Dependence of plastic strain and microstructure on elastic modulus reduction in advanced high-strength steels

Lajarin, Sérgio Fernando; Nikhare, Chetan P.; Marcondes, Paulo Victor Prestes

doi:10.1007/s40430-018-1008-9

Cited by 14 publications

(8 citation statements)

References 30 publications

(39 reference statements)

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“…Fundamental mechanical properties and true stress vs true strain curve obtained by [15]. Errors obtained by computational models for a BHL of (a), 80tf (b) and 130tf (c).…”

Section: Discussionmentioning

confidence: 99%

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Comparative study of six failure criteria via numerical simulation of stamped DP600 steel

Ribas

Gipiela

Lajarin

et al. 2022

Preprint

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During the development of an automobile part obtained by stamping process, time and money are required aiming process planning and set up of a new tooling. One of the difficulties in stamping is to know if the chosen material will have sufficient formability to reach the final form required by the project. Because of this difficulty it is very interesting to propose a method that can accurately simulate the forming process. The failure criteria can be mathematical or empirical models capable of determining the onset of necking for each stress/strain states. It is interesting to find a failure criterion that can be easily determined and provides a good ability to detect the failure accurately. In this study six different failure criteria were studied. Five of them are classified as ductile damage models and they depend on the stress triaxiality and plastic strain. The last criteria depend only on the deformations in the main directions and it is called the forming limit curve (FLC). It was used computational models through finite element analysis (FEA). The formability was evaluated by monitoring the displacement of the punch until the failure of the material. Some failure criteria have been able to provide approximation errors in the range of 0.7 - 5% which makes them interesting for practical implementation in the industry.

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“…Fundamental mechanical properties and true stress vs true strain curve obtained by [15]. Errors obtained by computational models for a BHL of (a), 80tf (b) and 130tf (c).…”

Section: Discussionmentioning

confidence: 99%

“…These values were used to implement the FLC criteria in the computational model. The fundamental mechanical properties and true stress-by-true strain curve for DP600 steel obtained by [15] as illustrated in Fig. 5 were also used.…”

Section: Methodsmentioning

confidence: 99%

Comparative study of six failure criteria via numerical simulation of stamped DP600 steel

Ribas

Gipiela

Lajarin

et al. 2022

Preprint

View full text Add to dashboard Cite

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“…is the rate of decrease with the increase of the plastic strain, p  [8]. Figure 2 presents a comparison between the numerical model reported for the two materials (labelled EMD) by the benchmark committee [4] and values reported in other studies for steels [7,9]. The analysis shows that the model suggested and adopted in this study leads to a trend like the one reported in other studies, although the variation is slightly higher for the DP980 steel under analysis than the one considered in [9].~ Both materials show a negligeable variation of the in-plane distribution of the flow stress.…”

Section: Elastic Propertiesmentioning

confidence: 99%

Influence of process and material parameters on the twist springback prediction of a panel

Oliveira

Gomes

Neto

et al. 2023

IOP Conf. Ser.: Mater. Sci. Eng.

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Both advanced high strength steels and aluminum alloys gained increasing popularity because of the constant effort to meet the social pressure of reducing the vehicle weight while keeping their safety. The ratio between material strength and weight is much higher when compared to other materials but, the high springback after forming is one of the disadvantages of these materials, particularly when exhibiting twisting and side wall curl, which are the two most difficult types of springback to control and compensate in die engineering. This study analysis the influence of several material and numerical parameters on the prediction of the twist springback, using the Twist Die. Two processing conditions were considered: (i) blank-holder force that constrains the metal flow and (ii) a stake bead, which changes the forming conditions from draw to stretch forming, at the end of the process. The modelling of the elastoplastic behavior of the sheet materials uses a wide range of experimental data, for a DP980 steel and a 6xxx aluminum alloy. In addition to the effect of the sheet material on springback, the effect of the following parameters is also analyzed numerically: (i) friction coefficient; (ii) beads; (iii) modulus of elasticity; (iv) work hardening law and (v) yield criterion. All numerical simulations were performed with the finite element in-house code DD3IMP. The process parameter that most affects the twist springback is the presence of the stake bead, reducing significantly the springback. In addition, the reduction of the friction coefficient and of the elastic modulus also leads to an increase in springback. On the other hand, the yield criterion has little influence on springback of this component. The twist springback shows a different trend for the steel and the aluminum alloy that seems to be related with the different yield strength but also with the distinct gap between the punch and the die.

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“…Barsanti et al [17] demonstrated that considering the elastic modulus degradation of steel due to plastic strain could enhance the precision of fatigue analysis. Lajarin et al [18] showed that the degradation of elastic modulus was dependent on both the plastic strain and the anisotropy of the material. The elastic modulus decrease of TRIP780 steel in 0, 45 and 90 to rolling direction could reach 28.5%,24.2% and 20.4%, respectively.…”

Section: Introductionmentioning

confidence: 99%

Effect of loading-path on the elastic modulus degradation of high strength steels

Chu

2022

IOP Conf. Ser.: Mater. Sci. Eng.

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Experiments of repetitive uniaxial tension are performed for DP590, TRIP590, TRIP780, and BH220 steels. Variation of chord modulus of the four materials with accumulated plastic strain is discussed. Large specimens of uniaxial tension, wide plate tension and cruciform tension are prestrained in different plastic strain. Uniaxial tension of sub-size samples which are machined from the prestrained large specimens is performed. Dependence of the normalized chord modulus of the four metals on strain path is discussed in detail. The results show that elastic modulus degradation is dependent on the material strength, accumulated plastic strain and strain path. At the same equivalent strain, the chord modulus degradation of TRIP780, TRIP590, DP590, BH220 steels decreases in turn. The chord modulus of TRIP780 steel at 0.24 equivalent strain reaches 20.5%. The chord modulus of DP590 steel is more sensitive to strain path change than the other three metals. The path of biaxial stretching combined with uniaxial tension provides the greatest chord modulus degradation among the six loading paths. Each material should have the most suitable loading path under which the elastic modulus variation can be minimized so springback can be easily controlled.

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Dependence of plastic strain and microstructure on elastic modulus reduction in advanced high-strength steels

Cited by 14 publications

References 30 publications

Comparative study of six failure criteria via numerical simulation of stamped DP600 steel

Comparative study of six failure criteria via numerical simulation of stamped DP600 steel

Influence of process and material parameters on the twist springback prediction of a panel

Effect of loading-path on the elastic modulus degradation of high strength steels

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