Digital Design And Dynamic Stiffness Analysis Of A New Portal Crane Structure

With the rapid development of the world economy,as a large machinery widely used in ports,shipbuilding and other fields,single boom gantry crane is facing challenges such as increasing market competition and diversified needs of users.The traditional design technology is far from meeting this challenge.The use of advanced design methods can improve the design quality,shorten the design cycle and reduce the manufacturing cost.In this paper,the metal structure of single boom gantry crane is studied by digital design method,the gantry optimization design and automatic modeling system are developed,and the dynamic stiffness of the whole machine is studied and analyzed.The main work completed is as follows:(1)The principles of digital design and mechanical vibration are described respectively.It includes optimization design and parametric modeling,and it explains the application of digital technology in crane design;This paper introduces the concept and classification of mechanical vibration,and focuses on the methods of analyzing mechanical vibration,which provides theoretical support for the work of the following chapters.(2)Taking the gantry of MQ35 A single boom gantry crane as the object,the design of gantry is optimized.Firstly,the complex method is improved according to the characteristics of plate thickness,so that it can be applied to the case where the design variable is discrete variable.The mathematical model is established with the total mass of the gantry as the objective function,the gantry section and steel plate thickness as the design variables,and the stress deformation and the definition domain of the design variables as the constraints.The improved complex method is used to optimize the gantry structure,and the python language is used to program the whole process of optimization design and finite element calculation(calculating the value of the objective function).The finite element model automatically established by the gantry is solved and calculated by Pyansys,and a better optimization result is obtained.(3)The key technologies of automatic 3D modeling are studied.The secondary development of Solid Works is carried out by using C + +.The C + + program for automatic modeling of gantry is compiled,and the program is integrated into Solid Works software.The object hierarchy and interface of Solid Works API are introduced,and the key technologies and secondary development methods of automatic modeling technology of size driven method and programming method is analyzed.(4)The dynamic stiffness of single boom gantry crane is analyzed.The dynamic stiffness of the whole machine is analyzed from the luffing plane and the rotation plane,which is simplified into their corresponding mechanical model,namely the spring mass system.The expression of the dynamic stiffness is deduced,and the factors affecting the dynamic stiffness are analyzed.