Quantitative ultrasound is a modality that is used to evaluate bone quality. It is considered tha... more Quantitative ultrasound is a modality that is used to evaluate bone quality. It is considered that the analysis of ultrasound guided wave propagating along cortical bone may be useful for the assessment of cortical bone quality. Because the frequency-dependent wavenumbers reflect the elastic parameters of the medium, high-resolution estimation of the wavenumbers at each frequency is important. We report an adaptive array signal processing method with a technique to estimate the numbers of propagation modes at each frequency using information theoretic criteria and the diagonal loading technique. The proposed method estimates the optimal diagonal loading value required for guided wave estimation. We investigate the effectiveness of the proposed method via simple numerical simulations and experiments using a copper plate and a bone-mimicking plate, where the center frequency of the transmit wave was 1.0 MHz. An experimental study of 4 mm thick copper and bone-mimicking plates showed t...
In the 1950s, the effect of ultrasound stimulation on bone healing has been discovered. Nowadays,... more In the 1950s, the effect of ultrasound stimulation on bone healing has been discovered. Nowadays, Low Intensity Pulsed Ultrasound Stimulation (LIPUS) is admitted to influence the mechanotransduction of bone. Nevertheless, despite a growing literature—cell cultures, animal models, and clinical studies—the underlying physical and biological mechanisms of LIPUS on bone healing are still misunderstood. Inspired from previous studies on the mechanotransduction induced by physiological loading, this work focuses on the effect of LIPUS on the osteocytes. These bone cells are thought to be the principal mechanosensors of bone. They are ubiquitous inside the bone matrix, immersed in the lacuno-canalicular network (LCN) filled with interstitial fluid (IF). The goal is to relate the ultrasound stimulation applied at the tissue scale, to the biological response at the cell scale. To tackle this question, two finite element models were implemented in the commercial software Comsol Multiphysics. ...
Cementless implants have become widely used for total hip replacement surgery. The long-term stab... more Cementless implants have become widely used for total hip replacement surgery. The long-term stability of these implants is achieved by bone growing around and into the rough surface of the implant, a process called osseointegration. However, debonding of the bone–implant interface can still occur due to aseptic implant loosening and insufficient osseointegration, which may have dramatic consequences. The aim of this work is to describe a new 3D finite element frictional contact formulation for the debonding of partially osseointegrated implants. The contact model is based on a modified Coulomb friction law by Immel et al. (2020), that takes into account the tangential debonding of the bone-implant interface. This model is extended in the direction normal to the bone-implant interface by considering a cohesive zone model, to account for adhesion phenomena in the normal direction and for adhesive friction of partially bonded interfaces. The model is applied to simulate the debonding ...
Computer Methods in Biomechanics and Biomedical Engineering, 2017
HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific r... more HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L’archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d’enseignement et de recherche français ou étrangers, des laboratoires publics ou privés. Biomechanics of the acetabular cup implant Influence of anisotropic bone properties on the biomechanical behavior of the acetabular cup implant: a multiscale finite element study Vu-Hieu Nguyen, Giuseppe Rosi, Salah Naili, Adrien Michel, Maria-Letizia Raffa, Romain Bosc, Jean-Paul Meningaud, Christine Chappard, Naoki Takano, Guillaume Haiat
Abstract In this paper, we present a new approach to study Lamb-type waves of anisotropic elastic... more Abstract In this paper, we present a new approach to study Lamb-type waves of anisotropic elastic plates in a probabilistic framework. The study and analysis are carried out on an elastic plate whose randomly varied elastic properties in the through-thickness direction. By introducing a stochastic model for quantitative description of heterogeneous elastic properties in the plate, the effect of material heterogeneity on Lamb modes may be investigated from a stochastic point of view. To the our best knowledge, this study is the first to investigate Lamb-type waves in a probabilistic framework. Different plate thicknesses are considered and associated dispersion curves are computed. A sensitivity study is performed, highlighting effect of the uncertainty of elasticity properties on the fluctuation of Lamb modes via phase velocities, energy velocities and modes shapes. Next, we discuss the relevance of introducing random media to identify branches associated with experimental dispersion curves.
