The inhomogeneous hardness distribution of high pressure torsion (HPT) processed IF steel disks along different directions is investigated. The results indicated that there exists inhomogeneous distribution in HPT pro...The inhomogeneous hardness distribution of high pressure torsion (HPT) processed IF steel disks along different directions is investigated. The results indicated that there exists inhomogeneous distribution in HPT processed IF steel disks, giving lower hardness in the center and higher hardness in the edge regions. However, on the axisymmetrical section testing plane of the disks’ thickness direction, there is a soft zone near the surface of disks. Further results from radius testing plane of different depths from the surface of HPT processed disks show that the inhomogeneity rules of hardness distribution on the radius direction are similar to that on the thickness direction. Compared with the initial state, different stages of HPT (compression and compression + torsion) can both remarkably increase the hardness of IF steel disks. Microstructure investigation results can give a well support to verify the rules of hardness distribution, showing hardly no change of grains in center and sever plastic deformation in edge. The inhomogeneous distribution of stress and strain with the huge friction between anvil and disks in the process of HPT play an important role of hardness and microstructure distribution.展开更多
In this paper, a miniaturized segment robot using solenoids is developed to mimic the plane locomotion of earthworms. The bioinspired robot is composed of five segmented bodies, and one segment has two solenoid actuat...In this paper, a miniaturized segment robot using solenoids is developed to mimic the plane locomotion of earthworms. The bioinspired robot is composed of five segmented bodies, and one segment has two solenoid actuators. This robot can move linearly and it can also turn due to the pair of solenoid actuators that facilitate the earthworm-like peristaltic locomotion. We have designed a miniaturized solenoid with a permanent magnet plunger in order to increase the total electromagnetic force. A theoretical analysis is performed to predict the linear and turning motions of each segment, and the optimal profiles of input signals are obtained for fast locomotion. Experiments are then conducted to determine the linear and turning motions of the segment robot. It takes about 0.5 s for the five segments to complete one cycle of the peristaltic locomotion. In experiments, the segment robot is shown to have the linear and angular velocities of 27.2 mm·s^-1 （0.13 body-length per second） and 2 degrees per second, respectively.展开更多
文摘The inhomogeneous hardness distribution of high pressure torsion (HPT) processed IF steel disks along different directions is investigated. The results indicated that there exists inhomogeneous distribution in HPT processed IF steel disks, giving lower hardness in the center and higher hardness in the edge regions. However, on the axisymmetrical section testing plane of the disks’ thickness direction, there is a soft zone near the surface of disks. Further results from radius testing plane of different depths from the surface of HPT processed disks show that the inhomogeneity rules of hardness distribution on the radius direction are similar to that on the thickness direction. Compared with the initial state, different stages of HPT (compression and compression + torsion) can both remarkably increase the hardness of IF steel disks. Microstructure investigation results can give a well support to verify the rules of hardness distribution, showing hardly no change of grains in center and sever plastic deformation in edge. The inhomogeneous distribution of stress and strain with the huge friction between anvil and disks in the process of HPT play an important role of hardness and microstructure distribution.
文摘In this paper, a miniaturized segment robot using solenoids is developed to mimic the plane locomotion of earthworms. The bioinspired robot is composed of five segmented bodies, and one segment has two solenoid actuators. This robot can move linearly and it can also turn due to the pair of solenoid actuators that facilitate the earthworm-like peristaltic locomotion. We have designed a miniaturized solenoid with a permanent magnet plunger in order to increase the total electromagnetic force. A theoretical analysis is performed to predict the linear and turning motions of each segment, and the optimal profiles of input signals are obtained for fast locomotion. Experiments are then conducted to determine the linear and turning motions of the segment robot. It takes about 0.5 s for the five segments to complete one cycle of the peristaltic locomotion. In experiments, the segment robot is shown to have the linear and angular velocities of 27.2 mm·s^-1 （0.13 body-length per second） and 2 degrees per second, respectively.
