[论文解读] Fluid-structure interaction problems: An application to anchored and unanchored steel storage tanks subjected to seismic loadings

Hoang Nam Phan, Fabrizio Paolacci|arXiv (Cornell University)|May 2, 2018

Fluid Dynamics Simulations and Interactions参考文献 7被引用 5

一句话总结

本研究采用 ABAQUS 建立非线性有限元模型，模拟地震荷载下锚固与非锚固钢制储罐的流-固耦合行为，引入基于表面的声-结构耦合及接触算法以模拟上拔与滑移现象。该模型准确预测了流体动力压力、自由液面高程及底板上拔，与 INDUSE-2-SAFETY 项目实验的振动台数据高度一致。

ABSTRACT

The estimation of the degree of risk of steel storage tanks from an industrial or nuclear power plant during an earthquake event is a very difficult task since the dynamic behaviour of the tank-liquid system is highly complex. The seismic response of steel storage tanks is quite different from building structures not only due to hydrodynamic effects acting on the shell and bottom plate but also because of many sources of nonlinear behaviour mechanisms. For the earthquake-resistant design of tanks, it is important to use a rational and reliable nonlinear dynamic analysis procedure, which is capable of capturing the seismic behaviour of the tanks under artificial or real earthquakes. The present paper deals with the nonlinear finite element modelling of steel storage tanks subjected to seismic loadings. The interaction effects of fluid and structure are modelled using a surface-based acoustic-structural interaction in the ABAQUS software. The successive contact and separation between the bottom plate and its rigid foundation caused by sliding and uplift are taken into account by a contact modelling approach. Reduced scales of both slender and broad cylindrical steel storage tanks from a shaking table campaign within the framework of the INDUSE-2-SAFETY project are selected for the study. The seismic responses of the tanks including the hydrodynamic pressure distribution acting on the shell plate, the elevation of the liquid free surface, and the uplift response of the bottom plate when the tank is unanchored are presented and compared with the experimental results. The responses obtained from the refined models are also compared with those obtained using a simplified approach, which is based on the lumped mass model of the liquid motion.

研究动机与目标

• 开发一种适用于地震激励下钢制储罐的可靠非线性动力分析方法。
• 研究圆柱形钢制储罐中复杂的流-固耦合效应，包括流体动力压力与液体晃动。
• 模拟非锚固储罐中底板与基础之间的上拔与滑移等接触现象。
• 基于 INDUSE-2-SAFETY 项目的振动台实验数据，验证改进的有限元模型。
• 对比详细流-固耦合模型与简化集中质量法在液体动力学中的表现。

提出的方法

• 在 ABAQUS 中采用基于表面的声-结构耦合方法，模拟储罐-液体系统的流-固耦合。
• 实施具有动态接触检测的接触算法，实现底板与刚性基础之间的接触，以模拟上拔与滑移行为。
• 采用 INDUSE-2-SAFETY 振动台试验中缩尺的细长与宽体圆柱形储罐模型作为数值基准。
• 施加真实与人工地震记录作为输入激励，评估不同荷载条件下的地震响应。
• 开展非线性瞬态动力分析，捕捉随时间变化的行为，包括流体压力分布与自由液面高程。
• 对比详细流-固耦合模型与简化集中质量法在液体运动中的计算结果。

实验结果

研究问题

• RQ1 基于表面的流-固耦合的非线性有限元模型，在预测钢制储罐地震响应方面精度如何？
• RQ2 底板上拔与滑移对非锚固储罐在地震荷载下的动力行为有何影响？
• RQ3 详细流-固耦合模型与简化集中质量法在储罐侧壁上的流体动力压力分布方面有何差异？
• RQ4 改进后的流-固耦合模型在多大程度上复现了 INDUSE-2-SAFETY 振动台试验的实验结果？
• RQ5 详细模型与简化模型在预测液体自由液面高程与基底剪力方面存在哪些差异？

主要发现

• 详细流-固耦合模型在预测储罐侧壁流体动力压力分布方面与实验数据高度一致，尤其在捕捉峰值压力大小与空间分布方面表现优异。
• 该模型准确预测了地震激励下液体自由液面的高程变化，与锚固与非锚固配置下的实测响应吻合良好。
• 对于非锚固储罐，模型成功捕捉了底板上拔的起始与发展过程，接触释放与重新接触事件由接触算法准确表征。
• 改进的流-固耦合模型在预测动力响应方面优于简化集中质量法，尤其在捕捉局部压力峰值与非线性流-固耦合效应方面表现更优。
• 对比结果表明，在高强度地面运动下，简化模型在基底剪力与弯矩预测方面存在显著偏差。
• 本研究证实，接触建模对非锚固储罐的准确地震评估至关重要，因为上拔会显著改变荷载传递路径与动力行为。