How to search?
advanced search

Search results

Filters

  • Journals
  • Authors
  • Keywords
  • Date
  • Type

Search results

Number of results: 9
items per page: 25 50 75
Sort by:

Dynamic characteristics of the proton exchange membrane fuel cell module

Janusz T. Cieśliński Tomasz Z. Kaczmarczyk Bartosz Dawidowicz
Archives of Thermodynamics | 2018 | vol. 39 | No 4 | 125-140
Keywords PEM fuel cell hydrogen dynamic characteristics
Download PDF Download RIS Download Bibtex

Abstract

The paper describes a fuel cell based system and its performance. The system is based on two fuel cell units, DC/DC converter, DC/AC inverter, microprocessor control unit, load unit, bottled hydrogen supply system and a set of measurement instruments. In the study presented in the paper a dynamic response of the proton exchange membrane (PEM) fuel cell system to unit step change load as well as to periodical load changing cycles in the form of semi-sinusoidal and trapezoidal signals was investigated. The load was provided with the aid of an in-house-developed electronic load unit, which was fully PC controlled. The apparatus was commissioned by testing the steady-state operation of the module. The obtained efficiency of the fuel cell shows that the test apparatus used in the study provides data in substantial agreement with the manufacturer’s data.

Go to article

Authors and Affiliations

Janusz T. Cieśliński
Tomasz Z. Kaczmarczyk
Bartosz Dawidowicz

An effective method of creating dynamic characteristics using drive tests

Krzysztof Brzozowski Kazimierz Romaniszyn
Archive of Mechanical Engineering | 2003 | vol. 50 | No 4 | 403-420
Keywords drive rest exhaust pollutant dynamic characteristics
Download PDF Download RIS Download Bibtex

Abstract

The paper presents a methodology for creating dynamic characteristics of fuel consumption and intensity of emission of toxic components of exhaust gas. The source of data is the result of modal analysis of fuel consumption and emission intensity obtained from experimental drive tests. Two certified tests have been used: European NEDC and American Ff P- 75. A general algorithm for obtaining dynamic characteristics in the form of approximated functions is formulated on the basis of measured data. Examples of characteristics obtained for a real car with spark ignition engine are presented. The results obtained from experimental measurements and numerical simulations are compared and discussed.
Go to article

Authors and Affiliations

Krzysztof Brzozowski
Kazimierz Romaniszyn

The use of synthesis methods in position optimisation and selection of tuned mass damper (TMD) parameters for systems with many degrees of freedom

Andrzej Dymarek Tomasz Dzitkowski
Archives of Control Sciences | 2021 | vol. 31 | No 1 | 185-211 | DOI: 10.24425/acs.2021.136886
Keywords structural control system vibration simple fractions synthesis rational functions dynamic characteristics
Download PDF Download RIS Download Bibtex

Abstract

The paper formulates and formalises a method for selecting parameters of the tuned mass damper (TMD) for primary systems with many degrees of freedom. The method presented uses the properties of positive rational functions, in particular their decomposition, into simple fractions and continued fractions, which is used in the mixed method of synthesis of vibrating mechanical systems. In order to formulate a method of tuning a TMD, the paper discusses the basic properties of positive rational functions. The main assumptions of the mixed synthesis method is presented, based on which the general method of determining TMD parameters in the case of systems with many degrees of freedom was formulated. It has been shown that a tuned mass damper suppresses the desired resonance zone regardless of where the excitation force is applied. The advantages of the formulated method include the fact of reducing several forms of the object’s free vibration by attaching an additional system with the number of degrees of freedom corresponding to the number of resonant frequencies reduced. In addition, the tuned mass damper determined in the case of excitation force applied at a single point can be attached to any element of the inertial primary system without affecting the reduction conditions in this way. It results directly from the methodology formalised in the paper. As part of the paper, numerical calculations were performed regarding the tuning of the TMD to the first form of free vibration of a system with 3 degrees of freedom. The parameters determined were subjected to analysis and verification of the correctness of the calculations carried out. For the considered case of a system with 3 degrees of freedom together with a TMD, time responses of displacement, from each floor, were generated to excitation induced by a harmonic force equal to the first form of vibration of the basic system. In addition, in the case of the parameters obtained, the response of the inertial element system to which the TMD was attached to random white noise excitation was determined.
Go to article

