Porous TiNiCu ternary shape memory alloys （SMAs） were successfully fabricated by powder metallurgy method. The microstructure, martensitic transformation behavior, damping performance and mechanical properties of th...Porous TiNiCu ternary shape memory alloys （SMAs） were successfully fabricated by powder metallurgy method. The microstructure, martensitic transformation behavior, damping performance and mechanical properties of the fabricated alloys were intensively studied. It is found that the apparent density of alloys decreases with increasing the Cu content, the porous Ti50Ni40Cu10 alloy exhibits wide endothermic and exothermic peaks arisen from the hysteresis of martensitic transformations, while the porous Ti50Ni30Cu20 alloy shows much stronger and narrower endothermic and exothermic peaks owing to the B2-B19 transformation taking place easily. Moreover, the porous Ti50Ni40Cu10 alloy shows a lower shape recovery rate than the porous Ti50Ni50 alloy, while the porous Ti50Ni30Cu20 alloy behaves reversely. In addition, the damping capacity （or internal friction, IF） of the porous TiNiCu alloys increases with increasing the Cu content. The porous Ti50Ni30Cu20 alloy has very high equivalent internal friction, with the maximum equivalent internal friction value five times higher than that of the porous Ti50Ni50 alloy.展开更多
Aiming at the impaction among granules of non obstructive particle damping(NOPD), the vibration absorption model for vertical impact of granules is established by adopting Hertz contact theory. The numerical simulati...Aiming at the impaction among granules of non obstructive particle damping(NOPD), the vibration absorption model for vertical impact of granules is established by adopting Hertz contact theory. The numerical simulation of the granules movement process is proceeded, and the vibration response of a free free uniform beam is obtained for the case when all granules act on it. Through this method, the effect on vibration absorption of impaction is investigated. The simulational data show that multi gra nule vertical impaction is not sensitive to the movement clearance. The vibration absorption is also very well when the clearance changes within a large range. Therefore, the phenomenon that the vibration magnitude may increase if the clearance in a single impact body is improperly selected will not happen. The effect of vibration suppression in the range of middle and high frequencies(2 500~6 000 Hz) is better than that in the range of low frequency(<2 500 Hz). It indicates that the effect on vibration absorption of multi granule can well restrain the vibration of middle and high frequencies.展开更多
基金Projects(50871039,51205135)supported by the National Natural Science Foundation of ChinaProject(S2011040001436)supported by the Guangdong Provincial Natural Science Foundation,China
文摘Porous TiNiCu ternary shape memory alloys （SMAs） were successfully fabricated by powder metallurgy method. The microstructure, martensitic transformation behavior, damping performance and mechanical properties of the fabricated alloys were intensively studied. It is found that the apparent density of alloys decreases with increasing the Cu content, the porous Ti50Ni40Cu10 alloy exhibits wide endothermic and exothermic peaks arisen from the hysteresis of martensitic transformations, while the porous Ti50Ni30Cu20 alloy shows much stronger and narrower endothermic and exothermic peaks owing to the B2-B19 transformation taking place easily. Moreover, the porous Ti50Ni40Cu10 alloy shows a lower shape recovery rate than the porous Ti50Ni50 alloy, while the porous Ti50Ni30Cu20 alloy behaves reversely. In addition, the damping capacity （or internal friction, IF） of the porous TiNiCu alloys increases with increasing the Cu content. The porous Ti50Ni30Cu20 alloy has very high equivalent internal friction, with the maximum equivalent internal friction value five times higher than that of the porous Ti50Ni50 alloy.
文摘Aiming at the impaction among granules of non obstructive particle damping(NOPD), the vibration absorption model for vertical impact of granules is established by adopting Hertz contact theory. The numerical simulation of the granules movement process is proceeded, and the vibration response of a free free uniform beam is obtained for the case when all granules act on it. Through this method, the effect on vibration absorption of impaction is investigated. The simulational data show that multi gra nule vertical impaction is not sensitive to the movement clearance. The vibration absorption is also very well when the clearance changes within a large range. Therefore, the phenomenon that the vibration magnitude may increase if the clearance in a single impact body is improperly selected will not happen. The effect of vibration suppression in the range of middle and high frequencies(2 500~6 000 Hz) is better than that in the range of low frequency(<2 500 Hz). It indicates that the effect on vibration absorption of multi granule can well restrain the vibration of middle and high frequencies.
