Application of the contact and non-contact measuring techniques for on-ground resonance testing of the mini-UAV

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Aleksander Olejnik ◽  
Robert Rogólski ◽  
Michał Szcześniak
Keyword(s):  
Dynamic Properties ◽  
Structural Parameters ◽  
Reference Beam ◽  
Measurement Methods ◽  
Measuring System ◽  
Vibration Measurement ◽  
Contact Method ◽  
Content Type ◽  
University Of Technology ◽  
Aviation Technology

Purpose The paper describes the application of two different vibration measurement methods for the identification of natural modes of the miniature unmanned aerial vehicle (UAV). The purpose of this study is to determine resonant frequencies and modes of mini-airplane within the specified range of frequency values. Design/methodology/approach Special measuring equipment was used including both contact and non-contact techniques. The measuring systems on equipment of the Institute of Aviation Technology in the Faculty of Mechatronics, Armament and Aerospace of Military University of Technology (Warsaw, PL) were used to conduct measurements. In traditional ground vibration testing (GVT) methods a large number of sensors should be attached to the aircraft. The weight of sensors and cables is negligible in relation to the mass of the large aircraft. However, for small and lightweight unmanned aerial vehicles, this could bring a significant mass component in relation to the total mass of the tested object. Findings The real mini-UAV construction was used to investigate its resonant modes in the range of frequencies between 0 and 50 Hz. After receiving the output values it is possible to perform some flutter calculations within the range of operational velocities. As there is no certainty that the computed modes are in accordance with those natural ones some parametric calculations are recommended. Modal frequencies depend on structural parameters which 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 In this paper, some specific techniques of performing the GVT test were presented. Two different measuring methods were applied, i.e. the contact method and the non-contact method. Using the dedicated apparatus in relation to the mini-airplane, properly prepared in terms of mass distribution, rudders deflection stiffness and proper support, some resonant characteristics can be determined. The contact measuring system consists of a multi-channel analyzer, piezoelectric accelerometers, electrodynamic exciters, amplifiers, impedance heads and a computer with the Test.Lab Software. As the non-contact method, a laser scanning vibrometer was used. The principle of its operation is based on the separation of the emitted laser beam. The returning beam reflected from a vibrating object is captured by the camera and compared to the reference beam. Dedicated software analyzes collected data and on the basis of it creates animations of structural vibrational shapes and spectral plots within the investigated frequency range. Originality/value The object used for research is the mini-UAV Rybitwa – composite mini-plane with a classic aerodynamic layout manufactured in Institute of Aviation Technology Military University of Technology. In the work, both measurement methods and some sample results were presented. Results referenced to dynamic properties of the mini-UAV can be applied in the future for its finite element model tuning, what would be useful for the needs of some parametric analyzes in case of some UAV modifications because of its structural or equipment modifications.

scholarly journals Technology of Ground Vibration Testing and its application in light aircraft prototyping

2019 ◽  
Vol 304 ◽  
pp. 01005
Author(s):  
Aleksander Olejnik ◽  
Stanisław Kachel ◽  
Robert Rogólski ◽  
Michał Szcześniak
Keyword(s):  
Early Stage ◽  
Ground Vibration ◽  
Measuring System ◽  
Vibration Measurement ◽  
Measurement Technology ◽  
Vibration Testing ◽  
Resonant Frequencies ◽  
Natural Modes ◽  
University Of Technology ◽  
The Military

