水工弧形钢闸门动力不稳定性研究

定量估计了3种情况下弧形钢闸门支臂动力失稳的可能性：小开度、支臂与面板联接处无切向位移与侧向位移，主梁相对挠度〈1／600。Iax〉Iay／3且闸门下游无旋滚时不会形成参数共振；大开度、支臂与面板联接处有侧向位移时，深孔弧形门容易引起参数共振，表孔弧形门不易形成参数共振；小开度．支臂与面板联接处有切向位移，两种负阻尼同时存在，若单位挡水面积上用钢置不足，有可能使负阻尼大于结构阻尼导致支臂动力失稳．给出了判断动力失稳所必须的弧形闸门结构阻尼比的原型观测结果，它表明表孔弧形闸门的结构阻尼比是很小的．

Research on dynamic instability of tainter gates

The conditions to cause the dynamic instability of the steel tainter gates for three cases are quantitatively analyzed and forecasted.Under the conditions of the small opening without lateral and tangential displacement at the juncture of the gate arm and the panel,the relative deflection less than 1/600,I_(ax)>I_(ay)/3,and without the roller just downstream of the tainter gates,the parameter resonance may not be formed.Under the conditions of the large opening with lateral displacement at the juncture of the gate arm and the panel,the parameter resonance easily occurs for the high head tainter gates but not for the low head tainter gates with better seal.Under the conditions of the small opening with the tangential displacement at the juncture of the gate arm and the panel,two kinds of the negative damping exist,and the dynamic instability of the gate arm may be caused due to the negative damping greater than the structure damping when the gate weight is not enough relative to the retaining water area.And the results of the four field tests on the structural damping and natural frequencies of the tainter gates are introduced,which are necessary for judging the dynamic instability of the tainter gate and show that the structural damping of the barrage tainter gates is very small.