针对混凝土、岩石等脆性材料,利用热传导和热-力耦合的相关理论,并结合材料在细观尺度上的损伤演化规律.提出了一种考虑损伤的热-力耦合模型,并在原有材料破坏过程分析系统RFPA(Realistic Failure Process Analysis)模型的基础上建立了脆性材料热破裂过程分析的数值模拟方法。该方法考虑了脆性材料在细观层次上力学性质的非均匀性(包括强度、弹模、传导系数等).并通过统计分布函数建立了宏、细观力学性能之间的联系。对不同均匀程度材料的数值模拟结果表明:材料的非均匀性对热传导规律、热应力分布以及热破坏模式有较大的影响。材料热力学性质的非均匀性加剧了材料内部热应力分布的非均匀性,这是致使非均匀材料热破裂的一个重要因素。对稳态和瞬态热传导两种条件下的脆性介质破裂过程模拟分析表明,考虑瞬态热传导计算所得到的破裂区小于相同条件下稳态热传导所得到的结果.表明在热破裂过程分析中,应注重考虑瞬态热传导对破裂过程的影响。
On the basis of the principle of thermal conduct equation and the coupling of thermo-mechani cal concept, and considering the characteristic of damage evolution law at mesoscopic level of brittle materials, we proposed a numerical model to simulate the coupling of thermo-mechanical behaviour and the damage evolution. For the remarkable feature of concrete-like materials, i.e. nonhomogeneity at mesoscopic, statistical method is employed to describe the relationship of mechanical response between mesoscopic level and macroscope level. It indicates that the temperature distribution and stresses fields are remarkably influenced by the heterogeneous of materials. The numerically simulated results are verified by the theoretical and experimental data. The comparison of the failure processes at steady state and transient state thermal conduction of the same sample indicate that the failure zone of steady state thermal conduction is large than that of transient state. The results reveal that the thermal cracking by considering the transient thermal conduction is more precise and reliable than that of steady state.