Numerical simulation of the femur fracture for different cemented hip femoral prosthesis under forces during stumbling

Total hip prosthesis was used for the patients who has the hip fracture and unable to recover naturally. To design highly durable prostheses one has to take into account the natural processes occurring in the bone. In this paper, the static load analysis is based, by selecting the peak load during the stumbling activity. Two different implant materials have been selected to study appropriate material. The results showed the difference of maximum von Misses stress and detected the fracture of the femur shaft for different model (Charnley and Osteal) implant with the extended finite element method (X-FEM), and after the results of the numerical simulation of X-FEM for different was used in determining the stress intensity factors (SIF) to identify the crack behavior implant materials for different crack length. It has been shown that the maximum stress intensity factors were observed in the model of Charnley

Numerical simulation of the femur fracture with and without prosthesis under static loading using extended finite element method (X-FEM) / Zagane Mohammed El Sallah … [et al.]

The strength of the bone depends on its mineralization state and its geometry, which depend on the loads supported. Thus the bone optimizes its mass and its geometry through the process of remodeling and improves its lift. This phenomenon can be altered by metabolic imbalances such as fall or trauma. The result is fractures, the most important of which are the proximal femur. The direct consequence of this type of fracture is the replacement of the joint by a Total Hip Prosthesis (PTH). The number of prosthetic implantations continues to increase given the longer life expectancy of patients.. This study is to compare the modeling to identify regions of fracture risk of femur and after the location of the total hip prosthesis (THP) by the extended finite element method (X-FEM) under static stress for a deferent orientation loading and for two materials (isotropic / orthotropic). The results show that the distribution of von mises stresses in the components of the femoral arthroplasty depends on the material and the design of the stem and show that the vertical loading leads to fracture of the femoral neck and the horizontal loading leads to the fracture of diaphysis femoral. The isotropic consideration of bone leads to bone fracture by propagation of the fissure, but the orthotropic consideration leads to the fragmentation of the bone. This modeling will help to improve the design of the indoor environment to be safer for the means of passenger transport

Mechanical Behavior of Bone Cement under Dynamic Loading

In orthopedic surgery and particularly in total hip arthroplasty, The fixation of the implant is generally made by the surgical cement, constituted essentially by polymer (PMMA), It is necessary to know the strengths applied to the prosthetic articulation during the current activities exercised by the patient in their life, to know the distribution of the constraints in the system (bone - cement - implant).This study aims to analyze numerically using the finite element method, the effect of activities (dynamic loads) of the patient on the level and distribution of stresses generated in the components of total hip prosthesis. Five activities, the most frequently performed by the patient such as normal walking, the up and down stairs, sitting and up from chair, were selected for this study. For this purpose, a three-dimensional model of the total hip prosthesis has been developed. The results obtained from this model show that the total hip replacement components and especially the bone cement are more highly stressed during the process of climbing stairs. These excessively high loads can lead to damage of the cement and thus the loosening of the prosthesis

The use of ultrasonic pulse velocity to estimate the water permeability of concretes

In this work we investigated the possibility of estimating the water permeability of concrete from the ultrasonic surface wave velocity (Rayleigh's waves). This is a method for the non-destructive permeability diagnosis of the in situ auscultation of a structure. Four ordinary concrete compositions with different W/C ratios and two self compacting concretes SCC were used. This study showed a decrease in of ultrasonic pulse velocity with the increase in the W/C ratio, this is due to the increase in porosity. Curing in air of the concrete specimens produces greater permeability than curing in water. The increase in the permeability with the increase of W/C ratio is more important for curing in water than for the curing in air. SCC1 has a lower permeability than that of SCC2, this difference is respectively 20% and 10 % for curing in air and in water. The study show that permeability estimation with ultrasonic surface waves is more reliable for curing in water mode than tin curing in air. The correlations obtained between the permeability and the indirect ultrasonic velocity are linear, with an inversely proportional relation

Finite element analysis of the behaviour of a crack in the orthopedic cement

In this paper, the finite element method is used to analyse the crack behaviour in the orthopedic cement of the total hip replacement by computing the stress intensity factors (SIFs) arround the crack tip. In this work, three cases are studied: crack emanating from a cavity, interaction effect of the crack emanating from a cavity with another cavity and the interaction effect of two cracks emanatingfrom two cavities. The stress intensity factors under mixed mode problems at the crack tip are computed for three zones of prosthesis: proximal, median and distal. The obtained results show that the crack initiated from a micro-cavity in the distal zone of cement can be propagated at the same time by opening and shearing of its lips. It is contrary to that initiated in the proximal zone which cannot be propagated. The mechanical behaviour of cracks in the medial zone depends of the crack initiation position

Mechanical Behavior of Bone Cement under Dynamic Loading

In orthopedic surgery and particularly in total hip arthroplasty, The fixation of the implant is generally made by the surgical cement, constituted essentially by polymer (PMMA), It is necessary to know the strengths applied to the prosthetic articulation during the current activities exercised by the patient in their life, to know the distribution of the constraints in the system (bone - cement - implant).This study aims to analyze numerically using the finite element method, the effect of activities (dynamic loads) of the patient on the level and distribution of stresses generated in the components of total hip prosthesis. Five activities, the most frequently performed by the patient such as normal walking, the up and down stairs, sitting and up from chair, were selected for this study. For this purpose, a three-dimensional model of the total hip prosthesis has been developed. The results obtained from this model show that the total hip replacement components and especially the bone cement are more highly stressed during the process of climbing stairs. These excessively high loads can lead to damage of the cement and thus the loosening of the prosthesis

Artificial Intelligence Approach for Bio-Based Materials’ Characterization and Explanation

This paper introduces a numerical methodology for classifying and identifying types of bio-based materials through experimental thermal characterization. In contrast to prevailing approaches that primarily focus on thermal conductivity, our characterization methodology encompasses several thermal parameters. In this paper, the physical characteristics of seven types of bio-based concrete were analyzed, focusing on the thermal properties of palm- and esparto-fiber-reinforced concrete. The proposed method uses artificial intelligence techniques, specifically the k-means clustering approach, to segregate data into homogeneous groups with shared thermal characteristics. This enables the elucidation of insights and recommendations regarding the utilization of bio-based insulation in building applications. The results show that the k-means algorithm is able to efficiently classify the reference concrete (RC) with a performance of up to 71%. Additionally, the technique is more accurate when retaining only six centroids, which, among other things, allows all the characteristics associated with each type of concrete to be grouped and identified. Indeed, whether for k clusters k = 7 or k = 5, the technique was not able to predict the typical characteristics of 2% or 3% esparto concrete (EC)