Determining time-dependent viscoelastic characteristics of liquid or fluid with solid component

The viscoelastic characteristics determination method involves a glass-fibre body (1) with its parts deflectable by vibrations, entirely immersed into a substance (4). The frequency of a mechanical excitation using a piezoelectric element (2) is transmitted to the body (1), and the phase position of one of its periodically varying physical values is determined relative to that of the excitatory frequency. The time dependency of the mechanical vibration of the body or of a part of it, is determined across an ultrasonic objective (3). This produces an electrical signal, the phase position of which is relative to that of the mechanical excitation, and is used for determining the connection between the relative phase position and the excitation frequency.