CAF—a simplified approach to calculate springback in Al 7050 alloys

Brandão, F.; Delijaicov, Sérgio; Bortolussi, Roberto

doi:10.1007/s00170-016-9839-y

Cited by 9 publications

(8 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…From Eqs. (21) and (25), the strain neutral layer ρ ε is calculated as and the loading moment is where * is the material constant.…”

Section: Stretch-bending Processmentioning

confidence: 99%

“…Finite element simulation is an effective method to solve engineering problems, which has a certain advantage to solve the springback of complex shape parts. However, its precision is sensitive to the simulation model [23], particularly material model [24], element type [25], boundary conditions [26] and other input parameters, leading to the uncertainty in the tool compensation. The accurate calculation model has not yet been established, although the theoretical analysis can analyze the trend of the iterative parameters [27][28][29].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

An Iterative Compensation Algorithm for Springback Control in Plane Deformation and Its Application

Wang

Zhai

2019

Chin. J. Mech. Eng.

View full text Add to dashboard Cite

In order to solve the springback problem in sheet metal forming, the trial and error method is a widely used method in the factory, which is time-consuming and costly for its non-direction and non-quantitative. Finite element simulation is an effective method to predict the springback of complex shape parts, but its precision is sensitive to the simulation model, particularly material model and boundary conditions. In this paper, the simple iterative method is introduced to establish the iterative compensation algorithm, and the convergence criterion of iterative parameters is put forward. In addition, the new algorithm is applied to the V-free bending and stretch-bending processes, and the convergence of curvature and bending angle is proved theoretically and verified experimentally. At the same time, the iterative compensation experiments for plane bending show that, the new method can predict the next compensation value based on the springback of each test, so that the target bending angle with the error of less than ± 0.1% and the target curvature with the error of less than 0.5% are obtained after 2-3 iterations. This research proposes a new iterative compensation algorithm to predict springback in sheet metal forming process, where each compensation value depends only on the iteration parameter difference before and after springback for the same forming process of same material.

show abstract

“…From Eqs. (21) and (25), the strain neutral layer ρ ε is calculated as and the loading moment is where * is the material constant.…”

Section: Stretch-bending Processmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

An Iterative Compensation Algorithm for Springback Control in Plane Deformation and Its Application

Wang

Zhai

2019

Chin. J. Mech. Eng.

View full text Add to dashboard Cite

show abstract

“…The predicted springback was compared to experimental data from Brandão [19] and [25]. The initial heat treatment of alloy AA7050 that Brandão [19] used was not essentially the same that Yang et al [15] used.…”

Section: Experimental Validationmentioning

confidence: 99%

“…This model was fitted to the creep experimental data published by Yang et al [15]. The final results were compared to CAF experimental data from Brandão [19] and Brandão et al [25], in which accomplished tests with the alloy AA7050 at similar conditions to the alloy applied by Yang et al [15].…”

Section: Introductionmentioning

confidence: 99%

Effect of the hardening rules on the creep age forming prediction of 7050 aluminum alloy with experimental verification

Oliveira

Delijaicov

Bortolussi

2018

J Braz. Soc. Mech. Sci. Eng.

Self Cite

View full text Add to dashboard Cite

The creep age forming (CAF) has been used in the aerospace sector due to its attractive characteristics that allows producing a component with low residual stress. The process has been studied from the finite-element simulations which are used mainly to predict the springback. However, to accomplish the simulation, it is necessary to set the CAF constitutive equations in the finite-element software. In addition, it is also necessary to define the hardening rule which is applied to determine the creep strain. This work aims to investigate CAF applying the finite-element analysis with the timehardening rule and strain-hardening rule and thus predicting creep strain, stress relaxation, and springback. The finiteelement simulations were accomplished in dies with single and double curvatures and the blank's material was the alloy AA7050. Furthermore, the Marin-Pao model was implemented in the MSC.Marc software through a user subroutine. This model was fitted to the creep experimental curves and it generated good agreement with the experimental data. The results of the simulations that used the time-hardening rule were similar to the strain-hardening rule, and therefore, if it had been chosen a hardening rule, it would not have generated a significant impact in the CAF simulation results. At the end, the simulated springback was compared to the experimental springback from the literature and the percentage error ranged from 0.46% to 15.33% that indicate the proximity with the literature data. Moreover, other experimental validation was performed, and when compared to the results of this methodology, the calculated error in springback was 6.3%.

show abstract

“…Holman [3] proved that CAF is a viable forming method to manufacture large aluminium panels for aircraft by using an autoclave and corresponding tools. As high springback usually occurs in a CAFed plate [1,4], a number of constitutive models have been proposed to model the creep-ageing/stress-relaxation behaviour for a range of aluminium alloys [5][6][7], which have been implemented into FE solvers for springback prediction and tool shape optimisation [8,9]. The CAF process has been successfully applied to manufacture aircraft skin panels, such as the EPC bulkhead of MT Aerospace Ariane V [10] and upper wing skins of the Airbus A380 [11], and it has been considered to be a promising technology for producing large/extra-large panels in other transport industries.…”

Section: Introductionmentioning

confidence: 99%

Development of similarity-based scaling criteria for creep age forming of large/extra-large panels

Shao

Rong

et al. 2018

Int J Adv Manuf Technol

View full text Add to dashboard Cite

A scaling method is developed for the creep age forming (CAF) process to downscale manufacturing of large/extra-large panels to lab-scale experimental trials for industrial application. Similarity theory is applied to identify both the geometrical and physical (non-geometrical) similarities between large-size prototypes and scaled-down models in all process stages of CAF, including loading, stress-relaxation and unloading (springback). A constitutive model is incorporated into the theory in order to identify the similarity in the highly non-linear stress-relaxation behaviour for aluminium alloy plates during CAF, and to obtain the effective scaling criteria for the CAFed plates after springback. The method was demonstrated by scaling down CAF manufacturing of both singly curved and doubly curved large plates under both proportional and non-proportional geometrical scaling conditions. The analytical results of the scaling method and numerical results obtained by CAF FE modelling were found to be in good agreement. Scaling diagrams linking the key deformation (springback) and structural (flexural rigidity) variables to scaling ratios under both proportional and non-proportional conditions were generated, and the developed scaling diagrams have been validated by corresponding CAF experiments. The scaling method developed in this study provides guidance on the design of scaled-down CAF experimental trials and will be used in the practical CAF process of large/extra-large panels.

show abstract

CAF—a simplified approach to calculate springback in Al 7050 alloys

Cited by 9 publications

References 8 publications

An Iterative Compensation Algorithm for Springback Control in Plane Deformation and Its Application

An Iterative Compensation Algorithm for Springback Control in Plane Deformation and Its Application

Effect of the hardening rules on the creep age forming prediction of 7050 aluminum alloy with experimental verification

Development of similarity-based scaling criteria for creep age forming of large/extra-large panels

Contact Info

Product

Resources

About