Comprehensive identification of aircraft coordination feature based on complete importance modeling and its engineering application

2018 ◽  
Vol 38 (4) ◽  
pp. 398-411 ◽  
Author(s):  
Feiyan Guo ◽  
Fang Zou ◽  
Jian Hua Liu ◽  
Bo Zhao ◽  
Zhongqi Wang
Keyword(s):  
Engineering Application ◽  
Laboratory Method ◽  
Correction Coefficient ◽  
Assembly Process ◽  
Quality Loss ◽  
Content Type ◽  
Aircraft Manufacturing ◽  
Close Relationship ◽  
Geometric Size ◽  
Assembly Precision

Purpose Coordination feature (CF) is the information carrier in dimension and shape transfer process in aircraft manufacturing. The change of its geometric size, shape, position or other attributes would affect the consistency of accumulated errors between two or more assemblies. To identify these “key characteristics” that have a close relationship with the assembly precision, a comprehensive method was developed under digital manufacturing environment, which was based on importance calculation. The multi-hierarchy and multi-station assembly process of aircraft products were also taken into consideration. Design/methodology/approach First, the interaction and evaluation relationship between components at different manufacturing stages was decomposed with a hierarchical net. Second, to meet coordination accuracy requirements, with the integrated application of Taguchi quality loss function, accuracy principal and error correction coefficient H, the quality loss between target features and candidate features at adjacent assembly hierarchies were calculated, which was based on their precision variation. Third, the influence degree and affected degree of the features were calculated with DEMATEL (decision-making trial and evaluation laboratory) method, and the concepts of centrality degree index and cause degree index were proposed for calculating the complete importance degree to eventually identify the CFs. Findings Based on the proposed methodology, CFs, affecting the skin profile and the flush coordination accuracy, were successfully identified at different assembly hierarchies to a certain type of wing flap component. Originality/value Benefit results for the engineering application showed that the deviation of skin profile was more accurate than before, and the tolerance was also closer to the centerline of required assembly precision range. Moreover, the stability in the assembly process was increased by 26.9 per cent, which could bring a higher assembly quality and an enhancement on aircraft’s flight performance.

Statistical tolerance design to minimize dual-responses of APFA height deviations with tolerance cost-quality loss model

2015 ◽  
Vol 32 (5) ◽  
pp. 434-455 ◽  
Author(s):  
Wichai Chattinnawat
Keyword(s):  
Transfer Functions ◽  
Minimum Cost ◽  
Tolerance Allocation ◽  
Assembly Process ◽  
Quality Loss ◽  
Conditional Distributions ◽  
Control Plan ◽  
Content Type ◽  
Assembly Cost ◽  
Tolerance Cost

Purpose – The purpose of this paper is to apply the statistical tolerancing technique to analyze the dual responses of APFA arm height deviation with respect to next stage of disk assembly process and simultaneously optimize and allocate the required tolerance of the responses onto its components at minimum cost of manufacturing and the quality loss. Design/methodology/approach – The relationships between the dual responses of APFA heights and the geometric dimensions and tolerances of APFA components, and orientation of the assembled part with respect to disk assembly were first defined. The effects of the APFA orientation, and the component tolerances on the distributions and variations of the responses were derived and investigated in terms of resultant product/process performance, quality loss, and the cost of assembly. The tolerance cost-based objective function is then formulated as the combined manufacturing/assembly cost and the quality loss. Direct search method was used to find the best feasible tolerance solutions satisfying the required product performance at minimum cost. Findings – The constructed relationship or transfer functions of the dual responses were probabilistic depending on the orientation of part with respect to the next assembly process. The Monte Carlo simulation is empirically suitable for the computation of the conditional distributions of the responses against the first-order linear approximation of component variances. The proposed solution of tolerance control plan increases the product performances, C pm , from 0.6 to be at least 1. The proposed tolerance allocation plans will reduce the amount of rework currently as high as 5 percent to at most 0.01 percent with minimally increased assembly cost. Practical implications – This proposed methodology to design and allocate component tolerances is suitable and applicable to the APFA assembly process. The derived assembly functions of probabilistic type relating the responses to the process and component characteristics can represent the actual dynamic of assembled part better than a traditional single deterministic function developed under static concept. This presented methodology can be applied to other assembly cases where quality characteristic depends on the part dynamic. Originality/value – This research simultaneously optimized the dual APFA height deviation responses with minimum cost of tolerance and quality loss using two different conditional distributions and transfer functions of the resultant deviations generated from dynamic of APFA with respect to disk.

