| dc.description.abstract | The purpose of this study is to investigate the phenomenon and causes of silo honking during silo discharging. The silo honking is a low-frequency noise with specific frequency, and it is always accompanied by vibration of characteristic frequency during silo discharging, called silo quake. In order to reproduce the phenomenon of silo honking, the experimental system is composed of an upper silo with various silo diameters and different orifices as well as a lower rigid supporting platform. The silos studied here include stainless steel silos with diameters of 101.6mm, 152.4mm, and 216.3mm, and an acrylic silo with a diameter of 200mm. These silos have a height of 2m. The orifice diameters are 40mm, 60mm, 80mm and 120mm respectively. The granular materials used in the study include two kinds of PVC particles and Al2O3 particles. The three-directional accelerations on silo walls and the sound pressure near the silo were measured using four accelerometers and one microphone, and the frequency and phase of the signals were further analyzed. In order to clarify the relation between silo honking and structural resonance, the experimental modal analysis was also performed. Key findings are highlighted below: (1) Silo quake is responsible for silo honking, both have the same characteristic frequency; (2) Structural resonance is not the main cause of silo quake, but it may amplify the phenomenon of silo quake; (3) The resultant force (friction force and radial force) which the particles exert on silo walls may be the cause of the silo quake; (4) The axial vibration is in the form of sinusoidal wave, while the radial vibration and the sound pressure exist in the form of pulse. The radial vibration of the silo leads to the sound generation, called silo honking; (5) The orifice diameter influences the intensity of silo quake and its duration. (6) The inserts installed on the silo bottom have no effect on the silo honking. | en_US |