混凝土断裂模量的尺寸与强度效应

Abstract

本文用有限元数值模拟的方法研究了混凝土的断裂模量，建立了断裂模量与试件尺寸以及混凝土强度等级的关系。数值试件采用了不同尺寸的三点弯曲混凝土简支梁。在数值模拟中采用弥散裂缝模型模拟混凝土开裂，用非线性拉应力与开裂应变软化曲线模拟混凝土裂缝的进一步扩展。数值试验中考虑影响混凝土断裂模量的因素为混凝土强度等级和梁的高度，最后在数值结果的基础上建立了混凝土断裂模量与脆性指标之间的关系。 In this paper, the flexural strength of plain concrete beams subjected to three-point bending was numerically studied using the finite element program DIANA. Instead of using a discrete crack model, a smeared crack model is adopted in the numerical simulation. A non-linear tension softening curve was used to model the gradually diminishing tensile strength of concrete upon further crack opening. The factors influencing the flexural strength of plain concrete beams considered in this paper are the concrete strength grade and the beam depth. These two factors can be combined into one material parameter and the brittleness index. A relationship between the ratio of flexural strength to the tensile strength and the brittleness index was proposed based on the numerical results.