航空扩口导管轴向收缩量快速预测方法

Fast Prediction Method of the Axial Contraction of Aviation Flared Tube

航空扩口导管的轴向收缩量是影响管路装配质量的重要因素,对于扩口段轴向长度不合格的管件,只能凭工人经验现场调整。常用的有限元法需多次模拟才可求得轴向收缩量,效率较低。自主开发扩口管一步逆成形程序,提出径向投影法获得初始解,并采用网格光顺算法提高初始解精度,经全量理论的塑性迭代获取初始管坯尺寸,从而在几秒内快速预测出精确的轴向收缩量,为设计阶段管坯尺寸的确定提供依据。将扩口管一步逆成形程序的轴向收缩量预测过程与商用有限元软件LS-DYNA、Abaqus对比,一步逆成形程序极大地简化了前处理操作,提高了计算效率。选取多个不同规格的典型航空用导管进行冲压扩口成形试验,一步逆成形程序模拟量相对于试验值的误差在6.33%以内。扩口管一步逆成形程序计算速度快,求解精度高,可准确预测扩口管轴向收缩量,具有工程应用意义。

The axial contraction of the aviation flared tube is an important factor affecting the pipeline assembly. Currently the flared tube whose axial length is not qualified for the flared section is only adjusted on site by the workers’ experience. Commonly used finite element methods require multiple simulations to obtain the axial contraction amount, and the computation efficiency is low. An one-step inverse analysis program of flared tube is developed. A radial projection method is proposed to obtain an initial guess, and the mesh smoothing algorithm is used to improve the precision of the initial guess. The size of the initial tube is obtained through the plastic iteration based on the full-scale theory, and the exact axial contraction is predicted within several seconds. The predicted axial contraction can provide basis for the determination of tube blank size in the design stage. Compared with the commercial finite element software LS-DYNA and Abaqus, the one-step inverse analysis program obviously simplifies the pre-processing operation and improves the calculation efficiency. Typical aviation flared tubes in different specifications are chosen for the stamping and flaring experiments. The error of results of one-step inverse analysis program is within 6.33% compared with experimental values. Generally speaking, the one-step inverse analysis program of flared tube has a fast calculation speed and high solution precision, can accurately predict the axial contraction of the flared tube and has a high practical application value.