农机链链板与套筒最优过盈量有限元分析及试验研究

正确选择链板与套筒的配合过盈量，可以有效降低链板应力幅和应力集中系数，提高疲劳强度。针对传统计算过盈应力方法不适合链板非轴对称结构，文中根据配合表面位移连续条件拟合过盈量，并利用配合表面上力的等值条件建立有限元模型，推导有限元程序。通过与厚壁筒理论值应力场计算比较，证实了该程序具有很高的可靠性和精度。对16A链板应力场有限元理论分析和疲劳试验的结果表明：随着过盈量增加，应力幅不断减小，当过盈量数值继续增加而应力幅保持不变时，此数值即为最优过盈量。而合理的过盈量应为最优过盈量开始的某一范围。16A链板合理过盈量为0.06～0.08 mm，相对无过盈时其疲劳强度可提高40%～50%。

Analysis and experiment of the optimum shrink range between chain plate and bush for agricultural machinery chain by using finite element method

Selecting suitably the shrink range between chain plate and bush can effectively decrease the stress and the factor of stress concentration, and increase the fatigue strength of chain. But the traditional method is unfitted for the non-axisymmetric structure of chain plate. A finite element method(FEM) model was set up based on the condition of equivalence on the fitted surface. Then a program is put forward by simulating the shrink range from the continuous displacement on the fitted surface. It is confirmed that the program has a high reliability and degree of accuracy by means of comparing the calculated results with the theoretical stress pattern of thick shell cylinder. The results of the FEM analysis and the fatigue test for Type 16A chain all indicate that the stress scope reduces with the shrink range increasing. The optimum shrink range value could be obtained when the shrink range increases while the stress remains unchanged. The reasonable shrink range should be within the certain range just beyond the optimum shrink point. It is obtained that the reasonable shrink range for Type 16A chain is from 0.06 mm to 0.08 mm. The fatigue strength at this value increases by 40% to 50% compared with that of no shrink range.