The Journal of the Acoustical Society of America, 2018
Quantitative ultrasound are used to characterize and stimulate osseointegration processes at the ... more Quantitative ultrasound are used to characterize and stimulate osseointegration processes at the bone-implant interface (BII). However, the interaction between an ultrasonic wave and the implant remains poorly understood. This study aims at investigating the sensitivity of the ultrasonic response to the microscopic and macroscopic properties of the BII and to osseointegration processes. The reflection coefficient R of the BII was modeled for different frequencies using a two-dimensional finite element model. The implant surface was modeled by a sinusoidal function with varying amplitude and spatial frequency and then by considering actual implant surface profiles. A soft tissue layer of thickness W was introduced between bone tissue and the implant in order to model non-mineralized fibrous tissue. For microscopic roughness, R is shown to increase from around 0.55 until 0.9 when k.W increases from 0 to 1 and to be constant for k.W>1. These results show that R depends on the proper...
Bio‐sourced epoxy resins from resorcinol diglycidyl ether (RDGE) have been obtained by using cati... more Bio‐sourced epoxy resins from resorcinol diglycidyl ether (RDGE) have been obtained by using cationic photopolymerization under UV‐light exposure. The photoinduced bulk resin samples were characterized by three‐point bending tests, dynamic mechanical analysis, as well as differential scanning calorimetry analysis, and thermogravimetric analysis. The influence of processing parameters, that is, reactant contents, UV irradiation time, and postcuring conditions on the thermomechanical behavior has been pointed out. For instance, the flexural modulus of the most performing materials reaches 4.1 GPa with the flexural strength and the glass‐transition temperature of around 105 MPa and 99°C, respectively. Interestingly, our optimized protocol has led to the synthesis of new bio‐based materials with more valuable thermal and mechanical properties than those of thermocured materials obtained from petroleum‐based commercial epoxy resins. Focus has been given on processing parameters to optimi...
The Journal of the Acoustical Society of America, 2019
The stress distribution around endosseous implants is an important determinant of the surgical su... more The stress distribution around endosseous implants is an important determinant of the surgical success but it remains difficult to be measured. So far, no method developed to determine the implant stability is sensitive to the loading conditions of the bone-implant interface (BII). The objective of this study is to investigate whether a quantitative ultrasound (QUS) technique may be used to retrieve information on compressive stresses applied to the BII. A dedicated acousto-mechanical device was conceived to compress 18 trabecular bovine bone samples onto coin-shaped implants and to measure the ultrasonic response of the BII during compression. The biomechanical behavior of the trabecular bone samples was modeled as Neo-Hookean. The reflection coefficient of the BII was shown to decrease as a function of the compressive stress during the elastic compression of the trabecular bone samples and during the collapse of the trabecular network, with an average slope of -4.82 GPa-1. Results...
Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine, 2019
Biomechanical phenomena occurring at the bone–implant interface during the press-fit insertion of... more Biomechanical phenomena occurring at the bone–implant interface during the press-fit insertion of acetabular cup implants are still poorly understood. This article presents a nonlinear geometrical two-dimensional axisymmetric finite element model aiming at describing the biomechanical behavior of the acetabular cup implant as a function of the bone Young’s modulus Eb, the diametric interference fit ( IF), and the friction coefficient µ. The numerical model was compared with experimental results obtained from an in vitro test, which allows to determine a reference configuration with the parameter set: μ* = 0.3, [Formula: see text], and IF* = 1 mm for which the maximal contact pressure tN = 10.7 MPa was found to be localized at the peri-equatorial rim of the acetabular cavity. Parametric studies were carried out, showing that an optimal value of the pull-out force can be defined as a function of μ, Eb, and IF. For the reference configuration, the optimal pull-out force is obtained f...
Despite the unique mechanical strength and adhesion properties of epoxy resins, they still suffer... more Despite the unique mechanical strength and adhesion properties of epoxy resins, they still suffer from poor toughness and brittleness inducing poor resistance to cracks. Herein, we report an efficient method of synthesis of bioepoxy resin nanocomposites filled with highly exfoliated epoxy-grafted montmorillonite. The filled resin network was produced by covalent incorporation of a binary nanocomposite (MMT-PGMA) synthesized via in situ photoinduced polymerization of glycidyl methacrylate, into a Bioepoxy resin matrix to design a ternary nanocomposite (MMT-PGMA/Bioepoxy) and this in the presence of a green polyamine used as curing agent. The materials structure and morphology were characterized by FTIR, TGA, XRD, SEM, and TEM which show the key role of the MMT surface modification on its interfacial adhesion with the epoxy resin. The results showed that the clay interlayer d-spacing increases from 1.23 nm to more than 2.2 nm upon grafting of the polymer. The homogeneous solvent-free dispersion of hybrid cl...
