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Diagnostics of separately excited DC motor based on analysis and recognition of signals using FFT and Bayes classifier

Witold Glowacz Zygfryd Glowacz
Archives of Electrical Engineering | 2015 | vol. 64 | No 1 March | 29-35 | DOI: 10.1515/aee-2015-0004
Keywords DC motor diagnostic investigations FFT Bayes classifier
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Abstract

In this article results of diagnostic investigations of separately excited DC motor were presented. In diagnostics were applied a Fourier analysis method based on the fast Fourier transform (FFT) and a recognition method using Bayes classifier. In training process a set of the most important frequencies has been determined for which differences of corresponding signals in two states are the largest. Three categories of signals have been recognized in identification process: faultless state, state of the rotor broken one coil and state of the rotor shorted three coils

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Authors and Affiliations

Witold Glowacz
Zygfryd Glowacz

The two-stage filtering of airborne laser data in a frequency domain

Urszula Marmol
Geodesy and Cartography | 2010 | vol. 59 | No 2 | DOI: 10.2478/v10277-012-0003-z
Keywords laser scanning terrain surface algorithms automation filtering FFT
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Abstract

In the paper a frequency method of filtering airborne laser data is presented. A number of algorithms developed to remove objects above a terrain (buildings, vegetation etc.) in order to obtain the terrain surface were presented in literature. Those all methods published are based on geometrical criteria, i.e. on a specific threshold of elevation differences between two neighbouring points or groups of points. In other words, topographical surface is described in a spatial domain. The proposed algorithm operates on topographical surface described in a frequency domain. Two major tools, i.e. Fast Fourier Transform (FFT) and digital filters are used. The principal assumption is based on the idea that low frequencies are responsible for a terrain surface, while high frequencies are connected to objects above the terrain. The general guidelines of this method were for the first time presented at (Marmol and Jachimski, 2004). Due to the fact that the preliminary results showed some limitations, two-stage filtering algorithm has been introduced. The frequency filter was modified in such a manner that different filter parameters are used to detect buildings than those to recognize vegetation. In the first stage of data processing the filtering concerning elimination of points connected with urban areas was applied. The low-pass filter with parameters determined for urban area was used for the whole tested terrain in that stage. The purpose of the second stage was to eliminate vegetation by using the filter for forest areas. The presented method was tested by using data sets obtained in the ISPRS test on extracting DTM from point clouds. The results of using the two-stage algorithm were com- pared with both reference data and with filtering results of eight method reported to ISPRS test. A numerical comparison of the filter output with a reference data set shows that the filter generates DTM of a satisfactory quality. The accuracy of DTM produced by the frequency algorithm fits the average accuracy of eight methods reported in the ISPRS test.
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Authors and Affiliations

Urszula Marmol

The effect of random and systematic errors in gravity data on geoid undulations calculated using FFT

Robert Duchnowski
Geodesy and Cartography | 2006 | vol. 55 | No 3 | 133-146
Keywords Uncertainty of gravity data accuracy of geoid modelling error propagation FFT technique
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Abstract

The paper presents an attempt to assess how random errors and systematic errors in gravity data affect the quality of the geoid model when it is computed using the FFf technique. Three groups of numerical tests were conducted with the use of gravity anomalies for Poland on 2' x 2' and 5' x 5' grid and with simulating random and systematic errors. In the first test, the effect of random errors on calculated geoid undulations was investigated, in the second one - the effect of systematic errors, and in the last one - the combined effect of both random and systematic errors. The effect of density of data set on the propagated error in geoid height was also examined. The results of numerical tests made possible to evaluate the effect of random errors as well as systematic errors on the accuracy of computed geoid undulation. They were also useful in evaluating the quality of the gravimetric quasigeoid model for Poland.
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Authors and Affiliations

