The Experts below are selected from a list of 321 Experts worldwide ranked by ideXlab platform
Chong-sool Choi - One of the best experts on this subject based on the ideXlab platform.
-
Damping Capacity of Fe-Ru alloys
Scripta Materialia, 2000Co-Authors: H.-c. Shin, Joong-hwan Jun, Chong-sool ChoiAbstract:In previous studies, some of the authors have reported that an Fe-17%Mn alloy undergoing non-thermoelastic {gamma}(fcc){r_arrow}{epsilon}(hcp) martensitic transformation possesses a high Damping Capacity, and that the Damping Capacity is closely related to the amount of {epsilon} martensite. Blackburn et al. investigated the transformation behaviors of Fe-Ru binary alloys, and reported that Fe-Ru alloys containing above 24%Ru (by weight) experience a {gamma}{r_arrow}{epsilon} martensitic transformation, while Fe-Ru alloys with below 19%Ru undergoes a {gamma}{r_arrow}{alpha}{prime}(bcc) martensitic transformation. it is, thus, expected that the Fe-Ru alloys which undergo a {gamma}{r_arrow}{epsilon} martensitic transformation would exhibit high Damping Capacity parallel to the Fe-17%Mn alloy. However, there are no studies about the Damping properties of a {gamma}{r_arrow}{epsilon} martensitic Fe-Ru alloy. In the present study, the authors investigate the sampling Capacity of a {gamma}{r_arrow}{epsilon} martensitic Fe-25%Ru alloy and evaluate the Damping mechanisms. In addition, the Damping Capacity of a {gamma}{r_arrow}{alpha}{prime} martensitic Fe-13%Ru alloy is investigated in comparison with an Fe-25%Ru alloy.
-
Effect of Si addition on the Damping Capacity of a high carbon steel
Materials Science and Engineering: A, 1999Co-Authors: Joong-hwan Jun, Shin-ho Lee, Young Kook Lee, Chong-sool ChoiAbstract:The aim of this study is to investigate the effects of Si addition and annealing process on the microstructure and Damping Capacity of Fe-1.1wt.%C and Fe-1.1wt.%C-2.0wt.%Si steels. The Damping Capacity increases with increasing annealing time, and for the same annealing time, the Damping Capacity is larger in Fe-1.1wt.%C-2.0wt.%Si steel than Fe-1.1wt.%C steel. It is revealed that the Damping Capacity consists of three parts: the Damping Capacity due to the migration of magnetic domain boundaries in matrix (Ddm), the Damping associated with the precipitated graphites (Ddgr) and the background Damping of the material (d0). The contributions of Ddm and Ddgr to the total Damping Capacity of the steels increase with increasing annealing time. The Ddgr is linearly dependent on the volume fraction of graphite to the 2:3 power, f 2:3 , which corresponds to the total surface area of graphites. This indicates that the plastic flow across the interphase boundaries between matrix and graphites is a Damping mechanism of Ddgr. © 1999 Elsevier Science S.A. All rights reserved.
-
Strain amplitude dependence of the Damping Capacity in Fe-17%Mn alloy
Scripta Materialia, 1998Co-Authors: Joong-hwan Jun, Chong-sool ChoiAbstract:Abstract The Damping Capacity of Fe-17%Mn alloy depending on the e martensite content represents three different trends in the range of 1 × 10 −4 to 10 × 10 −4 strain amplitude. A linear relationship between Damping Capacity and volume fraction of e martensite is established from 1 × 10 −4 to 3 × 10 −4 strain amplitude. It implies that the stacking fault boundaries in ϵ martensite and the ϵ martensite variant boundaries dominantly give rise to the Damping Capacity. In the range of 4 × 10 −4 to 6 × 10 −4 strain amplitude, however, the variation of Damping Capacity with ϵ martensite content is very similar to that of relative length of γ/ϵ interface. This result suggests that movement of γ/ϵ interfaces is introduced as an additional Damping mechanism above 4 × 10 −4 strain amplitude. The Damping behavior depending on the ϵ martensite volume percent in the 7 × 10 −4 to 10 × 10 −4 strain amplitude is nearly the same as that in the 4 × 110 −4 to 6 × 10 −4 strain amplitude range, except for the abnormally high Damping Capacity of the specimen with 35% of ϵ martensite. This is probably caused by microslip deformation in the austenite phase.
