Comparison of Meshing Strategies in THR Finite Element Modelling

Abstract

In biomechanics and orthopedics, finite element modelling allows simulating complex problems, and in the last few years, it has been widely used in many applications, also in the field of biomechanics and biotribology. As is known, one crucial point of FEM (finite element model) is the discretization of the physical domain, and this procedure is called meshing. A well-designed mesh is necessary in order to achieve accurate results with an acceptable computational effort. The aim of this work is to test a finite element model to simulate the dry frictionless contact conditions of a hip joint prosthesis (a femoral head against an acetabular cup) in a soft bearing configuration by comparing the performances of 12 common meshing strategies. In the simulations, total deformation of the internal surface of the cup, contact pressure, and the equivalent von Mises stress are evaluated by using loads and kinematic conditions during a typical gait, obtained from a previous work using a musculoskeletal multibody model. Moreover, accounting for appropriate mesh quality metrics, the results are discussed, underlining the best choice we identified after the large amount of numerical simulations performed.

Editorial: Biotribology and Biotribocorrosion Properties of Implantable Biomaterials

“…Considering the above, to date, in-silico wear prediction models of artificial human implants attract the attentions of researchers to obtain complete tribological theoretical and numerical models useful for the in-silico testing (O'Brien et al, 2015;Mattei et al, 2016;Affatato et al, 2018), which could avoid the standard in-vitro time-consuming investigation procedures (simulators) and could contribute as tool for a more and more accurate tribological design of human prostheses. Obviously, the accurate wear prediction of artificial joints requires to develop detailed tribological models accounting for the complexity and the multiscale of wear phenomenon (Vakis et al, 2018) which requires scientific knowledge in many fields, such as contact mechanics (Popov, 2010), topographic contact surfaces characterization (Merola et al, 2016), new materials formulations (Affatato et al, 2015), stress-strain analysis and FEM/BEM simulations (Ruggiero et al, 2018;Ruggiero and D'Amato R, 2019), musculoskeletal multibody modeling (Zhang et al, 2017), unsteady synovial lubrication modeling (boundary/mixed, hydro-dynamic and EHD) (Ruggiero and Sicilia, 2020), tribo-corrosion (Tan et al, 2016), metal transfer phenomena (Affatato et al, 2017), biomaterials characterizations (Ruggiero et al, 2016), etc. Moreover, innovative biomaterials and manufacturing procedures (e.g., 3D printing), novel surface modification (coatings) constitute new and exciting research areas (Ten Kate et al, 2017).…”

A Perspective on Biotribology in Arthroplasty: From In Vitro toward the Accurate In Silico Wear Prediction

“…The experimental tribological devices for the simulation of hip and knee prostheses have been improved over the years in order to make them able to reproduce tribological wear tests in kinematic and dynamic conditions very close to the real ones [30][31][32][33]. The new trend of an in silico approach to the evaluation of the articular prostheses' wear represents, nowadays, a fascinating scientific challenge, which involves many disciplinary fields and which requires a deep collaboration between scientists from different areas [41][42][43][44].…”

“…O'Brien et al proposed an interesting theory based on energy dissipation: the process of wear is inherently dynamically adaptive, and localized high wear can result in faster deformation in The in silico procedure starts by evaluating the human motion kinematics in the framework of inverse dynamic analysis (motion capture) with reference both to normal gait and other desired daily activities [32,45]. The obtained data are used for the calculation of the unsteady joint forces which are used as load conditions in joint Finite Element Analysis (FEM) [42][43][44]. The resulting stress-strain behavior of the artificial coupling have to be joined with the lubrication model for taking into account the complex synovial phenomena acting in the joint [41,46].…”

Anticipating local flaps closed‐form solution on 3D face models using finite element method

“…The attributes associated with mesh quality were Jacobian ratio and mesh skewness. A general rule is that the Jacobian matrix should be between 1 and 10 and in the same sign 33 . The skewness should be kept close to 0 as possible 33,34 .…”

“…A general rule is that the Jacobian matrix should be between 1 and 10 and in the same sign 33 . The skewness should be kept close to 0 as possible 33,34 . Off‐range values may lead to convergence difficulties and inaccurate results.…”