Assembly error propagation modeling and coordination error chain construction for aircraft

2019 ◽  
Vol 39 (2) ◽  
pp. 308-322 ◽  
Author(s):  
Feiyan Guo ◽  
Fang Zou ◽  
Jian Hua Liu ◽  
Qingdong Xiao ◽  
Zhongqi Wang
Keyword(s):  
Error Propagation ◽  
Engineering Application ◽  
Leading Edge ◽  
Transformation Process ◽  
Assembly Process ◽  
Content Type ◽  
Influence Matrix ◽  
Complex Products ◽  
Assembly Work ◽  
Assembly Error

Purpose Manufacturing errors, which will propagate along the assembly process, are inevitable and difficult to analyze for complex products, such as aircraft. To realize the goal of precise assembly for an aircraft, with revealing the nonlinear transfer mechanism of assembly error, a set of analytical methods with response to the assembly error propagation process are developed. The purpose of this study is to solve the error problems by modeling and constructing the coordination dimension chain to control the consistency of accumulated assembly errors for different assemblies. Design/methodology/approach First, with the modeling of basic error sources, mutual interaction relationship of matting error and deformation error is analyzed, and influence matrix is formed. Second, by defining coordination datum transformation process, practical establishing error of assembly coordinate system is studied, and the position of assembly features is modified with actual relocation error considering datum changing. Third, considering the progressive assembly process, error propagation for a single assembly station and multi assembly stations is precisely modeled to gain coordination error chain for different assemblies, and the final coordination error is optimized by controlling the direction and value of accumulated error range. Findings Based on the proposed methodology, coordination error chain, which has a direct influence on the property of stealthy and reliability for modern aircrafts, is successfully constructed for the assembly work of the jointing between leading edge flap component and wing component at different assembly stations. Originality/value Precise assembly work at different assembly stations is completed to verify methodology’s feasibility. With analyzing the main comprised error items and some optimized solutions, benefit results for the practical engineering application showing that the maximum value of the practical flush of the profiles between the two components is only 0.681 mm, the minimum value is only 0.021 mm, and the average flush of the entire wing component is 0.358 mm, which are in accordance with theoretical calculation results and can successfully fit the assembly requirement. The potential user can be the engineers for manufacturing the complex products.

Identification of barriers to PLM institutionalization in large manufacturing organizations

2019 ◽  
Vol 25 (6) ◽  
pp. 1335-1356 ◽  
Author(s):  
Shikha Singh ◽  
Subhas Chandra Misra
Keyword(s):  
Decision Making ◽  
Large Scale ◽  
Threshold Value ◽  
Laboratory Method ◽  
Product Lifecycle Management ◽  
Manufacturing Firm ◽  
Content Type ◽  
Aircraft Manufacturing ◽  
Manufacturing Organizations ◽  
Lifecycle Management

