对称Y型月牙肋钢岔管内压下弹塑性分析

为了研究月牙肋钢岔管在内水压力下的应力分布特点,确定超载情况下塑性区的出现部位及塑性的发展程度,以某水电站月牙肋钢岔管实际工程项目为例,建立带弹性地基的岔管有限元模型,开展水压试验工况下正常内水压及超载内水压的静力弹塑性分析。对不同管壁厚度和内水压力下塑性区域、第一主塑性应变和Mises应力进行了分析,表明:在内水压力作用下,塑性区域集中出现在管壳与月牙肋板相贯线附近主岔管最高点内壁处,月牙肋板与岔管接缝处附近出现小部分塑性区域。为月牙肋钢岔管的加肋补强及钢筋混凝土外包提供了设计依据。

Elastoplastic Analysis of Symmetrical Y-Shaped Steel Bifurcated Pipe with Crescent Rib Subjected to Internal Pressure

To study the stress distribution characteristics of steel bifurcated pipe with crescent rib subjected to internal hydrostatic pressure and to identify the site of plastic region and the degree of development of plasticity of steel bifurcation structure under overload conditions, this paper, taking a practical project of the steel bifurcated pipe with crescent rib of a hydropower station as an example, performs the static elastoplastic analysis on the bifurcation under normal and exceeding hydrostatic pressure by building a finite element model. Analysis of the plastic region, 1st principal plastic strain and the Mises stress under different wall thicknesses and internal hydrostatic pressures is carried out, which shows that subjected to the action of internal hydrostatic pressure, the plastic region is concentrated on the inner wall of the highest point of the main bifurcation near the intersecting line between the shell and the crescent rib, and there is a small plastic area near the welded joint between the crescent rib and the bifurcation. This analysis result provides the design basis for the reinforcement by ribbing of steel bifurcated pipe with crescent rib and outsourcing reinforced concrete.