跨行自走式采茶机机架有限元分析

Finite Element Analysis on Steel-frame Designed for Self-propelled Tea Picker

本文针对自走式采茶机的设计原理与农艺需求,设计了一种跨行自走式机架.经理论分析,确定该机架由空心圆钢焊接而成.同时运用ANSYS对设计的机架进行了静力学强度分析和振动特性分析.静力学分析结果显示最大应力、应变发生在机架左后方上部圆钢焊接处,分别为27 Mpa和0.2 mm,表明机架强度满足要求.约束模态分析得出了机架前六阶模态阵型与模态频率：第一、二、五阶为弯曲模态,第三、四为扭转模态,第六阶为弯扭组合模态;前六阶主频率分别为18.021、25.346、31.636、36.209、45.892、51.694 Hz.分析可知,自走式采茶机激振源主要包括：为发动机——38.3～41.7 Hz、切割器——20 Hz、路面激励低于3 Hz,与机架前六阶主频率相互错开,故而机架不会发生共振.研究表明设计的机架满足自走式采茶机的总体工作要求.

The design of a steel-pipe frame for the self-propelled tea picker was subjected to a finite element analysis to determine its engineering durability. Statics of the design, as evaluated by ANSYS, showed a maximum stress of 27 Mpa and strain of 0.2 mm could be exerted on the welding at the top-left-rear comer of the frame. And, they were within the design tolerance. The vibration analysis on the design indicated that the 1st, 2nd and 5th were in a bending mode, the 3rd and 4th a torsional mode, and the 6th a bending-and-torsion mode. The principle frequencies of the modes were 18.021, 25.346, 31.636, 36.209, 45.892 and 51.694 Hz for the 1st through the 6th mode, respectively. The analysis also showed the sources of vibrations were 38.3~41.7 Hz coming from the engine, 20 Hz from the cutter, and 3 Hz or lower from the ground-surface friction. Thus, the vibrations would not likely to resonate with the 6 modes listed above to cause a concern for the mechanical integrity of the picker frame. Consequently, the design was considered safe and fimctional for the engineering requirements.