Experimental study on micro-grinding force and subsurface microstructure of nickel-based single crystal superalloy in micro grinding

Yadong Gong,Yunguang Zhou,Xuelong Wen,Jun Cheng,Yao Sun,Lianjie Ma 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.7

Nickel-based single crystal superalloy has no grain boundary, which leads to the removal mechanism difference between single crystal material and polycrystalline material. Firstly, the removal mechanism of grinding nickel-based single crystal superalloy is analysed. Then, the developed prediction model of the tangential force F t and the normal force F n are established. Forthermore, the impacts of grinding parameters on grinding force and microstructure of grinding surface and sub-surface are analysed. Finally, some measurements to reduce or prevent recrystallization are proposed. As a result, the most shear slipping planes of nickel-based single crystal superalloy are {111} planes; with the increasing of the feeding rate and grinding depth, the micro-grinding force and the thickness of subsurface plastic deformation increase; the micro-grinding force and the thickness of subsurface plastic deformation decrease with the increasing of spindle speed. These results have some theoretical and engineering significance to the production of single crystal material parts.

Effects of concentrate level and chromium-methionine supplementation on the performance, nutrient digestibility, rumen fermentation, blood metabolites, and meat quality of Tan lambs

Jin, Yadong,Zhou, Yuxiang Asian Australasian Association of Animal Productio 2022 Animal Bioscience Vol.35 No.5

Objective: This study was conducted to evaluate the effects of concentrate level and chromium-methionine (Cr-Met) supplementation on the growth performance, carcass characteristics, meat quality, and fatty acid composition of Tan lambs. Methods: Sixty male Tan lambs (21±1.23 kg body weight) fed a finishing diet (concentrate-to-forage ratio: 35:65 [LC group] or 55:45 [HC group]) with daily Cr-Met supplementation (0, 0.75, or 1.50 g) were used in a completely randomized design with a 2×3 factorial arrangement of treatments. Results: Lambs from the HC group had higher average daily gain, dry matter (DM) digestibility, dressing percentages, leg proportions, intramuscular fat (IMF) contents, and saturated fatty acid levels, but lower feed conversion ratios, globulin (GLB) and total protein (TP) concentrations, shear force, and monounsaturated fatty acid (MUFA) levels (all p<0.05). Cr-Met supplementation increased the DM digestibility, GLB and TP concentrations, rack and loin percentages, and cooking loss, but decreased the IMF contents and leg proportions (all p<0.05). Cr-Met supplementation at 0.75 g/d increased the conjugated linoleic acid (CLA) content in both the HC and LC groups (p<0.01). Significant interactions between the concentrate level and Cr-Met dosage were observed for MUFA (p<0.01) and polyunsaturated fatty acid (PUFA) (p<0.01) levels. Meat from the lambs fed an unsupplemented LC diet presented the highest PUFA and MUFA levels (p<0.01). However, the MUFA and PUFA levels decreased significantly with increasing Cr-Met supplementation levels in the LC group (p<0.01), whereas the opposite trend was seen in the HC group. Conclusion: The HC diet improved the growth performance of Tan lambs, increased their profitability by increasing leg and rack joint proportions, and improved meat quality by promoting an IMF content that was more visibly acceptable to consumers. Cr-Met supplementation at 0.75 g/d in a HC diet was the best choice and may be economically beneficial.

Experimental study of micro-milling mechanism and surface quality of a nickel-based single crystal superalloy

Qi Gao,Yadong Gong,Yunguang Zhou,Xuelong Wen 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.1

Micro-milling is widely used as a method for machining of micro-parts with high precision and efficiency. Taking the nickel-based single-crystal superalloy DD98 as the research object, the crystal characteristics of single-crystal materials were analysed, and the removal mechanism of single-crystal micro-milled parts was described. Based on molecular dynamics, a simulation model for nickel-based single-crystal superalloy DD98 micro-milling was established. Based on the response surface method of central composite design, the influences of spindle speed, feed rate, and milling depth on the surface roughness were examined, and a second-order regression model of the DD98 surface roughness was established. Using analysis of variance and the residuals of the model, a significant influence on surface roughness was found in the following order from large to small: Feed rate, spindle speed, and milling depth. Comparisons were conducted between the micro-milling experimental values and the predicted model values for different process parameters. The results show that the model fit is relatively high, and the adaptability is good. Scanning electron microscopy analysis of the micro-milling surfaces was performed to verify the slip and the removal mechanism of single-crystal materials. These results offer a theoretical reference and experimental basis for micro-milling of single-crystal materials.

