钢桥面板典型疲劳细节贯穿型疲劳裂纹扩展能力分析

Analysis on Penetrating Fatigue Crack Expansion Capability of Typical Fatigue Details in Steel Bridge Decks

摘要:

贯穿型疲劳裂纹对钢桥面板的安全服役构成了严重威胁。以某高速公路斜拉桥钢桥面板为研究对象，选取纵肋顶板连接部位作为典型疲劳细节，基于实体有限元软件构建了包含裂纹体子模型的疲劳节段分析有限元模型，并对贯穿型疲劳裂纹进行了数值模拟分析。计算结果表明：纵肋顶板连接部位主要受垂直于裂纹面的横向拉应力作用；贯穿型疲劳裂纹主要表现为张开型疲劳裂纹特征，裂纹前缘等效应力强度因子峰值接近225.0 N/mm^3/2，相比于初始裂纹，扩展能力显著增强。

Abstract:

Penetrating fatigue cracks pose a serious threat to the safe service of steel bridge decks. Taking the steel bridge deck of an expressway cable-stayed bridge as the research object, selecting the connection part of the longitudinal rib roof as the typical fatigue detail, and based on the solid finite element software, a finite element analysis model of fatigue segment containing a crack body sub-model is established. And the numerical simulation analysis is carried out on the penetrating fatigue cracks. The calculation results show that the connection part of the longitudinal rib roof is mainly subjected to transverse tensile stress perpendicular to the crack surface. The penetrating fatigue cracks mainly exhibit the characteristics of open-type fatigue cracks, and the peak equivalent stress intensity factor at the crack front is close to 225.0 N/mm^3/2. Compared with the initial cracks, the expansion capability is significantly enhanced.