Coupling of dynamics and contact mechanics of artificial hip joints in a pendulum model

Abstract

To date, fully coupled dynamics and contact mechanics analysis is still limited by expensive computational cost and long computing time and has not been addressed comprehensively, particularly in the hip joint. To understand the influence of different parameters on the biomechanics of the total hip replacement (THR) and improve its design, two numerical approaches were developed and implemented in finite element models to investigate the coupling between the dynamics response and the contact mechanics for three different THR configurations, metal-on-polyethylene (MOP), metal-on-metal (MOM), and ceramic-on-ceramic (COC). The dynamic force and the contact pressure distribution at the bearing surfaces from the two methods were predicted and compared. The influences of various parameters (motion angle, load applied in the pendulum, friction coefficient, geometry, and material properties) were subsequently investigated. From the comparisons, the decoupled method, based on the rigid-body dynamics and the quasi-static elastic contact mechanics, was adequate to predict the performance of the THRs efficiently. The load had the greatest influence on the dynamics/contact mechanics among other factors.

Study Regarding the Transmissibility Vibrations about Hand-Arm System, Using Vibration Attenuation

“…18b,c and Fig. [8][9][10][11][12][13][14][15][16], which lead to the validation of the theoretical model and the results of the simulation.…”

“…Respectively, for the hand (z 1 ) displacement, for the forearm (z 2 ) displacement, for the arm displacements (x 3 , z 3 ), and rotation (Ɵ 3 ) for the Oy h -angular displacement produced in the elbow joint. Table 3 Visco-elastic coefficients of hand-arm system, under the conditions imposed by table 1 The solutions obtained [11][12][13][14][15][16][17] are the result of the integration of a differential equations system through the SimMechanics (Simulink) module using the 4th order Runge-Kutta method (ODE 45), and an integration period of 5s (Fig. 6, and Fig.…”