Research carried out in Granular Dynamics Lab.
Rolling particle damper
This damper is a type of tuned mass dampers (TMDs) that uses granular materials as a dissipative element of an auxiliary system. It consists of a rotary hollow cylinder placed on a curved track mounted on a primary system in which the hollow body is partially filled with granular materials. The dynamic characteristics were studied experimentally and numerically.
Tuned rolling-cylinder damper
This damper is an also kind of TMDs and consists of some rotary bodies placed on a circular arc surface attached to the primary system. The friction force between rotary bodies is a source of energy dissipation of the auxiliary system.
Particle damper
Particle damping is a passive vibration control technique that involves the uses of granular materials operating in the cavity of a primary system. Each collision of the particles with the wall of the cavity results in an attenuation of the response of the primary system. Particle damping with suitable materials can be performed in a wider temperature range than most other forms of passive damping. The aim of our research is to provide a comprehensive design methodology for particle dampers.
Removal of foreign objects in dried foods
It is very difficult to remove small foreign objects in dried foods such as lettuce or cabbage. The reason is that foreign objects are so small that they disappear behind the foods. Also, foreign objects become attached to the food owing to electrostatic forces. Our novel separator makes it possible to remove foreign objects in dried foods. The separator consists of an inclined rotating drum and a cylinder fixed at the center of the drum. The principle of the separation is based on the difference in the charging characteristics and weights of the food and foreign objects.
Effect of the particle shape on granularity
We are investigating a method for simulating the dynamics of granular materials composed of spherocylinders. Each detection of contact and contact force-overlap relation are defined precisely. From the comparison of experimental and calculated results for a vibratory conveyance, it was found that the calculated results follow the experimental trend with reasonable accuracy. ．
Separation of conductors and nonconductors
A technique for separating copper and polyvinyl chloride (PVC) from chopped waste electric cables has been investigated experimentally. The principle of the separation technique is based on the difference in electric conductivity. Separation tests were performed on a sample containing 50% PVC and 50% copper. The purity of PVC was more than 99% with a recovery rate of 93%, and the purity of copper was more than 99% with a recovery rate of 88％.
Electrostatic vibratory separator
This separator consists of a vibratory feeder equipped with two plate electrodes which can be inclined about two axes with respect to the horizontal plane. This separator has the advantage of the use of low voltage.
Electrostatic separator using cylindrical electrodes
This separator is of the freefall type and consists of four cylindrical electrodes. This approach makes it possible to avoid the collision of charged particles with the electrodes.．
Analysis of the behavior of charged Particles in an electrical relay device
A relay is an electrical device that provides a circuit with electricity by opening and closing the contacts of the relay electrodes using an electromagnet . Foreign objects are occasionally created, as a result of damage of a relay cover. When a foreign object moves between the contact points, electricity is not provided to the circuit. We carried out the experimental and analytical study to investigate the motion of a foreign object between relay electrodes.．
Numerical analysis combining the discrete element method and the finite element method
We have constructed an analytical model for investigating collisions between granular materials and a plate. The model is based on the DEM and FEM. The validity of the analytical model was examined by comparison with experimental results.
