应变片位置的应变水平对旋转弯曲疲劳试验的影响

旋转弯曲疲劳试验是检测航空导管合格率的重要手段之一。在无扩口导管旋转弯曲疲劳试验中,通常将应变片粘贴在靠近导管承受最大应力处,但二者之间难以避免地存在误差,影响试验结果。针对此问题,基于应力-应变的理论分析,采用Abaqus软件对7种常见规格的TA18无扩口导管进行有限元仿真模拟,得到其应变片位置处的应变值及导管最大应变值,并进行试验验证。结果表明：导管实际产生的最大应变与应变片位置处所测得的应变值的相对误差在7%左右。参照航标,采用以应变片读数低于理论应变值5%的修正方法来进行试验,对确保试验结果的准确性具有一定的指导意义。

Effect of Strain Level at Strain Gauge Position on Rotary Bending Fatigue Test

Rotary bending fatigue test is one of the important means to detect the qualification rate of aviation conduits. In the rotary bending fatigue test of the no flaring conduit, the strain gauge is usually pasted near the maximum stress that the conduit bears, but there are inevitably errors between them, which affect the test results. In order to solve this problem, based on the theoretical analysis of stress-strain, Abaqus software was used to carry out finite element simulation of 7 kinds of common specifications of TA18 no flaring conduit, and the strain value at the position of the strain gauge and the maximum strain value of the conduit were obtained, and the experiment was carried out. The results show that the relative error between the maximum strain actually generated by the conduit and the strain value measured at the position of the strain gauge is about 7%. Referring to the navigation mark, the test was carried out by the correction method that the reading of the strain gauge was lower than the theoretical strain value by 5%. It has certain guiding significance to ensure the accuracy of the test results.