Purpose The purpose of this paper is to study the barriers to institutionalize the product lifecycle management (PLM) in large manufacturing organizations. The paper explores the hurdles and identifies the causal barriers to support the organizations’ transformation into digitized firms. Design/methodology/approach The paper utilized the multi-criteria decision making technique, i.e., DEMATEL (DEcision MAking Trial and Evaluation Laboratory) method to find the causal barriers, and adopted maximum mean de-entropy (MMDE) algorithm to determine the threshold value based on the information entropy of the relations among the barriers to PLM institutionalization. Findings This study explored nine barriers to PLM institutionalization and empirically identified the four critical barriers among the nine. Research limitations/implications The present work is exploratory case-based research which is limited to a case of an Indian aircraft manufacturing firm with a limited number of respondents. More sophisticated statistical tools can be utilized to consider the subjectivity of the respondents. However, this research explores the various hurdles to PLM success and serves as a relevant outcome to identify the critical barriers to institutionalize the PLM concept. Practical implications The findings of the paper provide guidelines to the case company and similar firms for obtaining maximum benefits of PLM. The methodology shown in this paper will be useful to various large scale industries in identifying the critical barriers to PLM institutionalization among all existing barriers so that they can take appropriate measures before they proceed to adopt PLM. Originality/value The present work discusses the different reasons for which the companies are not able to derive the maximum benefits of PLM even after the implementation of PLM systems. This work uniquely applied the DEMATEL and MMDE methods to investigate the critical barriers to PLM institutionalization in an aircraft manufacturing firm.

scholarly journals Potentially Human-Pathogenic Escherichia coli O26 in Norwegian Sheep Flocks

2011 ◽  
Vol 77 (14) ◽  
pp. 4949-4958 ◽  
Author(s):  
C. Sekse ◽  
M. Sunde ◽  
B.-A. Lindstedt ◽  
P. Hopp ◽  
T. Bruheim ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Variable Number Tandem Repeat ◽  
Variable Number ◽  
Human Pathogens ◽  
Content Type ◽  
Representative Sampling ◽  
E Coli ◽  
Pathogenic Escherichia Coli ◽  
Close Relationship ◽  
Large Survey

ABSTRACTA national survey ofEscherichia coliO26 in Norwegian sheep flocks was conducted, using fecal samples to determine the prevalence. In total, 491 flocks were tested, andE. coliO26 was detected in 17.9% of the flocks. One hundred forty-twoE. coliO26 isolates were examined for flagellar antigens (H typing) and four virulence genes, includingstxandeae, to identify possible Shiga toxin-producingE. coli(STEC) and enteropathogenicE. coli(EPEC). Most isolates (129 out of 142) were identified asE. coliO26:H11. They possessedeaeand may have potential as human pathogens, although only a small fraction were identified as STEC O26:H11, giving a prevalence in sheep flocks of only 0.8%. Correspondingly, the sheep flock prevalence of atypical EPEC (aEPEC) O26:H11 was surprisingly high (15.9%). The genetic relationship between theE. coliO26:H11 isolates was investigated by pulsed-field gel electrophoresis (PFGE) and multilocus variable number tandem repeat analysis (MLVA), identifying 63 distinct PFGE profiles and 22 MLVA profiles. Although the MLVA protocol was less discriminatory than PFGE and a few cases of disagreement were observed, comparison by partition mapping showed an overall good accordance between the two methods. A close relationship between a few isolates of aEPEC O26:H11 and STEC O26:H11 was identified, but all theE. coliO26:H11 isolates should be considered potentially pathogenic to humans. The present study consisted of a representative sampling of sheep flocks from all parts of Norway. This is the first large survey of sheep flocks focusing onE. coliO26 in general, including results of STEC, aEPEC, and nonpathogenic isolates.

scholarly journals Molecular and Epidemiological Characterization of IMP-Type Metallo-β-Lactamase-Producing Enterobacter cloacae in a Large Tertiary Care Hospital in Japan

2014 ◽  
Vol 58 (6) ◽  
pp. 3441-3450 ◽  
Author(s):  
Kayoko Hayakawa ◽  
Tohru Miyoshi-Akiyama ◽  
Teruo Kirikae ◽  
Maki Nagamatsu ◽  
Kayo Shimada ◽  
...  
Keyword(s):  
Hospital Mortality ◽  
Tertiary Care ◽  
Enterobacter Cloacae ◽  
Control Measures ◽  
Care Hospital ◽  
Invasive Procedures ◽  
Content Type ◽  
Infection Control Measures ◽  
Large Tertiary Care ◽  
Close Relationship

