Junjie Niu, Weimin Sang, Qilei Guo, Aoxiang Qiu and Dazhi Shi
This paper aims to propose a method of the safety boundary protection for unmanned aerial vehicles (UAVs) in the icing conditions.
Abstract
Purpose
This paper aims to propose a method of the safety boundary protection for unmanned aerial vehicles (UAVs) in the icing conditions.
Design/methodology/approach
Forty icing conditions were sampled in the continuous maximum icing conditions in the Appendix C of the Federal Aviation Regulation Part 25. Icing numerical simulations were carried out for the 40 samples and the anti-icing thermal load distribution in full evaporation mode were obtained. Based on the obtained anti-icing thermal load distribution, the surrogated model of the anti-icing thermal load distribution was established with proper orthogonal decomposition and Kriging interpolation. The weather research and forecasting (WRF) model was used for meteorological simulations to obtain the icing meteorological conditions in the target area. With the obtained icing conditions and surrogated model, the anti-icing thermal load distribution in the target area and the variation with time can be determined. According to the energy supply of the UAVs, the graded safety boundaries can be obtained.
Findings
The surrogated model can predict the effects of five factors, such as temperature, velocity, pressure, median volume diameter (MVD) and liquid water content (LWC), on the anti-icing thermal load quickly and accurately. The simulated results of the WRF mode agree well with the observed results. The method can obtain the graded safety boundaries.
Originality/value
The method has a reference significant for the safety of the UAVs with the limited energy supply in the icing conditions.
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Junjie Niu, Weimin Sang, Feng Zhou and Dong Li
This paper aims to investigate the anti-icing performance of the nanosecond dielectric barrier discharge (NSDBD) plasma actuator.
Abstract
Purpose
This paper aims to investigate the anti-icing performance of the nanosecond dielectric barrier discharge (NSDBD) plasma actuator.
Design/methodology/approach
With the Lagrangian approach and the Messinger model, two different ice shapes known as rime and glaze icing are predicted. The air heating in the boundary layer over a flat plate has been simulated using a phenomenological model of the NSDBD plasma. The NSDBD plasma actuators are planted in the leading edge anti-icing area of NACA0012 airfoil. Combining the unsteady Reynolds-averaged Navier–Stokes equations and the phenomenological model, the flow field around the airfoil is simulated and the effects of the peak voltage, the pulse repetition frequency and the direction arrangement of the NSDBD on anti-icing performance are numerically investigated, respectively.
Findings
The agreement between the numerical results and the experimental data indicates that the present method is accurate. The results show that there is hot air covering the anti-icing area. The increase of the peak voltage and pulse frequency improves the anti-icing performance, and the direction arrangement of NSDBD also influences the anti-icing performance.
Originality/value
A numerical strategy is developed combining the icing algorithm with the phenomenological model. The effects of three parameters of NSDBD on anti-icing performance are discussed. The predicted results show that the anti-icing method is effective and may be helpful for the design of the anti-icing system of the unmanned aerial vehicle.
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Yuan-Jian Yang, Guihua Wang, Qiuyang Zhong, Huan Zhang, Junjie He and Haijun Chen
Gas pipelines are facing serious risk because of the factors such as long service life, complex working condition and most importantly, corrosion. As one of the main failure…
Abstract
Purpose
Gas pipelines are facing serious risk because of the factors such as long service life, complex working condition and most importantly, corrosion. As one of the main failure reasons of gas pipeline, corrosion poses a great threat to its stable operation. Therefore, it is necessary to analyze the reliability of gas pipelines with corrosion defect. This paper uses the corresponding methods to predict the residual strength and residual life of pipelines.
Design/methodology/approach
In this paper, ASME-B31G revised criteria and finite element numerical analysis software are used to analyze the reliability of a special dangerous section of a gas gathering pipeline, and the failure pressure and stress concentration of the pipeline under three failure criteria are obtained. Furthermore, combined with the predicted corrosion rate of the pipeline, the residual service life of the pipeline is calculated.
Findings
This paper verifies the feasibility of ASME-B31G revised criteria and finite element numerical analysis methods for reliability analysis of gas pipelines with corrosion defect. According to the calculation results, the maximum safe internal pressure of the pipeline is 9.53 Mpa, and the residual life of the pipeline under the current operating pressure is 38.41 years, meeting the requirements of safe and reliable operation.
Originality/value
The analysis methods and analysis results provide reference basis for the reliability analysis of corroded pipelines, which is of great practical engineering value for the safe and stable operation of natural gas pipelines.
