Analysis Of The Influence Of Process Parameters On Section Deformation In Flexible Multi-point Stretch-bending Of Aluminum Profile

The flexible multi-point stretch-bending process is widely used in the plastic processing domain of profiles due to its low tooling costs,product diversity and the possibility of forming three-dimensional parts at once.Due to the complexity of the forming process and the contact and non-contact areas between the die and the profile caused by the discrete die,defects such as section deformation,springback and wrinkling produced during forming are bound to be different from those in conventional stretch-bending and the forming accuracy of the part can hardly be effectively guaranteed.Combining the characteristics of multi-point stretch-bending process and finite element theory,this paper adopts the finite element analysis software ABAQUS to carry out finite element modeling of multi-point stretch-bending forming of aluminum profiles.The modeling process mainly includes selecting material model,reasonably simplifying model,selecting appropriate cell type and reasonably dividing mesh,setting contact,friction and boundary conditions,etc.to ensure accurate modeling accurately to obtain precise results.In the case where high dimensional accuracy is required,section deformation is an important factor to determine the forming accuracy of a part.By investigating the section deformation values at different locations of the part,determine the locations of the points that can effectively describe the section deformation.By analyzing the positive stresses at the nodes under different paths of the section,the mechanism of the section deformation during the stretch-bending of the part is investigated.The process parameters of flexible multi-point stretch-bending are the key factors affecting the section deformation.In this paper,the variation values of section width and section height are used to indicate the degree of section deformation.The control variable method is used to study the influence law of single process parameter(number of die heads,bending radius,pre-stretching amount,pro-stretching amount and friction coefficient)on the stress-strain distribution and section deformation distribution of the profile,and to explore the influence of each process parameter on the position of maximum section deformation.In order to better control the section deformation of the profile during stretchbending deformation,this paper firstly investigates the variation of the maximum section deformation value of the profile with the bending radius under certain process parameters.Then,the minimum bending radius when the section deformation of the profile does not exceed the given value is obtained by the data analysis method-curve fitting inversion.Finally,the processing boundary diagram of the section deformation is drawn according to the minimum bending radius,and the feasibility of the processing boundary diagram is verified through experiments.In order to comprehensively consider the influence of process parameters on section deformation,this paper adopts the orthogonal test method to analyze the variation law of section deformation under five process parameters(number of die heads,bending radius,pre-stretching amount,pro-stretching amount and friction coefficient).Combined with the results of the extreme difference analysis to determine the primary and secondary relationships of each process parameter on the section deformation and the optimal combination of process parameter levels.Finally,the effectiveness of the optimal combination of process parameters is verified by finite element analysis and experimental analysis.