Strain-rate dependence for Ni/Al hybrid foams
Strain-rate dependence for Ni/Al hybrid foams
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Ni/Al 混合泡沫的应变率依赖性
DOI：
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发表时间：
2015
期刊：
影响因子：
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通讯作者：
G. Solomos
中科院分区：
文献类型：
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作者：
A. Jung;Martin Larcher;O. Jiroušek;P. Koudelka;G. Solomos
减震通常需要坚硬但轻质的材料，并具有较大的动能吸收能力。开孔金属泡沫是人造结构，由于其平台应力（包括强滞后）原则上可以吸收大量能量。然而，它们的平台应力对于许多应用来说太低。在这项研究中，我们使用高度新颖且有前途的镍/铝混合泡沫，该泡沫由标准的开孔铝泡沫组成，其中纳米晶镍通过电沉积作为支柱表面上的涂层沉积。多孔材料的机械行为，包括它们在较高应变率下的行为，由其微观结构决定，这是由于支柱材料的特性、孔/支柱几何形状和支柱上的质量分布决定的。微惯性效应与微观结构密切相关。对于结论性模型，需要精确的真实微观结构。在这项研究中，微焦点计算机断层扫描 (μCT) 系统用于分析泡沫样品的微观结构并开发微观结构有限元 (micro-FE) 网格。微观结构有限元模型已用于模拟动态负载条件下镍/铝混合泡沫的机械行为。通过准静态压缩测试和动态分裂霍普金森压力棒测试对模拟进行了验证。
Shock absorption often needs stiff but lightweight materials that exhibit a large kinetic energy absorption capability. Open-cell metal foams are artificial structures, which due to their plateau stress, including a strong hysteresis, can in principle absorb large amounts of energy. However, their plateau stress is too low for many applications. In this study, we use highly novel and promising Ni/Al hybrid foams which consist of standard, open-cell aluminium foams, where nanocrystalline nickel is deposited by electrodeposition as coating on the strut surface. The mechanical behaviour of cellular materials, including their behaviour under higher strain-rates, is governed by their microstructure due to the properties of the strut material, pore/strut geometry and mass distribution over the struts. Micro-inertia effects are strongly related to the microstructure. For a conclusive model, the exact real microstructure is needed. In this study a micro-focus computer tomography (μCT) system has been used for the analysis of the microstructure of the foam samples and for the development of a microstructural Finite Element (micro-FE) mesh. The microstructural FE models have been used to model the mechanical behaviour of the Ni/Al hybrid foams under dynamic loading conditions. The simulations are validated by quasi-static compression tests and dynamic split Hopkinson pressure bar tests.