Autor: Mohammadzadeh, S. - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: Dynamic response of ladder track rested on stochastic foundation under oscillating moving load
Autorzy:: Mohammadzadeh, S.
Mehrali, M.
Powiązania:: https://bibliotekanauki.pl/articles/279454.pdf
Data publikacji:: 2017
Wydawca:: Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:: ladder track
moving load
stochastic stiffness
perturbation theory
Opis:: The ladder track is a new type of an elastically supported vibration-reduction track system that has been applied to several urban railways. This paper is devoted to the investigation of dynamic behavior of a ladder track under an oscillating moving load. The track is represented by an infinite Timoshenko beam supported by a random elastic foundation. In this regard, equations of motion for the ladder track are developed in a moving frame of reference. In continuation, by employing perturbation theory and contour integration, the response of the ladder track is obtained analytically and its results are verified using the stochastic finite element method. Finally, using the verified model, a series of sensitivity analyses are accomplished on effecting parameters including velocity and load frequency.
Źródło:: Journal of Theoretical and Applied Mechanics; 2017, 55, 1; 281-291
1429-2955
Pojawia się w:: Journal of Theoretical and Applied Mechanics
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: A finite element approach to develop track geometrical irregularity thresholds from the safety aspect
Autorzy:: Miri, A.
Mohammadzadeh, S.
Salek, H.
Powiązania:: https://bibliotekanauki.pl/articles/282067.pdf
Data publikacji:: 2017
Wydawca:: Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:: maintenance and inspection
track geometry parameters
finite element
Adams/rail software
Opis:: Riding quality and safety of rail tracks are directly influenced by track geometry; hence, their degradation along time could reduce safety and cause serious accidents. Standards propose thresholds for track geometrical parameters to keep track safety and riding comfort at an acceptable level. In this study, a method is proposed to select or define a set of proper thresholds for geometrical parameter irregularities according to desirable to safety level. The impact of track geometry irregularities on the derailment index has been investigated through the finite element model. The results suggest that twist and gauge shortage have a greater effect on the derailment index compared to the vertical profile of the track. Having the critical values of geometrical irregularities that result in derailment, safety factors of Iranian and Euro code standards in determining their thresholds are calculated and compared. It is shown that each standard has a unique set of safety factors that depend on speed and geometrical parameters.
Źródło:: Journal of Theoretical and Applied Mechanics; 2017, 55, 2; 695-705
1429-2955
Pojawia się w:: Journal of Theoretical and Applied Mechanics
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Beta-backscattering thickness-meter design and evaluation with fuzzy TOPSIS method
Autorzy:: Arjhangmehr, A.
Mohammadzadeh, M.
Feghhi, S. A. H.
Tasouji Hassanpour, S.
Powiązania:: https://bibliotekanauki.pl/articles/146456.pdf
Data publikacji:: 2014
Wydawca:: Instytut Chemii i Techniki Jądrowej
Tematy:: beta-ray effects
decision making
fuzzy sets
MCNPX
Opis:: An industrial gauge for measuring thickness of a gold coating layer deposited on a steel base through detection of the backscattered beta particles has been described. 3H, 14C and 63Ni pure beta emitters have been tested as the radioisotopic sources of the system individually in a fixed geometry. Analytical calculations have been performed in each case. Furthermore, simulations based on Monte Carlo stochastic technique (MCNP) have been processed. The obtained results from both methods have been compared to define the sensitivity of the system in each case. Finally for the first time, fuzzy TOPSIS method has been used for choosing the best source in the defined geometry for manufacturing, considering the following three criteria: (a) saturation thickness, (b) precision and (c) sensitivity. Results have shown that 3H source is the best alternative to the introduced measuring system.
Źródło:: Nukleonika; 2014, 59, 2; 53-59
0029-5922
1508-5791
Pojawia się w:: Nukleonika
Dostawca treści:: Biblioteka Nauki

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