Digital-Image-Driven Stochastic Homogenization for Recycled Aggregate Concrete Based on Material Microstructure

2019 ◽  
Vol 16 (07) ◽  
pp. 1850104 ◽  
Author(s):  
Yuching Wu ◽  
Jianzhuang Xiao
Keyword(s):  
Monte Carlo ◽  
Digital Image ◽  
Material Properties ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Image Method ◽  
Stochastic Homogenization ◽  
Aggregate Concrete ◽  
Macro Scale ◽  
Element Method

In this paper, a digital-image-driven stochastic homogenization method is developed to analyze elastic heterogeneous media such as recycled aggregate concrete (RAC), etc. This linking can be accomplished in an efficient manner by exploiting the excellent synergy of finite pixel-element method and Monte Carlo simulation for the computation of the effective properties of the random five-phase composite. The pixel-point discretization of system geometry is used for the approximation of the mechanical response of the elastic heterogeneous microstructure. Using nanoindentation technique and scanning electron microscopy, tens of digital images of modulus map of the five-phase heterogeneous material are made. Using the moving window technique and the Monte Carlo method, the random elastic moduli of the five phases at micro-scale are obtained. Then the effective elastic modulus of the meso-scale representative volume element (RVE) is computed based on spectral stochastic finite element method. Finally, the effective modulus is used to analyze the global behavior of RVE at macro-scale. Then the finite pixel-element method is used to investigate the effect of microscopic covariance noise on the global material properties, as well as the computational efficiency. The results show that the digital image method is an accurate and efficient tool to investigate the random material properties across scales.

scholarly journals Micromechanical Numerical Modelling on Compressive Failure of Recycled Concrete using Discrete Element Method (DEM)

Materials ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 4329
Author(s):  
Xin Tan ◽  
Zhengbo Hu ◽  
Wengui Li ◽  
Suhua Zhou ◽  
Tenglong Li
Keyword(s):  
Discrete Element Method ◽  
Numerical Simulations ◽  
Discrete Element ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Image Correlation ◽  
Recycled Aggregate ◽  
Nanoindentation Test ◽  
Aggregate Concrete ◽  
Element Method

This paper investigates the failure processes of recycled aggregate concrete by a model test and numerical simulations. A micromechanical numerical modeling approach to simulate the progressive cracking behavior of the modeled recycled aggregate concrete, considering its actual meso-structures, is established based on the discrete element method (DEM). The determination procedure of contact microparameters is analyzed, and a series of microscopic contact parameters for different components of modeled recycled aggregate concrete (MRAC) is calibrated using nanoindentation test results. The complete stress–strain curves, cracking process, and failure pattern of the numerical model are verified by the experimental results, proving their accuracy and validation. The initiation, growth, interaction, coalescence of microcracks, and subsequent macroscopic failure of the MRAC specimen are captured through DEM numerical simulations and compared with digital image correlation (DIC) results. The typical cracking modes controlled by meso-structures of MRAC are concluded according to numerical observations. A parameter study indicates the dominant influence of the macroscopic mechanical behaviors from the shear strength of the interfacial transition zones (ITZs).

The Multiscale Spectral Stochastic Finite Element Method for Chloride Diffusion in Recycled Aggregate Concrete

2017 ◽  
Vol 15 (01) ◽  
pp. 1750078 ◽  
Author(s):  
Yuching Wu ◽  
Jianzhuang Xiao
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Digital Image ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Chloride Diffusion ◽  
Stochastic Finite Element Method ◽  
Stochastic Finite Element ◽  
Aggregate Concrete ◽  
Chloride Diffusivity

In this study, the multiscale stochastic finite element method (MsSFEM) was developed based on a novel digital image kernel to make analysis for chloride diffusion in recycled aggregate concrete (RAC). It is significant to study the chloride diffusivity in RAC, because when RAC was applied in coastal areas, chloride-induced rebar corrosion became a common problem for concrete infrastructures. The MsSFEM was an efficient tool to examine the effect of microscopic randomness of RAC on the chloride diffusivity. Based on the proposed digital image kernel, the Karhunen–Loeve expansion and the polynomial chaos were used in the stochastic homogenization process. To investigate advantages and disadvantages of both generation and application of the proposed digital image kernel, it was compared with many other kernels. The comparisons were made between the method to develop the digital image kernel, which is called the pixel-matrix method, and other methods, and between the application of the kernel and various other kernels. It was shown that the proposed digital image kernel is superior to other kernels in many aspects.

Sign in / Sign up

Export Citation Format

Share Document