Structural model with controls of a very light airplane for numerical flutter calculations

2018 ◽  
Vol 92 (3) ◽  
pp. 304-317
Author(s):  
Robert Rogólski ◽  
Aleksander Olejnik
Keyword(s):  
Structural Model ◽  
Structural Parameters ◽  
Normal Modes ◽  
Element Model ◽  
Coefficient Matrix ◽  
Content Type ◽  
Aerodynamic Model ◽  
Aeroelastic Model ◽  
Uncertainty Of Results ◽  
Practical Implications

Purpose The finite element model developed for a new-designed aircraft was used to solve some problems of structural dynamics. The key purpose of the task was to estimate the critical flutter velocities of the light airplane by performing numerical analysis with application of MSC Software. Design/methodology/approach Flutter analyses processed by Nastran require application of some complex aeroelastic model integrating two separate components – structural model and aerodynamic model. These sub-models are necessary for determining stiffness, mass and aerodynamic matrices, which are involved in the flutter equation. The aircraft structural model with its non-structural masses was developed in Patran. To determine the aerodynamic coefficient matrix, some simplified aerodynamic body-panel geometries were developed. The flutter equation was solved with the PK method. Findings The verified aircraft model was used to determine its normal modes in the range of 0-30 Hz. Then, some critical velocities of flutter were calculated within the range of operational velocities. As there is no certainty that the computed modes are in accordance with the natural ones, some parametric calculations are recommended. Modal frequencies depend on structural parameters that are quite difficult to identify. Adopting their values from the reasonable range, it is possible to assign the range of possible frequencies. The frequencies of rudder or elevator modes are dependent on their mass moments of inertia and rigidity of controls. The critical speeds of tail flutter were calculated for various combinations of stiffness or mass values. Practical implications The task described here is a preliminary calculational study of normal modes and flutter vibrations. It is necessary to prove the new airplane is free from flutter to fulfil the requirement considered in the type certification process. Originality/value The described approach takes into account the uncertainty of results caused by the indeterminacy of selected constructional parameters.

Enhancing consumer engagement in e-commerce live streaming via relational bonds

2020 ◽  
Vol 30 (3) ◽  
pp. 1019-1041 ◽  
Author(s):  
Mingyao Hu ◽  
Sohail S. Chaudhry
Keyword(s):  
Relationship Marketing ◽  
Affective Commitment ◽  
Structural Model ◽  
Empirical Studies ◽  
Measurement Model ◽  
Live Streaming ◽  
Consumer Engagement ◽  
Content Type ◽  
Online Marketplace ◽  
Practical Implications

PurposeEnhancing consumer engagement in e-commerce live streaming is critical for e-commerce operators to build relationships and create consumer loyalty. Using the stimulus–organism–response model and theories from relationship marketing, the authors develop and test an integrative conceptual framework that combines various relational bonds, affective commitment, and consumer engagement.Design/methodology/approachUsing 327 valid responses from consumers of Taobao Live, the authors employed the software Mplus7.0 to evaluate the measurement model and the structural model.FindingsThe results empirically demonstrate that social and structural bonds positively affect consumer engagement directly and indirectly via affective commitment, while financial bonds have only an indirect effect via affective commitment on consumer engagement.Practical implicationsThe findings provide useful insights for e-commerce operators, who should invest in establishing relational bonds and stimulating affective commitment to improve consumer engagement.Originality/valueThis study adds to e-commerce research by being one of the first empirical studies on e-commerce live streaming, extends the marketing literature by integrating different relational bonds as antecedents of consumer engagement from the relational perspective, and enriches the affective commitment literature by distinguishing commitment to the online marketplace from commitment to the broadcaster.

Hovering rotor computations using an aeroelastic blade model

2012 ◽  
Vol 116 (1180) ◽  
pp. 621-649 ◽  
Author(s):  
F. Dehaeze ◽  
G. N. Barakos
Keyword(s):  
Structural Model ◽  
Element Model ◽  
Rotor Blades ◽  
Mesh Deformation ◽  
Computational Domain ◽  
Helicopter Rotor Blades ◽  
Aeroelastic Model ◽  
Adequate Test ◽  
Computational Fluid Dynamics Cfd ◽  
Blade Loads

AbstractIn this paper, helicopter rotor blades are analysed in hover using computational fluid dynamics (CFD) coupled with a structural model. The method relies on a mesh deformation algorithm that allows for exchange of forces and deformations between a beam-based finite-element model and the fluid flow volume mesh. The method is demonstrated against experimental data, and the aerodynamic predictions appear to improve when the aeroelastic model is used. For all employed cases the flexibility of the method allows the CFD mesh deformation to be spread over the computational domain in a controlled fashion. The influence of the aeroelastic deformations on the blade loads was limited yet evident on the rotor performance. The lack of adequate test cases and experiments for validation of CFD/CSD methods is also highlighted.