The article describes the vibration measurement technology used for light aircraft and some results obtained during the prototyping process. The aim of researches was to determine the resonant frequencies and natural modes of an aircraft or its selected structural components. Ground Vibration Testing is an essential dynamic structural test necessary to carry out before the aircraft certification. This test should be performed on the aircraft example which is predicted to test in flight. The measuring system used in the Institute of Aviation Technology of the Military University of Technology consists of a multi-channel LMS SCADAS analyzer, a set of piezoelectric accelerometers, two vibration exciters equipped with impedance heads and a computer with the Test.Lab Software. The aim of the article is to present the methodology of performing GVT tests. Using the equipment applied to an aircraft or its airframe component, key vibration characteristics corresponding to resonant points can be determined. Not only completed aircraft can be tested, but also its isolated fragments (wings, stabilizers, tail units) or just empty airframe. Testing separately supported components allows to examine their aeroelastic properties at early stage of prototyping. As examples of the use of vibration measurements in various stages of the prototyping process, three examples are presented herein. The isolated strut-braced wing from of the light reconnaissance aircraft OSA, the airframe of a light jet FLARIS LAR, and the light drone ATD JET-2 intended to be an aerial target for some anti-aircraft artillery sets. Some exemplary results obtained from testing these objects were presented. At the end, some observations and conclusions were noted in the context of usefulness of conducted researches.

Application of ground vibration testing in small manned or unmanned aircraft prototyping

2020 ◽  
pp. 095441002093401
Author(s):  
Aleksander Olejnik ◽  
Stanisław Kachel ◽  
Robert Rogólski ◽  
Michał Szcześniak
Keyword(s):  
Early Stage ◽  
Ground Vibration ◽  
Unmanned Aircraft ◽  
Measuring System ◽  
Vibration Measurement ◽  
Measurement Technology ◽  
Vibration Testing ◽  
University Of Technology ◽  
Testing Technology ◽  
The Military

The article describes the vibration measurement technology used in experimental investigation of light aircraft and some series of exemplary results obtained during the prototyping process. The aim of investigations presented herein was to determine the resonant frequencies and natural modes of an aircraft or its selected structural components. Ground vibration testing is an essential dynamic structural test necessary to carry out before the aircraft certification. This test should be performed on the aircraft example which is predicted to be tested in flight. The measuring system used for ground vibration testing in the Institute of Aviation Technology of the Military University of Technology consists of a multi-channel LMS SCADAS analyzer, a set of piezoelectric accelerometers, two vibration exciters equipped with impedance heads and a computer with the Test.Lab Software. The aim of the article was to present the methodology of performing ground vibration testing tests. Having applied the equipment to measure an airplane or its airframe component, key vibration characteristics corresponding to specific resonant points can be determined. Not only completed aircraft can be tested but also its isolated fragments (wings, stabilizers, tail units) or just empty airframe. Testing separately supported components allows examining their aeroelastic properties at early stage of prototyping. Ground vibration testing technology applied in various stages of the prototyping process was demonstrated in four peculiar research cases. The testing examples presented herein were the following: the isolated strut-braced wing of a light reconnaissance airplane, the light drone imitating an aerial target for some on-ground anti-aircraft artillery sets, the empty airframe of a very light jet and the miniature UAV. Some exemplary results obtained from testing these objects were presented. At the end, some observations and conclusions were noted in the context of usefulness of conducted researches.

Vibration analysis of an aviation engine turbine shaft shield

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Stanisław Noga ◽  
Kaja Maciejowska ◽  
Tomasz Rogalski
Keyword(s):  
Natural Frequencies ◽  
Dynamic Properties ◽  
Normal Modes ◽  
Measuring System ◽  
Mode Shapes ◽  
Modal Assurance Criterion ◽  
Natural Form ◽  
Content Type ◽  
Turbine Shaft ◽  
The Impact

