大型人字闸门结构变形和应力分析

葛洲坝1号船闸下闸首人字闸门用空间壳、梁和杆的组合有限单元成功地计算了在关闭档水状态下的变形和应力,所得结果与原型观测结果一致。计算和分析表明:主梁和次梁内均只出现压应力,在沿梁的长度方向即闸门的宽度方向压应力较大;挡水面板在水平方向膜应力较大且为压应力;同时在该方向存在大小与之相当的局部弯曲应力;挡水面板在铝直方向的局部弯曲应力最大。所得结果也揭示了一些与传统设计理论不一致的规律:主梁在靠近端部的横截面上的正应力不呈线性分布;次梁以压应力为主而弯曲应力很小;挡水面板被主、次梁和纵隔板分隔出来的部分并不完全等同于四边固定矩形板。本文作者认为,在门轴支承强度允许的情况下,减少主梁的数目,增加次梁的数目,也能保证闸门的强度;增加纵隔板数目不仅可以减小挡水面板在铅直方向的局部弯曲应力,而且能增强闸门的开门和关门刚度。

Structural Analysis on Huge Miter Gates

The finite element method is used for analyzing the lower miter gates of the No. 1 ship lock at the Gezhouba Hydroelectric Power Station. The computational results are well in accord with corresponding observations. It is demonstrated that there is no tension anywhere in the horizontal girders and stringers (secondary beams, the skinplate stiffeners), in which the stress is larger in the axial direction of the girders or stringers. The axial compressive stress in the skinplate is large in the horizontal direction in comparison with the vertical direction. The maximum bending stresses in the skinplate are relatively large in both horizontal and vertical directions. The largest stress for the gate appears in the skinplate in the vertical direction. The results are different from the expectations of traditional design theory in that the axial stress in the girder webs is actually nonlinearly distributed at the cross section near either quoin or miter end, while the stringers are mainly subjected to axial com- pression other than bending. In addition a subdomain of the skinplate supported by a girder, a stringer and two vertical diaphragms is not identical in stress with a corresponding rectangular plate whose four edges are clamped. It is suggested in this paper that we may reduce the number of girders on condition that we add enough stringers to the gate. One more vertical diaphragm needs to be added to the gate in order that the skinplate is strong enough to withstand the maximum water-head and that the gate is stiff enough for opening and closing.