Papers by Keyword: Hip Joint

Abstract: On account of the steadily increasing number of road casualties, the present research study underpins a thorough investigation on the impact issue between the driver’s knee and the vehicle’s dash board. Such type of impacts tends to occur especially in frontal collisions between a vehicle and an obstacle or another vehicle. Thus, aiming at determining the impact force in the coxofemoral joint, we have carried out a series of virtual simulations by means of the LS-DYNA software package. Also, we had to consider the influence the vehicle’s velocity impact displays upon the injury degree in the driver’s lower limbs area. Furthermore, an additional method to determine the impact force in this joint was to implement a mathematical modelling of the impact phenomenon. In the end, after having completed the two processes, we sought compare the results obtained both by the virtual simulation, and mathematical modelling.

Abstract: The acetabular liner of an artificial hip joint (AHJ) is easily damaged locally in case of impingement, i.e. in case of contact of the liner wall with the stem neck, especially when it is made from relatively soft material such as ultra high molecular weight polyethylene (UHMWPE). Frequent impingement will severely damage the acetabular liner, requiring replacement of the AHJ. The aim of this study is to reduce AHJ impingement for specific combinations of flexion, internal rotation, and adduction of the thigh, by optimizing the design of the AHJ. The presented new design is based on modifying a conventional AHJ into a bipolar version with a higher free range of motion (RoM). Results show that the proposed design is able to prevent impingement for RoM. The latter range of motion corresponds well with the requirements of Shalat.

Abstract: The hip joint is one of the body's important joints, most of the lower limb activities of the human body are inseparable from the hip joint, a novel bionic robot hip joint was proposed based on 3-DOF spherical parallel mechanism. The statics performance of the bionic robot hip joint was analyzed, and the structure parameters were designed. First, the static transmission equation of the bionic robot hip joint was established using the principle of virtual works, which simplifies the calculation process of the bionic robot hip joint. Further, using the norm in Matrix theory, the force Jacobian matrix was introduced into the statics performance evaluation index, and the statics performance evaluation index and the global torque performance evaluation index was defined, and the performance atlas of the statics performance evaluation index was plotted at the workspace of the bionic robot hip joint. Moreover the objective optimal function was established basing on the global torque performance evaluation index, and the relation of the objective optimal function and the global torque performance evaluation index were analyzed. By use of fully automatic searching method, the optimal structural parameter ranges of the bionic robot hip joint were obtained. Analysis results show that the bionic robot hip joint has good static transmission performance at initial position, and the static transmission performance is decreased with increasing the workspace. Finally, using a set of optimal structural sizes parameters, a novel bionic robot hip joint was designed, which established the theoretical foundation for the bionic robot design and apply.

Abstract: The aim of the article is to analyze the experimental behavior of a rehabilitation equipment during a recovery program. It is known the high incidence of the human knee/ankle/hip dysfunctions. So, it had been conceived a pneumatic muscle actuated rehabilitation equipment, for rehabilitation of those types affections. It is presented the components and the experimental researches made considering that on the equipment is a 20 kilos load (considered as a human foot weight). The results of experiments shows the behaviour of the equipment: slider position, speed and acceleration in time – under different commands.

Abstract: The purpose of this research is to form a layer of alumina on Ti-6Al-4V alloy for hip joint by deposition of Al layer on the Ti alloy and its subsequent oxidation. In this work, a thick layer of Al was deposited onto the Ti alloy by cold spraying. The reaction layer of Al₃Ti was formed by heat treatment of cold sprayed Al at 640°C in air/Ar atmosphere to ensure a good adhesion between cold sprayed Al layer and the Ti alloy. A thick Al₃Ti layer formed by heat treatment of Al layer at 640°C for 12 h in air, was subjected to heat treatment at 850°C for 96 h in air to form a-alumina and Al₂Ti. Thus, alumina scales can be formed on the top surface of the Ti alloy and can be densified by increasing the time duration of heat treatment.

