基于细观数值模拟的玄武岩纤维泡沫混凝土力学性能

Mechanical properties of basalt fiber foam concrete based on microscopic numerical simulation

  • 摘要: 为研究不同密度和纤维掺量的玄武岩纤维泡沫混凝土(BFRFC)的孔隙特征与单轴压缩力学性能,本文对两种密度下三种纤维掺量的试样进行X-CT与单轴压缩试验,分析实测孔隙和纤维分布特征,利用Matlab软件二次开发了BFRFC微观结构的三维重构模型,基于Hashin失效准则和损伤变量建立BFRFC的渐进损伤模型,并采用Comsol有限元软件进行单轴压缩试验仿真模拟。研究发现,BFRFC的孔隙直径服从对数正态分布,孔隙率和平均孔径随着密度的增加及纤维掺量的增多而减小;BFRFC内部的纤维极角主要集中在15°~90°之间,而方位角则在0°~360°之间均匀分布;基于微观结构所建立的BFRFC试样仿真模型,结合材料软化特性的渐进损伤模型,可以有效模拟BFRFC单轴压缩过程;BFRFC中玄武岩纤维的添加显著提升了材料的力学性能,包括峰值强度和吸能能力,且单轴压缩过程中材料内部力学响应从外层向内层进行逐层传递。

     

    Abstract: To explore the pore characteristics and uniaxial compression mechanical properties of basalt fiber reinforced foam concrete (BFRFC) with varied densities and fiber mixtures, this study carries out X-ray computed tomography (X-CT) and uniaxial compression tests on samples featuring three types of fiber mixtures at two different densities. It examines the pore and fiber distribution within these samples and leverages MATLAB to develop a three-dimensional reconstruction model of BFRFC's microstructure. Additionally, a progressive damage model, grounded in Hashin's failure criteria and damage variables, has been formulated. The uniaxial compression test simulations were executed using Comsol's finite element software. The findings indicate that BFRFC's pore diameter follows a lognormal distribution. Notably, both porosity and average pore diameter exhibit a decrease with increasing density and fibre content; within BFRFC, the polar angle of the fibers predominantly ranges from 15° to 90°, whereas the azimuthal angle is uniformly distributed across 0° to 360°. The microstructure-based simulation model of BFRFC, integrated with the progressive damage model that accounts for the material's softening characteristics, proves effective in simulating the material's progressive damage. Furthermore, the microstructure-based simulation model, when coupled with the progressive damage model that considers the softening traits of the material, accurately simulates the uniaxial compression behavior of BFRFC. The incorporation of basalt fibers into BFRFC notably enhances its mechanical properties, such as peak strength and energy absorption capacity. Moreover, during the uniaxial compression process, the material's mechanical response is progressively relayed from the outer to the inner layers, enhancing its structural integrity and resilience.

     

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