Proposal for reducing press working load and highly accurate evaluation of springback error in bending automobile sheet metal

Nishino, Souichiro; Ohya, Kunio; Naruishi, Keisuke

doi:10.1016/s0389-4304(03)00048-1

Cited by 12 publications

(10 citation statements)

References 3 publications

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“…3. The two types of experimental form-forming dies 13) shown in Fig. 4 and the draw-forming die shown in Fig.…”

Section: Forming Methodsmentioning

confidence: 99%

“…Nevertheless, the most important problem when high tensile strength steel plate is used is dimensional accuracy, and the focus in process technology research is on ways to improve shape accuracy [5][6][7][8][9][10][11][12][13] . The basic approach is to give the die a shape that differs from the actual part shape so that the part has the speci ed shape (dimensions) after spring-back, a technique called anticipation .…”

Section: Introductionmentioning

confidence: 99%

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Evaluation of the Form-Forming Mechanism for High-Tensile-Strength Steel Plate

2017

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Steel plate with tensile strengths of from 440 MPa to 980 MPa is increasingly being adopted for the structural elements of automobile bodies to both reduce weight and increase collision safety. However, the use of such material brings defects in press forming and other problems. The research reported here focuses on the form-forming method, which is effective for forming high tensile strength steel plate. To clarify the features of form-forming, we used eight types of steel plate having tensile strengths of from 270 MPa to 980 MPa in three forming processes, draw-forming, one-step form-forming, and two-step form-forming, to evaluate the shape freezing property. The results showed that the shape freezing property depends on the mechanical properties of the material; speci cally, a correlation with tensile strength, 0.2% proof stress, and elongation was seen. The effectiveness of form-forming for materials of higher strength was con rmed. Improved shape freezing by dividing the form-forming process into two steps was also con rmed. For draw-forming, the entire shaped surface was affected by unbending, so form-forming effectively suppresses unbending. The spatial distribution of unbending was evaluated quantitatively by measuring the residual stress distribution, con rming that residual stress serves as a useful index for clarifying the forming mechanism.

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“…3. The two types of experimental form-forming dies 13) shown in Fig. 4 and the draw-forming die shown in Fig.…”

Section: Forming Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Evaluation of the Form-Forming Mechanism for High-Tensile-Strength Steel Plate

2017

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“…[1][2][3][4][5] In a previous report, we proposed a new method for accurately predicting the amount of springback in V-bending by a combination of experiment and FEM simulation used as a hybrid bending technique. 6) However, one major problem that results from giving a sheet metal a high strength is an increase in bending load. In V-bending, it has been reported that the target shape of the bent part is given by pressing in the final step of processing.…”

Section: Introductionmentioning

confidence: 99%

Reducing Work Load and Increasing Dimensional Accuracy in Parts for Bending of High-Strength Steel Sheets for Automobiles

Nishino

Ohya

2011

Mater. Trans.

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In this paper, we propose a method suitable for increasing the dimensional accuracy in the bending of high-strength steel sheets with a small work load by controlling the amount of a punch indentation in V-bending. The optimal indentation for obtaining the desired bending angle exactly could be calculated by finite-element-method (FEM) simulation using many types of high-strength steel sheets with different material characteristics. This method is effective for reducing the work load and obtaining a small radius of curvature in bent steel sheets; thus, it is suitable for forming high-strength steel sheets, which have been used widely for the fabrication of automobiles.

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“…As an approximation, a 10% reduction in mass produces a 5% improvement in fuel economy. To achieve higher vehicle energy efficiencies, lighter high strength materials should be used, with the disadvantage of their reduced formability (Nishino et al, 2003;Gomes et al, 2005;Chien et al, 2004). Since designers/manufacturers have less experience with these materials, research is needed to support their use in vehicle applications.…”

Section: Introductionmentioning

confidence: 99%