Estimation of the magnetic pressure in tube expansion by electromagnetic forming

Lee, Sung Ho; Lee, Dong Nyung

doi:10.1016/0924-0136(95)02086-1

Cited by 31 publications

(9 citation statements)

References 2 publications

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“…The Ca 2p3/2 core level spectrum for [Ca 2+ ] H /rhBMP-2 was composed of two peaks: one at 347.8 eV representing CaCl 2 25 and one at 347.3 eV representing Ca-O bonds 27 from the interaction between calcium ions and carboxylate group of rhBMP-2 ( Fig. 4d ).…”

Section: Resultsmentioning

confidence: 99%

Calcium ion-induced formation of β-sheet/-turn structure leading to alteration of osteogenic activity of bone morphogenetic protein-2

Zhang

Tian

et al. 2015

Sci Rep

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Preserving bioactivity of bone morphogenetic protein 2 (BMP-2) still remains a challenge in protein-based therapy. It is not known how Ca2+ released from extracellular matrix or existing in physiological environment influences bioactivity in situ till now. Here, effects of extracellular Ca2+ on conformation and osteogenic bioactivity of recombinant human BMP-2 (rhBMP-2) were investigated systematically. In vitro results indicated that Ca2+ could bind rhBMP-2 rapidly and had no obvious effect on cell behaviors. Low concentration of Ca2+ (0.18 mM) enhanced rhBMP-2-induced osteogenic differentiation, while high Ca2+ concentration (>1.80 mM) exerted negative effect. In vivo ectopic bone formation exhibited similar trend. Further studies by circular dichroism spectroscopy, fluorescence spectroscopy, together with cell culture experiments revealed at low concentration, weak interaction of Ca2+ and rhBMP-2 slightly increased β-sheet/-turn content and facilitated recognition of BMP-2 and BMPRIA. But, high Ca2+ concentration (>1.8 mM) induced formation of Ca-rhBMP-2 complex and markedly increased content of β-sheet/-turn, which led to inhibition binding of rhBMP-2 and BMPRIA and thus suppression of downstream Smad1/5/8, ERK1/2 and p38 mitogen-associated protein kinase signaling pathways. Our work suggests osteogenic bioactivity of BMP-2 can be adjusted via extracellular Ca2+, which should provide guide and assist for development of BMP-2-based materials for bone regeneration.

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Section: Resultsmentioning

confidence: 99%

Calcium ion-induced formation of β-sheet/-turn structure leading to alteration of osteogenic activity of bone morphogenetic protein-2

Zhang

Tian

et al. 2015

Sci Rep

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“…The following assumptions are made in the developed model [5]. • Displacement current and free charge density are neglected.…”

Section: Numerical Simulationmentioning

confidence: 99%

Electromagnetic Expansion and Fragmentation of Hollow Aluminium 5052 Tube

Choudhary¹,

Gupta²,

Tiwari³

et al. 2020

JMMCE

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Electromagnetic forming is a high-speed forming technology by which hollow profiles can be compressed or expanded. It is done with a pulsed magnetic field to apply Lorentz' forces at electrically conductive material. Electromagnetic hollow tube expansion is limited by the fragmentation tendency. This work attempts to use a combination of analytical and computational approach to compute the net tangential stress during tube expansion. A simplified analytical framework to estimate the temporal evolution of plastic stresses present in aluminium alloy AA5052 at low and high applied magnetic pressures is developed based upon dynamic imaging. The time resolved images captured using current synchronised high speed camera record the overall dimensional changes of the tube that is validated by multi-physics simulation of expansion process. Imaging of hollow tube expansions at two selected peak currents has been carried out at various current levels in the range 76-160 kA. The direct visualisation of the increase in the tube diameter at two current levels provided a comparison of the developing net tangential stresses in the hollow tube during the undamaged and fragmented expansion. Imaging of tube expansion also facilitates the estimation of the strain rate experienced by the tube and was in the range of ~1700 s −1 to ~1200 s −1. The propensity of fragmentation was found to be due to the level and duration of generated tangential stresses above the yield stress during expansion of the aluminium tubes. Presented study provides a mean of exploiting the enhanced formability of aluminium alloys using electromagnetic forming.

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“…Recently, the numerical simulation method has become more and more widely used in the analysis of magnetic pressure in electromagnetic forming. And it is reported that the precision of the results is greatly enhanced [4,5].…”

Section: Introductionmentioning

confidence: 96%

The effect of tube length on magnetic pressure in tube electromagnetic bulging

Zhao

et al. 2005

Journal of Materials Processing Technology

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Estimation of the magnetic pressure in tube expansion by electromagnetic forming

Cited by 31 publications

References 2 publications

Calcium ion-induced formation of β-sheet/-turn structure leading to alteration of osteogenic activity of bone morphogenetic protein-2

Calcium ion-induced formation of β-sheet/-turn structure leading to alteration of osteogenic activity of bone morphogenetic protein-2

Electromagnetic Expansion and Fragmentation of Hollow Aluminium 5052 Tube

The effect of tube length on magnetic pressure in tube electromagnetic bulging

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