DESIGN OPTIMIZATION OF BOX TYPE GIRDER OF AN OVERHEAD CRANE

Document Type: Research Paper

Authors

1 Interdisciplinary Research Centre, COMSATS Institute of Information Technology, Wah Cantt, Pakistan & Faculty of Mechanical Engineering, GIK Institute of Engineering Sciences and Technology Topi, Pakistan

2 Faculty of Mechanical Engineering, GIK Institute of Engineering Sciences and Technology Topi, Pakistan

3 Department of Mathematics, COMSATS Institute of Information Technology, Lahore, Pakistan & Department of Electrical Engineering, Faculty of Engineering, Islamic University of Medina, Al-Medina Al- Munawarah, K.S.A.

Abstract

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

Keywords