-
strain amplitude dependence of the Damping Capacity in fe 17 mn alloy
Scripta Materialia, 1998Co-Authors: Joong-hwan Jun, Chong-sool ChoiAbstract:Abstract The Damping Capacity of Fe-17%Mn alloy depending on the e martensite content represents three different trends in the range of 1 × 10 −4 to 10 × 10 −4 strain amplitude. A linear relationship between Damping Capacity and volume fraction of e martensite is established from 1 × 10 −4 to 3 × 10 −4 strain amplitude. It implies that the stacking fault boundaries in ϵ martensite and the ϵ martensite variant boundaries dominantly give rise to the Damping Capacity. In the range of 4 × 10 −4 to 6 × 10 −4 strain amplitude, however, the variation of Damping Capacity with ϵ martensite content is very similar to that of relative length of γ/ϵ interface. This result suggests that movement of γ/ϵ interfaces is introduced as an additional Damping mechanism above 4 × 10 −4 strain amplitude. The Damping behavior depending on the ϵ martensite volume percent in the 7 × 10 −4 to 10 × 10 −4 strain amplitude is nearly the same as that in the 4 × 110 −4 to 6 × 10 −4 strain amplitude range, except for the abnormally high Damping Capacity of the specimen with 35% of ϵ martensite. This is probably caused by microslip deformation in the austenite phase.
-
Damping Capacity in Fe-Mn based alloys
Scripta Materialia, 1997Co-Authors: Kwang-koo Jee, W.y. Jang, Seung-han Baik, Myung-chul Shin, Chong-sool ChoiAbstract:Abstract 1. 1) Stacking faults and e martensite both act for Damping with the latter much more effective. The Damping Capacity by e martensite is proposed to be caused by the phase boundary movement with the static hysteresis on vibration. 2. 2) We show that Damping Capacity of Fe-Mn based alloys depends on the area and mobility of Y/E boundary by varying microstructure. At a low strain amplitude, the area is more dominant than the mobility, and reverse is also true.
Hideo Nakajima - One of the best experts on this subject based on the ideXlab platform.
-
vibration Damping Capacity of lotus type porous magnesium
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2006Co-Authors: Zhenkai Xie, Masakazu Tane, Soong-keun Hyun, Yoshiyuki Okuda, Hideo NakajimaAbstract:Abstract Lotus-type porous magnesium with cylindrical pores aligned unidirectionally was fabricated by the unidirectional solidification of molten magnesium under pressurized hydrogen atmosphere. The apparent attenuation coefficient of the free vibration of lotus-type porous magnesium was measured by hammering–vibration–Damping tests, which revealed that the apparent attenuation coefficient increases with increase in porosity, i.e., the Damping Capacity of lotus magnesium is higher than that of non-porous magnesium. The mechanism of high Damping Capacity was analyzed by using the Fourier transform technique, which revealed that various vibration modes of high frequency are excited by a hammering. The excited vibrations of high frequency enhance the Damping Capacity of lotus-type porous magnesium.
-
Vibration-Damping Capacity of Lotus-Type Porous Magnesium at Room Temperature
Materials Science Forum, 2006Co-Authors: Zhenkai Xie, Masakazu Tane, Soong-keun Hyun, Takumi Banno, Yasuo Yamada, Yosiyuki Okuda, Hideo NakajimaAbstract:Lotus-type porous magnesium with a large number of unidirectional cylindrical pores was fabricated by unidirectional solidification of melt dissolving hydrogen in a pressurized hydrogen atmosphere. The vibration-Damping Capacity of the lotus-type porous magnesium plate which has many open pores was measured in this work. The attenuation coefficients of the free vibration of lotus-type porous magnesium were measured by hammering-vibration-Damping test, which revealed that the attenuation coefficients increase with increase in porosity; the Damping Capacity of lotus magnesium is higher than that of non-porous magnesium. The mechanism for high Damping Capacity was analyzed on the basis of the Fourier transform technique, which indicates that various vibration modes of high frequency are observed. The excited vibrations of high frequency enhance the Damping Capacity of lotus-type porous magnesium.
-
Vibration–Damping Capacity of lotus-type porous magnesium
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2005Co-Authors: Zhenkai Xie, Masakazu Tane, Soong-keun Hyun, Yoshiyuki Okuda, Hideo NakajimaAbstract:Abstract Lotus-type porous magnesium with cylindrical pores aligned unidirectionally was fabricated by the unidirectional solidification of molten magnesium under pressurized hydrogen atmosphere. The apparent attenuation coefficient of the free vibration of lotus-type porous magnesium was measured by hammering–vibration–Damping tests, which revealed that the apparent attenuation coefficient increases with increase in porosity, i.e., the Damping Capacity of lotus magnesium is higher than that of non-porous magnesium. The mechanism of high Damping Capacity was analyzed by using the Fourier transform technique, which revealed that various vibration modes of high frequency are excited by a hammering. The excited vibrations of high frequency enhance the Damping Capacity of lotus-type porous magnesium.