Robert Duchnowski
ORCID: ORCID

Fault Analysis of Worm Gear Box Using Symlets Wavelet

Narendiranath Babu Thamba Kiran Kamesh Thatikonda Venkata Sathvik Nutakki Rama Prabha Duraiswamy Noor Mohammed Razia Sultana Wahab Ramalinga Viswanathan Mangalaraja Ajay Vannan Manivannan
Archives of Acoustics | 2020 | vol. 45 | No 3 | 521-540 | DOI: 10.24425/aoa.2020.134069
Keywords worm gear box FFT symlet wavelets artificial neural network
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Abstract

This research highlights the vibration analysis on worm gears at various conditions of oil using the experimental set up. An experimental rig was developed to facilitate the collection of the vibration signals which consisted of a worm gear box coupled to an AC motor. The four faults were induced in the gear box and the vibration data were collected under full, half and quarter oil conditions. An accelerometer was used to collect the signals and for further analysis of the vibration signals, MATLAB software was used to process the data. Symlet wavelet transform was applied to the raw FFT to compare the features of the data. ANN was implemented to classify various faults and the accuracy is 93.3%.

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Authors and Affiliations

Narendiranath Babu Thamba
Kiran Kamesh Thatikonda Venkata
Sathvik Nutakki
Rama Prabha Duraiswamy
Noor Mohammed
Razia Sultana Wahab
Ramalinga Viswanathan Mangalaraja
Ajay Vannan Manivannan

DAC Testing Using Modulated Signals

Pavel Fexa Josef Vedral Jakub Svatoš
Metrology and Measurement Systems | 2011 | No 2 | 283-294 | DOI: 10.2478/v10178-011-0010-0
Keywords Digital-to-analog converter ENOB Signal-to-noise and distortion - SINAD FFT analysis Crest Factor (CF)
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Abstract

This document analyses qualities of methods used for testing dynamical parameters of Digital-to-Analog Converters (DAC) using a multi-frequency signal. As the source for these signals, Amplitude Modulated (AM) and Frequency Modulated (FM) signals are used. These signals are often used in radio engineering. Results of the tests, like Effective Number of Bits (ENOB), Signal-to-Noise and Distortion (SINAD), are evaluated in the frequency domain and they are compared with standard results of Sine Wave FFT test methods. The aim of this research is firstly to test whether it is possible to test a DAC using modulated signals, secondly to reduce testing time, while estimating band performance of DAC.

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Authors and Affiliations

Pavel Fexa
Josef Vedral
Jakub Svatoš

DAC Testing Using Impulse Signals

Josef Vedral Pavel Fexa
Metrology and Measurement Systems | 2012 | No 1 | 105-114 | DOI: 10.2478/v10178-012-0009-8
Keywords DAC ENOB SINAD FFT test Crest Factor Damped Sine Wave SINC signal Multi-Tone signal
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Abstract

The Multi-Tone (MT) signal with uniform amplitudes can be used for DAC testing. This paper shows an easier way to generate a MT signal using several impulse signals. The article also analyzes qualities of methods for testing the dynamic parameters of Digital to Analog Converters using an impulse signal. The MT, Damped Sine Wave (DSW) and Sinx/x (SINC) signals will be used as the source for these tests. The Effective Number of Bits (ENOB) and Signal to noise and distortion (SINAD) are evaluated in the frequency domain and they are modified using the Crest Factor (CF) correction and compared with the standard results of the Sine Wave FFT test. The first advantage of the test using an impulse signal is that you need fewer input parameters to create the band signal for testing the DAC. The second one is to reduce the testing time using a band signal in comparison with multiple tests using a single sine wave.

