scholarly journals Constraining Internal States in Progressive Rock Failure of Carrara Marble by Measuring Residual Strains With Neutron Diffraction

2020 ◽  
Vol 125 (6) ◽  
Author(s):  
A. Voigtländer ◽  
K. Leith ◽  
J. M. Walter ◽  
M. Krautblatter
Keyword(s):  
Neutron Diffraction ◽  
Rock Failure ◽  
Carrara Marble ◽  
Progressive Rock ◽  
Internal States ◽  
Residual Strains

Residual Stresses in Overlapping Friction Taper Stud Welds

2010 ◽  
Vol 652 ◽  
pp. 111-115 ◽  
Author(s):  
D.G. Hattingh ◽  
Axel Steuwer ◽  
M. Neil James ◽  
I.N. Wedderburn
Keyword(s):  
Solid State ◽  
Neutron Diffraction ◽  
Residual Stresses ◽  
Creep Damage ◽  
Local Damage ◽  
Planar Defects ◽  
Repair Technique ◽  
Damage Repair ◽  
Stud Welding ◽  
Residual Strains

This paper presents microstructural, hardness and residual strain information for solid-state welds in creep-resistant Cr-Mo steel, made using the new local damage repair technique offered by friction taper stud welding (FTSW). The technique is suitable for making single welds to repair, for example, localised creep damage but can also be extended to deal with planar defects through the use of overlapping welds. Neutron diffraction was used to measure residual strains at a number of positions along a series of 5 overlapping FTS welds.

Investigation of Residual Strains of the Second Kind in Plastically Deformed Metallic Materials

1994 ◽  
Vol 376 ◽  
Author(s):  
M. Vrána ◽  
P. Klimanek ◽  
T. Kschidock ◽  
P. Lukáš ◽  
P. Mikula
Keyword(s):  
High Resolution ◽  
Neutron Diffraction ◽  
Stacking Faults ◽  
Metallic Materials ◽  
Line Broadening ◽  
X Ray Diffraction ◽  
X Ray ◽  
Neutron Diffractometer ◽  
Residual Strains ◽  
Good Agreement

ABSTRACTInvestigation of strongly distorted crystal structures caused by dislocations, stacking-faults etc. in both plastically deformed f.c.c. and b.c.c. metallic materials was performed by the analysis of the neutron diffraction line broadening. Measurements were realized by means of the high resolution triple-axis neutron diffractometer equipped by bent Si perfect crystals as monochromator and analyzer at the NPI Řež. The substructure parameters obtained in this manner are in good agreement with the results of X-ray diffraction analysis.

Analytical model for neutron diffraction peak shifts due to the surface effect

2013 ◽  
Vol 46 (3) ◽  
pp. 628-638 ◽  
Author(s):  
Jan Šaroun ◽  
Joana Rebelo Kornmeier ◽  
Michael Hofmann ◽  
Pavol Mikula ◽  
Miroslav Vrána
Keyword(s):  
Neutron Diffraction ◽  
Analytical Model ◽  
Surface Effect ◽  
Perfect Crystal ◽  
Optimum Configuration ◽  
Gauge Volume ◽  
Spurious Peak ◽  
Incomplete Filling ◽  
Broad Variety ◽  
Residual Strains

Residual strains measured by neutron diffraction near sample boundaries can be biased by the surface effect as a result of incomplete filling of the instrumental gauge volume. This effect is manifested as anomalous shifts of diffraction lines, which can be falsely interpreted as a lattice strain unless appropriate data corrections are made. A new analytical model for the surface effect has been developed, which covers a broad variety of instrumental arrangements, including flat mosaic and bent perfect crystal monochromators, narrow slits, and Soller and radial collimators. This model permits the spurious peak shifts to be predicted quantitatively, and also allows the optimum configuration parameters, such as curvature of a focusing monochromator, which lead to suppression of the surface effect, to be calculated. The model has been thoroughly validated by comparisons with Monte Carlo simulations and experiments on a stress-free calibration sample. Predictions of the model proved to be very accurate, often within the interval of experimental errors, which makes it suitable for use in data analysis.

Variation of Residual Stresses in Drawn Copper Tubes

2008 ◽  
Vol 571-572 ◽  
pp. 21-26 ◽  
Author(s):  
Adele Carradò ◽  
D. Duriez ◽  
Laurent Barrallier ◽  
Sebastian Brück ◽  
Agnès Fabre ◽  
...  
Keyword(s):  
Neutron Diffraction ◽  
Residual Stresses ◽  
Material Flow ◽  
Cold Drawing ◽  
Axisymmetric Deformation ◽  
Tube Length ◽  
Inhomogeneous Deformation ◽  
Drawing Process ◽  
Process Step ◽  
Residual Strains

Seamless tubes are used for many applications, e.g. in heating, transport gases and fluids, evaporators as well as medical use and as intermediate products for hydroforming and various mechanical applications, where the final dimensions normally are given by some cold drawing steps. The first process step – piercing of the billet, for example by extrusion or 3-roll-milling - typically results in ovality and eccentricity in the tube causing non-symmetric material flow during the cold drawing process, i.e. inhomogeneous deformation. Because of this non-axisymmetric deformation and of deviations over tube length caused by moving tools, this process step generates residual stresses. To understand the interconnections between the geometrical changes in the tubes and the residual stresses, the residual strains in a copper tube had been measured by neutron diffraction.

