弧门主框架及启闭机系统结构布置的多工况多目标优化

The single working condition and objective optimizationis often based on experience and thus global optimal solution cannot be reached for the structure layout of main frame of tainter gate (cantilever length of main girder,unit stiffness ratio of main frame,and radius of tainter gate) and hydraulic hoist.Global layout optimization of tainter gate and hoist system under multi-conditions and objectives is carried out based on the current design code for steel gate in water resources and hydropower projects of China and the design of hydraulic steel structures and the design of spillway tainter gates of America.The optimization objectives are:1) The positive bending moment in the middle of the girder is equal to the absolute value of negative moment of the support,and the maximum value reaches the minimum in the conditions of normal water level of the full closeure,check flood water level of instant open and full open;2) The radius of the tainter gate reached is the minimum,and the maximum value of absolute value of negative moment of the strut tends to minimum in the conditions;3) The capacity of hydraulic hoist tends to minimum in the conditions.The constraints are determined to be:1) Range of cantilever length of main girder;2) Range of unit stiffness ratio of main frame;3) Operation conditions of hydraulic hoist in the opening and closing processes of tainter gate;4) Range of the ratio between the radius and height;5) Allowable range of opening force of hydraulic hoist;6) Layout requirements of hydraulic hoist.Global layout optimization of tainter gate and hoist system under multi-conditions and objectives is built based on the above conditions.The optimal structures of the main frame and hoist are obtained by solving the engineering example:the non-dimensional cantilever length was 0.160,and the non-dimensional unit stiffness ratio of girder and strut was 8.69,the non-dimensional ratio between the radius and height was 1.3,and the non-dimensional lifting point position between the side wall of pier was 0.13,and the angle between the pull rod and the strut was 34.6° when the gate was full closed.The results showed that the method of global layout optimization of tainter gate and hoist system under multi-conditions and objectives was simple and practical.Moreover,the internal force of the tainter gate and the capacity of the hoist were greatly reduced and achieves the unity of security and economy of the global optimization layout of tainter gate and hoist. It also makes up for the deficiencies that cannot consider different working conditions,and the random arrangement of the cantilever length of main girder,unit stiffness ratio of main frame,radius and hydraulic hoist by experience,and also provides the simple method of the global optimal arrangement for the revision of the codes of China and America.