Experimental investigation of large radius air bending

Vorkov, Vitalii; Aerens, Richard; Vandepitte, Dirk; Duflou, Joost R.

doi:10.1007/s00170-017-0346-6

Cited by 20 publications

(28 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Similar results on the effect of friction on multi-breakage and gap formation were also obtained in an FE-simulation by Burchitz [17]. Vorkov et al [2,15,18] studied the contact point shift in multibreakage and its effects on the moment distribution, bending force, springback and bend allowance. Ruoppa et al [19] measured the inner sheet radii and punch-sheet gaps among other cross-sectional measurements in large radius bending of UHSS to 90° angles.…”

Section: Introductionsupporting

confidence: 61%

“…Various analytical and semi-analytical models have been developed throughout the years for calculating springback, bend allowance, bend shape, bending forces, deformation etc. in air bending based on the tool geometry and material properties [7][8][9][10][11][12][13][14][15][16]. However, most of the models found in literature choose to ignore the multi-breakage phenomenon and its effects due to the convenience of the wrap-around assumption.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Strain distribution during air bending of ultra-high strength steels

Pokka¹,

Arola²,

Kaijalainen³

et al. 2021

Esaform 2021

View full text Add to dashboard Cite

Air bending is a widely used method for forming ultra-high strength steels (UHSS). However, the limited formability of UHSS poses some challenges for the bending process in the form of strain localisation, surface defects, punch detachment (multi-breakage) and pseudo-polygonal “nut-like” shape of the bend. In this study, the bendability of three UHSS grades (700, 900 and 1100 MPa) is investigated with 3-point bending tests, utilising Digital Image Correlation (DIC) for measuring the strain distributions on the outer curvature. The differences in the extent of multi-breakage and the bend shapes are also studied, and these observations are correlated with the findings from the bending force and strain measurements. The differences between the investigated UHSS grades are significant. The 900 MPa grade produces more localised strain distributions and pronounced multi-breakage compared to the other grades, along with a more polygonal “nut-like” geometry. The reasons and effects of the multi-breakage phenomenon, as well as the causes for the observed differences in the behaviour of the materials are discussed in this paper. The presented results and the measurement data provide more information about the behaviour of the investigated materials in bending, and can be used for improving bending simulation, numerical models, and workshop instructions.

show abstract

Section: Introductionsupporting

confidence: 61%

Section: Introductionmentioning

confidence: 99%

Strain distribution during air bending of ultra-high strength steels

Pokka¹,

Arola²,

Kaijalainen³

et al. 2021

Esaform 2021

View full text Add to dashboard Cite

show abstract

“…Fu and Mo used integrated neural network back propagation and genetic algorithm to develop the prediction model of spring back in the air bending process of high-strength sheet metal [10]. Vorkov et al, investigated the spring back behaviour of high strength steels experimentally with different parameters (different material, large radius punches, sheet thickness, die openings) using the air bending technique [11]. Vasudevan et al, investigated the spring back behaviours of electrogalvanised steel sheets in air bending operations.…”

Section: Introductionmentioning

confidence: 99%

Optimization of Spring Back in Air V Bending Processing using Taguchi and RSM Method

Özdemir

2020

mech

View full text Add to dashboard Cite

In this study, springback behaviour of Dp600 (Dual Phase Steel) sheet material was investigated using air V bending technique. As bending parameters, four different punch tip radii and four different sheet thicknesses were used. The springback values obtained from the experiments were compared with each other. At the same time, the experimental data were analysed with Response Surface Method (RSM) and Taguchi (L16) orthogonal array. The experimental data and the simulation results were found to be consistent. The signal-to-noise (S/N) ratio is used to determine the most appropriate parameter of minimum springback behaviour. Additionally, it is possible to estimate the optimal combination of the bending parameters. The signal-to-noise (S/N) ratio and the design of experiment (DOE) were utilised for the analysis of the experimental results. It was determined that the effect of these parameters on the air V bending process was based on springback behaviours.

show abstract

“…The increasing industrial utilization of high-strength steels is causing a shift to the use of large radius punches. Based on tooling dimensions, large radius bending is defined as the forming process where the ratio of a punch radius to a die opening is larger than 1/4 [1]. The high-strength steels have limited cold formability, and the use of large radius punches is inevitable to restrict the strain level during forming.…”

Section: Introductionmentioning

confidence: 99%

“…In particular, the gradual change of the loading scheme due to the multi-breakage effect is not properly addressed. The authors already investigated the problem of large radius bending by means of experimental [1,13,14], numerical [15][16][17], and regression approaches [18,19]. This contribution aims to develop a simple analytical method that predicts the bending characteristics in a fast and reliable way.…”

Section: Introductionmentioning

confidence: 99%

Analytical Prediction of Large Radius Bending by Circular Approximation

Vorkov

Aerens

Vandepitte

et al. 2018

Journal of Manufacturing Science and Engineering

Self Cite

View full text Add to dashboard Cite

An accurate analytical method is normally the preferred choice in engineering practice since this approach usually does not require additional software and can be applied for different situations. A number of analytical methods have been proposed for the air bending process, however, none of them has the capacity to deal with large radius bending. Large radius bending is characterized by a high ratio of the punch radius to the die opening and it is often applied for high-strength steels because of their limited bendability. This bending mode is used to fulfill the imposed level of maximum strain during the forming process. This contribution develops an analytical solution based on the assumption that the bent plate profile can be represented by two straight lines and a circular segment. Three different hardening laws—linear, Swift, and Aerens—are used for the bending moment calculation. Unit moment measurements are used in order to avoid extrapolation of hardening curves obtained by tensile testing. The model is compared with a wide range of experiments using the coefficient of determination, relative and absolute average errors, in addition to the mean standard error. The analytical prediction based on the circular approximation is found to be an accurate and robust tool for the calculation of the major bending characteristics for large radius air bending of high-strength steels.

show abstract

Experimental investigation of large radius air bending

Cited by 20 publications

References 24 publications

Strain distribution during air bending of ultra-high strength steels

Strain distribution during air bending of ultra-high strength steels

Optimization of Spring Back in Air V Bending Processing using Taguchi and RSM Method

Analytical Prediction of Large Radius Bending by Circular Approximation

Contact Info

Product

Resources

About