Etsuo Marui - One of the best experts on this subject based on the ideXlab platform.
-
The Damping Capacity improvement of machine tool structures by balls packing
International Journal of Machine Tools and Manufacture, 2004Co-Authors: Yasunori Wakasawa, Masatoshi Hashimoto, Etsuo MaruiAbstract:Efficient manufacturing is achieved by the Damping Capacity improvement of machine tool structure. The purpose of this study is to clarify the parameters influencing the Damping Capacity of machine tool structures packed with balls. In structures closely packed with balls, various Damping characteristics appear in correspondence with the ball size and other conditions. The effect of ball size is the most significant factor in these structures. Excitation of structure is necessary for close packing, however, this process is troublesome. Excitation of structure is required to achieve an optimum packing ratio where the maximum Damping Capacity is obtained. For a 50% packing ratio, this excitation process is not necessary to obtain a stable Damping Capacity. Therefore, the effects of magnitude of impulse, packed ball material, and structure size on the Damping Capacity are investigated at a 50% packing ratio. Finally, actual machine tool structure models are constructed, and the effectiveness of the balls packing for the Damping Capacity improvement is investigated.
-
Additional effect of electroless plating film (Damping Capacity improvement)
Industrial Lubrication and Tribology, 2002Co-Authors: Hiroki Endo, Etsuo MaruiAbstract:Electroless plating treatment is one surface modification technique. An added effect due to electroless plating is expected, and the vibration Damping Capacity of the structures may be improved by this technique. In the present study, the vibration Damping Capacity of such electroless plated structures is measured experimentally. Damping Capacity can be improved regardless of the plated film materials. Improvement efficiency with an electroless plating film with dispersed foreign particles such as SiC ceramics is higher than with a uniform electroless plating film.
-
Damping Capacity improvement of machine structures by close packing with balls
International Journal of Machine Tools and Manufacture, 2002Co-Authors: Yasunori Wakasawa, Masatoshi Hashimoto, Etsuo MaruiAbstract: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.
-
Plate insertion as a means to improve the Damping Capacity of a cutting tool system
International Journal of Machine Tools & Manufacture, 1998Co-Authors: Etsuo Marui, Masatoshi Hashimoto, Satoshi Ema, Yasunori WakasawaAbstract:Effective chatter prevention during cutting operations is achieved by increasing the Damping Capacity of a cutting tool system. It is well known that Damping Capacity is generated through (i) micro-slip at the interface between the tool shank and tool post, (ii) slip at the grain boundary within a vibrating body (that is, internal friction), and (iii) friction between the surface of the vibrating body and the surrounding air. Among these three causes of Damping Capacity, micro-slip at the interface between the tool shank and tool post is the greatest factor affecting the Damping Capacity of the cutting tool system. In the research investigation, it is shown that the Damping Capacity of a cutting tool system is improved by friction acting between the inner wall of a rectangular hole made at the overhanging shank of the cutting tool system and the surface of a plate inserted into this rectangular hole. The Damping Capacity improvement proposed in this paper is realized by a mechanism similar to the inner friction mechanism.
-
Damping Capacity of Turning Tools, Part 2: Mechanism Initiating the Damping Capacity
Journal of Engineering for Industry, 1993Co-Authors: Masatoshi Hashimoto, Etsuo Marui, Shinobu KatoAbstract:This paper examines the mechanism initiating the Damping Capacity of a turning tool. The turning tool is considered as a beam on an elastic foundation. Parameters of the model are estimated from the experimental result of the free damped vibration frequency. Next, the magnitude of Damping energy is calculated from the friction resistance and the relative slip between the tool shank and the tool post (elastic foundation) during vibration in both tangential and normal directions. The calculated result of Damping energy agrees well with the experimental result of the Damping Capacity qualitatively, for various clamping loads and various surface topographies. This result indicates that the Damping Capacity of the turning tool system is mainly caused by the relative slip at the tool shank.
Haowei Wang - One of the best experts on this subject based on the ideXlab platform.
-
Damping Capacity of in situ tib2 particulates reinforced aluminium composites with ti addition
Materials & Design, 2007Co-Authors: Yijie Zhang, Haowei WangAbstract:Abstract The Damping Capacity of in situ aluminium (Al)/TiB2 composite and composite with Ti excess was investigated. The composites were fabricated with an exothermic reaction process via K2TiF4 and KBF4 salts. The Damping behavior of materials over a temperature range of 30–300 °C was investigated using a dynamic mechanical thermal analyzer. Experimental findings indicate that Damping Capacity of composite with Ti excess is lower than that of Al/5 wt% composite when temperature below 110 °C and higher than of Al/5 wt% composite above 110 °C. The main effect of Ti is the formation of thin layer on TiB2 particulates resulted in the change of Damping Capacity.
