Structural Strengthen Analysis Of 36-ton U Type Gantry Crane

Crane is essential in the production of modern industrial production of auxiliary equipment, which has achieved the mechanization and automation of production, It has more and more species and the technical level is higher and higher. Gantry crane in this paper is widely used in domestic railway freight yard-handling equipment. Domestic railway freight yard cranes include A type, U type and C type base on the form of the leg, U-crane has the advantage of large gauge of the crane gauge and wide space of the leg, which is suitable for loading and unloading large cargos. But since its leg without saddle and the shape is open, the rigidity of the whole structure is small along the direction of the track of travel mechanism, so when the crane stare and brake, its structural will vibrate heavily, which lead to the driver fatigue easily, and pose a security risk to the crane operations.In order to reduce the vibrate of the crane, the paper come up with a structural transformation plan to strengthen the leg,the bottom cross grider and the connection between girder and carriage aim at the 36-ton U type gantry crane in a certain railway freight yard, Using large-scale finite element analysis software ANSYS for finite element analysis for the crane before and after reinforced.Firstly, according to the characteristic structure of the gantry crane, build a finite element model of the 36-ton U gantry crane In the APDL, there use BEAM4 unit, LINK8 unit and MASS21 unit during the modeling process.Secondly, have an analysis of static stiffness characteristics of the crane, Analysis and calculate the transverse stiffness of the crane when the crane trolley cart full of located at the crane girder span position, left leg and right leg position. The displacement of the crane girder span position after reinforced has decreased 25.31% than before. The displacement of the driver chamber position after reinforced has decreased 34.45% than before. The crane stability has been greatly improved and relieve the security risks for the staff.Again, have an analysis of modal characteristics of the crane, extract the crane’s first ten modes of natural frequencies and mode shapes with the block Lanczos method when the crane trolley cart full of located at the crane girder span position. The natural frequency value of the reinforced has a different degree of improvement, in which the grider vibration amplitude is the biggest, which should focus on attracting attention.Finally, have an analysis of transient analysis of the crane with the full method, get the acceleration curve of the position of crane girder span and the driver chamber in three conditions when the crane trolley cart full of located at the crane girder span, left leg and right leg position when the travel mechanism stare and brake. The acceleration curve of the crane girder span position after reinforced has decreased 15.49% than before. The acceleration curve of the driver chamber position after reinforced has decreased 13.54% than before. The crane stability is improved and the shaking is weakened.