Comparative study of superelastic Ti–Zr–Nb and commercial VT6 alloy billets by QForm simulation

Author(s):  
Ta Dinh Xuan ◽  
V. A. Sheremetyev ◽  
V. S Komarov ◽  
A. A. Kudryashova ◽  
S. P. Galkin ◽  
...  

A comparative simulation of hot radial shear rolling (RSR) of billets made of a superelastic Ti–Zr–Nb and a commercial VT6 alloy was performed using the QForm finite element modeling program. Rolling in 48 modes with a variable feed angle and elongation ratio at 4 levels and initial rolling temperature at 3 levels was investigated for each alloy. The Ti–Zr–Nb alloy rheology during hot deformation was determined experimentally by hot upset forging and imported into the QForm program. The presence of maxima on the flow curves at the initial stage of deformation, which are absent in the VT6 alloy, is revealed. Simulation results are presented in the form of fields of the stiffness coefficient, strain rate intensity, cumulative strain degree in the maximum reduction section depending on the rolling mode. General regularities of the Ti–Zr–Nb and VT6 behavior in RSR are similar. The gradient of the fields studied decreases, and the roll pressure and torque increase with an increase in the feed angle and elongation ratio. The initial rolling temperature does not significantly affect the deformation pattern, but it significantly affects the roll pressure and torque. At the same time, the experimental alloy demonstrated the greater tendency to localize deforming forces in the near-contact zone and to increase the gradient of stress-strain state parameters over the billet section. The study of the tightening shape and depth of rolled billet ends showed that the Ti–Zr–Nb alloy has a 3.5–9.6 % greater tightening depth. It is shown that experimental alloy rolling requires 1.6–2.4 times higher roll pressure and torque as compared to the commercial alloy.

Author(s):  
Mohammed S. Shamkhi ◽  
Jasim Mohammed Ridha Azee ◽  
Ali A. Abdul-Sahib

The Al-Shewicha Trough represents a serious flood hazard to Kut City (the capital of Wasit Province, Iraq) and to the other cities along the Tigris River downstream Kut Barrage, especially in heavy monsoon years. In this study, The Geographic Information System software ArcGIS was used in the morphologic analysis of six river basins that represent the main feeding sources for the Al-Shewicha Trough. The results revealed that the high values for the greatest length of Basins 1, 5, and 6 meant that these watersheds had high concentration time (tc) values, which delay peak flow. All basins consisted of very coarse and permeable subsurface strata that were of coarse texture. Circularity ratio form factor and elongation ratio suggested an elongated shape for all basins with lower peak flow and long duration. Analyses of soil data demonstrated that the soil type that covered a large area was loam soil (classified as hydrologic soil group B), which indicates that all basins had low permeability and high runoff. The predominant land use was bare soil, and all basins had a covering of poor vegetation, which highlighted the fact that basins were highly susceptible to erosion, thus resulting in the generation of higher sedimentation.


Author(s):  
Ilias Lazos ◽  
Sotirios Sboras ◽  
Christos Pikridas ◽  
Spyros Pavlides ◽  
Alexandros Chatzipetros

JOM ◽  
2017 ◽  
Vol 69 (10) ◽  
pp. 1806-1811 ◽  
Author(s):  
Huizhong Li ◽  
Yelong Qi ◽  
Xiaopeng Liang ◽  
Zijun Wang ◽  
Fengjian Sang ◽  
...  

2021 ◽  
pp. 004051752110191
Author(s):  
Hiroyuki Kanai ◽  
Kentaro Ogawa ◽  
Tetsu Sasagawa ◽  
Kiyohiro Shibata

The stretch property of fabrics is one of the most important factors that provide comfort to wearers. It is expected that tension building up in the fabric can be relaxed and the garment pressure on the body can be reduced by appropriately exploiting its stretch property. Currently, the stretch property is predominantly realized using spandex. However, weaving or knitting elastic threads cannot be employed for the worsted fabric used to design men’s suits because of their effects on the mechanical properties of the fabric (e.g., embrittlement), which deteriorate with time. In this study, worsted fabric with a graded mechanical stretch property was produced, and the effect of the mechanical stretch property on comfort was verified. The mechanical stretch property is developed from the tension relaxation and fabric shrinkage along the weft yarn during the crabbing, scouring, and drying stages of the finishing process. Then, the form of the fabric is set by heating. In this study, the worsted fabric had an elongation ratio varying from 5.9% to 16.1% along the weft direction that was produced without using elastic thread. Furthermore, men’s suit pants were made from the fabrics. The effect of the stretch property on the garment comfort was verified through sensory evaluation and garment pressure measurement. The contribution of the mechanical stretch property in improving the garment comfort of men’s suit pants is discussed.


2019 ◽  
Vol 9 (14) ◽  
pp. 2920
Author(s):  
Lorena Salazar-Llano ◽  
Camilo Bayona-Roa

One challenging problem is the representation of three-dimensional datasets that vary with time. These datasets can be thought of as a cloud of points that gradually deforms. However, point-wise variations lack information about the overall deformation pattern, and, more importantly, about the extreme deformation locations inside the cloud. This present article applies a technique in computational mechanics to derive the strain-rate state of a time-dependent and three-dimensional data distribution, by which one can characterize its main trends of shift. Indeed, the tensorial analysis methodology is able to determine the global deformation rates in the entire dataset. With the use of this technique, one can characterize the significant fluctuations in a reduced multivariate description of an urban system and identify the possible causes of those changes: calculating the strain-rate state of a PCA-based multivariate description of an urban system, we are able to describe the clustering and divergence patterns between the districts of a city and to characterize the temporal rate in which those variations happen.


