A 3-dimensional computational fluid-structure interaction analysis in the hip-joint prosthesis during solat (prayer) activity

Artificial hip joint (AHJ) hailed as the current best solution to solve the damage hip joint issues that can lead to permanent disability. This study investigates the performance of artificial hip joint during the salat activity under seven salat position loading condition by introducing the existence of non-Newtonian synovial fluid and analyzed with two-way FSI methods. Based on the result, the amount of hydrodynamic pressure is affected by the external and internal rotation (z-axis) position. The external position enhances the hydrodynamic pressure value, while the internal position reduces the hydrodynamic pressure value. Meanwhile, the maximum equivalent stress on the inner liner under all salat position is insignificant to the elastic modulus of the Ultra-high-molecular-weight polyethylene (UHMWPE) therefore the artificial hip joint is statically safe to perform salat. Finally, the amount of load support is insufficient to prevent the direct contact between the femoral head and inner liner. Thus, the design modification is necessary to provide the sufficient value of load support on the artificial joint

Multiphase computational fluid dynamics analysis of hydrodynamic journal bearing under the combined influence of texture and slip

The drive to maintain the environmental sustainability and save the global energy consumption is urgent, making every powertrain system component a candidate to enhance efficiency. In this work, the combined effects of the slip boundary and textured surface in hydrodynamic journal bearing as one of the critical components in industrial powertrain and engine systems are assessed using a multiphase computational fluid dynamic analysis that allows for phase change in a cavitation process and arbitrary textured geometry. The texture studied consists of regularly spaced rectangular dimples through two-dimensional (infinitely long) journal bearing. The modified Navier-slip model is employed to describe the slip boundary condition. A systematic comparison is made for various textured configurations varying the texture depth and the length of the texturing zone with respect to the performance of a smooth (untextured) bearing for several eccentricity ratios. The effectiveness of the texture with or without slip at enhancing the load support over a corresponding smooth bearing is investigated with the parameters. The detrimental or beneficial effect of surface texturing as well as the slip promotion is explained in terms of the mechanisms of pressure generation for several eccentricity ratios. The results of the present work indicate that journal bearing textured by a proper texturing zone and dimple depth are characterized by substantial load support levels. However, in the range of high eccentricity ratios, the promotion of texturing and slip can significantly degrade the performance of the load support