Stochastic analysis of dynamic fracture of concrete using CT-image based mesoscale models with a rate-dependent phase field method

authored by
Yu jie Huang, Lu Hai, Qing hua Li, Hui Zhang, Zhi Cheng, Wen zheng Xu, Shi lang Xu
Abstract

Concrete structures are commonly exposed to dynamic loads spanning a wide range of strain rates, and the inherent mesoscale heterogeneities complicate stochastic dynamic fracture mechanisms even more. This work develops a numerical framework using mesoscale concrete models based on micro computed tomography (CT) images to investigate such mechanisms with meaningful stochastic analyses. A rate-dependent phase field model is proposed to characterise the dynamic initiation and propagation of cracks by incorporating both micro-viscosity and macroscopic viscoelasticity, which is described by two standard Maxwell elements with different relaxation times to consider a wide range of strain rates. Moreover, the viscoelastic constitutive relation is formulated in the full strain space, which allows for a spectral decomposition of the strain tensor to determine the effective damage driving force, thus effectively addressing the issue of compressive fracture. A numerical implementation scheme is developed by combining user-defined element and material subroutines in ABAQUS/Explicit solver. Extensive Monte Carlo simulations of dynamic tension up to a strain rate of 200 s−1 are performed with statistical analyses. This work reveals the intricate dynamics associated with mesoscale heterogeneities and identifies the critical transition state at 20 s−1. The transition is characterised by changing modes of fracture patterns, stress wave propagation, and load-carrying capacities. A new TDIF–strain rate–standard deviation relation is also proposed and aligns well with the increasing dispersion of experimental data. The relationship between void content and tensile strength reflects the formation characteristics of crack networks, with the void content exhibiting a positive correlation with the TDIF from 20 s−1 to 100 s−1.

Organisation(s)
Institute of Continuum Mechanics
External Organisation(s)
North University of China
Zhejiang University
Type
Article
Journal
International Journal of Impact Engineering
Volume
197
No. of pages
21
ISSN
0734-743X
Publication date
03.2025
Publication status
Published
Peer reviewed
Yes
ASJC Scopus subject areas
Civil and Structural Engineering, Automotive Engineering, Aerospace Engineering, Safety, Risk, Reliability and Quality, Ocean Engineering, Mechanics of Materials, Mechanical Engineering
Electronic version(s)
https://doi.org/10.1016/j.ijimpeng.2024.105188 (Access: Closed)
 

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