Influence of size effect on the springback of sheet metal foils in micro-bending

Liu, Jianguang; Fu, Ming; J, Lu; Chan, Wai Ming

doi:10.1016/j.commatsci.2011.04.002

Cited by 90 publications

(41 citation statements)

References 37 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Unlike the previous assumption [14] that the flow stress of surface layer is equal to that of grain interior, the grain boundary strengthening effect cannot be neglected in these two circumstances due to the limited quantities of grain boundaries. Since there is no good way to divide these structures into two portions just like the classic surface layer model, a new constitutive model is proposed in order to better describe these particular material size effects.…”

Section: Constitutive Modelmentioning

confidence: 84%

“…The flow stresses of grain interior and grain boundary of copper alloy is determined in the reference [14] shown in Fig. 8.…”

Section: The Two Sectors Andmentioning

confidence: 99%

“…They observed that springback is related to the ratio of sheet thickness to grain size, but all the ratios were larger than 1. Liu et al [14] developed a constitutive model considering the grain boundary strain hardening. Fu et al [15] studied the size effect on fracture behavior of the annealed copper foils with different thicknesses and grain sizes by tensile tests, and they found that the number of micro-voids as well as the fracture stress and strain decrease with T/D.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Grain size effect of thickness/average grain size on mechanical behaviour, fracture mechanism and constitutive model for phosphor bronze foil

Fang

Jiang

Wang

et al. 2015

Int J Adv Manuf Technol

View full text Add to dashboard Cite

X. (2015). Grain size effect of thickness/average grain size on mechanical behaviour, fracture mechanism and constitutive model for phosphor bronze foil. International Journal of Advanced Manufacturing Technology, 79 (9-12), 1905Technology, 79 (9-12), -1914 Grain size effect of thickness/average grain size on mechanical behaviour, fracture mechanism and constitutive model for phosphor bronze foil AbstractSize effects play a significant role in microforming process, and any dimensional change can have a great impact on materials' mechanical properties. In this paper, the size effects on deformation behaviour and fracture of phosphor foil were investigated in the form of grain size effect: the ratio of materials' thickness (T) to average grain size (D) by micro tensile tests. The ratio was designed to be closed to but larger than, less than and equal to 1, respectively. The results show that the amount of plastic deformation decreases with the decrease of the ratio of T/D, which indicates that the grain size plays a significant role and grain deformation modes differ when the ratio changes. It is also found that their fractograph reflects different features in terms of micro-dimples and cleavage planes, further demonstrating that when T/D >1, its materials have a tendency to fracture ductilely, while materials would like to conduct brittle fracture when T/D Grain size effect of thickness/average grain size on mechanical behaviour, fracture mechanism and constitutive model for phosphor bronze foil Abstract: In this paper, the size effects on deformation behaviour and fracture of phosphor foil were investigated in terms of the ratio of materials' thickness (T) to average grain size (D) by micro tensile tests. The results show that the amount of plastic deformation decrease with the decrease of the ratio of T/D, which indicates that the grain size plays a significant role and grain deformation modes differ when the ratio changes. It is also found that their fractograph reflect different features in terms of micro-dimples and cleavage planes, further demonstrating that when T/D>1, its materials have a tendency to fracture ductilely, while materials would like to conduct brittle fracture when T/D<1. So the ratio of T/D which is close to 1 can be regards as the divide of ductile fracture and brittle fracture. For T/D<1, a new constitutive model is proposed based on the classic composite model. The model's results are compared with the experimental ones and the efficiency of the developed models is verified.

show abstract

Section: Constitutive Modelmentioning

confidence: 84%

“…The flow stresses of grain interior and grain boundary of copper alloy is determined in the reference [14] shown in Fig. 8.…”

Section: The Two Sectors Andmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Grain size effect of thickness/average grain size on mechanical behaviour, fracture mechanism and constitutive model for phosphor bronze foil