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Dong Guan, Li Jing, Junjie Gong, Zhengwei Yang and Hui Shen
Rotary disc is a key component in the compact spherical pump, connecting shaft and piston, bearing hydraulic force conformally and constituting dynamic working chambers…
Abstract
Purpose
Rotary disc is a key component in the compact spherical pump, connecting shaft and piston, bearing hydraulic force conformally and constituting dynamic working chambers alternatively. Motion of rotary disc comprises two components. One is rotating around its own axis and the other is sliding on a cone surface. Therefore, it is necessary to investigate the friction and wear mechanism between rotary disc and cylinder under a complicated operation condition.
Design/methodology/approach
Structural properties of rotary disc are analyzed first. Frictional moment of rotary disc is modeled based on its structural characteristics and working mechanism, and the constraints of the structural parameters are considered. Besides, the concept of dimensionless contact area is proposed. Comparison is performed between the proposed concept and the frictional moment to determine an optimized beginning angle for spherical pump with a given displacement. The wear model of rotary disc is also established based on its kinematic property, a velocity coefficient is proposed and its common values are presented.
Findings
Effects of structural parameters, i.e. beginning angle and ending angle on the frictional moment, are obtained quantitatively. The frictional moment increases with beginning and ending angle with different rates. While the dimensionless contact area decreases with beginning angle. The larger the piston angle, the larger the velocity coefficient will be. The rotary disc wears severely with a larger beginning angle and smaller ending angle, while it has the smallest wear rate under a smaller beginning angle and a larger ending angle.
Originality/value
The originality lies in modeling the complex contact force of rotary disc based on its specific structure. These conclusions can be used to optimize the structural parameters of rotary disc.
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Guohao Chen, Lingyun Li, Jian Ouyang, Zhuoyan Zhu, Feng Wang, Yuanyuan Wang, Junjie Xue and Jingmao Zhao
The aim of the present paper was to investigate the inhibition performance of the OF and/or IM on L360 steel in CO2/H2S environments. The pipeline steel surface usually has been…
Abstract
Purpose
The aim of the present paper was to investigate the inhibition performance of the OF and/or IM on L360 steel in CO2/H2S environments. The pipeline steel surface usually has been pre-treated before using in the oil/gas field, such as by passivation, blackening, and phosphiding. The effectiveness of inhibition can vary because there are many differences between the metal matrix and the treated film.
Design/methodology/approach
Imidazoline (IM) was synthesized by using oleic acid and diethylenetriamine, and its composition was verified using Fourier transform infrared spectroscopy. The oxide film (OF) covering a sample of L360 steel was characterized using X-ray diffraction, and its surface morphology was observed using scanning electron microscope. Electrochemical impedance spectroscopy measurements were conducted to study the inhibition performance of IM- and/or OF-covered L360 steel in the CO2/H2S environments.
Findings
The results show that IM and OF can prevent corrosion on L360 steel in CO2/H2S environments, and the synergistic inhibition effect of IM and OF was very evident. A possible model is proposed to explain the synergistic inhibition effect in the CO2/H2S environments of IM and OF on L360 steel.
Originality/value
Few reports have concerned the effect of the OF on the inhibitor’s performance, especially in CO2/H2S systems. The aim of the present study was to investigate the inhibition performance of the OF and/or IM on L360 steel in CO2/H2S environments. A model is proposed to explain the synergistic inhibition effect mechanism between IM and OF.
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Shanlin Zhong, Ziyu Chen and Junjie Zhou
Human-like musculoskeletal robots can fulfill flexible movement and manipulation with the help of multi joints and actuators. However, in general, sophisticated structures…
Abstract
Purpose
Human-like musculoskeletal robots can fulfill flexible movement and manipulation with the help of multi joints and actuators. However, in general, sophisticated structures, accurate sensors and well-designed control are all necessary for a musculoskeletal robot to achieve high-precision movement. How to realize the reliable and accurate movement of the robot under the condition of limited sensing and control accuracy is still a bottleneck problem. This paper aims to improve the movement performance of musculoskeletal system by bio-inspired method.
Design/methodology/approach
Inspired by two kinds of natural constraints, the convergent force field found in neuroscience and attractive region in the environment found in information science, the authors proposed a structure transforming optimization algorithm for constructing constraint force field in musculoskeletal robots. Due to the characteristics of rigid-flexible coupling and variable structures, a constraint force field can be constructed in the task space of the musculoskeletal robot by optimizing the arrangement of muscles.
Findings
With the help of the constraint force field, the robot can complete precise and robust movement with constant control signals, which brings in the possibility to reduce the requirement of sensing feedback during the motion control of the robot. Experiments are conducted on a musculoskeletal model to evaluate the performance of the proposed method in movement accuracy, noise robustness and structure sensitivity.
Originality/value
A novel concept, constraint force field, is proposed to realize high-precision movements of musculoskeletal robots. It provides a new theoretical basis for improving the performance of robotic manipulation such as assembly and grasping under the condition that the accuracy of control and sensory are limited.
