Analysis of Residual Stresses in High-Pressure Sheet Metal Forming

Kleiner, Matthias; Krux, Rainer; Homberg, Werner

doi:10.1016/s0007-8506(07)60681-7

Cited by 27 publications

(22 citation statements)

References 8 publications

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“…The strain induced in the relaxation is measured, using a strain gauge rosette and the residual stresses are back calculated [11]. The residual stresses can also be measured by carefully slicing (by electric discharge machining or laser cutting) a section of the component under study.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of yield criteria for forming simulations based on residual stress measurement

et al. 2010

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Process induced anisotropy in sheet metal is accounted for in analytical modeling by anisotropic yield criteria. The suitability of a yield criterion for predicting sheet metal forming process is generally validated by way of its ability to predict surface strains. However, the sensitivity of surface strains to yield criteria is dependent upon strain modes, with plane strain mode exhibiting higher sensitivity. To eliminate dependency on strain modes, stresses are used to evaluate yield criteria, since forming stresses are less sensitive to strain modes. In the study, the residual stresses remaining in a hemispherical cup formed in plain strain mode is predicted using Hill48 and Barlat89 criteria. The residual stresses are experimentally characterized by using X-Ray diffraction method. Suitable yield criterion for forming simulation is validated based on the correlation of theoretical predictions with experimental residual stress values.

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Section: Introductionmentioning

confidence: 99%

Evaluation of yield criteria for forming simulations based on residual stress measurement

et al. 2010

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“…Residual stresses and their distribution along the sheet thickness were measured by means of the hole-drilling strain-gage method . The results (figure 12) indicate that the qualitative residual stress distr ibution in the bottom of this large-scale structure (compressive stress at the outer side and tensile stress at the inner side) is approximately the same as in cylindrical parts with the same depth of draw h = 40 rnm, as shown in [9). The absolute values of the residual stress distribution in the formed part depend on several parameters which influence the stress states during the forming operation, e.g.…”

Section: Investigations On the Large-scale Structurementioning

confidence: 82%

“…the fluid pressure and the blank holder pressure. For the chosen process parameters, the absolute values of the residual stress at the inner and the outer sheet surface in the bottom of the large-scale structure are lower than for the above mentioned cylindric al shapes in [9].…”

Section: Investigations On the Large-scale Structurementioning

confidence: 99%

Properties of Large-Scale Structure Workpieces in High-Pressure Sheet Metal Forming of Tailor Rolled Blanks

Krux

Homberg

Kleiner

2005

steel research international

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In order to manufacture components optimised in regard to lightweight construction, the use of innovative forming processes like high‐pressure sheet metal forming (HBU) in combination with the use of tailor rolled blanks (TRB) as innovative semi‐finished material is a promising solution. Fundamental investigations on the HBU of TRB have been carried out in a joint research project at the Institute of Forming Technology and Lightweight Construction (IUL), University of Dortmund, and the Institute of Metal Forming (IBF), RWTH Aachen. The experiments performed with cylindrical parts have provided basic knowledge on the sheet material flow and resulting part properties. To achieve sufficient process reliability, a non‐adjustable as well as an adjustable seal system have been tested and proved to be suitable solutions, depending on thickness ratio and thickness gradient within the TRB. In order to demonstrate the lightweight potential of this process chain, a forming tool for an automotive body structure has been designed and tested. The experiments have shown that this large‐scale structure can well be manufactured in the HBU process from a TRB.

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“…Furthermore, workpieces formed by the HBU-process have specific, characteristic residual stress distributions which can be controlled, e.g. by the fluid pressure [9].…”

Section: Introductionmentioning

confidence: 99%

High‐Pressure Sheet Metal Forming of Large Scale Structures from Sheets with Optimised Thickness Distribution

Kleiner

Homberg

Krux

2005

steel research international

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In order to manufacture components optimised in regard to lightweight construction, the use of innovative forming processes like high‐pressure sheet metal forming (HBU) in combination with the use of tailor rolled blanks (TRB) as innovative semi‐finished materials is a promising solution. To realise a sufficient forming process reliability, at first, investigations on the seal system were carried out. Hereby, a non‐adjustable as well as a new adjustable seal system have been investigated and qualified as sufficient solutions for this process depending on thickness ratio and thickness gradient within the TRB. One typical workpiece geometry which offers a promising lightweight potential and which can be manufactured from TRB with the HBU‐process is the class of body structures. Therefore, an idealised large scale structure has been designed and investigated in theoretical (numerical) and experimental research. The research work has shown that this large scale structure can be manufactured sufficiently by the HBU of TRB.

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Analysis of Residual Stresses in High-Pressure Sheet Metal Forming

Cited by 27 publications

References 8 publications

Evaluation of yield criteria for forming simulations based on residual stress measurement

Evaluation of yield criteria for forming simulations based on residual stress measurement

Properties of Large-Scale Structure Workpieces in High-Pressure Sheet Metal Forming of Tailor Rolled Blanks

High‐Pressure Sheet Metal Forming of Large Scale Structures from Sheets with Optimised Thickness Distribution

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