Simulation of the Wing-to-Fuselage Assembly Process

2019 ◽  
Vol 141 (6) ◽  
Author(s):  
Sergey Lupuleac ◽  
Nadezhda Zaitseva ◽  
Maria Stefanova ◽  
Sergey Berezin ◽  
Julia Shinder ◽  
...  
Keyword(s):  
Statistical Analysis ◽  
Contact Problem ◽  
Assembly Process ◽  
Multistage Process ◽  
Stochastic Nature ◽  
Closing The Gap ◽  
Compliant Parts ◽  
Level Parallelism ◽  
Task Level

The paper presents a simulation of the Airbus A350-900 wing-to-fuselage assembly process. The latter is a complex multistage process where the compliant parts are being joined by riveting. The current research analyzes the quality of the temporary fastener arrangement. The fastener arrangement is being checked to ensure that the residual gap between joined parts is small, and the fastener loads closing the gap are calculated. The deviations of the part shape from nominal are modeled via initial gaps. A cloud of initial gaps is generated based on the statistical analysis of the available measurements assuming the stochastic nature of local gap roughness. Through the reduction of the corresponding contact problem to a quadratic programming (QP) problem and the use of efficient QP algorithms together with the task-level parallelism, the mass contact problem solving on refined grids is accomplished.

Simulation and Optimization of Airframe Assembly Process

2018 ◽  
Author(s):  
Sergey Lupuleac ◽  
Nadezhda Zaitseva ◽  
Maria Stefanova ◽  
Sergey Berezin ◽  
Julia Shinder ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Statistical Analysis ◽  
Problem Solving ◽  
Contact Problem ◽  
Quality Measures ◽  
Assembly Process ◽  
Variation Analysis ◽  
Simulation And Optimization ◽  
The Mathematical Model ◽  
Variation Simulation

An approach for simulating the assembly process where compliant airframe parts are being joined by riveting is presented. The foundation of this approach is the mathematical model based on the reduction of the corresponding contact problem to a Quadratic Programming (QP) problem. The use of efficient QP algorithms enables mass contact problem solving on refined grids, which is needed for variation analysis and simulation as well as for the consequent assembly process optimization. To perform variation simulation, the initial gap between the parts is assumed to be stochastic and a cloud of such gaps is generated based on statistical analysis of the available measurements. The developed approach is illustrated with two examples, simulation of A350-900 wing-to-fuselage joining and optimization of A320 wing box assembly. New contact quality measures are discussed.

scholarly journals Numerical Approach for Detecting the Resonance Effects of Drilling during Assembly of Aircraft Structures

Mathematics ◽  
2021 ◽  
Vol 9 (22) ◽  
pp. 2926
Author(s):  
Alexey Vasiliev ◽  
Sergey Lupuleac ◽  
Julia Shinder
Keyword(s):  
Contact Problem ◽  
Numerical Procedure ◽  
Numerical Approach ◽  
Mean Value ◽  
Assembly Process ◽  
Drilling Force ◽  
Resonance Effects ◽  
Stationary Analysis ◽  
Quadratic Programming Problems ◽  
Compliant Parts

This paper is devoted to the development of a numerical approach that allows quick detection of the conditions favorable for the beginning of noticeable vibrations during drilling. The main novelty of the proposed approach lies in taking into account the deviations of the assembled compliant parts during non-stationary contact analysis by means of variation simulation. The approaches to stationary analysis of assembly quality are expanded and generalized for modeling such non-stationary effects as vibration and resonance. The numerical procedure is based on modeling the stress–strain state of the assembled structures by solving the corresponding transient contact problem. The use of Guyan reduction, the node-to-node contact model and the application of the generalized α method allow the reformulation of the contact problem in terms of a series of quadratic programming problems. The algorithm is thoroughly tested and validated with commercial software. The efficiency of the developed numerical procedure is illustrated by analysis of the test joints of two aircraft panels. The unsteady process of drilling the panels with periodic drilling force was simulated. The influence of deviations in the shape of the parts on the non-stationary interlayer gap was modeled by setting different initial gaps between parts. It is shown that the oscillation amplitudes of the interlayer gap depend on the initial gaps and do not correlate with the mean value of the stationary residual gap. Thus, non-stationary analysis provides new information about the quality of the assembly process, and it should be applied if the assembly process includes periodic impact on the assembled parts.

