HYGROTHERMAL STRESSES IN A SOLID - CONSTANT SURFACE STRESS

The hygrothermal stresses in a solid with a boundary condition of constant surface stress have been investigated. Three simple geometries: thin slab, sphere, and cylinder, have been considered. The effect of geometry on temperature distribution and moisture absorption inside the solid from small to large follows the sequence: thin slab, cylinder, and sphere. If the temperature on the surface is a function of time whereas the moisture on the surface remains constant, the location of plastic deformation appears in the interior region during the coupled transfer process. On the other hand, when the moisture absorption is a function of time whereas the temperature is kept constant, the plastic deformation always occurs on the surface if possible. The maximum shear stress (sigma(z)-sigma(r))/2 of cylinder is similar to the maximum shear stress sigma(gammagamma)/2 of thin slab, and the maximum shear stress (sigma(r)-sigma(t))/2 of sphere is similar to the maximum shear stress (sigma(r)-sigma(theta))/2 of cylinder.