Static And Dynamic Analysis Of Mechanical Arm Structure Based On Finite Element

In the design of modern mechanical equipment,the finite element method is usually used for structural optimization and static and dynamic analysis.This paper aims at the needs of two horizontal projects,that is,the lightweight design of the upper limb rehabilitation manipulator and the mechanical performance analysis of the static and dynamic loads on the large storage rack.In view of the key problems such as the simplification of the structural model,the selection of the element type,the application of the constraint form and the effect of the equivalent load,a more in-depth analysis and research are carried out.Combined with the verification of the analytical solution of material mechanics,a reasonable calculation and analysis result is obtained.In this paper,according to the specific analysis of the lightweight requirements of the manipulator,the topological optimization analysis method is selected.Firstly,the most basic spatial distribution of the structural mass is calculated,and then the specific structural form is determined based on the technological requirements of the manipulator.On the premise of meeting the static and dynamic strength and stiffness,the mass and moment of inertia of the manipulator are effectively reduced,achieving the goal of lightweight design.The scale of the large storage shelf to be analyzed in this paper is 2 rows × 18 rows × 7 layers,and the number of nodes of the calculation unit is 6899076,which exceeds the existing calculation capacity of the laboratory.Therefore,this paper makes full use of the principle of symmetrical structure,simplifies the shelf model reasonably,and meets the requirements of the existing calculation force.According to the dynamic analysis requirements of a column breaking suddenly in the storage rack,this paper selects the life and death element method to establish the model for the column breaking suddenly through the analysis and Research on the characteristics of the relevant elements,and the other column models remain unchanged,which effectively simulates the fracture of the member,and the calculation results meet the requirements of the demand side of the subject.In view of the impact of earthquake on storage shelves,this paper chooses the seismic shear wave action analysis as the main method according to the actual situation.According to the intensity requirements specified by the demand side of the subject,the seismic shear wave action is simplified as the equivalent action on the unit node at the bottom of the column,and the analysis results satisfying the demand side are obtained.Based on the above research and master of the basic theory and calculation method of the finite element method,the specific results achieved in this paper can be summarized as follows:(1)According to the characteristics of upper limb rehabilitation arm and storage rack structure,simplify the structure,select the element type,and establish the finite element model.(2)The finite element method is used to design the rehabilitation manipulator.Based on the analysis of the mechanical properties of the rehabilitation arm structure,the topology optimization of the horizontal arm plate and the column of the main stressed parts is carried out according to the analysis results of the rehabilitation arm.According to the results of topology optimization,the model is simplified,and the weight of the structure is obviously reduced after structure optimization.The center of gravity of the rehabilitation manipulator is close to the center of rotation,the moment of inertia is smaller,and the mechanical properties of the structure are obviously improved.(3)The finite element method is used to analyze the deformation and stress caused by gravity when the storage rack is full.The transient dynamic analysis of the storage rack was carried out to simulate the column fracture by killing the unit.The maximum deformation of the storage rack was 4.1mm.According to the analysis of seismic response spectrum of storage rack,the deformation of storage rack under the influence of horizontal seismic load is 0.019 mm.The above analysis proves that the design of storage shelf is reasonable.