The chapter presents recent advances in developing numerical models for multiscale simulation of the femur–endoprosthesis system for the case of hip resurfacing arthroplasty. The models are based on the movable cellular automaton method, which is a representative of the discrete element approach in solid mechanics and allows correctly simulating mechanical behavior of a variety of elastoplastic materials including fracture and mass mixing. At the lowest scale, the model describes sliding friction between two rough surfaces of TiN coatings, which correspond to different parts of the friction pair of hip resurfacing endoprosthesis. At this scale, such parameters of the contacting surfaces as the thickness, roughness, and mechanical properties are considered explicitly. The next scale of the model corresponds to a resurfacing cap for the femur head rotating in the artificial acetabulum insert. Here, sliding friction is explicitly computed based on the effective coefficient of friction obtained at the previous scale. At the macroscale, the proximal part of the femur with a resurfacing cap is simulated at different loads. The bone is considered as a composite consisting of outer cortical and inner cancellous tissues, which are simulated within two approaches: the first implies their linear elastic behavior, the second considers these tissues as Boit’s poroelastic bodies. The later allows revealing the role of the interstitial biological fluid in the mechanical behavior of the bone. Based on the analysis of the obtained results, the plan for future works is proposed.
The chapter presents recent advances in developing numerical models for multiscale simulation of the femur–endoprosthesis system for the case of hip resurfacing arthroplasty. The models are based on the movable cellular automaton method, which is a representative of the discrete element approach in solid mechanics and allows correctly simulating mechanical behavior of a variety of elastoplastic materials including fracture and mass mixing. At the lowest scale, the model describes sliding friction between two rough surfaces of TiN coatings, which correspond to different parts of the friction pair of hip resurfacing endoprosthesis. At this scale, such parameters of the contacting surfaces as the thickness, roughness, and mechanical properties are considered explicitly. The next scale of the model corresponds to a resurfacing cap for the femur head rotating in the artificial acetabulum insert. Here, sliding friction is explicitly computed based on the effective coefficient of friction obtained at the previous scale. At the macroscale, the proximal part of the femur with a resurfacing cap is simulated at different loads. The bone is considered as a composite consisting of outer cortical and inner cancellous tissues, which are simulated within two approaches: the first implies their linear elastic behavior, the second considers these tissues as Boit’s poroelastic bodies. The later allows revealing the role of the interstitial biological fluid in the mechanical behavior of the bone. Based on the analysis of the obtained results, the plan for future works is proposed.
“…Thus, the performance of multilayer film is mainly affected by phase structure of different layers. [33][34][35] Subsequently, further studies about DR-5 sample are carried out, as shown in Fig. 7.…”
Section: Resultsmentioning
confidence: 99%
“…Thus, the performance of multilayer film is mainly affected by phase structure of different layers. 33-35 6 Multilayer structure of DR-5 sample…”
By using direct current (DC) and radio frequency (RF) co-sputtering deposition, multilayer Si 3 N 4 films composed of alternately DC layer and RF layer were prepared. Phase composition, microstructure, and hardness/toughness of different Si 3 N 4 films were studied. X-ray diffraction results showed that DC layer was amorphous Si 3 N 4 film, while RF layer was nanocrystalline Si 3 N 4 film. The hardness of amorphous Si 3 N 4 film was higher than that of nanocrystalline Si 3 N 4 film and the plasticity of nanocrystalline Si 3 N 4 film was higher than that of amorphous Si 3 N 4 film. Furthermore, the hardness/toughness of multilayer Si 3 N 4 films was obviously higher than that of the single Si 3 N 4 film and the plasticity was higher than that of single nanocrystalline Si 3 N 4 film, which can be attributed to the fact that a large number of interface hindered the increasing of particles, thus, the fine particles and the interface strengthened the multilayer films, while the propagation of micro-crack was prevented by amorphous/nanocrystalline layer of multilayer Si 3 N 4 film.
“…The EDX analysis reveals the presence of a Ti interlayer + compound coating layer. The Ti interlayer applied to the base material increases the bond strength and provides a simple approach to control residual stresses due to the stress-buffering effect [40,41]. base material increases the bond strength and provides a simple approach to control residual stresses due to the stress-buffering effect [40,41].…”
Section: Coating Characterizationmentioning
confidence: 99%
“…The Ti interlayer applied to the base material increases the bond strength and provides a simple approach to control residual stresses due to the stress-buffering effect [40,41]. base material increases the bond strength and provides a simple approach to control residual stresses due to the stress-buffering effect [40,41]. The hardness measurement of the samples prepared from Ti6Al4V alloy was determined at two stages, before and after coating.…”
Titanium-based alloys have gained worldwide application over the past century. However, their low wear resistance remains an unresolved challenge for the Ti6Al4V alloy, which has significant industrial use. Therefore, it is an integral part in material selection and surface treatment in friction-wear applications. Tribological properties are not only material parameters but also system parameters where test conditions are essential. Hardness, roughness and contact conditions of coatings, which are especially important in surface treatments, affect wear modes. In this study, titanium nitride, titanium aluminum nitride and titanium carbon nitride coatings were obtained by unbalanced reactive magnetron sputtering to improve the weak tribological properties of Ti6Al4V alloy. The wear behavior was studied at room temperature in dry conditions. Wear tests were conducted under different loads and different sliding rates, which were followed by comparative analyses of their wear resistances. While the coated samples showed higher wear resistance than the uncoated Ti6Al4V alloy, the lowest wear track width was observed in TiN coating. Depending on the surface properties of the coatings, adhesion, abrasion and oxidation wear mechanisms were observed. It was concluded that a TiN coating could be a material of choice for applications where triple abrasive wear is dominant.
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