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Authors and Affiliations

Josef Vedral
Pavel Fexa

The effect of topography and quality of a digital terrain model on the accuracy of terrain corrections for centimetre quasigeoid modelling

Małgorzata Grzyb Jan Kryński Magdalena Mank
Geodesy and Cartography | 2006 | vol. 55 | No 1 | 23-46
Keywords terrain correction digital terrain model DTED SRTM prism method FFT quasigeoid
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Abstract

Modelling quasigeoid with centimetre accuracy requires taking into account irregularities of topography in the vicinity of a gravity station. i.e. the terrain correction w surveyed gravity. Accuracy of determination of the terrain correction affects quality of quasi geoid model determined. It depends on the resolution and accuracy of terrain data that usually is provided in the form of a digital terrain model DTM. Investigations were conducted with the use of the Digital Terrain Elevation Data - DTED2 model developed for Poland according to the NATO-STANAG 3809 standard, as well as global models SRTM3 and SRTM30 (The Shuttle Radar Topography Mission). Also height data from the gravity database was considered. The prism method of determination of terrain corrections was applied in majority of numerical tests. Practical method for determining the optimum radius of the integration cap considering roughness of topography as well as required accuracy of terrain corrections was developed. The effect of vertical and horizontal uncertainty of a DTM as well as its resolution on the quality of the terrain corrections was investigated. The terrain corrections obtained using a prism method were also compared with the respective ones calculated using the FIT approach. The usefulness of the available topography data for precise terrain correction computation in Poland was discussed. The results of the investigations were used to determining the strategy of computation of the terrain corrections to point gravity data in the gravity database for Poland. The "2005" terrain correction set calculated for I 078 046 gravity stations contributes to the increase of precision of gravimetric quasigeoid models developed for Poland.
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Authors and Affiliations

Małgorzata Grzyb
Jan Kryński
ORCID: ORCID
Magdalena Mank

Design and computation of a lightning protection system in an urban 110 kV substation

Mohammed Ibrahim Taha Lin Li Ping Wang
Archives of Electrical Engineering | 2020 | vol. 69 | No 3 | 723-738 | DOI: 10.24425/aee.2020.133928
Keywords CDEGS software fast Fourier transform (FFT) IEC 62305-3 lightning protection system (LPS) NFPA 780 level 1
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Abstract

A lightning protection system (LPS) of an urban 110 kV substation is designed and analysed according to NFPA 780 and IEC 62305-3 standards. The analysis of the LPS is established on the value of risk assessment. The total area of the plant is described by one soil layer with uniform resistivity. This study aims to improve the understanding of an unexpected manner of the grounding system beneath lightning currents by clarifying the basic concepts of the lightning protection level and the new design procedure in this paper was clarified according to NFPA-780 level 1 for a lightning protection system. The program is integrated with the CDEGS software, which provides effective geometrical modeling with object and result visualization. Furthermore, module and automated fast Fourier transform (FFT) is implemented in this study to simulate electromagnetic fields in the time and frequency domains. These current values are compared to the desired protection levels within the standards. The study results show that for the improved protection of the system against lightning, the total power grid must be considered as a source of improvement for studying shielding influence and the protection levels provided inside this substation.

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Authors and Affiliations

Mohammed Ibrahim Taha
Lin Li
Ping Wang

A smart fault identification system for ball bearing using simulation-driven vibration analysis

Pallavi Khaire Vikas Phalle
Archive of Mechanical Engineering | 2023 | vol. 70 | No 2 | 247-270 | DOI: 10.24425/ame.2023.145583
Keywords condition monitoring bearing defect FFT analyzer BPFI BPFO multiclass support vector machine
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Abstract

Bearings are one of the pivotal parts of rotating machines. The health of a bearing is responsible for the hassle-free operation of a machine. As vibration signatures give intimations of machine failure at an earlier stage, mostly vibration-based condition monitoring is used to monitor bearing’s health for avoiding the risk of failure. In this work, a simulation-based approach is adopted to identify surface defects at ball bearing raceways. The vibration data in time and frequency domain is captured by FFT analyzer from an experimental setup. The time frequency domain conversion of a raw time domain data was carried out by wavelet packet transform, as it takes into account the transients and spectral frequencies. The rotor bearing model is simulated in Ansys. Finally, most influencing statistical features were extracted by employing Principal Component Analysis (PCA), and fed to Multiclass Support Vector Machine (MSVM). To train the algorithm, the simulated data is used whereas the data acquired from FFT analyzer is used for testing. It can be concluded that the defects are characterized by Ball Pass Frequency (BPF) at inner race and outer raceway as indicated in the literature. The developed model is capable to monitor bearing’s health which gives an average accuracy of 99%.
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Bibliography

