Testing of a hot stamped axial crush member with tailored properties – Experiments and models

Omer, Kaab; Kortenaar, Lukas ten; Butcher, Cliff; Worswick, Michael J.; Malcolm, Skye; Detwiler, Duane

doi:10.1016/j.ijimpeng.2017.01.003

Cited by 61 publications

(21 citation statements)

References 28 publications

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“…However, with physically relevant data, such as from the micromechanical study of Dunand and Mohr [7], they can be calibrated to describe those results. This is not intended to be critical of the models that have been successfully applied in the literature to describe the failure behavior of sheet materials, including by the authors in Anderson et al [21] and Omer et al [53]. Instead, it is to emphasize that the framework is largely empirical and built upon failure characterization in a constant stress state that treats coaxial and non-coaxial loading conditions equally since they are based upon isotropic yield functions.…”

Section: Phenomenological Descriptions Of the Failure Locusmentioning

confidence: 99%

On Phenomenological Failure Loci of Metals under Constant Stress States of Combined Tension and Shear: Issues of Coaxiality and Non-Uniqueness

Butcher

Abedini

2019

Metals

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The present study investigates how the choice of characterization test and the composition of the stress state in terms of tension and shear can produce a non-unique failure locus in terms of stress triaxiality under plane stress conditions. Stress states that are composed of tensile and simple shear loadings result in a loss of proportionality between the cumulative strain and stress such that the principal frames become non-coaxial despite a constant stress triaxiality. Consequently, it is shown that the conventional interpretation of a failure locus in plane stress is based upon an implicit assumption of proportional coaxial loading. The use of simple shear tests along with traditional in-plane tensile tests for fracture characterization is only one “path” that can be taken in terms of the stress triaxiality, which may produce a bifurcation at uniaxial tension while the tension–torsion path does not. In general, the failure locus in terms of the equivalent strain is a failure surface and must consider the composition of the stress state that produces a given triaxiality. A comprehensive review of phenomenological fracture loci within a modified Mohr-Coulomb (MMC) framework is performed to highlight how the choice of stress states obtained using different characterization tests can change the apparent fracture locus of a material. The finite strain solutions for the work conjugate equivalent strain are derived for various loading paths that produce the same stress triaxiality. It is then shown that accounting for non-coaxiality leads to equivalent failure strains that are even higher than previously reported in tension–torsion tests within the literature. The equivalent plastic strains integrated from finite-element simulations are work-conjugate by definition. The equivalent strains estimated from the cumulative principal strains using DIC strain measurement depend upon a coaxial or non-coaxial assumption. Finally, an analytical solution for the onset of diffuse necking that accounts for the stabilizing influence of shear loading against a tensile instability is considered. Even under plane stress conditions, a failure surface arises in terms of the equivalent strain at necking, the stress triaxiality, and the severity of shear loading.

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Section: Phenomenological Descriptions Of the Failure Locusmentioning

confidence: 99%

On Phenomenological Failure Loci of Metals under Constant Stress States of Combined Tension and Shear: Issues of Coaxiality and Non-Uniqueness

Butcher

Abedini

2019

Metals

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“…As mentioned, many studies have been conducted upon multi-cell extrusions, primarily with aluminum extrusions. A swarm optimization had been conducted by Fang et al to obtain a cross-sectional design of a longitudinal rail, this constraint driven algorithm highlighted the trend of the material being pushed toward 40 Y N N N Sun et al 41 Y N N N Fang et al 42 Y N N N Ito et al 43 N/A N/A N/A Y Lee and Park 44 P N P N Gao et al 45 Y Y N N Qiu et al 46 Y Y N N Noversa and Peixinho 47 Y N N N Asanjarani et al 38 Y N N N An et al 48 Y N Y N Sun et al 49 Y N N N Reddy et al 35 Y N N N Kamran et al 50 Y N N N Hou et al 51 Y N N N Ma et al 52 Y N N N Zaidi et al 53 N N Y Y Zhu et al 54 Y Y Y N Kohar et al 55 Y N N N Kohar et al 56 Y N N N Omer et al 57 Y N N N Schlosser et al 58 N N Y N Li et al 59 Y N N N Sun et al 60 Y N N N Zahran et al 37 Y N N Y Xu et al 61 Y N N Y Nia and Chahardoli 62 Y N N P Zhang et al 63 Y N N N Reddy et al 64 Y N N N the corners of the member. This had been identified to aid in the increase of energy absorption by inducing more folds under the crush load.…”

