混凝土尺寸效应机理的有限元分析

An Investigation on the Mechanism of Size Effect of Concrete Structure

混凝土断裂破坏时产生尺寸效应是普遍存在的一种现象,在假设裂尖形状、大小及裂纹宽度不变而裂纹长度随结构尺寸按比例变化的前提下,用有限元方法分析了三点弯曲梁内应力的分布情况,并讨论了裂尖形状对应力分布的影响。结果表明:在加载点相对位移相同时,梁内最大应力随结构尺寸的增加而增大,裂尖形状对梁内最大应力影响很小;当尺寸较小时,结构尺寸效应比较显著,随着尺寸的增加,结构尺寸效应逐渐减小。

The size effect of concrete structures is important for the design of concrete structures. In this paper, the stress distribution of a beam under three-point-bend is analyzed with finite element method under the assumptions that the shape, size and width of crack tip are constant and the length of the crack changes with the size of the structure proportionally. The results show, that the maximum tensile stress in the structure increase with the increase of the structure size, but with increase of the structure size, the size effect is reduced gradually and the size effect is less affected by shape of the crack tip.