The Effects of Exercise Commitment Facilitated by Service Quality of Smartphone Exercise Applications on Continued Exercise Intention

2019 ◽  
Vol 118 (1) ◽  
pp. 14-19
Author(s):  
Boo-Gil Seok ◽  
Hyun-Suk Park
Keyword(s):  
College Students ◽  
Factor Analysis ◽  
Regression Analysis ◽  
Statistical Analysis ◽  
Correlation Analysis ◽  
Service Quality ◽  
Frequency Analysis ◽  
Primary Data ◽  
Exercise Intention

Background/Objectives: The purpose of this study is to examine the effects of exercise commitment facilitated by service quality of smartphone exercise Apps on continued exercise intention and provide primary data for developing and/or improving smartphone exercise Apps. Methods/Statistical analysis: A questionnaire survey was conducted amongst college students who have experiences in using exercise App(s) and regularly exercise. The questionnaire is composed of four parts asking about service quality, exercise commitment, continued exercise intention, which were measured with a 5-point Likert Scale, and demographics. Frequency analysis, factor analysis, correlation analysis, and regression analysis were carried out to analyze the obtained data with PASW 18.0.

Relationships between Population Dynamics and Operating Parameters in an Activated Sludge-Plant by Statistical Analysis

1992 ◽  
Vol 25 (4-5) ◽  
pp. 399-400 ◽  
Author(s):  
L. Cingolani ◽  
M. Cossignani ◽  
R. Miliani
Keyword(s):  
Population Dynamics ◽  
Statistical Analysis ◽  
Activated Sludge ◽  
Treatment Plant ◽  
Operating Conditions ◽  
Statistical Analyses ◽  
Operating Parameters ◽  
Aerobic Treatment

Statistical analyses were applied to data from a series of 38 samples collected in an aerobic treatment plant from November 1989 to December 1990. Relationships between microfauna structure and plant operating conditions were found. Amount and quality of microfauna groups and species found in activated sludge proved useful to suggest the possible causes of disfunctions.

Comparative Analysis of Patients with Robotic Hiatal Hernia Repairs with and without Collis Gastroplasty

2021 ◽  
pp. 000313482198905
Author(s):  
John A. Perrone ◽  
Stephanie Yee ◽  
Manrique Guerrero ◽  
Antai Wang ◽  
Brian Hanley ◽  
...  
Keyword(s):  
Quality Of Life ◽  
Statistical Analysis ◽  
Hospital Stay ◽  
Hiatal Hernia ◽  
Collis Gastroplasty ◽  
Significant Difference ◽  
Related Quality

Introduction After extensive mediastinal dissection fails to achieve adequate intra-abdominal esophageal length, a Collis gastroplasty(CG) is recommended to decrease axial tension and reduce hiatal hernia recurrence. However, concerns exist about staple line leak, and long-term symptoms of heartburn and dysphagia due to the acid-producing neoesophagus which lacks peristaltic activity. This study aimed to assess long-term satisfaction and GERD-related quality of life after robotic fundoplication with CG (wedge fundectomy technique) and to compare outcomes to patients who underwent fundoplication without CG. Outcomes studied included patient satisfaction, resumption of proton pump inhibitors (PPI), length of surgery (LOS), hospital stay, and reintervention. Methods This was a single-center retrospective analysis of patients from January 2017 through December 2018 undergoing elective robotic hiatal hernia repair and fundoplication. 61 patients were contacted for follow-up, of which 20 responded. Of those 20 patients, 7 had a CG performed during surgery while 13 did not. There was no significant difference in size and type of hiatal hernias in the 2 groups. These patients agreed to give their feedback via a GERD health-related quality of life (GERD HRQL) questionnaire. Their medical records were reviewed for LOS, length of hospital stay (LOH), and reintervention needed. Statistical analysis was performed using SPSS v 25. Satisfaction and need for PPIs were compared between the treatment and control groups using the chi-square test of independence. Results Statistical analysis showed that satisfaction with outcome and PPI resumption was not significantly different between both groups ( P > .05). There was a significant difference in the average ranks between the 2 groups for the question on postoperative dysphagia on the follow-up GERD HRQL questionnaire, with the group with CG reporting no dysphagia. There were no significant differences in the average ranks between the 2 groups for the remaining 15 questions ( P > .05). The median LOS was longer in patients who had a CG compared to patients who did not (250 vs. 148 min) ( P = .01). The LOH stay was not significantly different ( P > .05) with a median length of stay of 2 days observed in both groups. There were no leaks in the Collis group and no reoperations, conversions, or blood transfusions needed in either group. Conclusion Collis gastroplasty is a safe option to utilize for short esophagus noted despite extensive mediastinal mobilization and does not adversely affect the LOH stay, need for reoperation, or patient long-term satisfaction.