-
Mechanical properties and Damping Capacity of magnesium matrix composites
Composites Part A: Applied Science and Manufacturing, 2006Co-Authors: Xiuqing Zhang, Lihua Liao, N. H., Haowei WangAbstract:Magnesium matrix composites reinforced by TiC particulates was prepared using in situ synthesis method. The mechanical properties and Damping Capacity of the composites was examined. The experimental results revealed that the TiC particulates play an important role on mechanical properties and Damping Capacity of the composites. In our study, compared to AZ91 magnesium alloy, Damping Capacity and tensile strength of the composites improve. The mechanical characterization is explained with the strengthening mechanisms as grain size and Orowan bowing. The Damping characterization is explained with dislocation motion, twinning, grain boundary slip and interface slip.
-
mechanical properties and Damping Capacity after grain refinement in a356 alloy
Materials Letters, 2005Co-Authors: Yijie Zhang, Haowei WangAbstract:Abstract JR-6 nano-grain refiner was employed to investigate mechanical properties and Damping Capacity of A356 alloy after grain refinement. Experimental findings indicate that α-Al dendritic arm spacing reduced from 44 μm to 23 μm in size after grain refinement. With T6 heat treatment, gliding fracture only was observed by SEM on fracture region after refinement, which filled with dimple fully. Tensile testing results show that A356 alloy after refinement has better mechanical properties, which increased by 30 MPa, 24 MPa, 4.1% in tensile strength, yield strength and elongation, respectively. Damping measurement shows Damping Capacity of A356 alloy after grain refinement is higher than that of without refinement. Moreover, Damping Capacity increases with increasing the temperature and decreases with increasing frequency. With testing condition of room temperature and frequency of 0.5 Hz Damping Capacity of A356 alloy after grain refinement is 13 × 10− 3, increased by 5 × 10− 3 compared to A356 without refinement in same case. Also Damping mechanisms are discussed basing on experimental results.
Yasunori Wakasawa - One of the best experts on this subject based on the ideXlab platform.
-
The Damping Capacity improvement of machine tool structures by balls packing
International Journal of Machine Tools and Manufacture, 2004Co-Authors: Yasunori Wakasawa, Masatoshi Hashimoto, Etsuo MaruiAbstract:Efficient manufacturing is achieved by the Damping Capacity improvement of machine tool structure. The purpose of this study is to clarify the parameters influencing the Damping Capacity of machine tool structures packed with balls. In structures closely packed with balls, various Damping characteristics appear in correspondence with the ball size and other conditions. The effect of ball size is the most significant factor in these structures. Excitation of structure is necessary for close packing, however, this process is troublesome. Excitation of structure is required to achieve an optimum packing ratio where the maximum Damping Capacity is obtained. For a 50% packing ratio, this excitation process is not necessary to obtain a stable Damping Capacity. Therefore, the effects of magnitude of impulse, packed ball material, and structure size on the Damping Capacity are investigated at a 50% packing ratio. Finally, actual machine tool structure models are constructed, and the effectiveness of the balls packing for the Damping Capacity improvement is investigated.
-
Damping Capacity improvement of machine structures by close packing with balls
International Journal of Machine Tools and Manufacture, 2002Co-Authors: Yasunori Wakasawa, Masatoshi Hashimoto, Etsuo MaruiAbstract: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.
-
Plate insertion as a means to improve the Damping Capacity of a cutting tool system
International Journal of Machine Tools & Manufacture, 1998Co-Authors: Etsuo Marui, Masatoshi Hashimoto, Satoshi Ema, Yasunori WakasawaAbstract:Effective chatter prevention during cutting operations is achieved by increasing the Damping Capacity of a cutting tool system. It is well known that Damping Capacity is generated through (i) micro-slip at the interface between the tool shank and tool post, (ii) slip at the grain boundary within a vibrating body (that is, internal friction), and (iii) friction between the surface of the vibrating body and the surrounding air. Among these three causes of Damping Capacity, micro-slip at the interface between the tool shank and tool post is the greatest factor affecting the Damping Capacity of the cutting tool system. In the research investigation, it is shown that the Damping Capacity of a cutting tool system is improved by friction acting between the inner wall of a rectangular hole made at the overhanging shank of the cutting tool system and the surface of a plate inserted into this rectangular hole. The Damping Capacity improvement proposed in this paper is realized by a mechanism similar to the inner friction mechanism.
