DESIGN OPTIMIZATION OF BOX TYPE GIRDER OF AN OVERHEAD CRANE

Abstract

Double bridge girder overhead cranes are used for heavy duty applications in theindustry. In this paper a detailed parametric design optimization of the main girder of box type isperformed for a 150Ton capacity and 32m long span crane, after its basic design using availabledesign rules. Design optimization is performed using detailed 3D finite element analysis bychanging the number, shape and location of horizontal stiffeners along the length of the girder andnumber and location of stiffeners along the vertical direction to control any possible buckling, withminimum possible weight and for safe stress and deflection. Optimization is performed in twosteps. In the first step, keeping plates thickness constant different types and number of stiffenersare added and optimized geometry is found. In the second step, the best geometry of the first stepis further optimized for maximum allowable bending stress by changing thickness, height andwidth of the box girder with minimum possible weight. Effect of added stiffeners is highlighted incontrolling its buckling.