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Computer Methods in Biomechanics and Biomedical Engineering

M Pietsch, F Niemeyer, U Simon, A Ignatius, K Urban
We present a novel numerical model of the fracture-healing process using interface-capturing techniques, a well-known approach from fields like fluid dynamics, to describe tissue growth. One advantage of this method is its direct connection to experimentally observable parameters, including tissue-growth velocities. In our model, osteogenesis, chondrogenesis and revascularisation are triggered by mechanical stimuli via mechano-transduction based on previously established hypothesis of Claes and Heigele. After experimentally verifying the convergence of the numerical method, we compare the predictions of our model with those of the already established Ulm bone-healing model, which serves as a benchmark, and corroborate our results with existing animal experiments...
June 2018: Computer Methods in Biomechanics and Biomedical Engineering
Anne D Koelewijn, Eva Dorschky, Antonie J van den Bogert
Whether humans minimize metabolic energy in gait is unknown. Gradient-based optimization could be used to predict gait without using walking data but requires a twice differentiable metabolic energy model. Therefore, the metabolic energy model of Umberger et al. ( 2003 ) was adapted to be twice differentiable. Predictive simulations of a reaching task and gait were solved using this continuous model and by minimizing effort. The reaching task simulation showed that energy minimization predicts unrealistic movements when compared to effort minimization...
June 2018: Computer Methods in Biomechanics and Biomedical Engineering
Amirhossein Bagheri Sarvestani, Ebrahim Goshtasbi Rad, Kamyar Iravani
In this study, laryngeal flow fields are investigated and compared in normal larynx and models of larynx with unilateral vocal fold paralysis (UVFP). In paralytic models, three fixed initial glottal gaps are considered to understand the positive or probable negative impacts of surgical operation on unilaterally paralytic larynx, by which the paralyzed vocal fold is brought closer to the mid-plane. Various features of the flow fields have been discussed in detail including glottal gap width, glottal flow rate, glottal exit pressure pattern and glottal jet evolution...
June 2018: Computer Methods in Biomechanics and Biomedical Engineering
Henrique Takashi Idogava, Pedro Yoshito Noritomi, Gregory Bregion Daniel
The temporomandibular joint (TMJ) is an anatomical set of the buco-maxillary system that allows the movement of the mandible in most varied ways. Several factors can influence the malfunctioning of the joint and lead to the use of a total prosthesis. However, current prostheses do not supply the maximum amplitude of movement during protrusion and opening, due to mainly the anatomical differences between patients. For this reason, this article aims to study the patient's kinematic characteristics for a better comprehension of the problem and, consequently, to develop a numerical model for TMJ prostheses able to recover the healthy movement...
June 2018: Computer Methods in Biomechanics and Biomedical Engineering
Ju Zhang, David Ackland, Justin Fernandez
Non-rigid registration is a common part of bioengineering model-generation workflows. Compared to common mesh-based methods, radial basis functions can provide more flexible deformation fields due to their meshless nature. We introduce an implementation of RBF non-rigid registration with iterative knot-placement to adaptively reduce registration error. The implementation is validated on surface meshes of the femur, hemi-pelvis, mandible, and lumbar spine. Mean registration surface errors ranged from 0.37 to 0...
May 2018: Computer Methods in Biomechanics and Biomedical Engineering
Panagiotis Kelidis, Efstathios Konstantinidis
In this paper, we investigate pulsatile flow through a constricted tube with the aim of assessing the effect of stenosis morphology on hemodynamic parameters. The fluid-solid interaction of pulsatile flow through a compliant tube with elastic walls was simulated using an arbitrary Lagrangian-Eulerian (ALE) finite-element method. We consider blood flow through various mild stenoses of 25.8% severity in diameter with trapezoidal and bell-like morphologies at a fixed Womersley number of 7.75. The results show that the distribution of the time-averaged wall shear stress (TAWSS), which is the main factor affecting the hemodynamic parameters, strongly depends on the axial stretch of the stenosis; elongation of the stenotic region increases by 41...
May 2018: Computer Methods in Biomechanics and Biomedical Engineering
Oliver Röhrle, Harnoor Saini, Peter V S Lee, David C Ackland
The evaluation of three-dimensional occlusal loading during biting and chewing may assist in development of new dental materials, in designing effective and long-lasting restorations such as crowns and bridges, and for evaluating functional performance of prosthodontic components such as dental and/or maxillofacial implants. At present, little is known about the dynamic force and pressure distributions at the occlusal surface during mastication, as these quantities cannot be measured directly. The aim of this study was to evaluate subject-specific occlusal loading forces during mastication using accurate jaw motion measurements...
