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Rolling element bearings absolute life prediction using modal analysis
Mostafa Yakout,A. Elkhatib,M. G. A. Nassef 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.1
In this paper, the authors introduce an experimental procedure for predicting the fatigue life of each individual rolling element bearing separately using vibration modal analysis. The experimental procedure was developed based on a statistical analysis. A statistical analysis was performed to find an empirical model that correlates the dynamic load capacity of rolling bearings to their dynamic characteristics (Natural frequencies and damping). These dynamic characteristics are obtained from the frequency response function of each individual bearing that results from vibration modal analysis. A modified formula to the already known Lundberg-Palmgren life formula is proposed for rolling element bearings. Given the modified formula, one can predict the fatigue life of each individual rolling element bearing based on its dynamic characteristics. The paper compares the results from the modified formula with those from Lundberg-Palmgren formula. The modified formula provides an accurate prediction for the fatigue life of each individual bearing based on its dynamic characteristics. The experimental validation of the modified formula is considered for future work. Therefore, it can be used in various applications of rolling element bearings in machinery systems.
Mostafa Yakout,M. G. A. Nassef,Soheir Backar 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.5
The performance of rolling element bearings is one of the machine quality measures in industry. The fatigue life and performance of rolling element bearings depends mainly on the dynamic characteristics of those bearings. This paper studied the effect of the internal radial clearance on the damping characteristics, natural modes of vibration, and fatigue life of rolling element bearings. Vibration modal analysis was performed on rolling bearings of the same size and type to measure their dynamic characteristics. These dynamic characteristics include the natural frequency of the first mode of vibration, damping, and amplitude of frequency response function at resonance. The internal radial clearances of these bearings were measured. A statistical analysis was performed to study the correlation between the internal radial clearance and the dynamic characteristics of rolling bearings. It was found that the damping ratio of the bearing assembly increased by reducing the internal radial clearance of the bearing. Similarly, rolling bearings that have large internal clearances showed short predicted fatigue life. It is concluded that the dynamic characteristics, and consequently the dynamic performance, of rolling bearings are significantly affected by the internal radial clearance.
C*-compactness in L-Fuzzy Topological Spaces
Kandil,O.Tantawy,M.Yakout,S.Saleh 한국지능시스템학회 2009 INTERNATIONAL JOURNAL of FUZZY LOGIC and INTELLIGE Vol.9 No.4
In this paper we introduce stronger form of the notion of cover so-called p-cover which is more appropriate. According to this cover we introduce and study another type of compactness in L-fuzzy topology so-called C*-compact and study some of its properties with some interrelation.
C<sup>*</sup>-compactness in L-Fuzzy Topological Spaces
Saad, Ali Kandil,Tantawy, Osama A. E.,Yakout, Mohammed Mostafa,Saleh, Salem Ali M. Korean Institute of Intelligent Systems 2009 INTERNATIONAL JOURNAL of FUZZY LOGIC and INTELLIGE Vol.9 No.4
In this paper we introduce stronger form of the notion of cover so-called p-cover which is more appropriate. According to this cover we introduce and study another type of compactness in L-fuzzy topology so-called $C^*$-compact and study some of its properties with some interrelation.
Mohamed E. Mahmoud,Amr A. Yakout,Kholoud H. Hamza,Maher M. Osman 한국공업화학회 2015 Journal of Industrial and Engineering Chemistry Vol.25 No.-
A simple and solvent-free method is proposed for synthesis of novel magnetic nano-sorbents. Dioctyl phthalate (DOP) was used to encapsulate nano-Fe3O4 and produce a nano-Fe3O4-DOP sorbent. This was treated with triethylenetetramine (TETA) in another solvent-free procedure for the formation of a novel nano-Fe3O4-DOP-TETA. The synthesized nano-sorbents were characterized by FT-IR, TGA, SEM and HRTEM (3.0–12.0 nm). The magnetic solid phase sorption characteristics were studied and optimized. The potential applications of these magnetic solid phase extractors for removal of Ni(II), Cd(II) and Pb(II) from drinking tap water, industrial wastewater and sea water samples were accomplished using a multi-stage micro-column technique
C<SUP>*</SUP>-compactness in L-Fuzzy Topological Spaces
Ali Kandil Saad,Osama A. E. Tantawy,Mohammed Mostafa Yakout,Salem Ali M. Saleh 한국지능시스템학회 2009 INTERNATIONAL JOURNAL of FUZZY LOGIC and INTELLIGE Vol.9 No.4
In this paper we introduce stronger form of the notion of cover so-called p-cover which is more appropriate. According to this cover we introduce and study another type of compactness in L-fuzzy topology so-called C<SUP>*</SUP>-compact and study some of its properties with some interrelation.