Fang

Jiang

Wang

et al. 2015

Int J Adv Manuf Technol

View full text Add to dashboard Cite

show abstract

“…Liu et al [4] found that a large springback occurs with thickness decreasing or grain size increasing. Besides, an increasing of elastic anisotropy of surface grains with the reduction of grains along the thickness direction will cause the springback angle scattering [4,5]. Chen et al [6] discovered that yield strength and maximum punch force decrease with a decrease of t/d ratio.…”

Section: Introductionmentioning

confidence: 99%

Preliminary Investigation of Micro-V-Bending

2017

View full text Add to dashboard Cite

Abstract. Bending in sheet metal forming is defined as uniformly straining process around a linear axis. A V-bending process is normally used in sheet metal working due to the tool and process simplicity. The main problem in bending process is a springback occurrence which causes an error in part dimension. In a micro level, the springback angle is difficult to be assessed because of the influence of size effects in all aspects of the system. The springback behavior has been investigated in many previous kinds of research. However, the springback correction is still needed to be studied extensively so that it can be implemented reliably in micro-bending. The purpose of this research is to investigate the influence of punch velocity and holding time to the springback angle. The process is performed to the 0.1 mm thickness of copper foil. The punch velocities are 0.1 mm/s, 1 mm/s, and 10 mm/s. While the variation of holding time, which is set during the bottoming stage, are 7 s, 9 s, and 11 s. The result shows that the punch velocity clearly influences the springback angle. In addition, the holding time during the bottoming stage is a potential factor in springback angle correction.

show abstract

“…Hence, several studies on springback in microforming have been conducted: Gau et al [11] studied the relationship between the ratio of thickness and grain size and springback angles by three points bending with annealed brass thin sheet, and concluded that when the thickness of material is less than 350µm, the conventional springback theory cannot be applicable. Liu et al [12] modelled three points bending with commercial finite element (FE) software ABAQUS/standard. The elastic properties in the simulation were connected with the elastic anisotropy which represents different Young's moduli in different grain orientations.…”

Section: Introductionmentioning

confidence: 99%

Effect of Grain Size on Springback and System Energy in Micro V-Bending with Phosphor Bronze Foil

Fang

Jiang

Wang

et al. 2015

Metall Mater Trans A

View full text Add to dashboard Cite

In this paper, the effect of grain size on springback in the micro V-bending process of phosphor bronze foil (face-centered cubic structure) is investigated. Grain size effect is expressed by the ratio of material thickness (T) to average grain size (D), and these T/D values are divided into three groups: larger than 1, less than 1, and approximately equal to 1. It has been found that springback angles were the lowest when T/D ≈ 1. Electron backscattering diffraction (EBSD) measurement results show that the twinning boundaries change with the ratios of T/D before and after bending. When T/D > 1, the high relative frequency of Σ3 implies that the specimen has a high system energy, which can result in large springback behavior. The equal relative frequencies of Σ3 for specimens with three ratios also prove that twinning boundaries can be regarded as an indicator of system energy. The effect of grain size on grain reorientation during bending is also discussed, and it was found that the least quantities of high surface energy {110} planes in the T/D ≈ 1 material could contribute to the least springback angles. the high relative frequency of Σ3 implies that the system specimen has a high system energy, which can result in large springback behaviour. The equal relative frequencies of Σ3 after bending for three ratios' specimens also prove that twinning boundaries can be regarded as an indicator of system energy. Moreover, the effect of grain size on grain reorientation during bending was discussed, and the least quantities of high surface energy {110} planes in the T/D≈1 material could contribute to the least springback angles.

show abstract

Influence of size effect on the springback of sheet metal foils in micro-bending

Cited by 90 publications

References 37 publications

Grain size effect of thickness/average grain size on mechanical behaviour, fracture mechanism and constitutive model for phosphor bronze foil

Grain size effect of thickness/average grain size on mechanical behaviour, fracture mechanism and constitutive model for phosphor bronze foil

Preliminary Investigation of Micro-V-Bending

Effect of Grain Size on Springback and System Energy in Micro V-Bending with Phosphor Bronze Foil

Contact Info

Product

Resources

About