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Click on “Download PDF” for the PDF version or on the title for the HTML version. If you are not an ASABE member or if your employer has not arranged for access to the full-text, Click here for options. Mechanical Admittance Measurement and Analysis of Chinese Hickory Trees under Impact ExcitationsPublished by the American Society of Agricultural and Biological Engineers, St. Joseph, Michigan www.asabe.org Citation: 2012 Dallas, Texas, July 29 - August 1, 2012 121341162.(doi:10.13031/2013.42070)Authors: Shaozhong Chen, Xiaoqiang Du, Chuanyu Wu Keywords: Chinese hickory, mechanical harvest, mechanical admittance, vibration transmission, impact test Beating is the usual way to harvest Chinese hickory (Carya cathayensis Sarg.) nuts because of large size of trees and scattered distribution of nuts. Analyzing and comprehensively understanding the dynamic characteristics of Chinese hickory trees is important to design high efficiency mechanical harvester. An impact testing system consisting of a data acquisition and analysis system, an impact hammer and an acceleration sensor was used to measure the mechanical admittance of a Chinese hickory tree sample. Its resonance frequencies, as well as the influence of the tree structure on transmission and attenuation of dynamic response, were analyzed based on the mechanical admittance analysis. The obtained primary resonance frequencies were detected on the main part of the sample tree. The variation of the dynamic response along the testing tree was greatly related to the Chinese hickory tree structure. The effect of the crotch and chain nodes on the acceleration response was quantified using the attenuation ratio of the acceleration admittance. Results obtained from this study revealed that the leader top crotch may amplify the acceleration admittance no matter what the crotch angle and the branch diameter was. Unlike the crotches, the branch chain nodes generally had depressed influence on the acceleration admittance along the branch chains which heavily depended on the branch chain configuration. However, the branch chains with large chain angle and uniform wood diameter could produce little influence on the vibration transmission which suggests that high mechanical harvest efficiency could be obtained on such branches. (Download PDF) (Export to EndNotes)
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