ABSTRACTIMP-type metallo-β-lactamase enzymes have been reported in different geographical areas and in various Gram-negative bacteria. However, the risk factors and epidemiology pertaining to IMP-type metallo-β-lactamase-producingEnterobacter cloacae(IMP-producingE. cloacae) have not been systematically evaluated. We conducted a retrospective, matched case-control study of patients from whom IMP-producingE. cloacaeisolates were obtained, in addition to performing thorough molecular analyses of the clinically obtained IMP-producingE. cloacaeisolates. Unique cases with IMP-producingE. cloacaeisolation were included. Patients with IMP-producingE. cloacaewere matched to uninfected controls at a ratio of 1 to 3. Fifteen IMP-producingE. cloacaecases were identified, with five of the isolates being obtained from blood, and they were matched to 45 uninfected controls. All (100%) patients from whom IMP-producingE. cloacaeisolates were obtained had indwelling devices at the time of isolation, compared with one (2.2%) uninfected control. Independent predictors for isolation of IMP-producingE. cloacaewere identified as cephalosporin exposure and invasive procedures within 3 months. Although in-hospital mortality rates were similar between cases and controls (14.3% versus 13.3%), the in-hospital mortality of patients with IMP-producingE. cloacae-caused bacteremia was significantly higher (40%) than the rate in controls. IMP-producingE. cloacaeisolates were frequently positive for other resistance determinants. The MICs of meropenem and imipenem were not elevated; 10 (67%) and 12 (80%) of the 15 IMP-producingE. cloacaeisolates had a MIC of ≤1 μg/ml. A phylogenetic tree showed a close relationship among the IMP-producingE. cloacaesamples. Indwelling devices, exposure to cephalosporin, and a history of invasive procedures were associated with isolation of IMP-producingE. cloacae. Screening for carbapenemase production is important in order to apply appropriate clinical management and infection control measures.

Vasoconstrictor activity in cerebrospinal fluid from patients subjected to early surgery for ruptured intracranial aneurysms

1981 ◽  
Vol 55 (2) ◽  
pp. 237-245 ◽  
Author(s):  
David J. Boullin ◽  
Lennart Brandt ◽  
Bengt Ljunggren ◽  
Philip Tagari
Keyword(s):  
Cerebrospinal Fluid ◽  
Content Type ◽  
Vasoactive Substances ◽  
Angiographic Vasospasm ◽  
Close Relationship ◽  
Surgical Adjunct ◽  
Serial Samples ◽  
Subarachnoid Blood ◽  
Ruptured Intracranial Aneurysms ◽  
Isolated Tissues

✓ Vasoconstrictor activity was examined in serial samples of cerebrospinal fluid (CSF) obtained from 10 patients undergoing aneurysm clipping within 48 hours after subarachnoid hemorrhage (SAH). There was no close relationship between vasoconstrictor activity in postoperative CSF samples and the patient's clinical condition or angiographic vasospasm. The identity of the vasoconstrictor substance(s) in CSF was not established, but serotonin, histamine, norepinephrine, epinephrine, acetylcholine, or angiotensinII were eliminated as prime vasoconstrictor agents inducing cerebral vasospasm. Differences in the temporal profile of the responses of isolated tissues to CSF from patients with early and late surgery suggested that differing substances were involved in the production of spasm. A correlation between CSF potassium concentrations and vasoactive substances was found, but potassium could not account for vasoconstrictor activity of CSF. A log:linear correlation between total vasoconstrictor activity and total CSF collected could not be explained. Also, because of possible differences in the identity of vasoactive substances in CSF in this study compared to earlier studies, clinical comparisons based on apparent differences in pharmacological potency of CSF were not warranted. Nevertheless, removal of subarachnoid blood by cisternal rinsing seemed to be a useful surgical adjunct.