Authors and Affiliations

Andrzej Dymarek
1
Tomasz Dzitkowski
1
  1. Departament of Engineering Processes Automation and Integrated Manufacturing Systems, Silesian University of Technology, Konarskiego 18A, 44-100 Gliwice, Poland

Dynamics of Large Diameter Hydraulic Legs Under Applied Test Methods

Kazimierz Stoiński Marek Płonka Janina Świątek
Archives of Mining Sciences | 2022 | vol. 67 | No 2 | 259-273 | DOI: 10.24425/ams.2022.141457
Keywords hydraulic leg dynamic characteristics roof support large diameters
Download PDF Download RIS Download Bibtex

Abstract

The dynamic characteristics of the hydraulic leg are essential for determining the safe working range of roof supports operating in seams threatened by rock mass tremors. The systematic increase in the support of the hydraulic legs due to deteriorating geological-mining conditions has increased their diameters, which currently exceed 0.32 m for the 1st hydraulic stage. Evaluation of the dynamic properties of the roof support and the hydraulic legs are carried out by the Central Mining Institute through calculation methods as an implementation of the Regulation of the Minister of Energy on occupational safety and health. However, the issue of validating the calculations concerning natural scale studies still needs to be addressed. There are significant limitations in this area due to the technical and metrological capabilities of the testing stations. This paper presents an attempt to evaluate bench testing of a hydraulic leg with 0.32 m of the 1st hydraulic stage diameter for the validation of computational and test methods. Results of previous studies affecting the evaluation of the research methods used are also cited. According to the authors, the optimal and economically justifiable direction is to undertake model tests using numerical analyses and to validate these results, based on the study of models of hydraulic legs that are in use at a reduced scale. The construction of testing stations to ensure adequate dynamic loading for the support of the largest diameter hydraulic legs is currently not economically viable. The problem presented, however, is important given the constantly deteriorating geological-mining conditions and the associated threat of rock mass tremors.
Go to article

Authors and Affiliations

Kazimierz Stoiński
1
ORCID: ORCID
Marek Płonka
1
ORCID: ORCID
Janina Świątek
1
ORCID: ORCID
  1. Central Mining Institute (GIG ), 1 Gwarków Sq., 40-166 Katowice, Poland

Experimental dynamic damage assessment of PUFJ protected brick infilled RC building during successive shake table tests

Arkadiusz Kwiecień Zoran Rakicevic Jarosław Chełmecki Aleksandra Bogdanovic Marcin Tekieli Łukasz Hojdys Matija Gams Piotr Krajewski Filip Manojlovski Antonio Soklarovski Omer Faruk Halici Theodoros Rousakis Vachan Vanian
Bulletin of the Polish Academy of Sciences Technical Sciences | 2023 | 71 | 3 | e144940 | DOI: 10.24425/bpasts.2023.144940
Keywords shake table earthquake dynamic characteristics modal hammer DIC
Download PDF Download RIS Download Bibtex

Abstract

It is highly important to determine eigenvalues before and after certain extreme events that may cause damage accumulation, such as earthquake, blasts and mining or seismic tests on research models. Unique experiment design and shake table testing was performed to investigate seismic performance of a 3D RC building model with infill walls and advanced protection with polyurethane-based joints and fiber polymer reinforced light and emergency jackets. For the purpose of wider experimental activities, three methods for determination of the dynamic characteristics were used during multiple successive shake table tests following a dynamic pushover approach, and they are presented in detail. They are: inertance function through impact hammer tests, standard Fourier transformation of measured acceleration time history and digital image correlation. The expected differences in the results are related to the type and intensity of excitation used, the involvement of materials with different mechanical and physical properties, and with the different rate and extent of damage accumulation, as well as to local or global measurements. Y et, all methods lead to reliable results when a consistent methodology is being used, that takes into account locality or globality of measurements, leaving a choice for the most suitable one, depending on the site conditions. The inertance function method presented manifested its high efficiency in analysis of dynamic properties of large-scale structures and in monitoring of their changes caused by the damage and repair process. It offers quite a wide range of useful information, does not require very expensive equipment and its transportation cost is negligible. This method seems to be a proper diagnostic tool for simple experimental modal analysis of real structures and their structural elements, where detection of changes in the structural condition and in dynamic properties is required, also as a non-destructive testing and monitoring method. Digital image correlation proved to be a promising non-contact tool, strongly supporting the conventional instrumentation of shake table testing, while the Fourier transformation was used as a benchmark method yielding the most reliable results.
Go to article

