钢筋混凝土锈蚀开裂的有限元分析方法

基于Abaqus非线性有限元软件,通过投放不同形状、粒径、级配的骨料,模拟钢筋锈蚀膨胀导致混凝土保护层开裂的精细化建模分析. 针对混凝土裂缝开展形态,对网格映射方法、几何剖分方法,以及几何剖分方法+Cohesive单元细观模型等几种建模技术的运算效率进行对比;同时针对两种不同混凝土骨料形状对锈胀混凝土裂缝开裂的影响进行比较分析.结果表明:网格映射方建模简单、运算效率较高,但分析结果较粗糙;几何剖分方法收敛速度快,计算效率高,但建模时需要对骨料进行剖分;几何剖分+Cohesive单元方法得到的裂缝开展形态更加精细化更接近实际情况,但运算效率低,只适用于局部精细化分析要求较高的场合.骨料的形状和分布对裂缝分布和扩展趋势均产生一定影响,实际分析中,骨料形状应尽可能接近于实际骨料.此外,通过几何剖分+Cohesive单元法建立的模型计算结果锈蚀开裂时间与理论计算值对比误差小于10%,说明该模拟方法在一定程度上符合钢材锈胀挤压附近混凝土导致开裂的理论.

Finite Element Analysis for Corrosion and Cracking in Reinforced Concrete

Based on the Abaqus nonlinear finite element software, the fine model is construsted to analyze the cracking of the concrete protective layer caused by the corrosion and expansion of steel bars with aggregates of different shapes, particle sizes, and gradations. Several modeling techniques such as grid mapping method, geometric subdivision method, and adding Cohesive elements are introduced. The development pattern of concrete cracks and calculation efficiency are compared; the cracks of corroded concrete are discussed according to two concrete aggregate shapes. The result shows: the mesh mapping method is simple and has high calculation efficiency, but the analysis results are not good; the geometric mesh method has fast convergence speed and high calculation efficiency, but the aggregates need to be partitioned during modeling; the crack development pattern obtained by the geometric division + Cohesive element method is benign and close to the actual situation, but the calculation efficiency is low, and it is only suitable for local fine analysis with high requirements; the shape and distribution of the aggregate affect the distribution of cracks. In the actual analysis,the shape of the aggregate should be as close to the actual aggregate as possible; the error of rust cracking time between the calculation result by the geometric division + Cohesive element method and theoretical calculation value is less than 10%, to a certain extent, this simulation method conforms to the theory of cracking caused by steel expanding and extruding surrounding concrete.