Application of Neutron Diffraction to Measure Residual Strains in Various Engineering Composite Materials

1991 ◽  
Vol 113 (1) ◽  
pp. 51-59 ◽  
Author(s):  
S. Majumdar ◽  
J. P. Singh ◽  
D. Kupperman ◽  
A. D. Krawitz
Keyword(s):  
Crystal Structure ◽  
Composite Materials ◽  
Neutron Diffraction ◽  
Measured Data ◽  
Unidirectional Fibers ◽  
Residual Strains ◽  
Neutron Diffraction Technique ◽  
Multiphase Composite ◽  
Oriented Single Crystal ◽  
Ceramic Matrices

An experimental neutron diffraction technique was used to measure residual strains that developed in multiphase composite materials during postfabrication cooling as a result of thermal expansion mismatch or volume expansion due to change in crystal structure. The reinforcement geometries that were studied include unidirectional fibers, randomly oriented single crystal whiskers, and equiaxed particles. Both metal and ceramic matrices and reinforcements were considered. In some cases, the measured data compared fairly well with predictions based on simple elastic models. In other cases, either creep was shown to relax the residual strains during cooling, or the interpretation of the measured data contained uncertainties due to texture in the samples or lack of a clearly defined crystal structure for the reinforcement phase.

Residual Stress Measurements in Continuous Fiber Titanium Matrix Composites

1992 ◽  
Vol 36 ◽  
pp. 481-488 ◽  
Author(s):  
M. R. James ◽  
M. A. Bourke ◽  
J. A. Goldstone ◽  
A. C. Lawson
Keyword(s):  
Residual Stress ◽  
Neutron Diffraction ◽  
Thin Sheet ◽  
Matrix Composites ◽  
X Ray ◽  
Residual Stress State ◽  
Longitudinal Residual Stress ◽  
The Matrix ◽  
Reinforcement Fiber ◽  
Residual Strains

AbstractMetal matrix composites develop residual strains after consolidation due to the thermal expansion mismatch between the reinforcement fiber and the matrix. X-ray and neutron diffraction measured values for the longitudinal residual stress in the matrix of three titanium MMCs are reported. For thick composites (> 6 plies) the surface stress measured by x-ray diffraction matches that determined by neutron diffraction and therefore represents the stress in the bulk region consisting of the fibers and matrix. For thin sheet composites, the surface values are lower than in the interior and increase as the outer rows of fibers are approached. While a rationale for this behavior has yet to be developed, accounting for composite thickness is important when using x-ray measured values to validate analytic and finite element calculations of the residual stress state.

scholarly journals Triaxial residual strains in a railway rail measured by neutron diffraction

2009 ◽  
Vol 44 (7) ◽  
pp. 563-568 ◽  
Author(s):  
T-S Jun ◽  
F Hofmann ◽  
J Belnoue ◽  
X Song ◽  
M Hofmann ◽  
...  
Keyword(s):  
Neutron Diffraction ◽  
Railway Rail ◽  
Residual Strains

Three-dimensional welding residual stresses evaluation based on the eigenstrain methodology via X-ray measurements at the surface

2014 ◽  
Vol 03 (04) ◽  
pp. 1450023
Author(s):  
Masaru Ogawa
Keyword(s):  
Neutron Diffraction ◽  
Residual Stresses ◽  
Three Dimensional ◽  
Strain Gauges ◽  
X Ray Diffraction ◽  
Stress Evaluation ◽  
X Ray ◽  
Residual Strains ◽  
Non Destructive ◽  
Evaluation Accuracy

In order to assure structural integrity for operating welded structures, it is necessary to evaluate crack growth rate and crack propagation direction for each observed crack non-destructively. Here, three dimensional (3D) welding residual stresses must be evaluated to predict crack propagation. Today, X-ray diffraction is used and the ultrasonic method has been proposed as non-destructive method to measure residual stresses. However, it is impossible to determine residual stress distributions in the thickness direction. Although residual stresses through a depth of several tens of millimeters can be evaluated non-destructively by neutron diffraction, it cannot be used as an on-site measurement technique. This is because neutron diffraction is only available in special irradiation facilities. Author pays attention to the bead flush method based on the eigenstrain methodology. In this method, 3D welding residual stresses are calculated by an elastic Finite Element Method (FEM) analysis from eigenstrains which are evaluated by an inverse analysis from released strains by strain gauges in the removal of the reinforcement of the weld. Here, the removal of the excess metal can be regarded as non-destructive treatment because toe of weld which may become crack starters can be eliminated. The effectiveness of the method has been proven for welded plates and pipes even with relatively lower bead height. In actual measurements, stress evaluation accuracy becomes poorer because measured values of strain gauges are affected by processing strains on the machined surface. In the previous studies, the author has developed the bead flush method that is free from the influence of the affecting strains by using residual strains on surface by X-ray diffraction. However, stress evaluation accuracy is not good enough because of relatively poor measurement accuracy of X-ray diffraction. In this study, a method to improve the estimation accuracy of residual stresses in this method is formulated, and it is shown numerically that inner welding residual stresses can be estimated accurately from the residual strains measured by X-ray diffraction.

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