The behavior of the lubricated rib-roller end contact of a tapered roller bearing is studied both theoretically and experimentally. A theoretical hydrodynamic approach was first developed for smooth and rigid surfaces for the particular geometry and kinematic conditions found in this contact. Simultaneous measurements of traction forces and film thicknesses by optical interferometry are performed in a special device made of a flat glass disk and a steel toric specimen which simulates this contact, lubricated with a mineral oil at ambient temperature. Good argeement is noted for both film thickness and traction forces between the hydrodynamic theoretical and experimental results. The experiments which are extended to the elasto-hydrodynamic regime show that central and minimum film thicknesses are lower than the calculated values using classical fully flooded and starved elastohydrodynamic theories. This departure is attributed to side flow effects. Traction curves obtained in this regime, under moderate pressures, show that the oil behavior remains newtonian.

The aim of this article is to create a new technique for predicting discontinuity formation, its place and magnitude during aluminium alloy (AA6061) friction stir welding (FSW). The effectiveness of the technique was demonstrated using visual inspection, hardness and tensile test of the friction stir welded joints. The measured current was analysed through power calculations. In each of the FSW stages, the energy consumption is significantly varied, clearly distinguishing the penetration of the tool, its revolution, its traverse movement and its metal removal rate. The findings of tracking the energy consumption indicate that using power consumption means the significance of weld quality. FSW has been carried out based on two factors - two levels. Response surface methodology (RSM) is employed to develop a mathematical model. Analysis of variance (ANOVA) technique checks the adequacy of the developed mathematical model, which is used effectively at 95% confidence level. In contrast, tensile and hardness tests also showed that welds at high power usage failed continuously within the welding area, due to reduced welding temperature and absence of penetration in the welding zone.

This paper explains the precept and methodology of FSW. It covers some of the technical sides which influence the process and quality of FSW joint. Large advance has been accomplished in friction stir welding (FSW) of aluminum in every side of tool manufacture, microstructure properties estimate in the last decennia. With the development of reliable welding tools and precise control systems, FSW of aluminum has reached a new level of technical maturity. influence on butt joint arrangement is studied. Effect on welding quality of main parameters:  rotation speed, travel speed, tool tilt angle, axial force and weld time has been studied. Finally, FSW is identified as an additional area for research can be carried out in the welding science.

The fracture behavior of ceramic/polymer laminates has been investigated to improve fracture behavior of ceramic by reinforcing with ductile polymer layers. Epoxy is used to toughen ceramic laminates (partially stabilized Zirconia (PSZ) or Alumina). It is assumed that interface bonding between laminates takes place which was represented by cohesive zone model CZM. The ductile polymer layers are assumed ductile and cause bridging stress. A virtual model based on FEM is developed to calculate the J-integral of ceramic/polymer laminated composite numerically and as a mathematical expression for fracture toughness. The fracture toughness is studied by applying 3-point bend test on laminates. A parametric study of variables affecting J-integral is conducted. A verification of the finite element model has been performed by a comparison with previous research results which has been experimentally conducted by. A reasonable indication has been approved.

This study concerns the photoelastic analysis of dry contact between a cylinder and a plane under combined loading. Both static and dynamic cases are experimentally dealt with. A test rig is specially designed to collect essential data within and in the vicinity of the contact area. Data obtained have been analysed to estimate the contact area, normal and tangential stress distributions, coefficient of friction and the position of maximum shear through the contact. Results are compared with theoretical and experimental values(previously published) by other authors. The comparison of dynamic with static experimental results clarifies the angle of assymmetry of maximum shear stress fringes corresponding to the angle of friction.