Image based simulation of one-dimensional compression tests on carbonate sand
Image based simulation of one-dimensional compression tests on carbonate sand
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DOI：
10.1007/s11012-018-0923-2
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发表时间：
2018-11
期刊：
影响因子：
2.7
通讯作者：
S. Nadimi;J. Fonseca
中科院分区：
文献类型：
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作者：
S. Nadimi;J. Fonseca
贝壳状碳酸盐土地基设计通常采用高安全系数和保守方法。因此，更好地了解这种材料的行为对于设计一些海上结构和海底管道的更可持续的方法至关重要。特别是，理解发生在微观尺度的物理现象有可能刺激强大的计算方法的发展。在这项研究中，一个一维的压缩测试内进行的X射线扫描仪，以获得三维图像的贝壳碳酸盐砂的内部结构的演变。通过五个加载增量的图像的初步检查已经表明，在加载下的晶粒重新排列，并且在某些情况下，裂纹在接触处发展。为了在数值域中复制实验，加载前土壤的3D图像被导入到微观有限元（µFE）框架中。这种基于图像的建模工具能够测量颗粒内部的接触力和应力图，同时利用土壤的真实的微观结构。这里展示了µFE模型在深入了解晶粒内屈服起始方面的潜力。这对于更好地理解支撑其高压缩行为的壳状颗粒的破碎是特别有意义的。
High factors of safety and conservative methods are commonly used on foundation design on shelly carbonate soils. A better understanding of the behavior of this material is, thus, critical for more sustainable approaches for the design of a number of offshore structures and submarine pipelines. In particular, understanding the physical phenomena taking place at the microscale has the potential to spur the development of robust computational methods. In this study, a one-dimensional compression test was performed inside an X-ray scanner to obtain 3D images of the evolving internal structure of a shelly carbonate sand. A preliminary inspection of the images through five loading increments has shown that the grains rearrange under loading and in some cases cracks develop at the contacts. In order to replicate of the experiments in the numerical domain, the 3D image of the soil prior to loading was imported into a micro Finite Element (µFE) framework. This image-based modelling tool enables measurements of the contact force and stress map inside the grains while making use of the real microstructure of the soil. The potential of the µFE model to contribute insights into yield initiation within the grain is demonstrated here. This is of particular interest to better understand the breakage of shelly grains underpinning their highly compressive behavior.