高强混凝土热-力响应的断裂相场分析方法研究

高强混凝土(High-Strength Concrete, HSC)的力学性能受温度影响较大，尤其在高温环境下性能衰退剧烈，因此在结构分析中宜采用随温度变化的材料性能参数．断裂相场方法基于Griffith变分断裂准则，无需复杂的裂纹拓展追踪技术便可处理多裂纹的问题，可方便地模拟裂纹的萌生、扩展、分岔及汇合过程．本文采用适宜进行结构断裂分析的断裂相场方法，基于能量泛函变分原理，将温度对混凝土材料弹性模量及断裂能的影响引入断裂相场分析方法中，用于高强混凝土高温环境下的强度和破坏分析．以高温作用下高强混凝土梁三点弯曲试验为算例，进行方法验证，通过与实测结果对比，证实了算法的有效性．

Study on Thermal-Stress Response of High Strength Concrete Based on Fracture Phase Field Method

The mechanical properties of High-Strength Concrete (HSC) are greatly affected by temperature, especially in high temperature environment. Therefore, the material performance parameters varying with temperature should be used in structural analysis. Based on Griffith variational fracture criterion, the fracture phase field method can deal with the problem of multiple cracks without complex crack propagation tracking technology, and can easily simulate the process of crack initiation, propagation, bifurcation and convergence. In this paper, the fracture phase field method is applied for structural fracture analysis. Based on the energy functional variational principle, the influences of temperature on the elastic modulus and fracture energy of concrete materials are introduced into the fracture phase field method for the strength and failure analysis of high-strength concrete under high temperature environment. The three-point bending test of high strength concrete beam under high temperature is presented as an example to validate the proposed method. The effectiveness of the calculation algorithm is verified by comparing with the measured results.