Nuclear material containment buildings are required to be periodically inspected to assure good quality conditions. To this end, there is increasing interest in developing efficient and economical testing techniques to monitor and inspect these structures. In this paper we study the dynamic behavior of a 1/3 mock-up containment structure and its internal pressure-dependence using testing techniques that may not interfere with the structure’s operation. The goal is to assess the possibility of monitoring internal pressure and potential leakage by measuring the structural frequency of vibration. The Vercors mock-up structure, a post-tensioned double-wall concrete structure of dimensions 15 m diameter and 30 m tall, was internally pressurized from 0 to 4 bar. We attached a pair of accelerometers at the outer surface of the inner structure and recorded signals periodically without imposing any controlled dynamic input; thus, we used an output-only dynamic analysis. We found that there is a clear positive correlation between internal pressure and the identified frequencies of vibration. We developed a multi-variable correlation, using several frequencies of vibration and the measured pressure, which could be used to monitor internal pressure. To study the underlying physical behavior, we built a finite element model. The observed frequency shift due to applied internal pressure could be partially explained by the effect of geometric nonlinearity, but it does not explain the entire range of frequency shift. Material nonlinearity should also be considered to assess this problem.

中文翻译：

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使用操作振动对后张式安全壳建筑物的内部压力进行监测

需要定期检查核材料安全壳建筑物以确保良好的质量条件。为此，人们越来越关注开发有效且经济的测试技术来监控和检查这些结构。在本文中，我们使用不会干扰结构运行的测试技术来研究 1/3 模型安全壳结构的动态行为及其内部压力依赖性。目标是通过测量振动的结构频率来评估监测内部压力和潜在泄漏的可能性。Vercors 模型结构是一种后张双壁混凝土结构，直径为 15 m，高为 30 m，内部加压为 0 至 4 bar。我们在内部结构的外表面安装了一对加速度计，并在不施加任何受控动态输入的情况下定期记录信号；因此，我们使用了仅输出动态分析。我们发现内部压力与确定的振动频率之间存在明显的正相关。我们开发了多变量相关性，使用多个振动频率和测量压力，可用于监测内部压力。为了研究潜在的物理行为，我们建立了一个有限元模型。由于施加的内部压力而观察到的频移可以部分地由几何非线性的影响来解释，但它并不能解释整个频移范围。还应考虑材料非线性来评估此问题。