Lightweighting And Non-Probabilistic Reliability Research Of L-Shaped Gantry Crane

Gantry crane is widely used in various fields as important lifting equipment, its structure lightweight design and reliability design is important to improve the design level. At present, lightweight design of gantry crane focused on the cross-sectional dimension parameter optimization of the main beam, legs, upper and lower beams, sometimes, bound by the structure, the effectiveness and efficiency of the optimization process was far from ideal. Reliability of structural properties focused on random reliability, in the absence of sufficient data to ensure the accuracy of the probability density function of the gantry crane’s uncertain variables, it will be difficult to ensure the accuracy and reasonableness of random reliability, in order to improve the design level, proposed an asymmetrical leg structure and introduced non-probabilistic reliability methods.Studied a 32t-26m L-Shaped single girder gantry crane with cantilever, parametric modeling by the finite element software ANSYS, and did the strength, stiffness analysis in accordance with the GB/T3811-2008. The results showed that the static stiffness of the cantilever cannot meet the requirements. To improve the design, the parametric model of gantry crane integrated into the multidisciplinary optimization software Isight, parameters optimization was carried out on the main girder cross section size. The strength and stiffness meted the requirements, but only a 0.44% reduction in weight, the optimization effect was not ideal. In the process of the lightweight design of gantry crane, the static stiffness of cantilever was the main control condition. In this paper, putted forward a kind of asymmetric leg structure, applied it to the lightweight design of gantry crane, strength and stiffness can meted the requirements, and a 12.85% reduction in weight, the effect improved obviously.Based on non-probabilistic reliability and interval analysis theory, the reliability of main girder was analyzed by comprehensive utilization of ANSYS parametric analysis and Isight approximate modeling, optimization techniques, putted forward a kind of non-probabilistic reliability analysis method of the gantry crane, in the process, considered the size parameters of the main girder, loads, material properties and dynamic load coefficients as uncertainties. This method had a good integration, avoided a large number of repeated operations, so it had some application value. Analysis results showed that the non-probabilistic reliability was 0.78, cannot meet the requirements.Structure performance of the crane interval uncertainty optimization model was created, with gantry crane girder cross section size parameters as design variables, in the process, considered loads, material properties and dynamic load coefficients as uncertainties. Used possibility degree of interval number to convert the uncertain optimization model to deterministic model, used response surface approximation model of gantry crane structure performance instead of the finite element analysis model, this method improved the efficiency, used interval structure analysis method to convert the nesting optimization to a single optimization problem, Finally the multi-island genetic algorithm was used to search the optimal solution of gantry crane girder cross section size. This method had a good optimization precision and high efficiency.