Author(s):  
Vivek K. Himanshu ◽  
A.K. Mishra ◽  
M.P. Roy ◽  
Ashish K. Vishwakarma ◽  
P.K. Singh

2020 ◽  
Vol 10 (1) ◽  
pp. 136-144
Author(s):  
P.K. Gautam ◽  
S. Rajesh ◽  
N. Kumar ◽  
C.P. Dabral

Abstract We investigate the surface deformation pattern of GPS station at MPGO Ghuttu (GHUT) to find out the cause of anomalous behavior in the continuous GPS time series. Seven years (2007-2013) of GPS data has been analyzed using GAMIT/GLOBK software and generated the daily position time series. The horizontal translational motion at GHUT is 43.7 ± 1 mm/yr at an angle of 41°± 3° towards NE, while for the IGS station at LHAZ, the motion is 49.4 ±1 mm/yr at 18 ± 2.5° towards NEE. The estimated velocity at GHUT station with respect to IISC is 12 ± 1 mm/yr towards SW. Besides, we have also examined anomalous changes in the time series of GHUT before, after and during the occurrences of local earthquakes by considering the empirical strain radius; such that, a possible relationship between the strain radius and the occurrences of earthquakes have been explored. We considered seven local earthquakes on the basis of Dobrovolsky strain radius condition having magnitude from 4.5 to 5.7, which occurred from 2007 to 2011. Results show irrespective of the station strain radius, pre-seismic surface deformational anomalies are observed roughly 70 to 80 days before the occurrence of a Moderate or higher magnitude events. This has been observed for the cases of those events originated from the Uttarakashi and the Chamoli seismic zones in the Garhwal and Kumaun Himalaya. Occurrences of short (< 100 days) and long (two years) inter-seismic events in the Garhwal region plausibly regulating and diffusing the regional strain accumulation.


2021 ◽  
Vol 76 (4) ◽  
pp. 299-304
Author(s):  
Fu Chen ◽  
Jian-Rong Yang ◽  
Zi-Fa Zhou

Abstract The electron paramagnetic resonance (EPR) parameters (g factor g i , and hyperfine structure constants A i , with i = x, y, z) and local structures for Cu2+ centers in M2Zn(SO4)2·6H2O (M = NH4 and Rb) are theoretically investigated using the high order perturbation formulas of these EPR parameters for a 3d 9 ion under orthorhombically elongated octahedra. In the calculations, contribution to these EPR parameters due to the admixture of d-orbitals in the ground state wave function of the Cu2+ ion are taken into account based on the cluster approach, and the required crystal-field parameters are estimated from the superposition model which enables correlation of the crystal-field parameters and hence the studied EPR parameters with the local structures of the Cu2+ centers. Based on the calculations, the Cu–H2O bonds are found to suffer the axial elongation ratio δ of about 3 and 2.9% along the z-axis, meanwhile, the planar bond lengths may experience variation ratio τ (≈3.8 and 1%) along x- and y-axis for Cu2+ center in (NH4)2Zn(SO4)2·6H2O and Rb2Zn(SO4)2·6H2O, respectively. The theoretical results show good agreement with the observed values.


2012 ◽  
Vol 457-458 ◽  
pp. 270-273
Author(s):  
Yi You Tu ◽  
Guo Zhong Li

Effect of superheat and initial rolling temperature on the morphology and distribution of sulfide in non quenched and tempered free cutting steel 30MnVS has been studied by optical microscope and scanning electron microscope. Results show that proper superheat and initial rolling temperature can turn rod-shaped sulfide into massive or globular sulfide,to alleviate sulfide segregation and pro-eutectoid ferrite distribution along the boundary of pearlite clusters in 30MnVS , increase the intragranular ferrite content and optimize the structure of continuous casting slab.


2012 ◽  
Vol 2012 ◽  
pp. 1-17 ◽  
Author(s):  
Kunlin Cao ◽  
Kai Ding ◽  
Joseph M. Reinhardt ◽  
Gary E. Christensen

Accurate pulmonary image registration is a challenging problem when the lungs have a deformation with large distance. In this work, we present a nonrigid volumetric registration algorithm to track lung motion between a pair of intrasubject CT images acquired at different inflation levels and introduce a new vesselness similarity cost that improves intensity-only registration. Volumetric CT datasets from six human subjects were used in this study. The performance of four intensity-only registration algorithms was compared with and without adding the vesselness similarity cost function. Matching accuracy was evaluated using landmarks, vessel tree, and fissure planes. The Jacobian determinant of the transformation was used to reveal the deformation pattern of local parenchymal tissue. The average matching error for intensity-only registration methods was on the order of 1 mm at landmarks and 1.5 mm on fissure planes. After adding the vesselness preserving cost function, the landmark and fissure positioning errors decreased approximately by 25% and 30%, respectively. The vesselness cost function effectively helped improve the registration accuracy in regions near thoracic cage and near the diaphragm for all the intensity-only registration algorithms tested and also helped produce more consistent and more reliable patterns of regional tissue deformation.


Sign in / Sign up

Export Citation Format

Share Document