2018 Volume 3 Pages 197-202
In recent years, the number of patients with articular cartilage disease has been increasing. To diagnose the disease at an early stage, a non-contact diagnostic method is required. This paper describes the development of a method for measuring the viscoelastic properties of articular cartilage by acoustic excitation at low frequency. In this method, the articular cartilage's complex shear modulus is obtained by measuring the phase velocity of a stationary wave on the articular cartilage that is excited by a wide range speaker; the displacement response at the surface of the specimen is simultaneously measured at multiple points by two laser displacement sensors. The phase velocities of shear waves are obtained from the displacement responses and then the viscoelastic properties are evaluated using a Voigt model. In this paper, the effectiveness of the system was investigated by measuring the viscoelastic properties of a gelatin phantom with a collagen concentration of 5 wt. % at 50~120 Hz excitation. The results showed that vibrations with the same frequencies as the input waves were produced in the specimen and that the obtained phase velocities and viscoelastic properties were similar to those obtained in previous studies.
