Department of Civil and Structural Engineering, The University of Sheffield, Sir Frederick Mappin Building, Mappin Street, Sheffield S1 3JD, UK.
Blastech Ltd., The Innovation Centre, 217 Portobello, Sheffield S1 4DP, UK.
Sensors (Basel). 2023 Jan 14;23(2):964. doi: 10.3390/s23020964.
The design of blast-resistant structures and protective systems requires a firm understanding of the loadings imparted to structures by blast waves. While empirical methods can reliably predict these loadings in the far field, there is currently a lack of understanding on the pressures experienced in the very near field, where physics-based numerical modelling and semi-empirical fast-running engineering model predictions can vary by an order of magnitude. In this paper, we present the design of an experimental facility capable of providing definitive spatially and temporally resolved reflected pressure data in the extreme near field (Z<0.5 m/kg1/3). The Mechanisms and Characterisation of Explosions (MaCE) facility is a specific near-field evolution of the existing Characterisation of Blast Loading (CoBL) facility, which uses an array of Hopkinson pressure bars embedded in a stiff target plate. Maraging steel pressure bars and specially designed strain gauges are used to increase the measurement capacity from 600 MPa to 1800 MPa, and 33 pressure bars in a radial grid are used to improve the spatial resolution from 25 mm to 12.5 mm over the 100 mm radius measurement area. In addition, the pressure bar diameter is reduced from 10 mm to 4 mm, which greatly reduces stress wave dispersion, increasing the effective bandwidth. This enables the observation of high-frequency features in the pressure measurements, which is vital for validating the near-field transient effects predicted by numerical modelling and developing effective blast mitigation methods.
抗爆结构和防护系统的设计需要对爆炸波传递给结构的荷载有坚实的理解。虽然经验方法可以可靠地预测远场的这些荷载，但目前对近场非常近的区域内的压力缺乏了解，而基于物理的数值模型和半经验快速运行的工程模型预测在该区域可能相差一个数量级。在本文中，我们介绍了一个实验设施的设计，该设施能够提供极端近场（Z<0.5 m/kg1/3）中具有明确空间和时间分辨率的反射压力数据。爆炸机制和特征（MaCE）设施是现有爆炸荷载特征（CoBL）设施的特定近场演化，该设施使用嵌入在刚性靶板中的一组霍普金森压力棒。马氏体时效钢压力棒和专门设计的应变计用于将测量能力从 600 MPa 提高到 1800 MPa，并且在 100 mm 半径测量区域内，33 个压力棒以径向网格的形式用于将空间分辨率从 25 mm 提高到 12.5 mm。此外，压力棒直径从 10 mm 减小到 4 mm，这大大减少了应力波的弥散，增加了有效带宽。这使得能够观察压力测量中的高频特征，这对于验证数值模型预测的近场瞬态效应和开发有效的爆炸缓解方法至关重要。
