Shock-induced brittle failure of boron carbide
Shock-induced brittle failure of boron carbide
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DOI：
10.1098/rspa.2002.0968
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发表时间：
2002-08-08
影响因子：
3.5
通讯作者：
Bourne, NK
中科院分区：
文献类型：
--
作者：
Bourne, NK
脆性材料在单轴压缩冲击加载过程中的破坏机理一直是人们讨论的主题。特别是，对屈服点--Hugoniot弹性极限的物理解释仍然知之甚少。此外，还假设不同的材料在弹性行为极限时表现出不同的变形模式。其他研究表明，碳化硼(B(4)C)表现出与其他脆性材料不同类型的行为。特别是，其他陶瓷在流动中的拉格朗日位置显示出平滑的应力和粒子速度分布，而碳化硼在这些点上显示出锯齿状的历史，可能表明传感器位置的碎裂更极端。为了试图解释这种行为的起源，我们探索了应力场的另一部分。通过使用纵向和现在的横向应力分布，可以阐明材料的强度如何在冲击波阵面上变化。在其他陶瓷中，失效发生在沿着被称为失效波的冲击波前沿的行进边界后面，穿过冲击波，材料的强度会大大降低。为了阐明这种破坏过程是否发生，在B(4)C中嵌入了量规来测量冲击波阵面后面的侧向应力。与其他材料一样，B(4)C中的应力被认为是在破坏前沿上上升的。然而，这种现象只在一定的应力范围内发生。更重要的是，该故障比在其他材料中看到的更深入陶瓷。建议用力学解释来解释观察到的行为。研究表明，碳化硼具有独特的冲击响应。虽然是多晶陶瓷，但它的行为与非晶态玻璃相似。它给出了脆性材料的全面材料描述的形式，这将成为未来工作的基础。
The mechanism for the failure of brittle materials during uniaxial compressive shock-loading has been the subject of much discussion. In particular, the physical interpretation of the yield point, the Hugoniot elastic limit, remains poorly understood. It is additionally hypothesized that different materials display differing modes of deformation at the limit of elastic behaviour. Other work has shown that boron carbide (B(4)C) exhibits a type of behaviour in a different class to that of other brittle materials. In particular, other ceramics show smooth stress and particle velocity profiles at Lagrangian positions within the flow, while boron carbide shows jagged histories at such points, perhaps indicating that fragmentation at the sensor position is more extreme. To try and explain the origin of this behaviour, another part of the stress field has been probed. By using the longitudinal and now the lateral stress profiles, it is possible to elucidate how the strength of the material varies across the shock front. In other ceramics, failure has been seen to occur behind a travelling boundary that follows a shock front that has been called a failure wave, across which the strength of the material is dramatically reduced. In order to elucidate whether this failure process occurs, gauges were embedded to measure the lateral stress behind the shock front in B(4)C. As in other materials, the stress in B(4)C was seen to rise across a failure front. However, this phenomenon only occurred over certain stress ranges. More significantly, the failure penetrated further into the ceramic than has been seen in other materials. A mechanical interpretation is suggested to explain the observed behaviour. This paper shows that boron carbide exhibits a unique shock response. Although a polycrystalline ceramic, it shows a behaviour similar to an amorphous glass. It gives indications of the form of a comprehensive material description for brittle materials that will form the basis for future work.