Application of Equivalent Moving Load Method in the Optimization of Main Girder Structure of Bridge Crane

The bridge crane is a lifting device for material transfer as a modern production workshop, which is widely used in the process of blocking the ground equipment. The main load position of the bridge crane in the working process is the main girder, so the topology optimization design of the main girder structure is of great significance for the lightweight of the crane. In practical work, the main girder of bridge crane is subjected to downward moving load. In view of the fact that the traditional structural design method cannot fully consider the influence of dynamic load on the structure, in this paper, on the basis of the structural topology optimization method based on the variable density method, the equivalent moving load method is used to design the main girder structure. The effect of load on the main girder at different time is transformed into multiple static equivalent moving load conditions to complete the construction of the model, combined with the structural characteristics of the main girder and the form of load motion, the weight coefficient of each working condition is determined. The number of equivalent moving loads is increased in multiples, and finally a stable optimization result is obtained, the quality of the optimized structure is 42.7% lower than that of the original structure, it provides an effective scheme for the lightweight design of the main girder of bridge crane.