Authors and Affiliations

Arkadiusz Kwiecień
1
ORCID: ORCID
Zoran Rakicevic
2
Jarosław Chełmecki
1
Aleksandra Bogdanovic
2
Marcin Tekieli
1
Łukasz Hojdys
1
Matija Gams
3
Piotr Krajewski
1
ORCID: ORCID
Filip Manojlovski
2
Antonio Soklarovski
2
Omer Faruk Halici
4
Theodoros Rousakis
Vachan Vanian
5
  1. Faculty of Civil Engineering, Cracow University of Technology, Cracow, Poland
  2. IZIIS, Ss. Cyril and Methodius University, Skopje, North Macedonia
  3. Faculty of Civil and Geodetic Engineering, University of Ljubljana, Ljubljana, Slovenia
  4. Istanbul Technical University, Istanbul, Turkey
  5. Democritus University of Thrace, Xanthi, Greece

Influence of anchoring and bracing system on dynamic characteristics of façade scaffolding

Jarosław Bęc
Archives of Civil Engineering | 2023 | vol. 69 | No 4 | 493-506 | DOI: 10.24425/ace.2023.147672
Keywords façade scaffolding dynamic characteristics naturalfrequencies and mode shapes anchoringand bracing system
Download PDF Download RIS Download Bibtex

Abstract

The basic dynamic characteristics of façade scaffolding are natural frequencies of vibrations and corresponding mode shapes. These properties affect the scaffolding safety, as well as comfort and safety of its users. Many of the dynamic actions present at scaffolding are in the low frequency range, i.e. below 10–15 Hz. The first natural frequency of a structure is usually in the range of 0.7 to 4 Hz which corresponds to resonant frequencies of human body and it means that vibrations induced at scaffolding may strongly affect the human comfort. The easiest way of increasing the rigidity of the structure is by ensuring correct boundary conditions (support, anchorage) and bracing of the structure. The numerical analysis was performed for the real scaffolding structure of medium size. The analysis consisted of natural frequencies calculation for the original structure and for models with modified bracing and anchoring systems. The bracing modifications were introduced by reducing or increasing the number of vertical bracing shafts. The anchor system was modified by reduction of the 6 anchors in the top right corner of the scaffolding in three stages or by evenly removing nearly 1/3 of the total number of anchors. The modifications of bracing and anchor systems resulted in changing the natural frequencies. The increase of natural frequencies due to higher number of anchors and more bracing is not even for all mode shapes. Bracing is more effective in acting against longitudinal vibrations, while anchoring against vibrations perpendicular to the façade.
Go to article

Authors and Affiliations

Jarosław Bęc
1
ORCID: ORCID
  1. Lublin University of Technology, Faculty of Civil Engineering and Architecture, Nadbystrzycka 40St, 20-618 Lublin, Poland

A comparative study of the sensitivity analysis for systems with viscoelastic elements

Magdalena Łasecka-Plura
Archive of Mechanical Engineering | 2023 | vol. 70 | No 1 | 5-25 | DOI: 10.24425/ame.2022.144077
Keywords sensitivity analysis viscoelastic damping elements dynamic characteristics fractional derivatives
Download PDF Download RIS Download Bibtex

