This paper aims to develop a multiscale thermo-mechanical coupling model across from meso-scale to macro-scale to study the tensile thermos-mechanical behavior of fiber-reinforced cementitious composite (FRCC) on the base of thermodynamics. In meso-scale, the coupling process of thermal effect and the development law of a single crack were creatively presented and formulated in energy potential function. The effects of fiber dispersion on cracking behavior and crack strength of matrix were determined. In macro-scale, the multiple-fine-cracks and strain-hardening/softening behavior under tension were defined and studied. The bridging action stress of fibers is calculated by considering the bonding stress in the interface transition zone (ITZ). The model can be upgraded for FRCC materials ranges from strain-hardening cementitious composite (SHCC) and engineered cementitious composite (ECC). The numerical calculations of the proposed model were conducted based on the Fortran program for validation. The residual tensile strength, multiple-fine-cracks and strain-hardening/softening behaviors of FRCC were predicted. The behaviors of FRCC with different fiber types were accurately captured in a range of temperature from 20°C to 600°C through the comparative study with six groups test results in literatures. A sensibility study was carried out to analyze the impact of modelling parameters and thermal effect on the strain-hardening/softening behaviors of FRCC.

中文翻译：

---

纤维增强水泥复合材料 (FRCC) 的多尺度热力耦合模型

本文旨在建立从细观尺度到宏观尺度的多尺度热力耦合模型，以热力学为基础研究纤维增强水泥基复合材料（FRCC）的拉伸热力行为。在细观尺度上，创造性地将热效应耦合过程与单个裂纹的发展规律表述为能量势函数。确定了纤维分散对基体开裂行为和开裂强度的影响。在宏观尺度上，定义并研究了拉伸下的多重细裂纹和应变硬化/软化行为。纤维的桥接作用应力是通过考虑界面过渡区（ITZ）中的粘合应力来计算的。该模型可以针对应变硬化水泥基复合材料 (SHCC) 和工程水泥基复合材料 (ECC) 等 FRCC 材料进行升级。所提出模型的数值计算基于Fortran程序进行验证。预测了 FRCC 的残余拉伸强度、多重细裂纹和应变硬化/软化行为。通过与文献中六组测试结果的对比研究，准确捕捉了不同纤维类型的FRCC在20°C至600°C温度范围内的行为。进行了敏感性研究，以分析建模参数和热效应对 FRCC 应变硬化/软化行为的影响。