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混凝土二维扩散分析的有限元法等常用数值法通常需要在空间域和时间域中同时采取细密的离散网格,计算量大。针对混凝土中氯离子二维扩散问题,提出了计算长度的概念及其计算表达式,首次建立了相应的边界元计算方法,确定了时间域离散的步长。通过该计算模型研究了混凝土结构的拐角等几何形状复杂位置的氯离子分布规律。由于边界元法可以将二维问题简化为一维离散问题,而且该计算模型在时间域内的离散网格非常稀疏,因此,相对于其他数值方法,该方法计算量很小,算例分析验证了该方法具有很高的计算精度和计算效率。同时,对角点等位置的氯离子浓度的计算结果表明,二维方法能够更准确地反映氯离子在混凝土结构中的扩散和积聚规律。
Commonly used numerical methods, such as the finite element method of two-dimensional diffusion analysis of concrete, usually need to take a dense discrete grid simultaneously in the space domain and the time domain, and the calculation is large. Aiming at the problem of two-dimensional chloride ion diffusion in concrete, the concept of calculation length and its calculation expression are proposed. The corresponding boundary element calculation method is established for the first time, and the discrete steps in time domain are determined. Through the calculation model, the distribution of chloride ion in the complex geometry such as corner of concrete structure is studied. Because the boundary element method can reduce the two-dimensional problem to one-dimensional discrete problem, and the discrete grid in the time domain of the calculation model is very sparse, compared with other numerical methods, this method has a small amount of computation. The example analysis verifies The method has high computational accuracy and computational efficiency. Meanwhile, the calculation of the chloride ion concentration at the diagonal point shows that the two-dimensional method can more accurately reflect the chloride ion diffusion and accumulation in the concrete structure.