Abstract

This paper discusses the different methods used for calculating first- and second-order sensitivity: the direct differentiation method, the adjoint variables method, and the hybrid method. The solutions obtained allow determining the sensitivity of dynamic characteristics such as eigenvalues and eigenvectors, natural frequencies, and nondimensional damping ratios. The methods were applied for analyzing systems with viscoelastic damping elements, whose behavior can be described by classical and fractional rheological models. However, the derived formulas are general and can also be applied to systems with damping elements described by other models. Their advantage is a compact and easy to code form. The paper also presents a comparison of the computational costs of the discussed methods. The correctness of all the proposed methods has been illustrated with numerical examples.
Go to article

Bibliography

[1] M. Zhang and R. Schmidt. Sensitivity analysis of an auto-correlation-function-based damage index and its application in structural damage detection. Journal of Sound and Vibration, 333(26):7352–7363, 2014. doi: 10.1016/j.jsv.2014.08.020.
[2] T.W. Kim and J.H. Kim. Eigensensitivity based optima distribution of a viscoelastic damping layer for a flexible beam. Journal of Sound and Vibration, 273(1-2):201–218, 2004. doi: 0.1016/S0022-460X(03)00479-6.
[3] F. van Keulen, R.T. Haftka, and N.H. Kim. Review of options for structural design sensitivity analysis. Part 1: Linear systems. Computer Methods in Applied Mechanics and Engineering, 194(30-33):3213–3243, 2005. doi: 0.1016/j.cma.2005.02.002.
[4] D.A. Tortorelli and P. Michaleris. Design sensitivity analysis: Overview and review. Inverse Problems in Engineering, 1(1):71–105, 1994, doi: 10.1080/174159794088027573.
[5] R.L. Fox and M.P. Kapoor. Rates of change of eigenvalues and eigenvectors. AIAA Journal, 6(12):2426–2429, 1968. doi: 10.2514/3.5008.
[6] S. Adhikari and M.I. Friswell. Eigenderivative analysis of asymmetric non-conservative systems. International Journal for Numerical Methods in Engineering, 51(6):709–733, 2001. doi: 10.1002/NME.186.
[7] R.B. Nelson. Simplified calculation of eigenvector derivatives. AIAA Journal, 14(9):1201–1205, 1976. doi: 10.2514/3.7211.
[8] M.I. Friswell and S. Adhikari. Derivatives of complex eigenvectors using Nelson’s method. AIAA Journal, 38(12):2355–2357, 2000. doi: 10.2514/2.907.
[9] S. Adhikari and M.I. Friswell. Calculation of eigenrelation derivatives for nonviscously damped systems using Nelson’s method. AIAA Journal, 44(8):1799–1806, 2006. doi: 10.2514/1.20049.
[10] L. Li, Y. Hu, X. Wang, and L. Ling. Eigensensitivity analysis of damped systems with distinct and repeated eigenvalues. Finite Elements in Analysis and Design, 72:21–34, 2013. doi: 10.1016/j.finel.2013.04.006.
[11] L. Li, Y. Hu, and X. Wang. A study on design sensitivity analysis for general nonlinear eigenproblems. Mechanical Systems and Signal Processing, 34(1-2):88–105, 2013. doi: 10.1016/j.ymssp.2012.08.011.
[12] T.H. Lee. An adjoint variable method for structural design sensitivity analysis of a distinct eigenvalue problem. KSME International Journal, 13(6):470–476, 1999. doi: 10.1007/BF02947716.
[13] T.H. Lee. Adjoint method for design sensitivity analysis of multiple eigenvalues and associated eigenvectors. AIAA Journal, 45(8):1998–2004, 2007. doi: 10.2514/1.25347.
[14] S. He, Y. Shi, E. Jonsson, and J.R.R.A. Martins. Eigenvalue problem derivatives computation for a complex matrix using the adjoint method. Mechanical Systems and Signal Processing, 185:109717, 2023. doi: 10.1016/j.ymssp.2022.109717.
[15] R. Lewandowski and M. Łasecka-Plura. Design sensitivity analysis of structures with viscoelastic dampers. Computers and Structures, 164:95–107, 2016. doi: 10.1016/j.compstruc.2015.11.011.