Quantitative ultrasound is a modality that is used to evaluate bone quality. It is considered tha... more Quantitative ultrasound is a modality that is used to evaluate bone quality. It is considered that the analysis of ultrasound guided wave propagating along cortical bone may be useful for the assessment of cortical bone quality. Because the frequency-dependent wavenumbers reflect the elastic parameters of the medium, high-resolution estimation of the wavenumbers at each frequency is important. We report an adaptive array signal processing method with a technique to estimate the numbers of propagation modes at each frequency using information theoretic criteria and the diagonal loading technique. The proposed method estimates the optimal diagonal loading value required for guided wave estimation. We investigate the effectiveness of the proposed method via simple numerical simulations and experiments using a copper plate and a bone-mimicking plate, where the center frequency of the transmit wave was 1.0 MHz. An experimental study of 4 mm thick copper and bone-mimicking plates showed t...
In the 1950s, the effect of ultrasound stimulation on bone healing has been discovered. Nowadays,... more In the 1950s, the effect of ultrasound stimulation on bone healing has been discovered. Nowadays, Low Intensity Pulsed Ultrasound Stimulation (LIPUS) is admitted to influence the mechanotransduction of bone. Nevertheless, despite a growing literature—cell cultures, animal models, and clinical studies—the underlying physical and biological mechanisms of LIPUS on bone healing are still misunderstood. Inspired from previous studies on the mechanotransduction induced by physiological loading, this work focuses on the effect of LIPUS on the osteocytes. These bone cells are thought to be the principal mechanosensors of bone. They are ubiquitous inside the bone matrix, immersed in the lacuno-canalicular network (LCN) filled with interstitial fluid (IF). The goal is to relate the ultrasound stimulation applied at the tissue scale, to the biological response at the cell scale. To tackle this question, two finite element models were implemented in the commercial software Comsol Multiphysics. ...
Cementless implants have become widely used for total hip replacement surgery. The long-term stab... more Cementless implants have become widely used for total hip replacement surgery. The long-term stability of these implants is achieved by bone growing around and into the rough surface of the implant, a process called osseointegration. However, debonding of the bone–implant interface can still occur due to aseptic implant loosening and insufficient osseointegration, which may have dramatic consequences. The aim of this work is to describe a new 3D finite element frictional contact formulation for the debonding of partially osseointegrated implants. The contact model is based on a modified Coulomb friction law by Immel et al. (2020), that takes into account the tangential debonding of the bone-implant interface. This model is extended in the direction normal to the bone-implant interface by considering a cohesive zone model, to account for adhesion phenomena in the normal direction and for adhesive friction of partially bonded interfaces. The model is applied to simulate the debonding ...
Computer Methods in Biomechanics and Biomedical Engineering, 2017
HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific r... more HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L’archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d’enseignement et de recherche français ou étrangers, des laboratoires publics ou privés. Biomechanics of the acetabular cup implant Influence of anisotropic bone properties on the biomechanical behavior of the acetabular cup implant: a multiscale finite element study Vu-Hieu Nguyen, Giuseppe Rosi, Salah Naili, Adrien Michel, Maria-Letizia Raffa, Romain Bosc, Jean-Paul Meningaud, Christine Chappard, Naoki Takano, Guillaume Haiat
Abstract In this paper, we present a new approach to study Lamb-type waves of anisotropic elastic... more Abstract In this paper, we present a new approach to study Lamb-type waves of anisotropic elastic plates in a probabilistic framework. The study and analysis are carried out on an elastic plate whose randomly varied elastic properties in the through-thickness direction. By introducing a stochastic model for quantitative description of heterogeneous elastic properties in the plate, the effect of material heterogeneity on Lamb modes may be investigated from a stochastic point of view. To the our best knowledge, this study is the first to investigate Lamb-type waves in a probabilistic framework. Different plate thicknesses are considered and associated dispersion curves are computed. A sensitivity study is performed, highlighting effect of the uncertainty of elasticity properties on the fluctuation of Lamb modes via phase velocities, energy velocities and modes shapes. Next, we discuss the relevance of introducing random media to identify branches associated with experimental dispersion curves.
