The main objective of this paper is to determine the effect of outer race defect of deep groove ball bearings for (SKF 6004) through experimental and numerical methods. Three-dimensional finite element model of the housing and outer race is simulated using commercial package ABAQUS/CAE. Angular position of the local defect on the outer race which changes from 0 to 315 with angular intervals 45 is investigated through the dynamic finite element model. Experimental results are obtained using bearing test rig to validate the simulated results. A good agreement is found between the results obtained by the finite element model and the experimental results.

In the present work, friction material composites were proposed to be used as automotive friction materials. The composites were reinforced by agricultural fibres of corn, palm, and sugar bars. The conventional friction materials based on asbestos cause serious lung diseases and being cancerous potential. The aim of the present work is to replace them by the proposed composites because they are environmentally friendly friction material for brake lining and clutch facings. Agricultural wastes of sugar bars, corn and palms fibres were prepared to obtain fibres of length less than 5 mm. The fibre materials were mixed by carbon, barium sulfate, silica, metallic powders and phenol formaldehyde. The proposed composites were pressed in the die at 105°C temperature. The produced specimens were subjected to machining processes to obtain the cylindrical form of 8 mm diameter. Experiments were carried out using test rig designed and manufactured to measure both friction and wear. It consists of a rotating hollow flat disc made of carbon steel, with an outside diameter of 250 mm and 16 mm thickness. The experiments investigated the effect of agriculture fibre wastes (corn, sugar bars, and palms fibres) on friction coefficient and wear. Wear mechanisms of the proposed composites were characterized by scanning electronic microscopy. The tribological properties of the proposed composites materials were compared to three commercial brake linings. Based on the experimental results it was found that, addition of agriculture fibre wastes (corn, sugar bars, and palms fibres) to composites materials increased friction coefficient and decreased wear. Friction coefficient slightly increased, while wear drastically decreased with increasing fibres content. The maximum friction value (0.58) was obtained by composites containing 30 wt.% iron and 25 wt.% sugar bar fibres. The corn fibres were more compatible with aluminum powder where it gave the highest friction coefficient and relatively lower wear compared to other composites. Wear resistance of the tested composites containing bunches and aluminum represented the lowest values among composites containing corn and bunches fibres. The lowest wear values were observed for composites containing 25 wt.% corn fibres and 30 wt.% aluminum and composites containing 20–25 wt.% sugar bar fibres.

Multiple defects are introduced on the outer race of vehicle gearboxes. The effect of the number of outer race defects in deep groove ball bearings are investigated using experimental and numerical methods. A three-dimensional model of the housing and outer race is developed using ABAQUS. Firstly, single defect located at 0˚and two defects located at 0˚ and 67.5˚ are analyzed. Then the number of defects was increased to three and the locations of the local defects are 0˚, 67.5˚ and 225˚. Finally the model with four defects located on the outer race at the angular positions 0˚, 67.5˚, 225˚ and 270˚, was investigated. The simulated data were also used to validate the experimental results.

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The objective of this research is to study counterface materials effect on the tribological behavior of dental polymethyl methacrylate reinforced by single-walled carbon nanotubes (SWCNT) of 0.1 wt. % content. PMMA denture base material is prepared in hot acrylic resins. The counterface materials effect on the tribological behavior of PMMA and SWCNT/PMMA composite was observed using a list of counterface materials that used in the oral cavity are used in both of dry and wet conditions. The lubrication liquid that used in the wet condition was artificial saliva. The counterface materials that used in the study were polymethyl methacrylate (PMMA), stainless steel, porcelain, amalgam and buffalo teeth. Friction coefficient and wear are measured by testing the specimens on a reciprocating device at room temperature. It can be noticed that the counterface materials had a distinct effect on the coefficient of friction, wear and \ surface roughness of the PMMA composites. According to the results, it was found that the buffalo tooth and porcelain counterface lead to higher wear resistance, while the amalgam material showed minimal wear resistance under dry and wet conditions.