轴向中空壁管抗冲击性能试验研究与数值分析∗

Experimental Study and Numerical Analysis of Anti-impact Performence of Axial-hollow-wall Pipe

摘要:

轴向中空壁管作为一种新型结构壁管，几何构型简单、空间利用率高、且能量耗散性好，近年来在市政工程中得到广泛应用。为研究轴向中空壁管在低速冲击作用下的力学响应和耗能特性，设计了 20 个试验工况，以落锤冲击试验模拟施工过程中受到的落石冲击和机械撞击作用，基于量纲分析法提出冲击力峰值的计算方法，通过有限元软件 ABAQUS 对试验结果进行验证，并根据有限元计算结果分析管道在低速冲击作用下的变形特性和损伤机理。研究表明：数值分析结果与试验结果吻合较好，冲击力时程曲线趋势基本一致，冲击力峰值误差在 5% 以内。 轴向中空壁管具有良好的抗冲击性能，其双壁中空结构具有较好的能量耗散性，落锤与管道接触瞬间会产生较大的冲击力，12.9 kg 的落锤从 2 m 处自由下落冲击管道可产生 15.28 kN 的冲击力。对比 20 个试验工况的冲击力峰值试验值与计算值，误差均较小，最大误差为 5.8%，即冲击力峰值计算方法准确性较高。随着落锤高度和质量的增加，冲击力峰值增大，损伤区域和凹痕深度也随之增大，最大塑性应变由外壁内侧转移到外壁与加劲肋的连接处， 呈现出外壁损伤和加劲肋损伤两种损伤模式。提出的冲击力峰值计算方法和管道塑性损伤规律可以为施工过程中轴向中空壁管在落石冲击和机械撞击作用下的安全评价提供理论依据。

Abstract:

As a new type of structural wall pipe， the axial-hollow-wall pipe is widely used in municipal engineering in recent years because of its simple geometry， high space utilization， and good energy dis-sipation. To study the mechanical response and energy dissipation characteristics of the axial hollow-wall pipe under the action of low-velocity impact， twenty experimental conditions were designed， and the drop weight impact experiment was used to simulate the rockfall impact and mechanical impact in the construction process. A calculation method for peak impact force based on dimensional analysis was proposed， and the finite element software ABAQUS was used to verify the experimental results and analyze the pipeline deformation properties and damage mechanism. The research shows that the numerical analysis results are in good agreement with the experimental results， the trend of the impact force curve is basically the same， and the error of the peak impact force is within 5%. The pipeline has good shock resistance， and its double-wall hollow structure has good energy dissipation. A large im-pact force can occur at the moment when the drop hammer hits the pipe. An impact force of 15.28kN can be produced by a 12.9kg hammer falling freely from a height of 2m. The calculated impact force is compared with the tested one for the 20 test conditions， indicating that the error is small， with a maxi-mum error of 5.8%， which proves the calculation method of the impact force has high accuracy. As the height and weight of the falling hammer increase， the impact force， damage area and dent depth al-so increase. The maximum plastic strain is transferred from the inner side of the outer wall to the con-nection between the outer wall and the stiffener， showing two damage modes of the outer wall damage and the stiffener damage. The calculation method for the impact force and the plastic damage laws of pipes provide a theoretical basis for the safety evaluation of axial hollow-wall pipelines under the action of rockfall impact and mechanical impact during the construction process.