Papers by Keyword: Damping Property

Abstract: Ductile iron was prepared through Sandwich Process and annealing treatment was carried out. The effects of annealing treatment on the microstructure, mechanical and damping properties of ductile iron were studied by means of metallographic microscope, scanning electron microscope, transmission electron microscope, universal test machine and dynamic thermal mechanical analyzer. The results show that annealing treatment has little effect on the morphology and distribution of graphite cast iron, but it will lead to the decrease of pearlite content in the matrix, the increase of ferrite content and the disappearance of cementite. Annealing transforms the fracture form of ductile iron from cleavage fracture to quasi-cleavage fracture, which greatly increases the ductile fracture area of the matrix compared with the as-cast, and tends to develop ductile fracture. The annealing treatment results in a decrease in the tensile strength of the ductile iron, but it can increase the plasticity and increase the elongation after fracture to 7.5 times that of the as-cast state. The damping value of as-cast ductile iron increases first and then decreases with the increase of temperature, and peaks at 190 °C when Q^-1 is 0.025. The damping value of annealing ductile iron decreases with increasing temperature. The damping value increases with increasing strain amplitude before and after annealing. Annealing treatment will reduce the sensitivity of the damping property of ductile iron to strain amplitude.

Abstract: 1-3 piezoelectric-damping composites were fabricated using piezoelectric ceramic as functional filler and epoxy resin as matrix by cut-filling method. The fabrication procedure of the composites was introduced. The effect of ceramic volume fraction on the damping behavior and the piezoelectric strain factor d₃₃ were studied. The results show that the damping property was firstly improved, and then decreased with the increase of the ceramic volume fraction. An optimal ceramic volume fraction of 15% was shown. TA increased from 29.78 to 32.34. The piezoelectric strain factor d₃₃ reached 323pC·N^-1.

Abstract: The nonlinear stiffness and damping properties of the hydro-pneumatic suspension system are introduced, and the nonlinear mathematical model of it is established. Using MATLAB 2009b to establish the computer simulation program and draw out the nonlinear stiffness curve and damping properties curve of the hydro-pneumatic suspension system. Then, researching the influences of related parameters' changes on the nonlinear stiffness and damping properties of the hydro-pneumatic suspension system. The simulation of vehicle dynamic performance research's foundation is provided.

Abstract: A series of thin, low-cost and environment-friendly organic hybrid composites consisting of reclaimed rubber (R-Rubber) which is a waste product of roller processing of textile mill filled with organic hindered phenol compound 2, 2-methylenebis (6-tert-butyl-4-methyl-phenol) (AO2246) were fabricated. In this study the damping property of the R-Rubber composites were tested in the dynamic mechanical analysis (DMA). The study concluded that R-Rubber/AO2246 composites exhibited an exceptional damping performance with a broad temperature range. Meanwhile, by addition of AO2246, the tan δ peak maximum (tan δ _max) of R-Rubber/AO2246 composite was remarkably increased up to 1.5. Furthermore, with increasing the AO2246 content, storage modulus (E') and loss modulus (E") increases up to R-Rubber/AO2246 (100/80) and then becomes smaller. There is critical value on E and E" increasing which is caused by the excessive crystallization. The Interaction of AO2246 crystallizing, hybridized state and Molecular hydrogen bond led not only to control Tan δ _max of R-Rubber, but also to regulate glass transition temperature and improve the storage modulus, which make R-Rubber have potential applications in fields of engineering.

Abstract: Based on the principle of stress-energy method, the functional relationship among maximum acceleration, static stress, dropping height and thickness of a given cushioning material is obtained. Then the comparison of cushioning performance between different cushioning materials is carried out, and the comparison of cushioning performance properties between honeycomb paper and corrugated paper is made. The conclusion is that the corrugated board has a good buffer capacity at the light load, while the honeycomb paperboard has good energy absorption and dissipation capability at the heavy load.

Abstract: The influence of addition elements Mo, Al and B on the Snoek damping behaviors of Ti-25Nb-1.5O were investigated, the alloys were prepared in a vacuum induction electric arc furnace. By means of X-ray diffraction, scanning electron microscopy and dynamic mechanics analyzer, it was found that Mo or Al element addition is unfavorable for the damping properties of the alloys, but Mo element addition improved the dynamic storage modulus. A few B elements addition can improve the damping capacity and the damping stability after the thermal cycle simultaneously. In addition, a large number of B elements additions can dramatically improve the dynamic storage modulus.

Abstract: Discontinuous NiTi SMA thin films were deposited on PZT substrate by magnetron sputtering method with a specially designed pore plate. The microstructure and damping property of the prepared composite were studied with X-Ray diffraction, scanning electric microscopy and dynamic elastic modulus apparatus. It was found that NiTi SMA thin films with physical dimension of width of less-than or equal to 2mm and distance between the adjacent thin films of 1mm are of best equiaxed crystal microstructure after crystallization at 600°C. The damping effect of the composite is still caused by PZT and the damping value is generally lower than that of pure PZT, about 9.9%.

Abstract: Polyurethane/poly (methylacrylate-butylmethacrylate-2-Hydroxyethylmethacrylate) Interpenetrating polymernetworks (IPNs) were prepared by sequential polymerization. Their glass transition performance was measured by using differential scanning calorimetry (DSC). DSC results revealed there are three glass transition temperatures (Tg) for both IPNs samples. Their damping properties were evaluated according to ASTM E756-05. Their loss factor (tan δ>0.3) from 10-1300Hz displays a wide temperature range of 94°C.

Abstract: This work was try to study the relationship between the damping properties and the hydrogen bonds, fractional free volumes of nitrile-butadiene rubber (NBR)/hindered phenol (AO-80) composites from the microstructural point of view by combining the experimental and molecular simulation studies. The results indicated that the hydrogen bonds (HBs) were formed between AO-80 small molecules and NBR polymer chains. According to simulation results, because of the formed strongest HBs, highest binding energy and the smallest fractional free volume in the NBR/AO-80 composites with the blending ratio of 100/68, it contributed the maximum loss factor and highest modulus. It concluded that there was a suitable proportion of rubber blended with small hindered phenol molecules in the design of damping materials.

Abstract: Discontinuous NiTi SMA thin films were deposited on PZT substrate by magnetron sputtering method with a specially designed pore plate. The microstructure and damping property of the prepared composite were studied with X-Ray diffraction, scanning electric microscopy and dynamic elastic modulus apparatus. It was found that the NiTi SMA thin films with physical dimension of the width of less-than or equal to 2mm and distance between the adjacent thin films of 1mm are of best equiaxed crystal structure after crystallization at 600°C. The damping effect of the composite is still caused by PZT and the damping value is generally lower than that of pure PZT, about 9.9%.