The Journal of the Acoustical Society of America, 2018
Quantitative ultrasound are used to characterize and stimulate osseointegration processes at the ... more Quantitative ultrasound are used to characterize and stimulate osseointegration processes at the bone-implant interface (BII). However, the interaction between an ultrasonic wave and the implant remains poorly understood. This study aims at investigating the sensitivity of the ultrasonic response to the microscopic and macroscopic properties of the BII and to osseointegration processes. The reflection coefficient R of the BII was modeled for different frequencies using a two-dimensional finite element model. The implant surface was modeled by a sinusoidal function with varying amplitude and spatial frequency and then by considering actual implant surface profiles. A soft tissue layer of thickness W was introduced between bone tissue and the implant in order to model non-mineralized fibrous tissue. For microscopic roughness, R is shown to increase from around 0.55 until 0.9 when k.W increases from 0 to 1 and to be constant for k.W>1. These results show that R depends on the proper...
Bio‐sourced epoxy resins from resorcinol diglycidyl ether (RDGE) have been obtained by using cati... more Bio‐sourced epoxy resins from resorcinol diglycidyl ether (RDGE) have been obtained by using cationic photopolymerization under UV‐light exposure. The photoinduced bulk resin samples were characterized by three‐point bending tests, dynamic mechanical analysis, as well as differential scanning calorimetry analysis, and thermogravimetric analysis. The influence of processing parameters, that is, reactant contents, UV irradiation time, and postcuring conditions on the thermomechanical behavior has been pointed out. For instance, the flexural modulus of the most performing materials reaches 4.1 GPa with the flexural strength and the glass‐transition temperature of around 105 MPa and 99°C, respectively. Interestingly, our optimized protocol has led to the synthesis of new bio‐based materials with more valuable thermal and mechanical properties than those of thermocured materials obtained from petroleum‐based commercial epoxy resins. Focus has been given on processing parameters to optimi...
The Journal of the Acoustical Society of America, 2019
The stress distribution around endosseous implants is an important determinant of the surgical su... more The stress distribution around endosseous implants is an important determinant of the surgical success but it remains difficult to be measured. So far, no method developed to determine the implant stability is sensitive to the loading conditions of the bone-implant interface (BII). The objective of this study is to investigate whether a quantitative ultrasound (QUS) technique may be used to retrieve information on compressive stresses applied to the BII. A dedicated acousto-mechanical device was conceived to compress 18 trabecular bovine bone samples onto coin-shaped implants and to measure the ultrasonic response of the BII during compression. The biomechanical behavior of the trabecular bone samples was modeled as Neo-Hookean. The reflection coefficient of the BII was shown to decrease as a function of the compressive stress during the elastic compression of the trabecular bone samples and during the collapse of the trabecular network, with an average slope of -4.82 GPa-1. Results...
Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine, 2019
Biomechanical phenomena occurring at the bone–implant interface during the press-fit insertion of... more Biomechanical phenomena occurring at the bone–implant interface during the press-fit insertion of acetabular cup implants are still poorly understood. This article presents a nonlinear geometrical two-dimensional axisymmetric finite element model aiming at describing the biomechanical behavior of the acetabular cup implant as a function of the bone Young’s modulus Eb, the diametric interference fit ( IF), and the friction coefficient µ. The numerical model was compared with experimental results obtained from an in vitro test, which allows to determine a reference configuration with the parameter set: μ* = 0.3, [Formula: see text], and IF* = 1 mm for which the maximal contact pressure tN = 10.7 MPa was found to be localized at the peri-equatorial rim of the acetabular cavity. Parametric studies were carried out, showing that an optimal value of the pull-out force can be defined as a function of μ, Eb, and IF. For the reference configuration, the optimal pull-out force is obtained f...
Despite the unique mechanical strength and adhesion properties of epoxy resins, they still suffer... more Despite the unique mechanical strength and adhesion properties of epoxy resins, they still suffer from poor toughness and brittleness inducing poor resistance to cracks. Herein, we report an efficient method of synthesis of bioepoxy resin nanocomposites filled with highly exfoliated epoxy-grafted montmorillonite. The filled resin network was produced by covalent incorporation of a binary nanocomposite (MMT-PGMA) synthesized via in situ photoinduced polymerization of glycidyl methacrylate, into a Bioepoxy resin matrix to design a ternary nanocomposite (MMT-PGMA/Bioepoxy) and this in the presence of a green polyamine used as curing agent. The materials structure and morphology were characterized by FTIR, TGA, XRD, SEM, and TEM which show the key role of the MMT surface modification on its interfacial adhesion with the epoxy resin. The results showed that the clay interlayer d-spacing increases from 1.23 nm to more than 2.2 nm upon grafting of the polymer. The homogeneous solvent-free dispersion of hybrid cl...
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