Study on Nonuniform Deformation of Tailor Rolled Blank During Uniaxial Tension

doi:10.1007/s40195-015-0313-x

Abstract

Abstract:

The deformation characteristics of tailor rolled blank (TRB) in the course of uniaxial tension were studied by means of analysis, test and simulation. The mechanical analytical model of TRB during uniaxial tension was set up, and the deformation formulae for the thinner side and for the thicker side were derived to quantify the deformation of TRB. On this basis, uniaxial tension tests on TRB and ordinary blanks (the thinner side and the thicker side of TRB) were conducted. Lagrange polynomial interpolation method was adopted to construct the stress-strain fields of unannealed and annealed TRBs for solving TRB material parameters, and then, uniaxial tension simulation on TRB was completed. Deformations and properties of unannealed TRB were compared with those of annealed TRB, and the thinner side and the thicker side were also compared. Finally, the research results were explained by metallurgical structure. The results show that nonuniform deformation happens in TRB during uniaxial tension, and the necking occurs on the thinner side. The agreement of analysis, test and simulation confirms the correctness of the analytical model and the deformation formulae. The findings of this paper can lay the foundation for the future study on TRB stamping formability and provide a way for TRB modeling.

Key words: Tailor rolled blank (TRB), Nonuniform deformation, Uniaxial tension, Annealing, Metallographical

Hua-Wei Zhang, Xiang-Hua Liu, Li-Zhong Liu, Ping Hu, Jia-Lu Wu. Study on Nonuniform Deformation of Tailor Rolled Blank During Uniaxial Tension[J]. Acta Metallurgica Sinica (English Letters), 2015, 28(9): 1198-1204.

Figures/Tables 13

Fig. 1 Mechanical analytical model of uniaxial tension for TRB.

Fig. 2 Dimension of tension specimen for TRB (mm).

Fig. 3 Schematic diagram of two-slope annealing process.

Table 1 Mechanical properties of unannealed TRBs with thicknesses of 1.2 and 2.0 mm

Thickness (mm)	E (GPa)	σ _s (MPa)	σ _b (MPa)	n	r	K (MPa)	δ (%)
1.2	179	209.6	300.9	0.24	1.56	533.9	35.2
2.0	195	209.4	271.7	0.22	1.09	459.8	38.2

Table 2 Mechanical properties of annealed TRBs with thicknesses of 1.2 and 2.0 mm

Thickness (mm)	E (GPa)	σ _s (MPa)	σ _b (MPa)	n	r	K (MPa)	δ (%)
1.2	186	170.7	237.5	0.27	1.98	443	42.5
2.0	196	179.5	264.9	0.24	1.50	472.5	45.2

Table 3 Comparisons of deformation between analytical result and experimental result of unannealed and annealed TRBs

TRB sample	Thinner		Thicker
TRB sample	Analytical	Experimental	Analytical	Experimental
Unannealed	10.65	11.21	0.23	0.42
Annealed	12.27	14.66	0.16	0.35

Fig. 4 Comparison between unannealed and annealed TRB specimens after test

Fig. 5 True stress-strain fields of TRBs: a unannealed, b annealed.

Fig. 6 Discretization of TRB transition zone.

Fig. 7 Finite element model of uniaxial tension for TRB in simulation.

Fig. 8 Equivalent strain distribution of TRB specimen when necking happens.

Fig. 9 Comparison of displacement-load curves of TRBs between tension test and simulation.

Fig. 10 Microstructures of unannealed and annealed TRBs: a unannealed 1.2 mm side, b unannealed transition zone, c unannealed 2.0 mm side, d annealed 1.2 mm side, e annealed transition zone, f annealed 2.0 mm side.

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