高度修正实现刚度等效的梁结构有限元建模方法

民用飞机中对于梁结构的有限元建模，一般采用刚度等效方法将梁建成杆单元与剪切板单元的组合形式，这种有限元简化方法仅能保证截面刚度与真实截面刚度近似等效，但有限元中的截面面积与实际面积却相差较大，致使有限元分析的结果不能准确反映结构严重部位的应力情况。针对传统刚度等效有限元建模方法的不足，提出一种采用高度修正的刚度等效有限元建模方法；将该方法的计算结果与传统建模方法的计算结果、理论计算结果、试验测量结果进行对比。结果表明：本文提出的高度修正的有限元建模方法比传统杆板系建模方法更准确，与试验结果更接近。将该方法用于民用飞机结构有限元建模，能够对真实结构进行更准确地模拟，分析结果也更精确，对民用飞机结构的强度分析和安全保障具有重要的意义。

A finite element modeling method of beam structures using height modification to realize equivalent stiffness

The safety of civil aircraft design is mainly guaranteed by the combination of finite element (FEM) analysis and experiment, the FEM analysis is an supplement to the experiment, while the experiment is a demonstration to the FEM analysis. Based on the principle of equivalent stiffness, the FEM modeling of beam structures in civil aircraft design are usually simplified to the combination of rod elements and shear plane elements, which ensures the stiffness of the FEM cross-section almost equal to the designed section, however the area of the two sections are not equivalent, thus the FEM results can not accurately reflect the stress in critical positions. To address the deficiencies in the existing method, a new method in which the height of the FEM cross-section is modified to realize stiffness equivalence is proposed in this article, the computation results of the traditional method and the proposed method are compared to analytical results, which demonstrates the accuracy of the proposed method.