Topological Lightweight Design Of Magnesium Alloy Body Structure Of Large New Energy Bus

Topology optimization,as an advanced design method,has been widely applied in the field of structural design.It can achieve optimal design without affecting the strength and stability of the structure,thus achieving multiple goals such as lightweight,energy saving,and material optimization.Currently,most engineering optimization designs are based on optimization algorithms built into finite element software,which have certain limitations.Therefore,this article applies the Floating Point Topology Optimization(FPTO)method to the skeleton design of the magnesium alloy body of a new energy bus in the conceptual design stage,by building the FPTO method in the ABAQUS-MATLAB platform,to achieve lightweight design of the bus.The specific research content includes:In the first part,this article first introduces the basic principles of finite element method and Floating Point Topology Optimization method,and determines the overall design scheme of the ABAQUS-MATLAB platform.Next,the establishment of the platform is described in detail from three aspects: reading the finite element analysis results from ABAQUS,calling the result files in MATLAB,and the interaction between the two.Then,based on the FPTO method,the flowchart of the main program is determined,and the functions and implementation methods of each subprogram are explained.In the second part,based on the structural characteristics and design standards of the fully bearing bus,the topology space of the body model is designed,including body parameters,doors,and emergency escape window presets,and the conceptual body of the bus is geometrically modeled using CATIA 3D modeling software.Then,the model is imported into ABAQUS software,and the finite element model of the magnesium alloy bus body topology optimization is established by meshing,assigning material properties,and applying equivalent loads.After simulating the suspension,the boundary conditions are set for the bus under four typical working conditions: horizontal bending,ultimate torsion,emergency turning,and emergency braking.Finally,the obtained finite element model Inp file is placed in the ABAQUSMATLAB platform based on the FPTO method to complete the optimization analysis of the magnesium alloy body.The optimal topology structure of the bus under different working conditions is obtained.In the third part,the front and rear surrounds,left and right surrounds,roof,and chassis of the magnesium alloy bus body topology structure are analyzed,and the skeleton design is carried out according to the design principles of the body skeleton,beam selection,and connection method.In order to verify the machinability of the skeleton,the designed skeleton is imported into ABAQUS software to establish a finite element model of the skeleton,and the bending stiffness and torsional stiffness of the body are calculated and analyzed.The results show that the designed body skeleton conforms to actual bus standards.Further analysis of the free mode of the bus body reveals that the first 12 natural frequencies of the bus skeleton are between7-30 Hz,reasonably avoiding resonance with low-frequency excitations during normal bus operation,which validates the rationality and stability of the body skeleton.