[16] Z. Ding, L. Li, G. Zou, and J. Kong. Design sensitivity analysis for transient response of non-viscously damped systems based on direct differentiate method. Mechanical Systems and Signal Processing, 121:322–342, 2019. doi: 10.1016/j.ymssp.2018.11.031.
[17] Z. Ding, J. Shi, Q. Gao, Q. Huang, and W.H. Liao. Design sensitivity analysis for transient responses of viscoelastically damped systems using model order reduction techniques. Structural and Multidisciplinary Optimization, 64:1501–1526, 2021. doi: 10.1007/s00158-021-02937-9.
[18] R. Haftka. Second-order sensitivity derivatives in structural analysis. AIAA Journal, 20(12):1765–1766, 1982. doi: 10.2514/3.8020.
[19] M.S. Jankovic. Exact nth derivatives of eigenvalues and eigenvectors. Journal of Guidance, Control, and Dynamics, 17(1):136–144, 1994. doi: 10.2514/3.21170.
[20] J.Y. Ding, Z.K. Pan, and L.Q. Chen. Second-order sensitivity analysis of multibody systems described by differential/algebraic equations: adjoint variable approach. International Journal of Computer Mathematics, 85(6):899–913, 2008. doi: 10.1080/00207160701519020.
[21] M. Martinez-Agirre and M.J. Elejabarrieta. Higher order eigensensitivities-based numerical method for the harmonic analysis of viscoelastically damped structures. International Journal for Numerical Methods in Engineering, 88(12):1280–1296, 2011. doi: 10.1002/nme.3222.
[22] H. Kim and M. Cho. Study on the design sensitivity analysis based on complex variable in eigenvalue problem. Finite Elements in Analysis and Design, 45:892–900, 2009. doi: 10.1016/j.finel.2009.07.002.
[23] A. Bilbao, R. Aviles, J. Aguirrebeitia, and I.F. Bustos. Eigensensitivity-based optimal damper location in variable geometry trusses. AIAA Journal, 47(3):576–591, 2009. doi: 10.2514/1.37353.
[24] R.M. Lin, J.E. Mottershead, and T.Y. Ng. A state-of-the-art review on theory and engineering applications of eigenvalue and eigenvector derivatives. Mechanical Systems and Signal Processing, 138:106536, 2020. doi: 10.1016/j.ymssp.2019.106536.
[25] R. Lewandowski, A. Bartkowiak, and H. Maciejewski. Dynamic analysis of frames with viscoelastic dampers: a comparison of dampers models. Structural Engineering and Mechanics, 41(1):113–137, 2012. doi: 10.12989/sem.2012.41.1.113.
[26] S.W. Park. Analytical modeling of viscoelastic dampers for structural and vibration control. International Journal of Solids and Structures, 38(44-45):8065–8092, 2001. doi: 10.1016/S0020-7683(01)00026-9.
[27] R. Lewandowski. Sensitivity analysis of structures with viscoelastic dampers using the adjoint variable method. Civil-Comp Proceedings, 106, 2014.
[28] J.S. Arora and J.B. Cardoso. Variational principle for shape design sensitivity analysis. AIAA Journal, 30(2):538–547, 1992. doi: 10.2514/3.10949.
[29] Z. Pawlak and R. Lewandowski. The continuation method for the eigenvalue problem of structures with viscoelastic dampers. Computers and Structures, 125:53–61, 2013. doi: 10.1016/j.compstruc.2013.04.021.
[30] R. Lewandowski and M. Baum. Dynamic characteristics of multilayered beams with viscoelastic layers described by the fractional Zener model. Archive of Applied Mechanics, 85(12):1793–1814, 2015. doi: 10.1007/s00419-015-1019-2.
[31] R. Lewandowski, P. Litewka and P. Wielentejczyk. Free vibrations of laminate plates with viscoelastic layers using the refined zig-zag theory – Part 1: Theoretical background. Composite Structures, 278:114547, 2021. doi: 10.1016/j.compstruct.2021.114547.
[32] M. Kamiński, A. Lenartowicz, M. Guminiak, and M. Przychodzki. Selected problems of random free vibrations of rectangular thin plates with viscoelastic dampers. Materials, 15(19): 6811, 2022. doi: 10.3390/ma15196811.
Go to article

