On constrained sintering-I. Constitutive model for a sintering body

In this series of papers, the constitutive equations used to analyze concurrent shear and densification are critically evaluated. In Part I, it is shown that the sintering materials are not linearly viscoelastic, so Laplace transform techniques cannot be applied. This is not a serious limitation, however, because the relevant deformation of the matrix can be treated as purely viscous flow. Assuming that the strains produced by sintering and applied stresses are linearly additive, a simple constitutive equation is obtained. This will be compared with other constitutive equations from the literature in Part II.