Purpose This paper aims to deal with the problem of vibration in an aircraft engine turbine shaft shield. The physical model of the system under study is inspired by the PZL-10W aviation jet engine shaft shield and is a structure of the profile circular arc. The main goal of the presented research is to develop a modal model of the discussed object. Another task is to determine the impact of the shaft shield damage on the change of dynamic parameters (the values of the natural frequencies and changing of the shape of the corresponding natural forms) of the discussed object. Finally, the task is connected with the calculation of the excitation speeds of the discussed shaft shield’s respective natural frequencies. Design/methodology/approach To realize the main goal finite element method simulation and experimental investigation were conducted. The quality of the achieved models is determined based on the relative error of natural frequencies and the similarity to normal modes established on the basis of the modal assurance criterion (MAC) indicator. The Campbell diagram was used to calculate the excitation speeds of the discussed shaft shield’s respective natural frequencies. Findings The obtained results indicate the changes in the dynamic properties of the shaft shield as a result of its cracking. On the basis of the adopted measurement (MAC indicator), the level of similarity was established between the numerical simulation results and the measurement results for the undamaged shield. Verification of the different mode shapes using the CrossMAC tool is an effective method, which allows comparing of the shape of the natural form and may be helpful in the process of adjusting modal models to the results of experimental tests. Practical implications It is important to note that as a result of using commercial software (ANSYS program) and a commercial measuring system (Bruel and Kjaer), the presented analysis can be attractive for design engineers dealing with the dynamics of aviation systems. Originality/value The paper presents the authors’ original approach to the dynamic analysis of the aviation engine turbine shaft shield, which can be useful for engineers dealing with the issue of vibration in shaft shield systems.

scholarly journals Evaluation of a non-contact method for measuring vibration of rolling bearings in industrial conditions

Mechanik ◽  
2020 ◽  
Vol 93 (2) ◽  
pp. 8-11
Author(s):  
Stanisław Adamczak ◽  
Mateusz Wrzochal ◽  
Numan Durakbasa
Keyword(s):  
Rolling Bearing ◽  
Measuring System ◽  
Vibration Measurement ◽  
Contact Method ◽  
Rolling Bearings ◽  
Measuring Systems ◽  
Measurement Systems ◽  
Contact Sensors

Using of laser vibrometers in vibration measurement systems brings additional benefits due to the lack of impact of the sensor on the tested measuring system. Recently, leading rolling bearing manufacturers are equipping their diagnostic measuring systems with non-contact sensors. Doppler laser vibrometers are used interchangeably for electrodynamic sensors. This paper attempts to assess the vibrometer in use for measuring vibration of rolling bearings in industrial conditions.

iMindMap as an innovative tool in teaching and learning accounting: an exploratory study

2016 ◽  
Vol 13 (1) ◽  
pp. 71-82 ◽  
Author(s):  
Wan Noor Hazlina Wan Jusoh ◽  
Suraya Ahmad
Keyword(s):  
Technology Acceptance ◽  
Teaching Methods ◽  
Teaching And Learning ◽  
Accounting Students ◽  
Content Type ◽  
Course Content ◽  
University Of Technology ◽  
Conventional Teaching ◽  
Innovative Tool ◽  
The University

Purpose The purpose of this study is to explore the use of iMindMap software as an interactive tool in the teaching and learning method and also to be able to consider iMindMap as an alternative instrument in achieving the ultimate learning outcome. Design/methodology/approach Out of 268 students of the management accounting at the University of Technology MARA (Terengganu), 97 students have participated in this survey to evaluate the effectiveness of iMindMap in teaching and learning. Findings Results indicate that the majority of the students acknowledged that iMindMap is more attractive than conventional teaching methods and found that iMindMap shows clearly how the points are all associated and linked together. Students could find that learning is an exciting experience and were able to visualize the whole course content remarkably via iMindMap. Originality/value This study presents an alternative instrument, which is innovative and interactive in teaching and learning, especially for accounting students where the students’ technology acceptance could also be viewed.