Review on Metrics and Prediction Methods of Civil Aviation Noise

Hao Feng,Yadong Zhou,Weili Zeng,Cong Ding 한국항공우주학회 2023 International Journal of Aeronautical and Space Sc Vol.24 No.5

Civil aviation noise is one of the main factors hindering the growth of the civil aviation industry. With the increase in global air traffic demand, the problem of aviation noise pollution will become more and more serious. It is of great significance to carry out research in aviation noise. First, by summarizing the characteristics of aviation noise metrics, this paper divides them into three categories: single event noise metrics, cumulative exposure metrics, and daily metrics. Representative metrics of each category are selected for explanation and in-depth analysis. Second, according to the principles of aviation noise prediction models, this paper classifies these existing models into three categories: best practice models, scientific models, and machine learning models. Relevant academic research results are summarized. The best practice model regards the aircraft as noise point source, and its specialty is to predict noise under complex air traffic conditions. The scientific model considers the noise from the level of aircraft components and reflects the underlying physical effects. Based on data, the machine learning model uses algorithms to mine the hidden relationship between various factors and noise to achieve the purpose of noise prediction. Then, this paper introduces two kinds of aviation noise simulation software based on the best practice and scientific models, and lists their access addresses. Finally, challenges and prospects are presented from three aspects: metrics, prediction models and simulation software.

Numerical Simulation and Measurement of Welding Residual Stresses in Orthotropic Steel Decks Stiffened with U-Shaped Ribs

Ying Gu,Yadong Li,Zihao Zhou,Songbo Ren,Chao Kong 한국강구조학회 2020 International Journal of Steel Structures Vol.20 No.3

This study aims to investigate the magnitude and distribution of welding residual stresses in orthotropic steel decks stiff ened with U-shaped ribs. Numerical simulation of the welding residual stresses is performed using the thermal elastic–plastic fi nite element method. The residual stresses are subsequently measured using the hole-drilling strain-gage method. Based on the results of this study, it can be determined that: (1) The longitudinal welding residual stresses ( σ z ) in the weld zones are tensile stresses, where the peak value exceeds the minimum yield strength ( f yl ); however, relatively low compressive stresses exist in the areas located far away from the welds; (2) The stress gradient in the weld zone is steep, and the widths of the areas experiencing tensile stress are narrow; (3) In the case of the upper surface of the deck, the weld that is fi rst deposited has the highest peak stress, while similar stresses are determined for the remaining welds. In the case of the lower surface of the deck, the peak stress in the weld zones is greater than that on the upper surface; (4) In the case of the weld zone of the U-shaped ribs, the tensile stresses reach up to 1.15 f yl ; however, at locations a short distance away from the welds, the σ z varies from tensile to compressive, and fi nally transforms into a small tensile stress at the base of the U-shaped ribs. In addition, the simulated and measured σ z are compared, and the deviation between them is analyzed.

Evaluation of failure criteria for composite plate under high-velocity impact

Yile Zhang,Yadong Zhou,Zhong Lu 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.7

Numerical simulations of bird-striking composite plates were conducted by using smoothed particle hydrodynamics and finite element method to evaluate the failure criteria. The damage prediction capability of four composite failure models (MAT22, MAT54, MAT55, and MAT58) with Shell and TShell element formulations was evaluated by using the finite element software LS-DYNA, and the numerical results were compared with the experimental results. Results show that the damage distributions of different composite material models differ significantly under high-velocity impact conditions. The time histories of the impact force and the kinetic energy of bird are similar for the four models. This condition can be attributed to the fact that the materials' strength and elastic parameters are the same between the different models. The damage characteristics of MAT55 and MAT22 with TShell elements are poorly related to the experimental results. MAT58 with Shell and TShell element formulations shows good agreement with the experiments, and the TShell element can better avoid the boundary effect during the impact process.

