A New Approach for the Tribological and Mechanical Characterization of a Hip Prosthesis Trough a Numerical Model Based on Artificial Intelligence Algorithms and Humanoid Multibody Model

Abstract

In recent years, thanks to the development of additive manufacturing techniques, pros-thetic surgery has reached increasingly cutting-edge levels, revolutionizing the clinical course of patients suffering from joint arthritis, rheumatoid arthritis, post-traumatic arthrosis, etc. This work aims to evaluate the best materials for prosthetic surgery in hip implants from a tribological and mechanical point of view by using a machine-learning algorithm coupling with multi-body modeling and Finite Element Method (FEM) simulations. The innovative aspect is represented by the use of machine learning for the creation of a humanoid model in a multibody software environment that aimed to evaluate the load and rotation condition at the hip joint. After the boundary conditions have been defined, a Finite Element (FE) model of the hip implant has been created. The material properties and the information on the tribological behavior of the material couplings under investigation have been obtained from literature studies. The wear process has been investigated through the implementation of the Archard’s wear law in the FE model. The results of the FE simulation show that the best wear behavior has been obtained by CoCr alloy/UHMWPE coupling with a volume loss due to a wear of 0.004 μm3 at the end of the simulation of ten sitting cycles. After the best pairs in terms of wear has been established, a topology optimization of the whole hip implant structure has been performed. The results show that, after the optimization process, it was possible to reduce implant mass making the implant 28.12% more lightweight with respect to the original one.

Smart design of customized hip prostheses in additive manufacturing by combining numerical and experimental methodologies

“…The Figure 2 shows the process of identifying and calculating vectors. [48] Figure 2. Angle measurements from video frame [46,47] .…”

“…• Lower limbs. The manikin was defined as in [48] The dimensions that characterize it are 32 as in [24]. The data reported in Table 1 were considered for evaluating the subject under examination.…”

“…The constraints are represented in blue, while the loads are secured according to their lines of action using a different colour for each axis (Figure 8). For the choice of material, AISI 316 L was selected, a material studied in the literature to produce custom hip prostheses [48]. Specimens were made, and the material was tested to obtain its properties.…”

“…Thanks to the development of additive manufacturing techniques, prosthetic surgery has reached increasingly advanced levels, revolutionizing the clinical course of patients with joint arthritis, rheumatoid arthritis, post-traumatic arthrosis, and congenital dysplasia. 3D printing has made it possible to obtain customized prostheses based [1] on the patient needs, using high-performance materials such as 316L stainless [2]steel or Ti-6Al-4V. However, wear caused by regular gait activities such as walking, sitting, or running, leads to the deterioration of the material used in the joint [3][4][5].…”

Adopted walking condition for computational simulation approach on bearing of hip joint prosthesis: review over the past 30 years

“…Bearing couples can experience friction, wear, and surface damage affecting overall performance and lead to failure at certain time [ 12 ]. For avoid failure of medical implants that could be harmful for patient, various studies in bearing couple have attempted to ensure that implant bearings can last a long time to minimize implant failure or no revision surgery is required in the future [ 13 , 14 , 15 ].…”