Wybrane parametry jakości ucisku i relaksacji klatki piersiowej wykonywanej przez personel pielęgniarski w ramach pozaszpitalnego nagłego zatrzymania krążenia ? badanie pilotażowe

2018 ◽  
Vol 21 (4) ◽  
Author(s):  
Paweł Więch ◽  
Marek Muster ◽  
Dariusz Bazaliński ◽  
Grzegorz Kucaba ◽  
Izabela Sałacińska ◽  
...  
Keyword(s):  
Health Care ◽  
Primary Health Care ◽  
Statistical Analysis ◽  
Discharge Rate ◽  
Statistical Significance ◽  
Sudden Cardiac Arrest ◽  
Initial Examination ◽  
Relaxation Parameters ◽  
Primary Health

Introduction. Sudden cardiac arrest (SCA) in out-of-hospital conditions is a frequent condition of immediate life-emergency of cardiological background. The survival and discharge rate in SCA patients treated by medical services is still at a low level. Aim. The aim of the study was to analyze selected parameters of the quality of chest compressions and relaxation performed by nursing staff as part of out-of-hospital SCA. Material and methods. The study covered a group of 48 nurses working in primary health care in branches of conservative (PRE/C = 24 people, mean age 33.04 ± 9.20) and surgery profile (PRE/I = 24 people, average age 31.88 ± 9.97), participating in the research project of the Center for Medical and Natural Sciences Research and Innovation, University of Rzeszów in Rzeszów. Two months after the initial examination and intervention, the test was repeated. The assessment of selected compression and relaxation parameters was performed using the True CPR Resuscitation Assistant. The statistical analysis of the collected material was carried out with the SPSS Statistics 20 software. The statistical analysis used the analysis of variables using parametric and non-parametric tests. The statistical significance was assumed at p < 0.05. Results. Initially, a high percentage of the effectiveness of the most important compression and relaxation parameters of the chest was obtained during 2-minute out-of-hospital cardiopulmonary resuscitation with no statistically significant differences between the two groups (PRE/C: 51 mm depth, 83.92% relaxation, frequency 115.46 vs. PRE/I: depth: 47.58 mm, relaxation: 92.54, frequency: 109.96, p < 0.05). After two months, similar parametric values were observed with no statistical significance (p < 0.05). Conclusions. The initial high quality of compressions and relaxation was found in nurses participating in the simulated out-of-hospital SCA, while there were no significant differences between primary health care nurses working at conservative departments and nurses from surgical ones. After a two-month interval from the initial examination and training, high CPR effectiveness was observed based on the guidelines of the European Resuscitation Council from 2015.

Statistical analysis of nematode counts from interlaboratory proficiency tests

Nematology ◽  
2014 ◽  
Vol 16 (2) ◽  
pp. 229-243 ◽  
Author(s):  
Wim Van Den Berg ◽  
Olaf Hartsema ◽  
Loes J.M.F. Den Nijs
Keyword(s):  
Statistical Analysis ◽  
Proficiency Test ◽  
Meta Analysis ◽  
Proficiency Tests ◽  
Free Living ◽  
Accuracy And Precision ◽  
Mean And Variance ◽  
The Mean ◽  
Interaction Variance

A series of proficiency tests on potato cyst nematode (PCN; ) and free-living stages of Meloidogyne and Pratylenchus () were investigated to determine the accuracy and precision of the nematode counts and to gain insights into possible trends and potential improvements. In each test, each participating laboratory received ten samples of soil collected from naturally infested fields and well mixed before distribution. The variance between the counts from the ten samples, estimated per test and laboratory, was constant for PCN cysts and free-living stages of Meloidogyne spp. and Pratylenchus spp. during the period monitored. However, during the initial years, the variance between the samples showed a downward trend for PCN living juveniles. The variance between the laboratories, estimated per test, was constant for PCN cysts over the period 1994-2010. For PCN living juveniles the variance between laboratory means declined from 1994-2000 and from 2000 it was more or less constant, which coincided with the introduction of a well-described new methodology. For Meloidogyne spp. and Pratylenchus spp., from 1998-2005 the variance between laboratory means was more or less constant or increased. From 2006, all participating laboratories incubated the organic matter and the variance between the laboratories was stable and below the levels observed during 2003-2005. After discarding data from initial years with unstable variances of the nematode counts, a meta-analysis was carried out on the remaining data using HGLMs to model the mean and variance of the counts simultaneously. The within-laboratory variance for the ten samples and the interaction variance of test and laboratory were estimated and combined to percentage coefficient of variation (%CV) per laboratory. For PCN cysts, %CV per laboratory ranged from 12.6 to 41.6 and for PCN juveniles in sandy soil from 24.4 to 67.4 and in loamy soil from 37.9 to 102.0. For Meloidogyne spp., %CV ranged from 53.2 to 84.4 and for Pratylenchus spp. from 24.3 to 90.6. The quality of a proficiency test is largely defined by random distribution of the nematodes over the samples allocated, statistical analysis of the data and communication of the results to participating laboratories. This study provides insights into the accuracy and precision at laboratories in recent years and the effect of concerted actions during the period in which the proficiency tests were conducted.

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