Thomas Mütze

Prediction of silo-vibrations using a modified lambdameter

Predicting silo-vibrations is not yet universally possible but only to a very limited extent. A mechanism of excitation of silo vibrations can be found in oscillating shear stresses between the bulk solid and the inner silo wall, the so-called “wall-stick-slip” effect. So if this wall-stick-slip occurs during shear experiments in shear testers, the probability of silo-vibrations in silos will be high. However if there is no slip-stick effect observed, this will not consequently exclude silo-vibrations. The influences on a stable stick-slip were studied in wall friction experiments with a rotational shear tester and in a specially developed silo model based on a lambdameter. The examined parameters are normal stress, shear velocity, wall roughness and particle shape. Plastic pellets which are known to honk (PET, PA) and plastic pellets that do not honk (PE) are considered [1]. It is shown that the silo model based on a lambdameter is more suitable for initiation and measurement of stable wall-stick-slip of...