基于全尺寸疲劳试验系统的海洋管道模态分析

Modal Analysis of Marine Pipeline Based on Full-scale Fatigue Test System

以往海洋管道全尺寸疲劳试验的试验类型多为弯曲疲劳,考虑到管道焊缝处环向受力不均且试验周期较长的问题,拟应用共振原理来完成海洋管道疲劳试验,而产生共振的关键在于使激振频率达到管道的固有频率。鉴于此,针对?323.9 mm×18.0 mm、X65钢级海洋管道,利用Workbench有限元分析软件模拟共振式全尺寸疲劳试验系统中海洋管道的工况对其进行了模态分析,采用改变约束个数和位置的方法分析了不同装夹方式对管道固有频率和模态振型的影响。由管道前6阶的固有频率和模态振型可知,随着约束的增加或位置的改变,可使海洋管道的固有频率增大。分析结果为共振式全尺寸疲劳试验系统的设计和优化提供了重要的理论依据。

In the past, the full-scale fatigue tests of marine pipelines were mostly focused on the bending fa-tigue. Considering the uneven circumferential force on the pipeline weld and the prolonged test period, the reso-nance principle is proposed for the fatigue test of marine pipelines. The key to resonance is to make the excitation frequency reach the natural frequency of the pipeline. In view of this, for the 0323. 9 mm X 18. 0 mm, X65 steel grade marine pipeline, the Workbench finite element analysis software was used to simulate the marine pipeline conditions in the resonance full-scale fatigue test system so as to conduct modal analysis. By changing the number of constraints and positions, the effects of different clamping methods on natural frequency and mode shape of pipe-line have been analyzed. According to the first six orders natural frequencies and mode shapes of the pipeline, it can be seen that the natural frequency of the marine pipeline increased with the increase of the constraints or the position change of the constraints. The results provide an important theoretical basis for the design and optimization of the resonant full-scale fatigue test system.