Non-linear ultrasonic and viscoelastic properties of gelatine investigated in the temperature range of 30 °C–60 °C

Abstract : Analysis based on the determination of the multifactorial non-linearity parameter (β) is a promising non-destructive investigation and testing technique. The contribution of temperature variations on the non-linear coefficient is known to be lower than that of hydrostatic pressure changes. We investigated the effect of temperature on the non-linearity parameter in the range 30 °C–60 °C for a viscous, gelatinous compound, resulting from controlled hydrolysis of the collagen protein. Considerable thermal effects are realized and are related to changes in viscous and elastic properties. Remarkable changes in the non-linearity coefficient at temperatures corresponding to the transition temperature of gelatine of 60 °C indicate a signature while no outspoken hysteresis effects were realized with cyclic temperature sweeps. Despite the non-Newtonian nature of the gel, our experiments show comparability to water within the examined range of temperature, which corresponds to a wavelength shift of about 40 μm.