Einfluss elastischer Kennwerte auf die Eigenschaften von Blechformteilen

Doege, E.; Zenner, H. P.; Palkowski, Heinz; Hatscher, A.; Schmidt-Jürgensen, R.; Kulp, Steffen; Sunderkötter, Christina

doi:10.1002/1521-4052(200211)33:11<667::aid-mawe667>3.0.co;2-s

Cited by 8 publications

(4 citation statements)

References 5 publications

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“…Examples for springback of hat profiles are shown in later sections. A less obvious aspect is the fact that the modulus of elasticity appears to be smaller during unloading from the plastic state than during the first loading , and seems to decrease further during subsequent reloadings and unloading s. This has been observed repeatedly in the literature [5][6][7][8][9], and also by the present authors. Although this phenomenon is probabl y a consequence of microplasticity, it is described most efficientl y in the simulations as a reduction of the elastic modulus.…”

Section: Introductionsupporting

confidence: 80%

Material Characterisation for Reliable and Efficient Springback Prediction in Sheet Metal Forming

Krasovskyy

Schmitt

Riedel

2006

steel research international

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In this paper, a novel experimental-numerical methodology for an accurate prediction of spring back after sheet forming is presented. An advanced phenomenological material model is implemented in the FE-code ABAQUS. It includes the Bauschinger effect, the apparent reduction of the elasticity modulus at load reversal after plastic deformation, the strain rate dependence and the elastic-plastic anisotropy and its evolution during the forming process. The required material parameters are determined from stress-strain curves measured in tension-compression tests. These tests are carried out with a special test rig designed to avoid buckling of the specimens during compression. The benefits of this procedure for springback predict ion are demonstrated. Additionally, parameters for the phenomenological models are determined from texture simulations.

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Section: Introductionsupporting

confidence: 80%

Material Characterisation for Reliable and Efficient Springback Prediction in Sheet Metal Forming

Krasovskyy

Schmitt

Riedel

2006

steel research international

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“…This is due to the fact that linear elastic strain depends on the initial modulus and the unloading stress. Since the modulus of elasticity is a constant magnitude, according to [1] linear elastic strain depends, on the tensile strength of the material. As the martensite content decrease, the non-linear strain rate affected the overall springback more remarkably, which is shown in figure 5 right.…”

Section: Discussionmentioning

confidence: 99%

“…A major disadvantage of these steels is the forming process, since with increasing strength, besides higher necessary forming forces, also their springback increases. [1] Cleveland and Gosh have shown in [2] that unloading after a plastic deformation is nonlinear. They demonstrated that springback after a plastic deformation of an aluminum alloy, as well as an AHSS consists of the known linear elastic and an additional non-linear elastic component.…”

Section: Introductionmentioning

confidence: 99%

Effect of the Pre-Strain on the Elastic Behavior of a Dual-Phase Steel with Different Martensite Contents

Wallner

Schneider

Steineder³

et al. 2021

MSF

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The modulus of elasticity is an important parameter for an accurate prediction of the springback in sheet metal forming processes. With increasing plastic deformation, this modulus behaves nonlinearly and declines, which leads to an unpredictable springback behavior. The most cited reason for this nonlinearity is the dislocation movement during plastic deformation that especially occurs with multiphase steels. The present contribution investigates the nonlinear unloading behavior and the resulting decrease of the elastic modulus from a differently heat treated DP980 steel. The heat treatments set five different microstructures with martensite volume fractions in the range of 42 to 95 %. By means of the tensile test, a decline of the elastic modulus according to pre-strain was examined by evaluating the chord-modulus during unloading at different strain levels. In addition, a nano-hardness test was performed. It turned out that in all heat treatment conditions, a pronounced decrease in the modulus of elasticity up to 25% from the initial value occurred. With decreasing annealing temperature and lower martensite volume fraction, respectively, the martensite hardness increased, leading to higher hardness differences between the ferrite and the martensite phase in the microstructure. This led to an increase of strain hardening, i.e. to an increased formation of fresh mobile dislocations in the vicinity of the harder martensite phase during plastic deformation. As a result, the modulus of elasticity decreased more sharply. Thus, in the present contribution, an interplay between the martensite volume fraction and its hardness on the decrease of elastic modulus could be clearly manifested.

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“…Furthermore, varying the modulus of elasticity permits the attainment of good correlations with real-life results. In addition [6] and [7] refer that there is an influence of the plastic strain on the modulus of elasticity.…”

Section: Sheet Metal 2007mentioning

confidence: 99%

Dimensional Deviation of Roll Formed Components Made of High Strength Steel

Groche

Henkelmann

2007

KEM

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During the last half century roll forming has become a highly productive metal forming technology, well-established in the industry for the manufacturing of mass products. About 8 % of the annual world production of steel is processed by roll forming mills. Roll forming technology enables the manufacturing of profile-shaped products with an extremely wide spectrum of geometrical shapes. In lightweight construction, the utilization of roll-formed structures of high and ultra-high-strength steels has increased remarkably in the recent years. However, the application of those types of steel entails some disadvantages resulting in a decreasing forming capacity and enormous efforts to reach the required dimensional accuracy. Until a profile leaves the roll forming machine with the target quality, it is mostly necessary to align the forming rolls several times. Sometimes even design changes are required. This is the result of unreliable process planning. Furthermore, typical profile failures such as twist, flare and spring-back occur even stronger compared to mild steels. Nowadays, it is usual to control the dimensional accuracy of the profiles after the last forming stand. This kind of quality control has the following disadvantage: manufacturing errors are detected very late. Therefore, a continuous quality control process and an active manipulation during the forming process promise a large potential for an improvement of the dimensional accuracy and an increase of roll forming productivity.

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Einfluss elastischer Kennwerte auf die Eigenschaften von Blechformteilen

Cited by 8 publications

References 5 publications

Material Characterisation for Reliable and Efficient Springback Prediction in Sheet Metal Forming

Material Characterisation for Reliable and Efficient Springback Prediction in Sheet Metal Forming

Effect of the Pre-Strain on the Elastic Behavior of a Dual-Phase Steel with Different Martensite Contents

Dimensional Deviation of Roll Formed Components Made of High Strength Steel

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