Engineering Transactions, 40, 1, pp. 115-131, 1992

Shrinkage Stresses in Dried Materials

S.J. Kowalski
Institute of Fundamental Technological Research, Poznań
Poland

G. Musielak
Institute of Fundamental Technological Research, Poznań
Poland

A. Rybicki
Institute of Fundamental Technological Research, Poznań
Poland

The aim of the paper is to analyse the shrinkage stresses in isotropic material when they do not exceed its strength. The model established in author's previous work is used for describing the problem undertaken. The model relates stresses with strains, moisture content and temperature, The state of dried material is described by a system of five differential equations with double coupling. Their solution must satisfy additionally the compatibility relations. The problem of convectively dried plate is solved as an example. The evolution of both the moisture content and the shrinkage stresses distributions as well as the deformation of the plate during drying process were determined. The finite difference method and the method of separation of variables were used and good agreement of the results obtained on the basis of these two methods were stated. They are presented on graphs.

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References

S.A.BOLEY and J.H.WEINER, Theory of thermal stresses, J.Wiley and Sons, New York-London 1960.

M.ILIC and I.W.TURNER, Drying of a wet porous material, Appl. Math. Modelling, 10, 2, pp.16-24, 1986.

M.ILIC and I.W.TURNER, Convective drying of a consolidated slab of wet porous material, Int. J. Heat Mass Transfer, 32, 12, pp. 2351-2362, 1989.

F.KNEULE, Drying [in Polish], Arkady, Warszawa 1970.

S.J.KOWALSKI, Thermomechanics of constant drying rate period, Arch. Mech. , 39, 3, pp.157-176, 1987.

S.J.KOWALSKI, Thermomechanics of dried materials, Arch. Mech., 42, 2, 123-149, 1990.

S.J.KOWALSKI and G.MUSIELAK, Mathematical modelling of the drying process of capillary-porous media; example of convective drying of a plate, [in Polish] Arch. Mech., 36, 2, pp. 239-252, 1988.

R.W.LEWIS, M.STRADA, and G.COMINI, Drying induced stresses of porous bodies, Int. J. Numer. Meth. Engng., 11, pp.1175-1184, 1977.

A.V.LUIKOV, System of differential equations of heat and mass transfer in capillary-porous bodies, Int. J. Heat. Mass Transfer, 18, pp., 1-14, 1975.

S.B.NASRALLAH and P.PERRE, Detailed study of a model of heat and mass transfer during convective drying of porous media, Int. J. Heat Mass Transfer, 31, 5, pp.957- 967, 1988.

W.NOWACKI, Theory of elasticity [in Polish] PWN, Warsaw 1970.

A.P.SHAPIRO and S.MOTAKET, Unsteady heat and mass transfer with phase change in porous slab: analytical solution and experimental results, Int.J .Heat Mass Trans­fer, 33, 1, pp. 173-174, 1990.

G.C.SIH and A.OGAWA, Transient thermal change on a solid surface: coupled diffusion of heat and moisture, J. Thermal Stresses, 5, pp.265-282, 1982.

G.C.SIH, M.T.SHIH and S.C.CHOU, Transient hygrothermal stresses in composites: coupling of moisture and heat with temperature varying diffusivity, Int. J. Engng. Sci., 18, pp.19-42, 1980.

CZ.STRUMiŁŁO, Elements and technology of drying [in Polish], Warszawa 1970.

I.W.TURNER and M.ILIC, Convective drying of a consolidated slab of wet porous material including the sorption region, Int. Comm. Heat Mass Transfer, 17, 1, pp.39-48, 1990.

S.WHITAKER, Simultaneous heat, mass and momentum transfer in porous media; a theory of drying, Adv. Heat Transfer, 13, pp.119-203, Academic Press, New York 1977.




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