scholarly journals Tourism sustainability in archaeological sites

2018 ◽  
Vol 8 (3) ◽  
pp. 276-292 ◽  
Author(s):  
Maria Francisca Blasco López ◽  
Nuria Recuero Virto ◽  
Joaquin Aldas Manzano ◽  
Jesús Garcia-Madariaga
Keyword(s):  
Market Orientation ◽  
Design Methodology ◽  
Structural Model ◽  
Social Sustainability ◽  
Archaeological Sites ◽  
Economic Sustainability ◽  
Content Type ◽  
Qualitative And Quantitative ◽  
Path Modelling ◽  
Practical Implications

Purpose The purpose of this paper is to determine a model for developing sustainable tourism in archaeological sites. A qualitative and quantitative approach has been assumed in order to test a model of market orientation, where 11 experts were interviewed and 122 employees of archaeological sites answered the e-questionnaire. Design/methodology/approach Partial least squares path modelling regression was employed to examine the measurement and structural model. Findings The findings have revealed that market orientation and innovativeness positively and significantly influence tourism sustainability, measured in economic and social terms. Besides, tourist functionality has been determined as an antecedent of market orientation. Research limitations/implications This study is limited by the sample sizes of both researches. The model has second order constructs (market orientation, innovativeness and tourism sustainability) that include related concepts to increase parsimony and understand relations with other variables. As a result, separate effects of these dimensions have not been measured, which could report interesting findings in future-related studies. Practical implications The results suggest useful insights for managers to improve social and economic sustainability in archaeological sites. Innovativeness affects tourism sustainability, which reinforces the idea that offering technological and organisational innovations improve economic and social sustainability. Besides, it has been proved that market orientation is a necessary precondition to guarantee social and economic sustainability. Originality/value This paper assists scholars and practitioners by shedding light on the comprehension of tourism sustainability.

Relationships between supply performance of pharmacies in Chile and their quality of customer service

2018 ◽  
Vol 12 (4) ◽  
pp. 433-446
Author(s):  
Fernando Rojas ◽  
Giulani Coluccio ◽  
Juan Vega
Keyword(s):  
Quality Of Service ◽  
Customer Service ◽  
Structural Equation ◽  
Structural Model ◽  
Structural Equation Models ◽  
Statistical Significance ◽  
Measurement Scales ◽  
Content Type ◽  
Practical Implications

Purpose This paper aims to describe relationships between constructs adapted to the pharmaceutical field with respect to the measurement of the supply chains strategic and operational performance in private pharmacies, relating it to the quality of service perceived by users. Design/methodology/approach Relationships among the indicated constructs were validated through the use of structural equation models. This study includes the use of questionnaires adapted and applied to suppliers (pharmaceutical chemists and supply staff), operational managers (pharmacy assistants) and users (patients and clients) who visit different segments of pharmacies, such as chain businesses and independents located in the region of Valparaíso, Chile. The sample collected information from 128 establishments and 601 people, through which different relationships between segments were compared. Findings A structural model was validated on the basis of statistical principles. Furthermore, positive relationships were observed in the constructs studied where pharmacy chains had a statistical significance of less than 5 per cent between the responsibility of the supply process and the experience of the users, whereas independent pharmacies had a very significant causal relationship between operational managers and users. Practical implications The proposal can help predict the quality of service perceived by the user based on the behavior of sales and supply staff, which may be similar in other markets with similar characteristics. Originality/value The structural model proposed is original and adapts measurement scales validated from previous studies to be able to apply them in the pharmaceutical retail market.

scholarly journals Aeroelastic behaviour of UAV wings due to morphing

2017 ◽  
Vol 89 (1) ◽  
pp. 30-38 ◽  
Author(s):  
Levent Ünlüsoy ◽  
Yavuz Yaman
Keyword(s):  
Structural Model ◽  
High Efficiency ◽  
Morphing Wing ◽  
Element Analysis ◽  
Content Type ◽  
Aerodynamic Model ◽  
Morphing Wings ◽  
Fast Solution ◽  
Order Of Magnitude ◽  
Aerial Vehicle

