Optimizacion Eot

EngOpt 2008 - International Conference on Engineering Optimization
Rio de Janeiro, Brazil, 01 - 05 June 2008.

Design Optimization of EOT Crane Bridge
Rehan H Zuberi1, Dr. Long Kai 2, Prof. Zuo Zhengxing3
(1) Doctoral Student, School of Mechanical and Vehicular Engineering, Beijing Institute of Technology (BIT), China, beri@bit.edu.cn (2) Post Doctoral Student, School of Mechanical andVehicular Engineering, Beijing Institute of Technology (BIT), China, longkai@bit.edu.cn (3) Prof. & Dean, School of Mechanical and Vehicular Engineering, Beijing Institute of Technology (BIT), China, zxzuo@bit.edu.cn 1. Abstract Electric Overhead Travelling (EOT) Crane is one of the essential industrial equipment for material handling job. In recent years little attention has been paid to the optimaldesign of Heavy Electric Overhead Travelling Crane Bridges. The motive might be, but not limited to the availability of prevailing FEM, DIN, ISO, CMAA, BS, Chinese and now CEN standards for the design of cranes. Most of the crane manufacturers have standardized the single dimensioned box section for multiple spans and duties of Crane Bridges for manufacturing simplicity. Owing to the recent upwardtrend in the price of structural materials not to mention the demanding dimensions of heavy duty crane box girders, utilization of modern design optimization tools is inevitable. This paper demonstrates design optimization of EOT crane thin walled welded box girder subjected to rolling loads. A simple and innovative procedure has been introduced to use Generalized Reduced Gradient (GRG2) nonlinearoptimization code for optimization of various parameters of the welded box section bridge and then comparing the results with the FE simulation. Local buckling of web and compression flange has also been taken in account while performing GRG2 optimization. Later vigorous random and 1st order Design Optimization is performed to establish design space and convergent solutions utilizing commerciallyavailable FEA software. Maximum allowable bending stress, allowable shear stress and deflection are constrained to recommended limits of design norms, keeping the volume of the bridge as objective function. The size and thicknesses of plates, stiffeners and reinforcement are included as design parameters (DV’s). Optimal girder so designed is efficient in respect of design technique and verifiedas cost-effective. 2. Keywords: Design Optimization, EOT Crane Bridge, Optimal Box Girder, Rolling wheel load 3. Introduction The escalating price of structural material and energy is a global problem consequently optimal consumption of the both can not be considered redundant. Overhead crane, which is a synonym for material handling in the industrial environment, utilizes structural steel for itsgirder and energy (mostly electrical) for its operation. Light girder for overhead cranes not only save material cost but also trim down energy expenditure because of subsequent employment of low powered drive units. The general procedure for design of EOT crane girders is accomplished through guidance stipulated in the prevailing codes and standards. Thus optimal design in such case is not theone which just exhibit stress criteria offered in structural design methods but the one which follows the limits restrained by the aforementioned codes and safety rules. Shape optimization of closed box type section was studied by Gibczynska et al [1]. Regarding optimal design of simple symmetrical welded box beam Farkas J & Jarmai K [2] incorporated bending stress, shear stress and bucklingconstraints while kept cost, mass and deflection as objective function. Megson, T H.G. Hallak [3], parametrically and numerically analysed load bearing diaphragms girder at single support point. Narayanan [4], in his two consecutive papers examined strength capacity of webs with cut-outs and rectangular holes and emphasized on prediction of stress in such cases. Recently little literature is found...