Dynamic characteristics of dwarf Chinese hickory trees under impact excitations for mechanical fruit harvesting

作     者：Du Xiaoqiang Wu Chuanyu He Leiying Tong Junhua 

作者机构：School of Mechanical Engineering and AutomationZhejiang Sci-Tech UniversityHangzhou 310018China Zhejiang Province Key Laboratory of Transplanting Equipment and TechnologyHangzhou 310018China 

出 版 物：《International Journal of Agricultural and Biological Engineering》 (国际农业与生物工程学报（英文）)

年 卷 期：2015年第8卷第1期

页      面：17-25页

核心收录：

学科分类：0710[理学-生物学] 0810[工学-信息与通信工程] 08[工学] 0805[工学-材料科学与工程（可授工学、理学学位）] 0812[工学-计算机科学与技术（可授工学、理学学位）] 

基　　金：financially supported by the National Natural Science Foundation of China(Grant No.51475433,51175476) the Research Fund for the Doctoral Program of Higher Education of China(RFDP)(Grant No.20113318110001) the Program for Scientific Research Innovation Team of Zhejiang Sci-Tech University(Grant No.13020049-Y) the 521 Talent Plan of Zhejiang Sci-Tech University 

主　　题：Chinese hickory mechanical harvest fruit acceleration admittance vibration transmission impact test 

摘      要：Mechanical vibration is an effective fruit harvesting *** evaluate the dynamic characteristics of dwarf Chinese hickory(Carya cathayensis Sarg.)trees and the influence of the tree structure on transmission and attenuation of dynamic response,a new method was proposed based on acceleration admittance measurement on dwarf Chinese hickory trees in orchard environment under impact *** primary resonance frequencies of the tree can be determined based on the acceleration admittance *** effect of the tree structure on the vibratory transmission was quantified using the attenuation ratio of the acceleration admittance.A 5-year-old dwarf Chinese hickory tree sample was *** responses at three resonance frequencies(5,9 and 12 Hz)were analyzed because they were identified as the most effective bands of excitation for the main part of the tree *** results reveal that the variation of the dynamic response along the testing tree is greatly related to the Chinese hickory tree *** attenuation ratio of the acceleration admittance at the branch crotches indicates the leader top crotch may amplify the acceleration admittance no matter what the crotch angle and the branch diameter *** the crotches,the branch chain nodes generally have negative influence on the acceleration admittance along the branch chains which heavily depend on the branch chain *** branch chains with a chain angle no less than 150°and a wood diameter ratio close to 1.0 could produce little influence on the vibration *** those branches with chain angle less than 150°,the vibration was generally attenuated at their chain nodes at three resonance *** impose impact excitations on the tree,high mechanical harvesting efficiency could be achieved on those branch chains which are almost straight and uniform.