罐底提离时的下节点应力计算
Calculation of Bottom Node Stresses in Oil Tank When Uplift Occurs due to Excessive Internal Pressure
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摘要: 当安装于罐顶上的呼吸阀失灵, 或罐内液体的汽化速度增大而又不能及时排放时, 罐内的压力增高, 部分罐底可能会离开基础而发生罐底提离现象。此时, 在下节点处存在着较大的应力, 甚至会造成油罐在下节点处的破坏。常用的计算下节点弯矩的J.B.Denham方法已不再适用于此种情况。根据板壳理论, 研究了罐底因内压过大而发生提离时下节点应力的计算方法, 并讨论了液体密度、液位高度和内压大小等因素对罐底提离和下节点应力的影响。Abstract: When breather vent attached on the tank roof does not work properly or vent capacities based on normal breathing is inadequate to cope with the increased rate of vaporization of the contained liquid, the internal pressure in the tank increase. As a result of the increase of internal pressure, part of the tank bottom may be raised from the foundation base, that is, uplift at the bottom occurs. The stresses increase and rupture may occure at the bottom-to-shell-joint or bottom node. The method of calculating bottom bending moment presented by J. B. Denham is not suitable for the situation. The paper presents the method for calculating bottom node stresses under the condition that uplift occurs due to excessive internal pressure in the tank. The influences of density, level of the contained liquid, and internal pressure on uplift and bottom node stresses are analyzed.