Effects of L-lysine on thermal gelation properties of chicken breast actomyosin

Zhen Lei,Yuan Fu,Yadong Zheng,Peng Xu,Cunliu Zhou 한국식품과학회 2017 Food Science and Biotechnology Vol.26 No.3

The effects of L-lysine (L-Lys) on the water holding capacity (WHC) and texture of actomyosin (AM) gel and the possible mechanisms were investigated. L-Lys increased the WHC and hardness of the AM gel. These effects may be related to the even and continuous microstructure of the gel according to the scanning electron microscopy analysis. Furthermore, L-Lys increased the surface hydrophobic residues and the reactive sulfhydryl groups. L-Lys decreased the storage modulus at the first transition temperature but increased it at the second transition temperature and the third transition enthalpy. These results suggested that L-Lys varied the thermal behaviors and the microstructure of the AM gel by increasing the surface hydrophobicity and reactive sulfhydryl groups, ultimately contributing to the increased WHC and hardness. The changes in pH did not fully explain the results from the present study. The results were useful for understanding previous findings and may serve as a reference for the preparation of reduced-sodium and phosphate-free meat products.

L-lysine and L-arginine inhibit the oxidation of lipids and proteins of emulsion sausage by chelating iron ion and scavenging radical

Xu, Peng,Zheng, Yadong,Zhu, Xiaoxu,Li, Shiyi,Zhou, Cunliu Asian Australasian Association of Animal Productio 2018 Animal Bioscience Vol.31 No.6

Objective: To evaluate the effects of L-lysine (Lys)/L-arginine (Arg) on lipid and protein oxidation of emulsion sausage during storage and its possible mechanism. Methods: Four samples were prepared based on the presence or absence of additional sodium isoascorbate, Lys, or Arg: sample A (control), sample B (0.05 g of sodium isoascorbate), sample C (0.4 g of Lys), and sample D (0.4 g of Arg). Peroxide value (POV), thiobarbituric reactive substances (TBARS), protein carbonyls and thiols were measured. 2,2-Diphenyl-1-picrylhydrazyl (DPPH) and hydroxyl radical-scavenging, ferrous ion-chelating ability were also measured. Results: Compared with the control, the sample treated with sodium isoascorbate, Lys or Arg had significantly lower POV during the initial 20 days, TBARS during the initial 15 days. Protein carbonyls were significantly lower compared Sample B, C, and D with A during the later storage (10 to 25 days); basically, protein thiols became lower during storage when the samples were treated with sodium isoascorbate, Lys, or Arg. Both Lys and Arg had weak reducing power but strong ferrous ion-chelating activity and DPPH radical- and hydroxyl radical-scavenging activity. Conclusion: Both Lys and Arg effectively inhibited the oxidation of lipids and proteins in emulsion sausage by scavenging free radicals and chelating ferrous ions. The results obtained may be favorable for the prevention of lipid and protein oxidation during processing and storage of meat products.

Effect of post-heat treatment on the microstructure and mechanical properties of laser metal deposition Inconel 718

Pengfei Li,Jianzhong Zhou,Yadong Gong,Xiankai Meng,Jinzhong Lu 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.7

The microstructure, hardness, and fracture strength of Inconel 718 fabricated with laser metal deposition are investigated. The solution treatment plus aging (STA) (including 980 °C, 720 °C, and 620 °C for 1, 8, and 8 h, respectively) and low-temperature stress-relief annealing (LTSLA) (including 650 °C for 1 h) are compared, which can respectively improve the hardness and tensile properties. Results show that the as-deposited sample mainly contained γ matrix, coarse Laves phase, granular carbides, and nitrides. STA and LTSLA post-heat treatments could respectively improve the hardness and tensile properties, while the elongation slightly decreased. The solution treatment promoted almost Laves phase to dissolve into γ matrix and homogenized the matrix, and the aging treatment promoted the precipitation of γ′ and γ′′ phases, which significantly improved the mechanical properties.

Influence of Molecular Weight on the Dielectric and Energy Storage Properties of Poly(vinylidene fluoride)

Yuetao Zhao,Wenyao Yang,Yujiu Zhou,Yan Chen,Yajie Yang,Jianhua Xu,Yadong Jiang 대한금속·재료학회 2016 ELECTRONIC MATERIALS LETTERS Vol.12 No.6

The molecular weight shows great influence on dielectricand energy storage performance of poly(vinylidenefluoride) (PVDF) films and related devices. In this letter,the influences of molecular weight on the dielectric andenergy storage properties of PVDF films were studied. Ithas been found that, under a 1000 kV/cm electric field,the low-molecular-weight PVDF film presents a muchhigher energy storage efficiency as high as 80.10%,nearly three times as much as the high-molecular-weightPVDF film. Moreover, the low-molecular-weight PVDFfilm also shows high resistivity, representing an order ofmagnitude improvement over the high-molecular-weightPVDF film, which is more desirable and promising forhigh performance pulse discharge capacitor application.