This paper deals with an experimental investigation on damping characteristics of structures packed with balls The structures for testing are square pipes packed with glass balls The effects of impulse magnitude, square pipe dimensions, ball size and excitation directions on damping characteristics are investigated The experiments show that the damping characteristics are markedly affected by the ball size, and the damping capacity is improved by the ball packing It is also shown that the damping capacity is affected by the packing arrangements, packing ratio and repulsion coefficient Dramatic improvement in damping capacity is achieved by leaving only a small space between the packed balls and the inner surface of the square pipe This fact is confirmed experimentally

Damping capacity improvement of machine structures by close packing with balls

Metodyka kształtowania wibrostabilności systemu obrabiarka-proces skrawania

Simulation for additive manufacturing

Since the beginning of the 21st century, the importance to manufacture products that involve highquality, hybrid properties, multi-functionality, low-cost, and environmentally-friendly characteristics has been highlighted in the development of new ideas and technologies. Therefore, given that the development of new materials has been following the same trend, a software for the creation of new materials with hybrid properties was developed and evaluated. The developed software involved and calculated several properties, such as density, Young’s modulus, coefficient of linear expansion, specific heat and thermal conductivity. This software was composed of the following two functions: (1) the calculation of the combination and ratio of constituent materials to create a composite material that achieves certain desired properties, and (2) the calculation of the properties shown by the generated composite material based on the combination and ratio of its constituent materials. Subsequently, a three-dimensional functional gradient material (FGM) was manufactured and evaluated based on the developed software. It was concluded from the evaluation that; (1) the proposed software was able to calculate properties such as density, Young’s modulus, coefficient of linear expansion, specific heat and thermal conductivity; (2) the software was useful for the development of a three-dimensional functional gradient material.

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Development of software for the creation of new materials with hybrid properties

Development of Technology for Creating Composite Materials of Machine Tool

The advantages of fiber-reinforced plastic (FRP) are that it has low density and high damping capacity. However, FRP had not yet been commonly used in machine tool structures because of its low Young's modulus, cheeping characteristics, and so on. The most probable use of FRP in machine tools seems to be in combination with a conventional material like steel in order to compensate for the low Young's modulus. In this paper, the damping characteristics of a composite structure beam, which is composed of a steel pipe and FRP, were investigated both theoretically and experimentally. The effects of the fiber direction, each wall thickness of the steel pipe and the FRP on the damping capacity were clarified. It has also been made clear that if the diameter of the composite structure is permitted to increase compared with that of the original steel structure, the damping capacity can be markedly increased under the condition of constant flexural rigidity.

Kazuhiko Shibata

Papers

On the Improvement of the Damping Capacity of a Steel Structure by Overlaying with Fiber-Reinforced Plastics.