Analysis of Symmetrical Three-Point Bending and Springback Process of Pipes
Abstract
:1. Introduction
2. Basic Assumptions and Mechanical Models
2.1. Basic Assumptions
- The cross-sections of the pipes remain planar after bending and deformation, with no distortion occurring.
- Throughout the deformation process, the stress state at any point on any cross-section of the pipe is either uniaxial tension or uniaxial compression.
- The conventional elastic–plastic material model posits that the pipe is a continuous and homogeneous elastic–plastic body, where elastic deformation follows Hooke’s law for linear elasticity and plastic flow adheres to the unloading principles of stable material conditions and classical elastoplastic theory.
- The small-deformation assumption implies a linear distribution of strain across the cross-section, as
2.2. Material Model
2.3. Symmetrical Three-Point Bending Mechanical Model of Pipes
3. Analysis of Fully Elastic Bending Stage
4. Analysis of Elastic–Plastic Bending Stage
4.1. Analysis of Bending Process
- 1.
- Elastic–plastic deformation zone
- 2.
- Elastic deformation zone
4.2. Analysis of the Springback Process
5. Experimental Validation
5.1. Material Properties of the Experimental Pipes
5.2. Experimental Molds and Equipment
5.3. Finite Element Simulation Model
5.4. Results and Discussion
6. Conclusions
- Based on the assumption of small deformation, a mechanical model of symmetrical three-point bending and its springback process for pipes was developed using a bilinear hardening material model. This model incorporates the effects of mold parameters, material performance parameters, and other factors on pipe forming, aligning with the actual conditions of pipe pressure straightening.
- The finite element analysis and physical simulation experiment results of smaller pipes have confirmed the accuracy and reliability of the theoretical model. The establishment of this model not only enhances the accuracy of single-pressure straightening but also provides a theoretical foundation for the online identification of material performance parameters during the straightening process.
- Theoretical analysis and experimental results both indicate that the relationship between the maximum deflection after springback and the stroke of the indenter is very close to linear, offering a convenient method to establish an intelligent straightening control system for identifying springback laws.
Author Contributions
Funding
Data Availability Statement
Conflicts of Interest
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Pipes Grade | E/GPa | D/MPa | /MPa |
---|---|---|---|
20 | 172 | 2564 | 298.7 |
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Song, X.; Zhao, J.; Ma, R.; Li, J. Analysis of Symmetrical Three-Point Bending and Springback Process of Pipes. Symmetry 2025, 17, 95. https://doi.org/10.3390/sym17010095
Song X, Zhao J, Ma R, Li J. Analysis of Symmetrical Three-Point Bending and Springback Process of Pipes. Symmetry. 2025; 17(1):95. https://doi.org/10.3390/sym17010095
Chicago/Turabian StyleSong, Xiaokang, Jun Zhao, Rui Ma, and Jian Li. 2025. "Analysis of Symmetrical Three-Point Bending and Springback Process of Pipes" Symmetry 17, no. 1: 95. https://doi.org/10.3390/sym17010095
APA StyleSong, X., Zhao, J., Ma, R., & Li, J. (2025). Analysis of Symmetrical Three-Point Bending and Springback Process of Pipes. Symmetry, 17(1), 95. https://doi.org/10.3390/sym17010095