Examination of Springback in Sheet Metal Forming by Finite Element Method (original) (raw)
Related papers
Design And Analysis Of A Spring Back Effect In Sheet Metal Forming
International Journal of Research in Engineering & Advanced Technology, 2016
One of the largest challenges in manufacturing is the consistency of final products. Two basic approaches have been investigated to achieve this goal. One is to use intelligent assembly methodologies to select a suitable set of parts to be assembled which is taking advantage of tolerance stack up. The other approach aims at each individual manufacturing process module, for example sheet metal forming process. The forming of sheet metal into a desired and functional shape is a process, which requires an understanding of materials, mechanics, and manufacturing principles. The major problem in fabrication of sheet metal parts is spring back effect i.e. the elastic strain recovery in the material after the tooling is removed. Spring back control is one of the key concerns of the sheet metal forming industry. The current trial-and-error method of testing and controlling for spring back is costly, time consuming, and remains as an obstacle in achieving shorter design production cycles. The elastic spring back at the end of a bending process plays an important role in determining the quality of final product thus in practice the constitutive relation that considers the elastic and plastic parts together has to be used. The factors have a non-linear interaction with each other so it is extremely difficult to develop an analytical model for spring back control including all these factors. So approach with FEA simulations are used to confront this difficulty.
Literature Review on Analysis of Spring Back in Sheet Metal Forming Processes
International Journal for Research in Applied Science & Engineering Technology (IJRASET), 2022
The spring back is the part of sheet metal bending that is most susceptible to failure during unbounding. Elastic and plastic deformation combine to completely distort the workpiece (sheet metal) during the metalworking process. When sheet metal is being worked on, it is put under a lot of pressure, which causes plastic deformation. However, when the pressure is released, the material recovers elastically. During the entire process. small amount of reduction in the total deformation takes place So, this phenomenon. is called as spring back-the change in sheet metal's geometry. The thickness of sheet metal ranges from 0.5 mm to 6 mm. Depending on the tooling geometry, material qualities, sheet thickness, and punch and die properties, spring back can affect the completed part's dimensional accuracy. Sheet metal elements / materials / appliances made in industries such as automotive OEM and ancillaries, enclosures aircraft, heavy machinery, medical devices etc. are affected by spring back in their correctness. This review study examines various factors influencing springback in sheet metal fabrication
Finite Element Analysis of sheet metal bending process to predict the springback
Materials & Design, 2010
Springback remains a major concern in sheet metal forming process. Springback, shape discrepancy between fully loaded and unloaded configuration due to elastic recovery of material, is mainly affected by geometrical parameters, material properties of sheet and lubrication condition between the blank and the tool. A total-elastic-incremental-plastic (TEIP) algorithm, for large deformation and large rotational problems, was incorporated in indigenous Finite Element software. This software was used to predict the springback in a typical sheet metal bending process and to investigate the influence of these parameters on springback. The results of simulation are validated with own experiments and published experimental results.
Sheet metal forming analyses with an emphasis on the springback deformation
Journal of Materials Processing Technology, 2008
Sheet metal forming Springback Bauschinger effect Finite element method Kinematic hardening a b s t r a c t An accurate modeling of the sheet metal deformations including the springback is one of the key factors in the efficient utilization of FE process simulation in the industrial setting. In this paper, a rate-independent anisotropic plasticity model accounting the Bauschinger effect is presented and applied in the FE forming and springback analyses. The proposed model uses the Hill's quadratic yield function in the description of the anisotropic yield loci of planar and transversely anisotropic sheets. The material strain-hardening behavior is simulated by an additive backstress form of the nonlinear kinematic hardening rule and the model parameters are computed explicitly based on the stress-strain curve in the sheet rolling direction. The proposed model is employed in the FE analysis of Numisheet'93 U-channel benchmark, and a performance comparison in terms of the predicted springback indicated an enhanced correlation with the average of measurements. In addition, the stamping analyses of an automotive part are conducted, and comparisons of the FE results using both the isotropic hardening plasticity model and the proposed model are presented in terms of the calculated strain, thickness, residual stress and bending moment
Algorithm Development and Application of Spring back Compensation for Sheet Metal Forming
2012
The aim of this research is to develop an algorithm to solve difficulty associated with spring back error in sheet metal forming. Spring back can be considered as a dimensional change which happens during unloading, due to the occurrence of primarily elastic recovery of the material. The die surface compensation is needed to obtain the accurate product due to geometrical deviations caused by spring back. Die-compensation simulation enables companies to increase competitiveness by increasing product accuracy and reducing the number of errors in sheet metal forming process. The proposed algorithm combines two methods of die compensation; Displacement Adjustment (DA) and Spring-Forward (SF) methods. Both are based on iteratively comparing the deformed shape with the target.