Deposition-induced effects of isotactic polypropylene and polycarbonate composites during fused deposition modeling

2017 ◽  
Vol 23 (5) ◽  
pp. 869-880 ◽  
Author(s):  
Ying-Guo Zhou ◽  
Bei Su ◽  
Lih-sheng Turng
Keyword(s):  
Mechanical Properties ◽  
Design Methodology ◽  
Fused Deposition Modeling ◽  
Content Type ◽  
Fused Deposition ◽  
Close Relationship ◽  
Molded Parts ◽  
Deposition Modeling ◽  
Injection Molded ◽  
First Time

Purpose Although the feasibility and effectiveness of the fused deposition modeling (FDM) method have been proposed and developed, studies of applying this technology to various materials are still needed for researching its applicability, especially with regard to polymer blends and composites. The purpose of this paper is to study the deposition-induced effect and the effect of compatibilizers on the mechanical properties of polypropylene and polycarbonate (PP/PC) composites. Design/methodology/approach For this purpose, three different deposition modes for PP/PC composites with or without compatibilizers were used for the FDM method and tested for tensile properties. Also, parts with the same materials were made by injection molding and used for comparison. In addition, different deposition speeds were used to investigate the different deposition-induced effects. Furthermore, the behavior of the mechanical properties was clarified with scanning electron microscope images of the fracture surfaces. Findings The research results suggest that the deposition orientation has a significant influence on the mechanical behavior of PP/PC composite FDM parts. The results also indicate that there is a close relationship between the mechanical properties and morphological structures which are deeply influenced by compatibilization. Compared with injection molded parts, the ductility of the FDM parts can be dramatically improved due to the formation of fibrils and micro-fibrils by the deposition induced during processing. Originality/value This is the first paper to investigate a PP/PC composite FDM process. The results of this paper verified the applicability of PP/PC composites to FDM technology. It is also the first time that the deposition-induced effect during FDM has been investigated and studied.

Recent advances in reliability analysis of aeroengine rotor system: a review

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Xue-Qin Li ◽  
Lu-Kai Song ◽  
Guang-Chen Bai
Keyword(s):  
Reliability Analysis ◽  
Surrogate Model ◽  
Engineering Application ◽  
Rotor System ◽  
Engineering Structures ◽  
Content Type ◽  
Reliability Design ◽  
Rotor Systems ◽  
Practical Engineering ◽  
Complex Engineering

PurposeTo provide valuable information for scholars to grasp the current situations, hotspots and future development trends of reliability analysis area.Design/methodology/approachIn this paper, recent researches on efficient reliability analysis and applications in complex engineering structures like aeroengine rotor systems are reviewd.FindingsThe recent reliability analysis advances of engineering application in aeroengine rotor system are highlighted, it is worth pointing out that the surrogate model methods hold great efficiency and accuracy advantages in the complex reliability analysis of aeroengine rotor system, since its strong computing power can effectively reduce the analysis time consumption and accelerate the development procedures of aeroengine. Moreover, considering the multi-objective, multi-disciplinary, high-dimensionality and time-varying problems are the common problems in various complex engineering fields, the surrogate model methods and its developed methods also have broad application prospects in the future.Originality/valueFor the strong demand for efficient reliability design technique, this review paper may help to highlights the benefits of reliability analysis methods not only in academia but also in practical engineering application like aeroengine rotor system.