[1] Z. Taha and N.T. Dung. Rolling element bearing fault detection with a single point defect on the outer raceway using finite element analysis. The 11th Asia Pacific Industrial Engineering and Management Systems Conference and the 14th Asia Pacific Regional Meeting of International Foundation for Production Research, Melaka, Malaysia, 7-10 Dec. 2010.
[2] P. Jayaswal, S.N. Verma, and A.K. Wadhwani. Development of EBP-Artificial neural network expert system for rolling element bearing fault diagnosis. Journal of Vibration and Control, 17(8):1131–1148, 2011. doi: 10.1177/1077546310361858.
[3] V.V. Rao and Ch. Ratnam. A comparative experimental study on identification of defect severity in rolling element bearings using acoustic emission and vibration analysis. Tribology in Industry, 37(2):176–185, 2015.
[4] S. Shah and A. Guha. Bearing health monitoring. Tribology in Industry, 38(3):297–307, 2016.
[5] C. Ratnam, N.M. Jasmin, V.V. Rao, and K.V. Rao. A comparative experimental study on fault diagnosis of rolling element bearing using acoustic emission and soft computing techniques. Tribology in Industry, 40(3):501–513, 2018. doi: 10.24874/ti.2018.40.03.15.
[6] K. Kappaganthu and C. Nataraj. Modelling and analysis of outer race defects in rolling element bearings. Advances in Vibration Engineering, 11(4):371–384, 2012.
[7] P.K. Kankar, S.C. Sharma, and S.P. Harsha. Fault diagnosis of ball bearings using continuous wavelet transform. Applied Soft Computing, 11(2):2300–2312, 2011. doi: 10.1016/j.asoc.2010.08.011.
[8] A. Sharma, M. Amarnath, and P.K. Kankar. Feature extraction and fault severity classification in ball bearings. Journal of Vibration and Control, 22(1):176–192, 2014. doi: 10.1177/1077546314528021.
[9] V. Hariharan and P.S.S. Srinivasan. Vibration analysis of parallel misaligned shaft with ball bearing system. Sonklanakarin Journal of Science and Technology, 33(1):61–68, 2011.
[10] J.D. Wu and C.H. Liu. An expert system for fault diagnosis in internal combustion engines using wavelet packet transform and neural network. Expert Systems with Applications, 36(3):4278–4286, 2009. doi: 10.1016/j.eswa.2008.03.008.
[11] J.S. Rapur and R.Tiwari. Experimental fault diagnosis for known and unseen operating conditions of centrifugal pumps using MSVM and WPT based analyses. Measurement, 147:106809, 2019. doi: 10.1016/j.measurement.2019.07.037.
[12] C. Cortes and V. Vapnik. Support vector network. Machine Learning, 20(3):273–297, 1995. doi: 10.1007/BF00994018.
[13] S. Damuluri, K. Islam, P. Ahmadi, and N.S. Qureshi. Analyzing navigational data and predicting student grades using support vector machine. Emerging Science Journal, 4(4):243–252, 2020. doi: 10.28991/esj-2020-01227.
[14] R. Tiwari. Rotor Systems: Analysis and Identification. CRC Press, 2017. doi: 10.1201/9781315230962.
[15] V.C. Handikherkar and V.M. Phalle. Gear fault detection using machine learning techniques -- A simulation-driven approach. International Journal of Engineering, 34(1):212–223, 2021. doi: 10.5829/IJE.2021.34.01A.24.
[16] S. Patil and V. Phalle. Fault detection of anti-friction bearing using ensemble machine learning methods. International Journal of Engineering, 31(11):1972–1981, 2018.
[17] A.S. Minhas, G. Singh, J. Singh, P.K. Kankarand, and S. Singh. A novel method to classify bearing faults by integrating standard deviation to refined composite multi-scale fuzzy entropy. Measurement,154:107441, 2020. doi: 10.1016/j.measurement.2019.107441.
[18] www.mfpt.org
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Authors and Affiliations

