A Structure for the Control of Geometry and Properties of a Freeform Bending Process

Ismail, Alaa M.; Maier, Daniel; Stebner, Sophie Charlotte; Volk, Wolfram; Münstermann, Sebastian; Lohmann, Boris

doi:10.1016/j.ifacol.2021.10.060

Cited by 11 publications

(5 citation statements)

References 6 publications

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“…Figures 7 and 8 show the numerical simulations and experiments (U = 12 mm) to investigate the effect of the active deflection processes on the tube. The radial stresses at the primary deformation zone (S11, the normal stress in X, Unit: MPa) were compressed inside and outside of the bending section, which is consistent with the theoretical analysis of Equations ( 15) and (16). The deflection angle of the finite element simulation was φ = 78.60° and the actual deflection angle was φ = 43.64°.…”

Section: Comparison Of Theoretical and Experimental Results Of Free B...supporting

confidence: 79%

“…From the aforementioned discussions, it is indicated that investigations on the 3D-FBF and other bending fields have mainly focused on the analysis of forming mechanisms and the improvement of forming limits [16]. Up to now, there have been relatively few studies on the active deflection and interference avoidance methods by using the original mechanical structure and the resulting defects.…”

Section: Introductionmentioning

confidence: 99%

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Effect of Active Deflection on the Forming of Tubes Manufactured by 3D Free Bending Technology

Zhang

El-Aty

Tao

et al. 2022

Metals

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The formed parts of tubes easily interfere with the equipment when forming complex tubes in 3D free bending forming technology. Consequently, to solve the interferential phenomenon, an active deflection method (ADM) to avoid interference was proposed to drive the deformed tube around its axis by controlling the bending die. The method extended the activity freedom of the equipment without installing the additional motion shafting. However, severe section distortion, surface scratches and other forming defects frequently occurred during the implementation of ADM, which reduced the structural strength and pressure resistance of the tubes. A mechanical model was developed to analyze the force state of the tube, and the results showed that the driving force of active deflection was mainly determined by the trajectory radius. The curve of the adopted bell-shaped transition structure was closer to the bending curvature of the tube than the rounded structure, which transformed the guider and the tube from linear contact to surface contact. The simulation and experiment results indicated that adding the trajectory radius could strengthen the rotation torque. The stress concentration in the tube was alleviated after applying the bell-shaped transition structure.

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Section: Comparison Of Theoretical and Experimental Results Of Free B...supporting

confidence: 79%

Section: Introductionmentioning

confidence: 99%

Effect of Active Deflection on the Forming of Tubes Manufactured by 3D Free Bending Technology

Zhang

El-Aty

Tao

et al. 2022

Metals

View full text Add to dashboard Cite

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“…These applications often require tubes with complex spatial shapes. Traditional bending forming methods, however, are typically limited to creating simpler axial shapes [9][10][11][12]. For instance, Ghiotti et al [13] utilized rotary draw bending to manufacture high-strength metallic alloy tubes with a nominal mean curvature radius of 100 mm and a bending angle of 90 • .…”

Section: Introductionmentioning

confidence: 99%

Modeling and Experimental Investigation of U-R Relationship of AA6061-T6 Tubes Manufactured via Free Bending Forming Process

Abd El-Aty,

Cheng,

et al. 2023

Materials

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Forming tubes with various bending radii without changing the bending dies is much easier for the 3D free bending forming (FBF) process. In the 3D-FBF process, different bending radii were realized by adapting the eccentricities of the bending dies. The accuracy of the U-R curve is crucial for the precision forming of complex bending components. In this study, the U-R relation curve of the Al alloy tube with a specific friction coefficient, fixed geometry size, clearance between tubes, and bending die was fitted first based on the forming results of AA6061-T6 tubes under different eccentricities. Second, the U-R relationship curve based on the experiment is used to propose the U-R relationship’s mathematical formula based on many hypotheses. Finally, the modified U-R mathematical formula was applied in the finite element (FE) simulation and the actual FBF experiments for the AA6061-T6 Al alloy complex shape space bending members. The U-R relationship curve’s reliability was verified by comparing the simulation and experimental results. The results obtained from the modified U-R relationship align well with the FE modeling results and can be directly applied to the bending process for the intended components.

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“…Furthermore, component failure due to unfavorable residual stress distribution, varying degrees of plastic deformation or excessive hardening of the material can be avoided. Finally, based on the soft sensor, a closed-loop property-control for the freeform bending process based on [6] will be designed.…”

Section: Introductionmentioning

confidence: 99%

Extension of a Simulation Model of the Freeform Bending Process as Part of a Soft Sensor for a Property Control

Stebner

Maier

Ismail

et al. 2022

KEM

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This work introduces an Abaqus CAE simulation model and its validation for freeform bending with movable die, which is extended in the simulation of a weld seam for the longitudinally welded tube. The superordinate goal is the development of a soft sensor, that can derive mechanical properties of a freeform bent tube as a basis for a closed-loop control. To guarantee a close monitoring of the mechanical properties, the soft sensor needs to be able to extrapolate the mechanical properties spatially. Because the investigated steel tubes are longitudinally welded, the weld depicts a disturbance regarding the rotational symmetry. In developing and validating a numerical simulation of the process, that quantitatively describes the influences the weld has on the mechanical properties, a significant improvement of the qualitative and quantitative prediction of the soft sensor can be achieved. The numerical modelling is done based on tensile tests on material taken from the weld seam, where hardness measurements are then used for the local validation of the model. The validated model now provides a time as well as cost efficient way of a primary investigation of the mechanical properties, especially regarding the local strength of the steel tube for a soft sensor and as input data for a feed forward control in the machine. Therefore, this work represents an important addition to the superordinate goal of developing a closed-loop property-control based on a soft sensor for freeform bending with movable die.

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A Structure for the Control of Geometry and Properties of a Freeform Bending Process

Cited by 11 publications

References 6 publications

Effect of Active Deflection on the Forming of Tubes Manufactured by 3D Free Bending Technology

Effect of Active Deflection on the Forming of Tubes Manufactured by 3D Free Bending Technology

Modeling and Experimental Investigation of U-R Relationship of AA6061-T6 Tubes Manufactured via Free Bending Forming Process

Extension of a Simulation Model of the Freeform Bending Process as Part of a Soft Sensor for a Property Control

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