Section: Cross-sectional Designsmentioning

confidence: 99%

Crashworthy structures for future vehicle architecture of autonomous pods and heavy quadricycles on public roads: A review

Harrison

Christensen

Bastien

et al. 2019

Proceedings of the Institution of Mechanical Engineers, Part D:

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With the development and deployment of lightweight vehicles to the market, inclusive of autonomous pods, a review of advanced crashworthy structures and the design methodology has been conducted as it is thought that super-lightweight vehicles may pose significant risk to the occupants if they are involved in a crash. It is suggested that tests should include oblique and multiple velocity impacts to cater for the effects of assisted driving systems of future vehicles. A review of current crash structures and design methodologies revealed that the most recent research do not cater to multiple crash scenarios, nor a shorter crush allowance, therefore resulting in poor crashworthiness performance. In addition, the arbitrary seat positioning shown in autonomous pods’ concepts vastly increases the risk to occupants. Greater enhancements to passive crashworthiness are imperative. To this end, functionally graded vehicle structures should be designed as it has been found that these can provide optimized solutions. Research into nonlinear optimization methods for computationally expensive problems will become central to this.

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“…Bardelcik et al [13] examined the mechanical properties, microstructure, and damage of tailored components. Omer et al [14] examined the crush behaviour of a component produced by tailored tempering from an experiment and FEM simulation. Nakagawa et al [15] developed tailored tempering processes without heating of dies.…”

Section: Introductionmentioning

confidence: 99%

Steel sheets partnered with quenchable sheet in hot stamping of tailor-welded blanks and its application to separation prevention of fractured components

Mori

Suzuki

Yokoo

et al. 2020

Int J Adv Manuf Technol

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The phase transformation and mechanical properties of non-quenchable steels partnered with the quenchable boron steel in hot stamping of tailor-welded blanks were evaluated to produce tailored components with partially balanced strength and ductility. The effect of the forming start temperature after natural air cooling on the phase transformation and mechanical properties for 270 MPa mild steel, non-quenchable steel, 440 MPa high strength steel, and 22MnB5 steel sheets was examined, and the 270 MPa and non-quenchable sheets had enough ductility after hot stamping. Tailored components having a hardness of about 500 HV1 in the high strength zone and a total elongation of about 30% in the high ductility zone were hot-stamped from a tailor-welded blank composed of 22MnB5 and 270 MPa sheets. It was found that the 270 MPa mild steel sheet is sufficient as a partner sheet of tailor-welded blanks. In addition, the safety of hot-stamped components was heightened by welding a 22MnB5 main blank with a 270 MPa steel patch. Even if the main blank is fractured by a collision, the hot-stamped component is not separated by the 270 MPa patch having high ductility.

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Testing of a hot stamped axial crush member with tailored properties – Experiments and models

Cited by 61 publications

References 28 publications

On Phenomenological Failure Loci of Metals under Constant Stress States of Combined Tension and Shear: Issues of Coaxiality and Non-Uniqueness

On Phenomenological Failure Loci of Metals under Constant Stress States of Combined Tension and Shear: Issues of Coaxiality and Non-Uniqueness

Crashworthy structures for future vehicle architecture of autonomous pods and heavy quadricycles on public roads: A review

Steel sheets partnered with quenchable sheet in hot stamping of tailor-welded blanks and its application to separation prevention of fractured components

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