Correlation between the evolution of double-K fracture toughness and microstructural parameters in thermally treated granite

IF 5.6 2区工程技术 Q1 ENGINEERING, MECHANICAL

Theoretical and Applied Fracture Mechanics Pub Date : 2025-09-15 DOI:10.1016/j.tafmec.2025.105240

Jian Li , Zhongping Guo , Dechun Ai

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引用次数: 0

Abstract

This study integrates Digital Image Correlation (DIC), Acoustic Emission (AE) in-situ monitoring, and quantitative microstructural analysis techniques to reveal the micromechanical control mechanisms of Double-K fracture toughness in heat-treated granite (25–800 °C). The observed evolution of the Fracture Process Zone (FPZ) by DIC, the broadband characteristics of AE time–frequency signals, and microstructural analysis collectively demonstrate that above 400 °C, grain boundary microcracks evolve from independent nucleation to networked interconnection, directly inducing a transition in granite fracture behavior from linear-elastic to nonlinear. By quantitatively characterizing microstructural parameters such as grain equivalent diameter, aspect ratio, and fractal dimension, it was found that the synergistic control of decreasing grain diameter, increasing aspect ratio, and rising fractal dimension governs the attenuation of Double-K toughness. Based on microstructural parameters including grain morphology and microcrack networks, an Artificial Neural Network (ANN) prediction model was constructed, achieving high-precision prediction of Double-K fracture toughness.

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热处理花岗岩双k断裂韧性演化与显微组织参数的相关性

本研究结合数字图像相关（DIC）、声发射（AE）原位监测和定量显微组织分析技术，揭示了热处理花岗岩（25-800℃）双k断裂韧性的微观力学控制机制。DIC观察的断裂过程区（FPZ）演化、声发射时频信号的宽带特征以及显微组织分析共同表明，在400℃以上，晶界微裂纹由独立成核演化为网状互连，直接导致花岗岩断裂行为由线弹性向非线性转变。通过对晶粒等效直径、长径比和分形维数等微观组织参数的定量表征，发现减小晶粒直径、增大长径比和增大分形维数的协同控制控制了双k韧性的衰减。基于晶粒形貌和微裂纹网络等显微组织参数，构建了人工神经网络（ANN）预测模型，实现了双k断裂韧性的高精度预测。

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来源期刊

Theoretical and Applied Fracture Mechanics 工程技术-工程：机械

CiteScore

8.40

自引率

18.90%

发文量

435

审稿时长

37 days

期刊介绍： Theoretical and Applied Fracture Mechanics'' aims & scopes have been re-designed to cover both the theoretical, applied, and numerical aspects associated with those cracking related phenomena taking place, at a micro-, meso-, and macroscopic level, in materials/components/structures of any kind. The journal aims to cover the cracking/mechanical behaviour of materials/components/structures in those situations involving both time-independent and time-dependent system of external forces/moments (such as, for instance, quasi-static, impulsive, impact, blasting, creep, contact, and fatigue loading). Since, under the above circumstances, the mechanical behaviour of cracked materials/components/structures is also affected by the environmental conditions, the journal would consider also those theoretical/experimental research works investigating the effect of external variables such as, for instance, the effect of corrosive environments as well as of high/low-temperature.