https://koreascience.or.kr:443/article/JAKO202026252109572.pdf

Analytic springback prediction in cylindrical tube bending for helical tube steam generator

The springback in the sheet metal forming process refers to the change of shape after the load removal. It is usually undesirable, causing problems in the subsequent forming operations, in the assembly and negatively affects the quality of the final product. Numerical prediction of the springback with the use of the numerical simulation is crucial for the reduction of forming tool try-outs, reducing manufacturing costs and increasing the accuracy of the stamped part. In this work, numerical simulation was used for the springback prediction of the hat-shaped part made of advanced high-strength dual-phase steel HCT600X+Z. These numerical predictions were performed with the use of various combinations of material models to try to improve the prediction results. Furthermore, this work includes the proposed springback reduction measure. The reduction of the springback was achieved by the tool design which includes a counterpunch. The springback analysis was carried out in the side view of the formed part; the springback prediction results were compared with the experimental values.

https://www.mdpi.com/2075-4701/10/9/1119/pdf

Numerical Prediction and Reduction of Hat-Shaped Part Springback Made of Dual-Phase AHSS Steel

Springback prediction of multiple reciprocating bending based on different hardening models

Nonlinear anelastic behavior and unloading-reloading constitutive models of severe plastic compressive deformation

The effect of the computational model and mesh strategy on the springback prediction of the thin sandwich material made of micro-alloyed steel was investigated in this paper. To verify the chosen computational strategy, a comparison of the experimentally obtained specimen (U-bending) with the FEA result was performed. The Vegter yield criterion combined both with the isotropic and kinematic hardening law was used for the calculation. In addition, the effect of the deformation mesh element (surface and volume) on the accuracy of the springback prediction was investigated. It was concluded that the choice of the volume deformation mesh does not significantly improve the accuracy of the results. Moreover, it is quite a time-consuming approach. The much greater influence was monitored by concerning the selection of hardening law, where the anisotropic one was more suitable to be used on the springback prediction of a given sandwich material.

/pdf/effect-of-the-computational-model-and-mesh-strategy-on-the-37ncsey5.pdf

Effect of the Computational Model and Mesh Strategy on the Springback Prediction of the Sandwich Material

In this paper, the uniaxial loading–unloading–reloading (LUR) tensile test was conducted to determine the elastic modulus depending on the plastic pre-strain. To obtain the material parameters and parameter of Yoshida-Uemori’s kinematic hardening models, tension–compression experiments were carried out. The experimental results of the cyclic loading tests together with the numerically predicted response of the plastic behavior were utilized to determine the parameters using the Ls-opt optimization tool. The springback phenomenon is a critical issue in industrial sheet metal forming processes, which could affect the quality of the product. Therefore, it is necessary to represent a method to predict the springback. To achieve this aim, the calibrated plasticity models based on appropriate tests (cyclic loading) were implemented in commercial finite element (FE) code Ls-dyna to predict the springback in the roll forming process. Moreover, appropriate experimental tests were performed to validate the numerical results, which were obtained by the proposed model. The results showed that the hardening models and the variation of elastic modulus have significant impact on springback accuracy. The Yoshida-Uemori’s hardening represents more accurate prediction of the springback during the roll forming process when compared to isotropic hardening. Using the chord modulus to determine the reduction in elastic modulus gave more accurate results to predict springback when compared with the unloading and loading modulus to both hardening models.

https://www.mdpi.com/2075-4701/9/9/1005/pdf

Jihad Naofal

Papers

Effects of Hardening Model and Variation of Elastic Modulus on Springback Prediction in Roll Forming