Purpose The purpose of this paper is to analyse the effects of morphing on the aeroelastic behaviour of unmanned aerial vehicle (UAV) wings to make an emphasis on the required aeroelastic tailoring starting from the conceptual design of the morphing mechanisms. Design/methodology/approach In this study, flutter and divergence characteristics of a fully morphing wing design were discussed to show the dilapidating effect of morphing on the related parameters. The morphing wings were intended to achieve a high efficiency at different flight phases; thus, various morphing concepts were integrated into a UAV wing structure. Although it is considered beneficial to have the morphing capabilities to avoid the failure due to a possible wear out in flutter and divergence parameters; it is necessary to include the aeroelastic analyses at the early design phases. This study utilizes a combination of a reduced order structural model and Theodorsen unsteady aerodynamic model as primary analyses tools for flutter and divergence. The analyses were conducted by using an in-house developed pk-algorithm coupled with a commercial finite element analysis (FEA) tool. This approach yielded a fast solution capacity because of the state-space form used. Findings Analyses conducted showed that transition between take-off, climb, cruise and loiter phases yield a change in the flutter and divergence speeds as high as 138 and 305 per cent, respectively. Practical implications The research showed that an extensive aeroelastic investigation was required for morphing wing designs to achieve a failure safe design. Originality/value The research intends to highlight the possible deteriorating effects on structural design of morphing UAV wings by focusing on the aeroelastic characteristics. In addition to that, fundamental morphing concepts are compared in terms of the order of magnitude of their deteriorating effects.

Perseverance of effort and consistency of interest for entrepreneurial career success

2020 ◽  
Vol 12 (2) ◽  
pp. 279-304 ◽  
Author(s):  
Isyaku Salisu ◽  
Norashidah Hashim ◽  
Munir Shehu Mashi ◽  
Hamza Galadanchi Aliyu
Keyword(s):  
Career Success ◽  
Structural Model ◽  
Sampling Technique ◽  
Cross Sectional ◽  
Content Type ◽  
Career Achievement ◽  
Entrepreneurial Action ◽  
Practical Implications ◽  
Collectivist Society

Purpose The purpose of this paper is to examine the effect of grit (consistency of interest and perseverance of effort) on entrepreneurial career success (career satisfaction, perceived career achievement and perceived financial attainment) through the role of resilience. Design/methodology/approach The study was cross-sectional, and the data were collected using questionnaires from 111 entrepreneurs in Nigeria who have been in business for over five years and were selected using purposive sampling technique. The study used Smart-PLS to assess the measurement and structural model. Findings The perseverance of effort was related to all the aspects of career success as well as resilience. But consistency of interest was positively related to only perceived financial attainment. It also predicted resilience. Resilience was also related to all the facets of career success. All three mediation hypotheses were supported. Research limitations/implications The study delivered fascinating understandings into the structures of grit. The Western conceptualisation of grit may not be valid in a collectivist society where consistency is not that very much considered. Practical implications The study helps to further validate grit in the entrepreneurship field; the construct is a facilitator of entrepreneurial action and an indispensable source of energy that can revitalise the entrepreneur along the arduous road to success. Originality/value The two components of grit can have a dissimilar influence on different outcomes – as prior investigations, although recognising that the two components are conceptually dissimilar, have rarely studied them so empirically.

Development of an aeroelastic model based on system identification using boundary elements method

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Rohollah Dehghani Firouz-Abadi ◽  
Mohammad Reza Borhan Panah
Keyword(s):  
Boundary Element Method ◽  
Boundary Element ◽  
Structural Models ◽  
Elastic Mode ◽  
Content Type ◽  
Reduced Order ◽  
Aerodynamic Model ◽  
Aeroelastic Model ◽  
Proposed Model ◽  
Element Method

Purpose The purpose of this paper is to analyze the stability of aeroelastic systems using a novel reduced order aeroelastic model. Design/methodology/approach The proposed aeroelastic model is a reduced-order model constructed based on the aerodynamic model identification using the generalized aerodynamic force response and the unsteady boundary element method in various excitation frequency values. Due to the low computational cost and acceptable accuracy of the boundary element method, this method is selected to determine the unsteady time response of the aerodynamic model. Regarding the structural model, the elastic mode shapes of the shell are used. Findings Three case studies are investigated by the proposed model. In the first place, a typical two-dimensional section is introduced as a means of verification by approximating the Theodorsen function. As the second test case, the flutter speed of Advisory Group for Aerospace Research and Development 445.6 wing with 45° sweep angle is determined and compared with the experimental test results in the literature. Finally, a complete aircraft is considered to demonstrate the capability of the proposed model in handling complex configurations. Originality/value The paper introduces an algorithm to construct an aeroelastic model applicable to any unsteady aerodynamic model including experimental models and modal structural models in the implicit and reduced order form. In other words, the main advantage of the proposed method, further to its simplicity and low computational effort, which can be used as a means of real-time aeroelastic simulation, is its ability to provide aerodynamic and structural models in implicit and reduced order forms.

