Analysis of the hickory tree motion under the excitation of eccentric-type vibratory mechanism

Abstract. In order to ensure the effective transmission of vibration energy and improve the efficiency of vibratory harvest, different forms of excitation force generated by different combinations of eccentric blocks were analyzed. First, according to the hickory tree structure, the finite element model of a hickory tree was established in the finite element analysis software ANSYS. Harmonic response analysis was applied to determine the steady-state response when a sine load was added to the hickory tree, and the best excitation frequency of 22Hz for the hickory tree was obtained. Next, the flexible model of the hickory tree was imported into ADAMS through the data exchange function between ANSYS and ADAMS. And the corresponding load was imposed on the tree model in ADAMS to simulate the hickory tree response under the excitations of different combinations of eccentric blocks. The results show that when excited at the treetop of the main branch, the response of the main branch was strong but those of the side branches were small. When excited at the trunk bifurcation, the main branch and the side branches had high response, and the acceleration response on each branch was very close. While excited at the trunk, the response was small. The eccentric block combination with space-vertical axes generated both radial excitation and axial excitation simultaneously, and made the acceleration response distribute more evenly in the hickory tree.