Author

K. Raptis

School of Mechanical Engineering, National Technical University of Athens, Iroon Polytexneiou 9, Athens 15780, Greece

2 articles in our journals

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Research ArticleOpen accessTHE ADVERSE EFFECT OF STEEL PARTICLE CONTAMINANTS ON FATIGUE LIFE OF GREASE LUBRICATED BALL BEARINGSA. Stathis, Th. Costopoulos, D. Koulocheris, K. RaptisThe rating life of ball bearings is reduced when hard particle contaminants are present in the lubricant. Usually, this life reduction is taken into account in the calculation of modified rating life by using the contamination factor through a general characterization of the lubrication conditions. However, the impact of contaminant’s variables such as size, hardness and concentration level has to … …American Journal of Applied Sciences, Vol. 11, Issue 9 · 14 Jul 2014 · 6,991 accessesView PDF Cite

Research ArticleOpen accessOperational Fault Diagnosis in Industrial Hydraulic Systems Through Modeling The Internal Leakage of its ComponentsP. Athanasatos, D. Koulocheris, T. Costopoulos, K. RaptisIn this study, a model of a high pressure hydraulic system was developed using the bond graph method to investigate the effect of the internal leakage of its main components (pump, cylinder and 4/2 way valve) on the operational characteristics of the system under various loads. All the main aspects of the hydraulic circuit (like the internal leakages, the compressibility … …American Journal of Applied Sciences, Vol. 10, Issue 12 · 7 Nov 2013 · 7,247 accessesView PDF Cite