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Changpeng Chen, Jie Yin, Haihong Zhu, Xiaoyan Zeng, Guoqing Wang, Linda Ke, Junjie Zhu and Shijie Chang
High residual stress caused by the high temperature gradient brings undesired effects such as shrinkage and cracking in selective laser melting (SLM). The purpose of this study is…
Abstract
Purpose
High residual stress caused by the high temperature gradient brings undesired effects such as shrinkage and cracking in selective laser melting (SLM). The purpose of this study is to predict the residual stress distribution and the effect of process parameters on the residual stress of selective laser melted (SLMed) Inconel 718 thin-walled part.
Design/methodology/approach
A three-dimensional (3D) indirect sequentially coupled thermal–mechanical finite element model was developed to predict the residual stress distribution of SLMed Inconel 718 thin-walled part. The material properties dependent on temperature were taken into account in both thermal and mechanical analyses, and the thermal elastic–plastic behavior of the material was also considered.
Findings
The residual stress changes from compressive stress to tensile stress along the deposition direction, and the residual stress increases with the deposition height. The maximum stress occurs at both ends of the interface between the part and substrate, while the second largest stress occurs near the top center of the part. The residual stress increases with the laser power, with the maximum equivalent stress increasing by 21.79 per cent as the laser power increases from 250 to 450 W. The residual stress decreases with an increase in scan speed with a reduction in the maximum equivalent stress of 13.67 per cent, as the scan speed increases from 500 to 1,000 mm/s. The residual stress decreases with an increase in layer thickness, and the maximum equivalent stress reduces by 33.12 per cent as the layer thickness increases from 20 to 60µm.
Originality/value
The residual stress distribution and effect of process parameters on the residual stress of SLMed Inconel 718 thin-walled part are investigated in detail. This study provides a better understanding of the residual stress in SLM and constructive guidance for process parameters optimization.
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Samaneh Khavidaki, Saeed Rezaei Sharifabadi and Amir Ghaebi
This paper aims to explore the realm of literature about personalization of digital library services. This paper focuses on users’ unique needs and will identify different types…
Abstract
Purpose
This paper aims to explore the realm of literature about personalization of digital library services. This paper focuses on users’ unique needs and will identify different types of personalized services. Therefore, this study has identified different types of services personalization in the context of digital academic libraries.
Design/methodology/approach
In this research, the systematic review method has been used to obtain the relevant indicators of different types of personalization in the context of libraries. To explain basic indicators, a Delphi method has been used. The Delphi panel’s members consisted of 15 experts (faculty members, researchers, professional users and software designers). A purposeful sampling and the Delphi fulfillment process were performed in three rounds. After collecting data, descriptive statistics (mean and standard deviation), inferential statistics (binomial distribution test) and the Kendall coordination coefficient were used to determine the consensus rate among experts.
Findings
A total of 103 indicators were extracted for different types of personalization through a systematic literature review. Of these, 90 indicators were considered significant in the experts’ view. Generally, content personalization, interactive personalization, collaborative personalization and information retrieval personalization are the main components of personalization types, each of which has its own indicators.
Originality/value
This study has dealt with the issue of what is personalized in the context of digital academic library. The findings should be helpful and effective in the development of a holistic view on personalization of services in digital libraries.
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Sareh Götelid, Taoran Ma, Christophe Lyphout, Jesper Vang, Emil Stålnacke, Jonas Holmberg, Seyed Hosseini and Annika Strondl
This study aims to investigate additive manufacturing of nickel-based superalloy IN718 made by powder bed fusion processes: powder bed fusion laser beam (PBF-LB) and powder bed…
Abstract
Purpose
This study aims to investigate additive manufacturing of nickel-based superalloy IN718 made by powder bed fusion processes: powder bed fusion laser beam (PBF-LB) and powder bed fusion electron beam (PBF-EB).
Design/methodology/approach
This work has focused on the influence of building methods and post-fabrication processes on the final part properties, including microstructure, surface quality, residual stresses and mechanical properties.
Findings
PBF-LB produced a much smoother surface. Blasting and shot peening (SP) reduced the roughness even more but did not affect the PBF-EB surface finish as much. As-printed PBF-EB parts have low residual stresses in all directions, whereas it was much higher for PBF-LB. However, heat treatment removed the stresses and SP created compressive stresses for samples from both PBF processes. The standard Arcam process parameter for PBF-EB for IN718 is not fully optimized, which leads to porosity and inferior mechanical properties. However, impact toughness after hot isostatic pressing was surprisingly high.
Originality/value
The two processes gave different results and also responses to post-treatments, which could be of advantage or disadvantage for different applications. Suggestions for improving the properties of parts produced by each method are presented.