International Journal of Mechanical Sciences, 2017
The high-strength steel sheets currently used in the automotive industry are prone to non-traditional behaviour during forming, being wrinkling and springback two of the most challenging geometrical predictions for numerical simulation. Thus, the finite element method requires accurate and reliable numerical models. This study presents the experimental and numerical analysis of a rail component with high tendency to develop wrinkling and 2D springback. Two different materials are used for the sheet blank, namely a mild steel (DC06) and a dual phase steel (DP600). The frictional behaviour between each metallic sheet and the forming tools is evaluated through the flat-die test, allowing the determination of a friction coefficient as a function of the normal pressure. The influence of the applied boundary conditions on the numerical results is evaluated by means of two distinct numerical models (full blank geometry and 1/4 of the blank with symmetry conditions). The results show that the wrinkling behaviour is strongly affected by the blank's material, as well as by the symmetry conditions defined in the numerical model. In fact, considering the full model of the blank, the numerical results are in better agreement with the experimental ones. However, the computational cost of the numerical simulation considering the full blank is substantially higher than using 1/4 of the blank.
IJERT-Sheet Metal Forming Analysis with An Emphasis on Spring Back Deformation
International Journal of Engineering Research and Technology (IJERT), 2013
https://www.ijert.org/sheet-metal-forming-analysis-with-an-emphasis-on-spring-back-deformation https://www.ijert.org/research/sheet-metal-forming-analysis-with-an-emphasis-on-spring-back-deformation-IJERTV2IS100016.pdf Stress analysis plays important role in structural design and manufacturing. Proper stress estimation helps to prevent objects from failing during working. Spring back is mainly due to nonlinear plasticity with friction and heat loss in the material. Bauschigner effect is the main cause of this spring back phenomenon. In the present work, an analysis is carried out to find the spring back on the metal forming process is. Initially a geometrical model in plane strain approach is built using ANSYS mixed approach. The geometry is split to form mappable areas to quad meshing. Later contact elements are defined between the punch and the sheet metal and second contact pair between sheet metal and die surface. The analysis is done using Newton raphson iterative method to find the cone angle effect on spring back phenomenon. The results shows with the reduction in the cone angle all these parameters are increasing. Increasing plastic strain and residual stress are the potential sources for crack formation and propagation and eventual failure of the members.
An Alternate Method to Springback Compensation for Sheet Metal Forming
Research Article, 2014
The aim of this work is to improve the accuracy of cold stamping product by accommodating springback. This is a numerical approach to improve the accuracy of springback analysis and die compensation process combining the displacement adjustment (DA) method and the spring forward (SF) algorithm. This alternate hybrid method (HM) is conducted by firstly employing DA method followed by the SF method instead of either DA or SF method individually. The springback shape and the target part are used to optimize the die surfaces compensating springback. The hybrid method (HM) algorithm has been coded in Fortran and testedin two-and three- dimensional models. By implementing the HM, thespringback error can be decreased and the dimensional deviation falls in the predefined tolerance range.
MATEC Web of Conferences
The process of sheet metal forming is one of the very important processes in manufacture of products mainly in the automotive field. In sheet metal forming, it is added a certain size at the die to tolerate a result of the elasticity restoration of material. Therefore, when the product is removed from the die then the process elastic recovery will end within the allowable tolerance size. Extra size of the die is one method to compensate for springback. The aim of this research is to optimize the die by entering a springback value in die design to improve product quality that is associated with accuracy the final size of the product. Simulation processes using AutoForm software are conducted to determine the optimal parameters to be used in the forming process. Variations the Blank Holder Force of 77 N, 97 N, and 117 N are applied to the plate material. The Blank Holder Force application higher than 97 N cannot be conducted because the Forming Limit Diagram indicates the risk of tearing. Then the Blank Holder Force of 37 N, 57 N and 77 N are selected and applied in cup drawing process. Even though a few of wrinkling are appear, however there is no significant deviation of dimension between the product and the design of cup.