Pallavi Khaire
1 2
ORCID: ORCID
Vikas Phalle
1
  1. Veermata Jijabai Technological Institute, Mumbai, India
  2. Fr. C. Rodrigues Institute of Technology, Navi Mumbai, India

Analysis of the backlash in the single stage cycloidal gearbox

Roman Król
Archive of Mechanical Engineering | 2022 | vol. 69 | No 4 | 693-711 | DOI: 10.24425/ame.2022.141521
Keywords cycloidal gearbox backlash dynamics multibody dynamics multibody simulation discrete Fourier transform spectral analysis FFT
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Abstract

In this paper the analysis of backlash influence on the spectrum of torque at the output shaft of a cycloidal gearbox has been performed. The model of the single stage cycloidal gearbox was designed in the MSC Adams. The analysis for the excitation with the torque and the analysis with constant angular velocity of the input shaft were performed. For these analyses, the amplitude spectrums of the output torque for different backlashes was solved using FFT algorithm. The amplitude spectrums of the combined sine functions composed of the impact to impact times between the cycloidal wheel and the external sleeves were computed for verification. The performed studies show, that the backlash has significant influence on the output torque amplitude spectrum. Unfortunately the dependencies between the components of the spectrum and the backlash could not be expressed by linear equations, when vibrations of the output torque in the range of (350 Hz – 600 Hz) are considered. The gradual dependence can be found in the spectrum determined for the combined sine functions with half-periods equal impact-to-impact times. The spectrum is narrower for high values of backlash.
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Bibliography

