模拟准脆性材料热开裂的热力耦合格构离散单元法

针对准脆性材料的热传导与热开裂问题，基于格构离散单元法（LDEM）提出新的热力耦合数值模型. 通过格构离散体系与连续体传热过程的等效换算，结合格构单元的线膨胀公式，在LDEM中实现温度传导与裂纹扩展的数值模拟. 以平板的热传导与热弹性应力问题、由温度梯度与热失配引起的开裂问题为例，验证所提模型. 将所提模型应用于细观混凝土温度?应力试验的数值模拟中. 结果表明，LDEM热力耦合模型能够有效模拟准脆性材料的热传导过程、在温度影响下的裂纹萌生与扩展，是研究准脆性材料热开裂过程与机理的有力工具.

Thermal-mechanical coupled lattice discrete element method for simulating thermal cracking of quasi-brittle materials

A new thermal-mechanical coupled numerical model was proposed based on the lattice discrete element method (LDEM), aiming at the heat conduction and thermal cracking of quasi-brittle materials. In LDEM, in order to simulate the numerical test of the temperature conduction and crack propagation, the equivalent conversion of the heat transfer process between the lattice discrete system and the continuum was carried out, combined with the linear expansion formula of the lattice element. Taking the heat conduction and thermoelastic stress of the plate, and the cracking caused by the temperature gradient and thermal mismatch as examples, the model was verified. In addition, the model was applied to the numerical simulation of the meso-level concrete temperature-stress test. Results show that the LDEM thermal-mechanical coupling model can simulate the heat conduction process of quasi-brittle materials, as well as the crack initiation and propagation under the influence of temperature effectively, which provides a powerful tool for studying the thermal cracking process and mechanism of quasi-brittle materials.