Study On Relationships Between Picea Species Structures Vibration Properties

This research aimed at the relationship between cell structure, cell alignment, growth characteristics of eight Picea wood and sound vibration parameters. The effects of different Picea wood structure factors on sound vibration properties were systematically investigated.The optimum data ranges were calculated and analyzed. This provided us theoreticalaccording for selecting the instrument wood.The wood characteristics were tested and analyzed, they were mainly the followings. Macroscopically structure characteristics were including annual ring width, latewood percentages and their variance coefficients. Anatomical characteristics were including tracheid length, tracheid diameter, cell thickness, cell wall in-diameter ratio, tracheid length-width ratio, cell wall percentages and fibril angles etc. which are measured by computer vision technique and x-ray diffraction machine. Physical features were including wood density, fibril cystalline index, which was also measured by x-ray diffraction machine. Wood sound characteristic parameters were including Young抯 module, shear module, specific Young抯 module, EIG, sound radiation resistance coefficient and tan 8 etc.According to the data of experiments, the effects on vibration parameters caused by wood structure characteristics were analyzed by excel. Therefore, the relationships between wood structures and sound characteristic parameters were set up. From the analysis not only the variance regulation of different species could be found, but also some factors, which influenced the vibration properties, could be compared. On the basis of above research, main component analysis method was used for screening factors to represent original information as much as possible. The main components had definite major signification, which could simply represent the quality of Picea wood. Further more, the synthesis coordinate value method and the synthesis marking method were applied to give the evaluation and the order of test wood by considering of weighing coefficient of cell alignment, wood growth idiosyncrasy and sound vibration properties.Measuring and testing lots of experiment specimens had identified the research conclusions coherently from many respects. The more even of the annual wood structure, the better of the wood vibration properties. The suitable annual ring width is 1.0-1.5 mm. Thelatewood percentages are l5O/o~28%. The less digital of the longitudinal and radial variance coefficients of the annual ring and the latewood percentage, the better of acoustical properties.Fiber crystallinity index is helpful to increase the vibration efficiency and to keep graceful tone charter, therefore the optimum ciystaJlinity index is about 59%. Besides, most test woodfiber length can reach 4000 L?m, it can keep a high Young抯 modulus, specific Young抯 modulus, so this figure is acceptable. In additionally, the suitable ratio of fiber length to widthis 100-110. The thickness of cell wail 0.030-0.050 ii m (both longitudinal and radial directions). The cell wall percentage is 0.55-0.60. The ratio of cell wall to cavity is 0.30 (both longitudinal and radial directions). The fiber angle is 90 - 170The research results can provide reliable scientific foundation and technique parameters to select instrument wood or to manufacture instrument. Therefore this research has great signil~cance.