基于相场法的混凝土梁断裂性能数值分析

Numerical Analysis of Fracture Performance in Concrete Beams Based on the Phase Field Method

摘要: 混凝土结构作为目前最主要的结构形式之一，其因荷载、环境等因素导致的断裂行为是不可忽视的。鉴于目前对多跨度混凝土梁研究较少，本文将基于相场法对多跨度的混凝土三点弯曲梁断裂性能进行模拟，旨在分析其断裂裂纹扩展及力学响应。首先，对相场法的相场长度尺寸参数l₀以及网格划分尺度参数h的敏感性问题，验证了该模型的合理性；然后，对比相场模拟与试验得到的P-CMOD (裂缝张开位移)和裂纹扩展；最后，分析了跨高比与最大荷载P_max之间的关系。结果表明相场法可以很好地再现混凝土梁的断裂裂纹扩展过程及其力学响应，进而为研究混凝土断裂提供一种新的模拟方法。

Abstract: As one of the most prominent structural forms, the fracture behavior of concrete structures due to loads, environmental factors, and other influences cannot be ignored. Given the limited research on multi-span concrete beams, this paper aims to simulate the fracture performance of multi-span concrete three-point bending beams based on the phase field method, analyzing their crack propagation and mechanical response. First, the sensitivity of the phase field length scale parameter l₀ and the mesh size parameter h is examined to validate the model’s reliability. Then, a comparison is made between the phase field simulation results and experimental data on the P-CMOD (crack mouth opening displacement) and crack propagation. Finally, the relationship between the span-to-depth ratio and the maximum load P_max is analyzed. The results indicate that the phase field method can effectively reproduce the crack propagation process and mechanical response of concrete beams, providing a new simulation method for studying concrete fracture.