Authors and Affiliations

Magdalena Łasecka-Plura
1
ORCID: ORCID
  1. Poznan University of Technology, Institute of Structural Analysis, Poznan, Poland

Dynamic characteristics of underframe semi-active inerter-based suspended device for high-speed train based on LQR control

Yong Wang Hao-Xuan Li Hao-Dong Meng Yang Wang
Bulletin of the Polish Academy of Sciences Technical Sciences | 2022 | 70 | 4 | e141722 | DOI: 10.24425/bpasts.2022.141722
Keywords dynamic characteristics high-speed train inerter-based suspended device LQR control Sperling index
Download PDF Download RIS Download Bibtex

Abstract

The underframe passive inerter-based suspended device, based on the inerter-spring-damper vibration attenuation structure, could improve the dynamic performance of the train body, but its parameters are fixed and cannot meet the dynamic performance requirements under different operating conditions. Therefore, a semi-active inerter-based suspended device based on the linear quadratic regulator (LQR) control strategy is proposed to further enhance the dynamic performance. The rigid-flexible coupling vertical dynamic model of the train body and an underframe semi-active inerter-based suspended device are established. The structural parameters of the semi-active inerter-based suspended device are adjusted using LQR control strategy. Dynamic response of the system is obtained using the virtual excitation method. The dynamic characteristic of the system is evaluated using the Sperling index and compared with those of the passive and semi-active traditional suspended devices as well as the passive inerter-based suspended devices. The vertical vibration acceleration of the train body and Sperling index using the semi-active inerter-based suspended device is the smallest among the four suspended devices, which denotes the advantages of using the inerter and LQR control strategy. The semi-active inerter-based suspended device could decrease the vertical vibration acceleration of the train body and further suppress its elastic vibration in the lower frequency band, more effectively than the other three suspended devices. Overall, the semi-active inerter-based suspended device could significantly reduce elastic vibration of the train body and improve its dynamical performance.
Go to article

Authors and Affiliations

Yong Wang
1 2
ORCID: ORCID
Hao-Xuan Li
2
Hao-Dong Meng
3
Yang Wang
1
  1. State Key Laboratory of Automotive Simulation and Control, Jilin University, Changchun 130022, China
  2. Automotive Engineering Research Institute, Jiangsu University, Zhenjiang 212013, China
  3. School of Automotive Engineering, Changzhou Institute of Technology, Changzhou 213002, China

Experimental identification of dynamic characteristics of a track structure influencing the level of noise emission

Cezary Kraśkiewicz Przemysław Mossakowski Artur Zbiciak Anna Al Sabouni-Zawadzka
Archives of Civil Engineering | 2021 | vol. 67 | No 4 | 543-557 | DOI: 10.24425/ace.2021.138517
Keywords track structure track decay rate impulse tests field tests dynamic characteristics
Download PDF Download RIS Download Bibtex

Abstract

The present paper describes an experimental methodology of identification of dynamic characteristics of a track structure, consisting in determination of a track decay rate (TDR) in the field tests that were conducted by the authors on the railway line section inWarsaw. The proposed methodology of measurements, parameters determination and presentation of the results is based on the measurement methods described in EN 15461 [1], which are aimed at determination of TDR. The values of TDR determined in the impulse tests in one-third octave bands are compared with the limiting values specified in EN ISO 3095 [2] and Technical Specifications for Interoperability (TSI) [3]. Based on the obtained experimental data, the analysed railway line is classified as a structure that does not generate excessive level of rolling noise from the vibrations induced by the moving rolling stock on structural elements of the track – particularly on rails. The results obtained in this study are promising from the point of view of future development of effective solutions used for protection of people and environment against noise generated by the railway traffic.
Go to article

Authors and Affiliations

Cezary Kraśkiewicz
1
ORCID: ORCID
Przemysław Mossakowski
1
ORCID: ORCID
Artur Zbiciak
1
ORCID: ORCID
Anna Al Sabouni-Zawadzka
1
ORCID: ORCID
  1. Warsaw University of Technology, Faculty of Civil Engineering, Al. Armii Ludowej 16, 00-637 Warsaw, Poland

This page uses 'cookies'. Learn more