Microstructural effects on ductile fracture in heterogeneous materials. Part I: Sensitivity analysis with LE-VCFEM

In the present work, the ductile fracture process of hydropiercing is simulated using Rice and Tracey ductile fracture criterion by means of the user subroutine VUMAT of ABAQUS. The simulations at different loading pressures coincide well with the experiments. Based on this criterion, the processes of hydropiercing at different technical conditions are simulated with orthogonal design and the sensitivity analysis of parameters is conducted. The sensitivity analysis shows that internal pressure plays the most important role in controlling quality of the hydropierced products, namely the sheared zone length, roll-over depth and whole coefficient Y. High pressure and better lubricant are better for all the three indexes. Large punch corner radius is better for sheared zone length and Y but worse for roll-over depth. Additionally, it is found that internal pressure and punch corner radius could be intensified each other at conditions of both larger values.

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On accuracy improvement of microscopic stress/stress sensitivity analysis with the mesh superposition method for heterogeneous materials considering geometrical variation of inclusions

International Journal for Numerical Methods in Engineering ◽

10.1002/nme.6233 ◽

2019 ◽

Vol 121 (3) ◽

pp. 534-559 ◽

Cited By ~ 1

Author(s):

S. Sakata ◽

Y. Chan ◽

Y. Arai

Keyword(s):

Sensitivity Analysis ◽

Heterogeneous Materials ◽

Stress Sensitivity ◽

Superposition Method ◽

Accuracy Improvement ◽

Geometrical Variation

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High Voltage Transmission Microscopy of Surveyor III Camera Shrouds

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100064748 ◽

1971 ◽

Vol 29 ◽

pp. 138-139

Author(s):

W. R. Duff ◽

L. E. Thomas ◽

R. M. Fisher ◽

S. V. Radcliffe

Keyword(s):

Alloy Sheet ◽

Transmission Microscopy ◽

Television Camera ◽

Window Method ◽

Transmission Electron ◽

Microstructural Effects ◽

Lunar Environment ◽

Successful Retrieval ◽

Materials Used ◽

Abrasive Paper

Successful retrieval of the television camera and other components from the Surveyor III spacecraft by the Apollo 12 astronauts has provided a unique opportunity to study the effects of a known and relatively extensive exposure to the lunar environment. Microstructural effects including those produced by micro-meteorite impact, radiation damage (by both the solar wind and cosmic rays) and solar heating might be expected in the materials used to fabricate the spacecraft. Samples received were in the form of 1 cm2 of painted unpainted aluminum alloy sheet from the top of the camera visor (JPL Code 933) and the sides (935,936) and bottom (934) of the lower camera shroud. They were prepared for transmission electron microscopy by first hand-grinding with abrasive paper to a thickness of 0.006". The edges were lacquered and the sample electropolished in 10% perchloric methanol using the “window” method, to a thickness of ~0.001". Final thinning was accomplished by polishing 3 mm punched disks in an acetic-phosphoric-nitric acid solution.

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Low-temperature annealing of YBa2Cu3O7-x

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100120849 ◽

1992 ◽

Vol 50 (1) ◽

pp. 88-89

Author(s):

R.L. Sabatini ◽

Yimei Zhu ◽

Masaki Suenaga ◽

A.R. Moodenbaugh

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

Low Temperature ◽

Oxygen Diffusion ◽

Diffusion Rate ◽

Oxygen Depletion ◽

Low Temperature Annealing ◽

Transmission Electron ◽

Microstructural Effects ◽

Oxygen Diffusion Rate

Low temperature annealing (<400°C) of YBa2Cu3O7x in a ozone containing oxygen atmosphere is sometimes carried out to oxygenate oxygen deficient thin films. Also, this technique can be used to fully oxygenate thinned TEM specimens when oxygen depletion in thin regions is suspected. However, the effects on the microstructure nor the extent of oxygenation of specimens has not been documented for specimens exposed to an ozone atmosphere. A particular concern is the fact that the ozone gas is so reactive and the oxygen diffusion rate at these temperatures is so slow that it may damage the specimen by an over-reaction. Thus we report here the results of an investigation on the microstructural effects of exposing a thinned YBa2Cu3O7-x specimen in an ozone atmosphere using transmission electron microscopy and energy loss spectroscopy techniques.

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