A Scheme of a Knowledge Based System for Optimal Modelling and Design of Robots

1994 ◽  
Author(s):  
Michael Lawo
Keyword(s):  
Structural Model ◽  
Natural Frequencies ◽  
Structural Parameters ◽  
Time History ◽  
Element Model ◽  
Identification Problem ◽  
Optimization Method ◽  
Knowledge Based System ◽  
Knowledge Based ◽  
History Of

Abstract Based on a finite element model the deformations and vibrations of a robot structure are calculated for different configurations (layouts). The results of the analysis are verified by measuring the corresponding deformations and velocities. The time history of velocities at different points of the structure in test positions is recorded. Out of the time history by modal analysis the natural frequencies are determined. The structural model is checked by the comparison of corresponding analysed and measured values A nonlinear optimization method with the structural parameters as variables of the model is used for the solution of this identification problem. The result is a verified and sufficient structural model of the real structure. Out of the experiences a knowledge based system for the modelling and simulation of robot structures is conceived. The concept of the system is presented.

scholarly journals Three-Dimensional CST Parameterization Method Applied in Aircraft Aeroelastic Analysis

2017 ◽  
Vol 2017 ◽  
pp. 1-15
Author(s):  
Hua Su ◽  
Chunlin Gong ◽  
Liangxian Gu
Keyword(s):  
Structural Model ◽  
Three Dimensional ◽  
Automatic Process ◽  
Shape Transformation ◽  
Design And Optimization ◽  
Aerodynamic Model ◽  
Conceptual Design Phase ◽  
Design Variables ◽  
Aeroelastic Analysis ◽  
Aeroelastic Model

Class/shape transformation (CST) method has advantages of adjustable design variables and powerful parametric geometric shape design ability and has been widely used in aerodynamic design and optimization processes. Three-dimensional CST is an extension for complex aircraft and can generate diverse three-dimensional aircraft and the corresponding mesh automatically and quickly. This paper proposes a parametric structural modeling method based on gridding feature extraction from the aerodynamic mesh generated by the three-dimensional CST method. This novel method can create parametric structural model for fuselage and wing and keep the coordination between the aerodynamic mesh and the structural mesh. Based on the generated aerodynamic model and structural model, an automatic process for aeroelastic modeling and solving is presented with the panel method for aerodynamic solver and NASTRAN for structural solver. A reusable launch vehicle (RLV) is used to illustrate the process for aeroelastic modeling and solving. The result shows that this method can generate aeroelastic model for diverse complex three-dimensional aircraft automatically and reduce the difficulty of aeroelastic analysis dramatically. It provides an effective approach to make use of the aeroelastic analysis at the conceptual design phase for modern aircraft.

Sustainable industry 4.0 – an exploratory study for uncovering the drivers for integration

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
N. Harikannan ◽  
S. Vinodh ◽  
Anand Gurumurthy
Keyword(s):  
Industry 4.0 ◽  
Structural Model ◽  
Public Awareness ◽  
Sustainable Manufacturing ◽  
Matrix Multiplication ◽  
Interpretive Structural Modeling ◽  
Content Type ◽  
Micmac Analysis ◽  
Societal Pressure ◽  
Practical Implications

Purpose The concept of sustainable manufacturing has been adopted by manufacturing organizations to develop eco-friendlier products and processes. In recent times, industries are progressing toward Industry 4.0 (I4.0). Guided with smart intelligent devices, I4.0 can possibly decrease excess production, material movement and consumption of energy. If so, it is hypothesized that there is a good synergy between I4.0 and sustainability, which warrants an integrated approach for implementation. This amalgamation is termed as “Sustainable industry 4.0.” Hence, this paper aims to systematically identify and analyze the drivers for this integration. Design/methodology/approach This paper presents the analysis of 20 drivers identified from literature review for simultaneous deployment of I4.0 and sustainable manufacturing. Interpretive structural modeling (ISM) is used to derive the structural model for analyzing the causal association between drivers. Cross-Impact Matrix Multiplication Applied to Classification (MICMAC) analysis is being performed to group the drivers. Findings The results showed that the dominant drivers derived are societal pressure and public awareness (D18), government policies on support I4.0 (D12), top management involvement and support (D15) and government promotions and regulations (D16). Also, the MICMAC analysis revealed many driving, dependent, linkage and autonomous drivers. Research limitations/implications The opinion from experts with combined expertise on I4.0 and sustainability was obtained. The respondent size could be increased in future studies. Practical implications The study has been done based on inputs from industry practitioners. Managerial and practical implications are presented. ISM shows that the drivers for deploying sustainable I4.0 are highly inter-related. It also reveals the pre-requisites for each level of the drivers. Originality/value The idea of analyzing the drivers for sustainable I4.0 is the original contribution of the authors.

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