scholarly journals Nondestructive Evaluation of Functionally Graded Subsurface Damage on Cylinders in Nuclear Installations Based on Circumferential SH Waves

2016 ◽  
Vol 2016 ◽  
pp. 1-7
Author(s):  
Zhen Qu ◽  
Xiaoqin Shen ◽  
Xiaoshan Cao
Keyword(s):  
Mechanical Properties ◽  
Phase Velocity ◽  
Nondestructive Evaluation ◽  
Surface Damage ◽  
Subsurface Damage ◽  
Functionally Graded ◽  
Horizontal Shear ◽  
Steel Cylinder ◽  
Sh Waves ◽  
Subsurface Layers

Subsurface damage could affect the service life of structures. In nuclear engineering, nondestructive evaluation and detection of the evaluation of the subsurface damage region are of great importance to ensure the safety of nuclear installations. In this paper, we propose the use of circumferential horizontal shear (SH) waves to detect mechanical properties of subsurface regions of damage on cylindrical structures. The regions of surface damage are considered to be functionally graded material (FGM) and the cylinder is considered to be a layered structure. The Bessel functions and the power series technique are employed to solve the governing equations. By analyzing the SH waves in the 12Cr-ODS ferritic steel cylinder, which is frequently applied in the nuclear installations, we discuss the relationship between the phase velocities of SH waves in the cylinder with subsurface layers of damage and the mechanical properties of the subsurface damaged regions. The results show that the subsurface damage could lead to decrease of the SH waves’ phase velocity. The gradient parameters, which represent the degree of subsurface damage, can be evaluated by the variation of the SH waves’ phase velocity. Research results of this study can provide theoretical guidance in nondestructive evaluation for use in the analysis of the reliability and durability of nuclear installations.

scholarly journals Asymptotic Analytical Solution on Lamb Waves in Functionally Graded Nano Copper Layered Wafer

2021 ◽  
Vol 11 (10) ◽  
pp. 4442
Author(s):  
Yifeng Hu ◽  
Xiaoshan Cao ◽  
Yi Niu ◽  
Yan Ru ◽  
Junping Shi
Keyword(s):  
Power Series ◽  
Phase Velocity ◽  
Nondestructive Evaluation ◽  
Lamb Waves ◽  
Variable Coefficients ◽  
Functionally Graded ◽  
Velocity Variation ◽  
Multilayered Structures ◽  
Power Series Method ◽  
Copper Wafers

In this study, the feasibility of using Lamb waves in functionally graded (FG) nano copper layered wafers in nondestructive evaluation is evaluated. The elastic parameters and mass densities of these wafers vary with thickness due to the variation in grain size. The power series technique is used to solve the governing equations with variable coefficients. To analyze multilayered structures, of which the material parameters are continuous but underivable, a modified transfer matrix method is proposed and combined with the power series method. Results show that multiple modes of Lamb waves exist in FG nano copper wafers. Moreover, the gradient property leads to a decrease in phase velocity, and the absolute value of the phase velocity variation is positively correlated with the gradient coefficient. The phase velocity variation and variation rate in Mode 2 are smaller than those in other modes. The findings indicate that Mode 4 is recommended for nondestructive evaluation. However, if the number of layers is greater than four, the dispersion curves of the Lamb waves in the multilayer structures tend to coincide with those in the equivalent uniform structures. The results of this study provide theoretical guidance for the nondestructive evaluation of FG nanomaterial layered structures.

scholarly journals Atomistic modelling of functionally graded Cu-Ni alloy and its implication on the mechanical properties of nanowires

2021 ◽  
Author(s):  
Md Shajedul Hoque Thakur ◽  
Mahmudul Islam ◽  
Nur Jahan Monisha ◽  
Pritom Bose ◽  
Md. Adnan Mahathir Munshi ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Functionally Graded ◽  
Atomistic Modelling ◽  
Ni Alloy

Microgrinding of Nanostructured Carbide Coatings: Ground Surface and Subsurface Damage Observations

2006 ◽  
Vol 304-305 ◽  
pp. 276-280 ◽  
Author(s):  
Y.H. Ren ◽  
Zhi Xiong Zhou ◽  
Zhao Hui Deng
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Material Removal ◽  
Ground Surface ◽  
Subsurface Damage ◽  
Removal Mechanism ◽  
Material Removal Mechanism ◽  
Carbide Coatings ◽  
Subsurface Layers ◽  
Scanning Electron

Surface microgrinding of the nanostructured WC/12Co coatings have been undertaken with diamond wheels under various conditions. Nondestructive and destructive approaches were utilized to assess damage in ground nanostructured coatings. Different surface and subsurface configurations were observed by scanning electron microscopy. This paper investigates the effects of microgrinding conditions on damage formation in the surface and subsurface layers of the ground nanostructured WC/12Co coatings. And the material-removal mechanism has been discussed.

Application of the Equivalent Transformation Layering Calculation Model in Heavy Cross-Section FGCs - Axis-Symmetrical Mechanics Problems

2005 ◽  
Vol 475-479 ◽  
pp. 1533-1536
Author(s):  
Liu Ding Tang ◽  
Xue Bin Zhang ◽  
Bing Zhe Li
Keyword(s):  
Mechanical Properties ◽  
Cross Section ◽  
Calculation Model ◽  
Functionally Graded ◽  
Equivalent Transformation ◽  
Metal Tube ◽  
Cross Sectional ◽  
Functionally Graded Composites ◽  
Graded Structure ◽  
Design And Practice

Based on equivalent transformation by means of mathematically rigorous analytics, the stress analysis of heavy cross-sectional, non-homogeneous Functionally Graded Composites (FGCs) has been performed by the layering calculation model in axis-symmetrical mechanics problems. The partially calculated results of the non-homogeneous layered thick-walled metal tube are similar to the design and practice of machine forging moulds manufactured with special welding electrodes developed by the German Capilla Company. The analysis is used complementary to the investigation of the quantitative analysis of thermo-mechanical properties, or the so-called anti-design and the optimization of the graded structure for FGCs.

Effects of abrasion on mechanical properties of Kevlar KM2-600 and S glass tows

2018 ◽  
Vol 89 (6) ◽  
pp. 989-1002
Author(s):  
A Abu Obaid ◽  
JW Gillespie
Keyword(s):  
Mechanical Properties ◽  
Abrasion Resistance ◽  
Glass Fibers ◽  
Fiber Surface ◽  
Surface Damage ◽  
Contact Length ◽  
Test Machine ◽  
Tension Level ◽  
Micro Cracks ◽  
Coating Removal

In this effort, the effects of abrasion on the mechanical properties of Kevlar KM2-600 and two types of S glass tows (AGY S2 and Owens Corning Shield Strand S) are studied. Data was generated from cyclic abrasion tests conducted at a tension level of 8% of failure load at10 mm/s (24 in/min) using a specially developed abrasion test machine. Fit curves for axial modulus and tenacity loss were established as a function of abrasion time/contact length for each tow type. Fiber surface damage and fiber breakage within the tows were identified as the major source of tow property degradation. Based on scanning electron microscopy measurements, glass fibers exhibited surface damage (micro-cracks and sizing/coating removal) that were more extensive in AGY S2 glass fibers. Kevlar KM2 fibers after tow abrasion tests exhibited fibrillation and peeling of broken fibrils from the fiber surface. In all three fibers, surface damage increased at longer abrasion times/friction contact length. Overall, the results indicated that the abrasion resistance is the highest for Kevlar KM2, followed by OCV Shield Strand and AGY S2 glass tows. The sizing material on OCV Shield Strand fibers contributed to the improved abrasion resistance compared to AGY S2.

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