coupled diffusion problems of temperature and humidity and the associated hygrothermoelastic problem in nonhomogeneous plate and nonhomogeneous hollow circular cylinder under hygrothermal environment and is to apply these analytical solutions to material tailoring of functionally graded material with a function of humidity regulation.
The coupling effect (Dufour effect) of change in humidity on diffusion of heat is much smaller than the coupling effect (Soret effect) of change in temperature on diffusion of humidity. So an analytical solution is presented to the uncoupled transient temperature field in the functionally graded material plate which has arbitrary nonhomogeneities of thermal properties and temperature variation only through the thickness. The transient temperature solution is determined by solving the nonhomogeneous heat conduction problem in a multilayred plate with piecewise-linear nonhomogeneous thermal conductivity, and different, homogeneous specific heat and density in each layr. The uncoupled humidity field in the functionally graded material plate has the same diffusion equation as the temperature field.
As Soret effect is the effect of temperature change with time on the diffusion of humidity, dynamic thermal stress problem in a functionally graded material plate is solved by the characteristic method for the case of impulsive heating with large temperature change with time.
Furthermore, an analytical solution is presented for a transient temperature and the associated thermal stress due to an abrupt heating on the plate surface in a functionally graded material plate which is composed of n plates with dissimilar piecewise-linear nonhomogeneities. The optimization of material composition taking the minimization of tensile thermal stress into account is carried out for functionally graded material plate composed of PSZ and SUS304 by using genetic algorithm.
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