The direct generalization of the well known method of symbolic (rheolo
gical) models is presented. Special attention is paid to Maxwell and B
ingham materials. It is shown that modified constitutive equations for
Maxwell and Bingham materials are not sensitive to the method of spli
tting the viscoelastoplastic deformation into two parts: elastic and v
iscous or viscoplastic. Different possible methods of splitting are pr
esented and discussed.