[1] M. Blagojević, M. Matejić, and N. Kostić. Dynamic behaviour of a two-stage cycloidal speed reducer of a new design concept. Tehnički Vjesnik, 25(2):291–298, 2018, doi: 10.17559/TV- 20160530144431.
[2] M. Wikło, R. Król, K. Olejarczyk, and K. Kołodziejczyk. Output torque ripple for a cycloidal gear train. Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science, 233(21–22):7270–7281, 2019, doi: 10.1177/0954406219841656.
[3] N. Kumar, V. Kosse, and A. Oloyede. A new method to estimate effective elastic torsional compliance of single-stage Cycloidal drives. Mechanism and Machine Theory, 105:185–198, 2016, doi: 10.1016/j.mechmachtheory.2016.06.023.
[4] C.F. Hsieh. The effect on dynamics of using a new transmission design for eccentric speed reducers. Mechanism and Machine Theory, 80:1–16, 2014, doi: 10.1016/j.mechmachtheory.2014.04.020.
[5] R. Król. Kinematics and dynamics of the two stage cycloidal gearbox. AUTOBUSY – Technika, Eksploatacja, Systemy Transportowe, 19(6):523–527, 2018, doi: 10.24136/atest.2018.125.
[6] K.S. Lin, K.Y. Chan, and J.J. Lee. Kinematic error analysis and tolerance allocation of cycloidal gear reducers. Mechanism and Machine Theory, 124:73–91, 2018, doi: 10.1016/j.mechmachtheory.2017.12.028.
[7] L.X. Xu, B.K. Chen, and C.Y. Li. Dynamic modelling and contact analysis of bearing-cycloid-pinwheel transmission mechanisms used in joint rotate vector reducers. Mechanism and Machine Theory, 137:432–458, 2019, doi: 10.1016/j.mechmachtheory.2019.03.035.
[8] D.C.H. Yang and J.G. Blanche. Design and application guidelines for cycloid drives with machining tolerances. Mechanism and Machine Theory, 25(5):487–501, 1990, doi: 10.1016/0094-114X(90) 90064-Q.
[9] J.W. Sensinger. Unified approach to cycloid drive profile, stress, and efficiency optimization. Journal of Mechanical Design, 132(2):024503, 2010, doi: 10.1115/1.4000832.
[10] Y. Li, K. Feng, X. Liang, and M.J. Zuo. A fault diagnosis method for planetary gearboxes under non-stationary working conditions using improved Vold-Kalman filter and multi-scale sample entropy. Journal of Sound and Vibration, 439:271–286, 2019, doi: 10.1016/j.jsv.2018.09.054.
[11] Z.Y. Ren, S.M. Mao, W.C. Guo, and Z. Guo. Tooth modification and dynamic performance of the cycloidal drive. Mechanical Systems and Signal Processing, 85:857–866, 2017, doi: 10.1016/j.ymssp.2016.09.029.
[12] L.X. Xu and Y.H. Yang. Dynamic modeling and contact analysis of a cycloid-pin gear mechanism with a turning arm cylindrical roller bearing. Mechanism and Machine Theory, 104:327–349, 2016, doi: 10.1016/j.mechmachtheory.2016.06.018.
[13] S. Schmidt, P.S. Heyns, and J.P. de Villiers. A novelty detection diagnostic methodology for gearboxes operating under fluctuating operating conditions using probabilistic techniques, Mechanical Systems and Signal Processing, vol. 100, pp. 152–166, 2018, doi: 10.1016/j.ymssp.2017.07.032.
[14] Y. Lei, D. Han, J. Lin, and Z. He. Planetary gearbox fault diagnosis using an adaptive stochastic resonance method. Mechanical Systems and Signal Processing, 38(1):113–124, 2013, doi: 10.1016/j.ymssp.2012.06.021.
[15] Y. Chen, X. Liang, and M.J. Zuo. Sparse time series modeling of the baseline vibration from a gearbox under time-varying speed condition. Mechanical Systems and Signal Processing, 134:106342, 2019, doi: 10.1016/j.ymssp.2019.106342.
[16] G. D’Elia, E. Mucchi, and M. Cocconcelli. On the identification of the angular position of gears for the diagnostics of planetary gearboxes. Mechanical Systems and Signal Processing, 83:305–320, 2017, doi: 10.1016/j.ymssp.2016.06.016.
[17] X. Chen and Z. Feng. Time-frequency space vector modulus analysis of motor current for planetary gearbox fault diagnosis under variable speed conditions. Mechanical Systems and Signal Processing, 121:636–654, 2019, doi: 10.1016/j.ymssp.2018.11.049.
[18] S. Schmidt, P.S. Heyns, and K.C. Gryllias. A methodology using the spectral coherence and healthy historical data to perform gearbox fault diagnosis under varying operating conditions. Applied Acoustics, 158:107038, 2020, doi: 10.1016/j.apacoust.2019.107038.
[19] D. Zhang and D. Yu. Multi-fault diagnosis of gearbox based on resonance-based signal sparse decomposition and comb filter. Measurement, 103:361–369, 2017, doi: 10.1016/j.measurement.2017.03.006.
[20] C. Wang, H. Li, J. Ou, R. Hu, S. Hu, and A. Liu. Identification of planetary gearbox weak compound fault based on parallel dual-parameter optimized resonance sparse decomposition and improved MOMEDA. Measurement, 165:108079, 2020, doi: 10.1016/j.measurement.2020.108079.
[21] W. Teng, X. Ding, H. Cheng, C. Han, Y. Liu, and H. Mu. Compound faults diagnosis and analysis for a wind turbine gearbox via a novel vibration model and empirical wavelet transform. Renewable Energy, 136:393–402, 2019, doi: 10.1016/j.renene.2018.12.094.
[22] R. Król. Resonance phenomenon in the single stage cycloidal gearbox. Analysis of vibrations at the output shaft as a function of the external sleeves stiffness. Archive of Mechanical Engineering, 68(3):303–320, 2021, doi: 10.24425/ame.2021.137050.
[23] MSC Software. MSC Adams Solver Documentation.
[24] MSC Software. MSC Adams View Documentation.
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Authors and Affiliations

Roman Król
1
ORCID: ORCID
  1. Faculty of Mechanical Engineering, Kazimierz Pulaski University of Technology and Humanities in Radom, Poland

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