A study of techniques in the evaluation of springback and residual stress in hydroforming

Bruni, C.; Celeghini, M.; Geiger, Manfred; Gabrielli, F.

doi:10.1007/s00170-006-0539-x

Cited by 21 publications

(10 citation statements)

References 21 publications

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“…The residual stresses can also be measured by carefully slicing (by electric discharge machining or laser cutting) a section of the component under study. The distortion of the section is a measure of locked in residual stresses [5]. However, all the destructive methods are limited to one measurement as the original stress distribution contained in the component is altered during destruction.…”

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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“…The initial shape of this second mold corresponds to the final freeform shape and is iteratively modified to take into account the springback effect. 17 The FEA is performed in order to start a parametric analysis and to extract two relevant cases for the study using method one. The face-sheets are modeled with quadrangle elements that allow a fine meshing of the mirrors section.…”

Section: Modeling Methods and Study Casesmentioning

confidence: 99%

Design and development of a freeform active mirror for an astronomy application

et al. 2014

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International audienceThe advent of extremely large telescopes will bring unprecedented light-collecting power and spatial resolution, but it will also lead to a significant increase in the size and complexity of focal-plane instruments. The use of freeform mirrors could drastically reduce the number of components in optical systems. Currently, manufacturing issues limit the common use of freeform mirrors at short wavelengths. This article outlines the use of freeform mirrors in astronomical instruments with a description of two efficient freeform optical systems. A new manufacturing method is presented which seeks to overcome the manufacturing issues through hydroforming of thin polished substrates. A specific design of an active array is detailed, which will compensate for residual manufacturing errors, thermoelastic deformation, and gravity-induced errors during observations. The combined hydroformed mirror and the active array comprise the Freeform Active Mirror Experiment, which will produce an accurate, compact, and stable freeform optics dedicated to visible and near-infrared observations. (C) 2014 Society of Photo-Optical Instrumentation Engineers (SPIE

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“…The evaluation of residual stress was performed using the x-ray diffraction. It was observed that high pressure allowed the obtaining of high equivalent plastic strain on the top region of the samples, with a subsequent reduction in springback [5] . The residual stress in the machined surface has three kinds of distribution: tensile stress, compressive stress and tensile-compressive stress.…”

Section: Introductionmentioning

confidence: 99%

The Relationship between Tensile Strain and Residual Stress of High Strength Dual Phase Steel Sheet

a¹,

Meng²,

Tian³

et al. 2018

MATEC Web Conf.

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Abstract. The relation between residual stress and tensile strain is an important factor for evaluating plastic formation grade of steel sheet. The degree of plastic deformation (Δl) and elastic recovery (δ) were obtained by measuring the length of DP600 steel sheet sample under different tensile test conditions, i.e. five tensile strains (ε). Furthermore, the average residual stress value in the surface middle (the diameter of 10 mm) region of above tensile samples was analyzed by x-ray diffraction (XRD) in the crystal plane of (211). By processing the diffraction peak angle (2θ) with half width high method (FWHM), the relationship between sin 2 (ψ) and diffraction angle is attained by least squares method. On this basis, a mathematical model was established to correlate the tensile strain with the residual stress in the present study. The results show that the residual stress decreases and the elastic recovery increases with the increase of tensile strain (ε≤0.205). The relation between residual stress and tensile strain can be described with an exponential function . Finally, a function of tensile strain, elastic recovery and surface residual stress is established, by which a reasonable forming condition, viz. ε=0.205, δ=2.65 mm is determined for achieving the smallest σψ.

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A study of techniques in the evaluation of springback and residual stress in hydroforming

Cited by 21 publications

References 21 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

Design and development of a freeform active mirror for an astronomy application

The Relationship between Tensile Strain and Residual Stress of High Strength Dual Phase Steel Sheet

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