Abstract: In this changing global scenario, modification, transplantation, and replacement can be the eternal solution for most of the problems in the medical field. Hence replacement technique finds a very prominent place in medicine as a remedy having closely tied up with biomechanics. One of the most important joints in the human body is the hip joint, the big and complex joint. Many researches were conducted and many are in progress, but most of these works use simplified models with either 2D or 3D approaches. The hip joint is formed by four components like femoral head cortical bone, stem, and neck. In this system we can find orthotropic and isotropic materials working together. The main objective of this research is to develop a three dimensional surface and solid finite element model of the hip joint to predict stresses in its individual components. This model is a geometric non-linear model, which helps us understand its structural mechanical behavior, seeming to suggest with advanced research in the future new hip joint prosthesis, as well as to prove the prosthesis joint interaction before being implanted in the patient. This research explains a complete human hip joint model without cartilaginous tissue, using ANSYS 10.0 Multiphysics Analysis for nine different postures in hip joint using three different materials (CoCr, Ti6Al4V, and UHMWPE) to calculate fatigue life. The result obtained from the analysis of surface model and solid model serve to help in predicting the life cycle, surface characteristics, shear stress in XY plane, stress concentration and areas that are prone to failure. Von Mises stress on the surface of our model facilitates us to equip and design an optimized prosthesis device having unique materials composition , with a highly bio-compatible and durable alloy at a low cost could be produced. In this way, a first important step towards the structural characterization of human hip joint has been developed.

Abstract: Kinematics research of mechanism is very important, the dynamic analysis and the design are based on linematics analysis. In this paper, a novel robot hip joint based on 3-RRR orthogonal spherical parallel mechanism is proposed, and Jacobin matrix is established. Then the linematics transmission performance evaluation index is defined. Furthermore the linematics transmission performance index is analyzed. The hip joint has good linematics transmission performance at the initial position. With the increase of workspace, linematics transmission performance gradually decreased. 3-RRR parallel mechanism is the ideal prototype of bionic robot and rehabilitation robot hip joint.

Abstract: Using finite element (FE) method, this work established and comparatively analyzed the basic femoral head model, and six innovative femoral head models with different micropore surface distribution, aiming to explore the most rational surface morphology to have better effect on artificial hip implant. The inboard and outboard femur, the metal handle, and the femoral head’ stress responses were concerned. As the results showed, compared with type A (original femur head, with “smoothed” surface), the other six shaped femur head design all have reduced the maximal stress with different degrees. However, femur model surface type C arranged with 1mm-diametre distributed in three rows of micropore caused the best effect. Within the scope of the study, both micropore size and arranging way influenced the stress distribution at key components of artificial hip joint, especially the effect of micropore size exceeded arranging way of them. Based on the simulation results, it is proposed the whole rigidity of the artificial femoral head with microporous morphology, was reduced to some degree and therefore reducing the stress shielding effect, decreasing the possibility of embedded part being deformed or flexible, which is beneficial to improving life span of the prosthesis.

Abstract: The paper present the analysis of metal prosthesis head stress state of hip joint endoprosthesis which is a result of variable loads during human motor activity and its influence on the erosion of materials. The analysis of stress state was made with use of FEM – ADINA numerical tool. The analysis of surface erosion process was made with use of the scanning electron microscope. To the researches was taken for heads from CoCrMo bearing shell and polyethylene UHMWPE.

Abstract: To solve the problem of the time-delay, nonlinear and time-variable characteristics of hip-joint rehabilitation training device driven by pneumatic muscle actuator, an implicit generalized predictive controller was designed based on parameter model in this paper. It was applied to the isokinetic continuous passive motion control of the hip-joint rehabilitation training device. Experimental results proved that the controller has the property of high control accuracy, anti-disturbance capability and excellent adaptive abilities for the changes of system model parameters, compared with PID controller. This control method provides the beneficial reference for improving the control performance of such system.