최적화 프로니 급수를 이용한 콘크리트 건조수축 균열해석

Abstract

If the concrete members are restrained, drying shrinkage strain develops tensile stress and consequently develops cracks. Creep which is another long term characteristic of concrete relaxes the tensile stress due to shrinkage. Creep is represented in the form of creep function or relaxation function and the relaxation effect of creep can be considered by numerical integration. Creep function or relaxation function depend on two time variables representing creep effect and aging effect, respectively. In general purpose finite element program like Abaqus, Prony series are used in creep analysis to evade the complexity of numerical integration of creep function. However, Prony series in Abaqus has critical deficiency that it can represent only creep effect excluding aging effect. In this paper, optimized Prony series was proposed to complement the weakness of Prony series in Abaqus. The optimized Prony series can include not only creep effect but also aging effect. Drying shrinkage crack analysis was performed using XFEM features in Abaqus to demonstrate the efficiency of the optimized Prony series. Analysis model representing the drying shrinkage crack test specimen specified in KS F 2595 was used to compare with the shrinkage crack development measured in experiment. Analysis results with the optimized Prony series were quite similar to the experiment results and show the effectiveness of the proposed method in long term analysis of concrete structures.