Education for sustainable development at Chemnitz University of Technology

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Martin Albert ◽  
Maria Uhlig
Keyword(s):  
Sustainable Development ◽  
Education For Sustainable Development ◽  
Cognitive Domain ◽  
New Combination ◽  
General Direction ◽  
Content Type ◽  
University Of Technology ◽  
Study Results ◽  
Study Programs ◽  
Further Development

Purpose This paper aims to examine the current state of education for sustainable development (ESD) at Chemnitz University of Technology (CUT) and to propose a guide for analysing sustainability at higher education institutions (HEI) in terms of implementation of the sustainable development goals (SDGs) and sustainability dimensions in the cognitive domain of education. Design/methodology/approach This paper uses a new combination of two frameworks, the “Phase Model of Sustainability in MBA (Master of Business Administration) Education”, developed by Hart et al. (2017), to classify sustainability-focused topics and United Nations Educational, Scientific and Cultural Organization’s (UNESCO’s) learning objectives for ESD (UNESCO, 2017) to classify sustainability-related topics. This paper analysed CUT’s study programs and faculties, the websites of the study programs and the (junior) professorships, using documentary analysis with a new set of keywords relating to the topic of incorporating sustainability in curricula. Findings The faculties and study programs of CUT are at different stages of integrating ESD. However, topics such as sustainable energy and production, recycling, sustainable management and innovation are prominent in the educational offerings of CUT. As the university is a technical university, the focus on these topics reflects the general direction of the organisation. Based on this study results, this study gives recommendations for further development for ESD at CUT. Originality/value This paper presents the case of CUT and a new guide for analysing sustainability at HEI, including recommendations for further development in relation to ESD.

Friction reduction in EHL contacts by surface microtexturing – tribological performance, manufacturing and tailored design

2019 ◽  
Vol 71 (8) ◽  
pp. 986-990 ◽  
Author(s):  
Stephan Tremmel ◽  
Max Marian ◽  
Michael Zahner ◽  
Sandro Wartzack ◽  
Marion Merklein
Keyword(s):  
Product Life Cycle ◽  
Structural Parameters ◽  
Surface Texturing ◽  
Friction Reduction ◽  
Forming Process ◽  
Friction Behavior ◽  
Holistic View ◽  
Content Type ◽  
Efficient Manufacturing ◽  
Tailored Design

Purpose This paper aims to derive tailor-made microtextures for elastohydrodynamically lubricated (EHL) contacts under consideration of manufacturing possibilities. Design/methodology/approach Component tests were used for the evaluation of the influence of surface texturing on the friction behavior in the cam/tappet contact. Furthermore, the manufacturing possibilities and limitations of a combined μEDM and micro-coining process and the feasibility of integration into a forming process were studied. Finally, a methodology based on transient EHL simulations and a meta-model of optimal prognosis was exemplarily used for microtexture optimization. Findings It was found that surface texturing in EHL contacts with high amount of sliding is promising. Moreover, the combination of μEDM and micro coining and the integration into established production processes allow the manufacturing of microtextures with desirable structural parameters and sufficient accuracy. Originality/value This paper gives a holistic view on surface microtexturing over several phases of the product life cycle, from the design, over efficient manufacturing to application-related testing.

The Dynamic Characteristics of Rigid Frame Single-Rib Arch Bridge

2013 ◽  
Vol 368-370 ◽  
pp. 1426-1430
Author(s):  
Li Xiong Gu ◽  
Rong Hui Wang
Keyword(s):  
Dynamic Characteristics ◽  
Bending Strength ◽  
Dynamic Properties ◽  
Structural Parameters ◽  
Bending Stiffness ◽  
Torsional Stiffness ◽  
Lateral Stiffness ◽  
Arch Bridge ◽  
Vertical Stiffness ◽  
Rigid Frame

In this paper, by establishing the finite element model to study the dynamic characteristics of rigid frame single-rib arch bridge. By respectively changing structural parameters of the span ratios, and the compressive stiffness of arch, and the bending stiffness of arch, and the bending stiffness of bridge girder, and the layout of boom to find out the regularity of the structure on lateral stiffness, and vertical stiffness, and torsional stiffness as well as dynamic properties, it come out the results of that lateral stiffness of the structure is weaker, and increasing the span ratios and the compressive strength of arch are conducive to the improvement of the overall stiffness, and improving the bending strength of arch and layout of boom are less effect on the overall stiffness and mode shape.

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