Analysing the interrelationship of knowledge creation and diffusion challenges of renewable energy technologies development in Iran

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Kiarash Fartash ◽  
Amir Ghorbani ◽  
Mohammadsadegh Khayatian ◽  
Mahdi Elyasi
Keyword(s):  
Renewable Energy ◽  
Knowledge Creation ◽  
Causal Effect ◽  
Academic Research ◽  
Laboratory Method ◽  
Policy Implications ◽  
Content Type ◽  
Renewable Energy Technologies ◽  
Energy Technologies ◽  
And Diffusion

Purpose This paper aims at identifying knowledge creation and diffusion challenges and explaining their causal relationship in renewable energy technologies in Iran. Design/methodology/approach By reviewing literature of renewable energy technologies development, key knowledge creation and diffusion challenges are extracted. Then, the decision-making trial and evaluation laboratory method is used to investigate the cause-effect relationships as well as the influence structure of aforementioned challenges in Iran. Findings The results indicate that lack of specialized higher education and research institutions (C4), limited international product development and technological cooperation with international pioneer firms (C8), insufficient international research interactions of institutions and academic research centres (C6), tight and temporary subsidies to domestic institutes (C13), limited and non-systematic government grants (C14), insufficient tax incentives with low impact on investment (C12), weak enforcement of intellectual property rights (C5), low number and relatively poor performance of NGOs and scientific and trade associations (C19) and the limited number of conferences, workshops, meetings and specialized journals (C15) are among the most instrumental challenges of knowledge creation and diffusion of renewable energy technologies development in Iran. Originality/value This paper identifies knowledge creation and diffusion challenges of renewable energy technologies development in Iran, which is applicable for other developing countries. It also analyses the interrelationship and causal effect between challenges which is a neglected issue in the literature and has beneficial theoretical and policy implications.

Accurate LBM appraising of pin-fins heat dissipation performance and entropy generation in enclosures as application to power electronic cooling

2019 ◽  
Vol 30 (2) ◽  
pp. 742-768 ◽  
Author(s):  
Ridha Djebali ◽  
Abdallah Jaouabi ◽  
Taoufik Naffouti ◽  
Said Abboudi
Keyword(s):  
Heat Transfer ◽  
Aspect Ratio ◽  
Entropy Generation ◽  
Heat Dissipation ◽  
Engineering Application ◽  
Industrial Applications ◽  
Cooling Performance ◽  
Content Type ◽  
Depth Analysis ◽  
Pin Fins

Purpose The purpose of this paper is to carry out an in-depth analysis of heat dissipation performance by natural convection phenomenon inside light-emitting diode (LED) lamps containing hot pin-fins because of its significant industrial applications. Design/methodology/approach The problem is assimilated to heat transfer inside air-filled rectangular cavity with various governing parameters appraised in ranges interesting engineering application and scientific research. The lattice Boltzmann method is used to predict the dynamic and thermal behaviors. Effects of monitoring parameters such as Rayleigh number Ra (103-106), fin length (0-0.25) and its position, pin-fins number (1-8), the tilting-angle (0-180°) and cavity aspect ratio Ar (0.25-4) are carried out. Findings The rising behaviors of the dynamic and thermal structures and heat transfer rate (Nu), the heatlines distribution and the irreversibility rate are appraised. It was found that the flow is constantly two contra-rotating symmetric cells. The heat transfer is almost doubled by increasing Ra. A lack of cooling performance was identified between Ar = 0.5 and 0.75. The inclination 45° is the most appropriate cooling case. At constant Ra, the maximum stream-function and the global entropy generation remain almost unchanged by increasing the pin number from 1 to 8 and the entropy generation is of thermal origin for low Ra, so that the fluid friction irreversibility becomes dominant for Ra larger than 105. Research limitations/implications Improvements may include three-dimensional complex geometries, accounting for thermal radiation, high unit power and turbulence modelling. Such factors effects will be conducted in the future. Practical implications The cooling performance/heat dissipation in LED lamps is a key manufacturing factors, which determines the lifetime of the electronic components. The best design and installation give the opportunity to increase further the product shelf-life. Originality/value Both cooling performance, irreversibility rate and enclosure configuration (aspect ratio and inclination) are taken into account. This cooling scheme will give a superior operating mode of the hot components in an era where energy harvesting, storage and consumption is met with considerable attention in the worldwide.

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