May 2018: Computer Methods in Biomechanics and Biomedical Engineering
Sean M Finley, Darrel S Brodke, Nicholas T Spina, Christine A DeDen, Benjamin J Ellis
Finite element analysis has proven to be a viable method for assessing many structure-function relationships in the human lumbar spine. Several validated models of the spine have been published, but they typically rely on commercial packages and are difficult to share between labs. The goal of this study is to present the development of the first open-access models of the human lumbar spine in FEBio. This modeling framework currently targets three deficient areas in the field of lumbar spine modeling: 1) open-access models, 2) accessibility for multiple meshing schemes, and 3) options to include advanced hyperelastic and biphasic constitutive models...
May 2018: Computer Methods in Biomechanics and Biomedical Engineering
Ying Xu, Lian Yun Chen, Hai Bo Zhang, Xin Zhao, Yin Sheng Tian, Li Ding
With the development of high-performance fighters, the function of pilot helmets is also constantly upgrading, and helmet-mounted display (HMD) has become a future development trend. To solve the inter-restriction between the eye position control and the pressure comfort under high overloads of pilot helmets, this paper optimizes the helmet design by building a head-helmet finite element model: (1) Under a 10 G overload, the deformation of helmet soft liner should not exceed 2 mm; and (2) The combination of liner materials used in various areas should satisfy the requirements of most comfortable head pressure distribution (Pfront : Ptop : Pside : Pback  = 2:2:1:3)...
May 2018: Computer Methods in Biomechanics and Biomedical Engineering
Carla F Santos, Jorge Belinha, Fernanda Gentil, Marco Parente, Bruno Areias, Renato Natal Jorge
Vertiginous symptoms are one of the most common symptoms in the world, therefore investing in new ways and therapies to avoid the sense of insecurity during the vertigo episodes is of great interest. The classical maneuvers used during vestibular rehabilitation consist in moving the head in specific ways, but it is not fully understood why those steps solve the problem. To better understand this mechanism, a three-dimensional computational model of the semicircular ducts of the inner ear was built using the finite element method, with the simulation of the fluid flow being obtained using particle methods...
May 2018: Computer Methods in Biomechanics and Biomedical Engineering
Yeliz Kılınç, Zeynep Fatma Zor, Mehmet Kemal Tümer, Erkan Erkmen, Ahmet Kurt
The relationship between mandibular third molar (M3) angulation and mandibular angle fragility is not well established. The aim of this study was to evaluate the impact of M3 angulation on the mandibular angle fragility when submitted to a trauma to the mandibular body region. A three-dimensional (3D) mandibular model without M3 (Model 0) was obtained by means of finite-element analysis (FEA). Four models were generated from the initial model, representing distoangular (Model D), horizontal (Model H), mesioangular (Model M) and vertical (Model V) angulations...
May 2018: Computer Methods in Biomechanics and Biomedical Engineering
Enrique Morales-Orcajo, Ricardo Becerro de Bengoa Vallejo, Marta Losa Iglesias, Javier Bayod, Estevam Barbosa de Las Casas
The aim of the present study is to examine the impact absorption mechanism of the foot for different strike patterns (rearfoot, midfoot and forefoot) using a continuum mechanics approach. A three-dimensional finite element model of the foot was employed to estimate the stress distribution in the foot at the moment of impact during barefoot running. The effects of stress attenuating factors such as the landing angle and the surface stiffness were also analyzed. We characterized rear and forefoot plantar sole behavior in an experimental test, which allowed for refined modeling of plantar pressures for the different strike patterns...
May 2018: Computer Methods in Biomechanics and Biomedical Engineering
Haobo Li, Yanxi Chen, Minfei Qiang, Kun Zhang, Yuchen Jiang, Yijie Zhang, Xiaoyang Jia
To analyze the biomechanical effect of syndesmotic screw through three and four cortices, a total of 12 finite element models simulating healthy ankles, tibiofibular syndesmosis injured ankles, and post-operative ankles by screw fixations through three or four cortices were built. A set of biomechanical data were obtained to find that screw fixation methods for inferior tibiofibular syndesmosis can help recover most of the biomechanical relations of the ankle especially the tricortical fixation, while the screw of quadricortical fixation bear more stress than the tricortical fixation...
April 2018: Computer Methods in Biomechanics and Biomedical Engineering
C Loosli, L Moy, G Kress, E Mazza, P Ermanni
We aim to maximize the pumping volume of a pulsatile ventricular assist device, where the diaphragm is covered with an endothelial cell layer. These cells are estimated to survive a cyclic strain up to fifteen percent. To increase the pumping volume under this strain constraint we use an approach based on corrugation of the diaphragm in its reference configuration. The paper explains the parametrization scheme for finding corrugation shapes, addresses modeling and evaluation schemes and reports on the results of a parameter study...
April 2018: Computer Methods in Biomechanics and Biomedical Engineering
Y W Wang, L Z Wang, S Y Liu, Y B Fan
Both finite element models and multi-body models of human head-neck complex had been widely used in neck injuries analysis, as the former could be used to generate detailed stress strain information and the later could generate dynamic responses with high efficiency. Sometimes, detailed stress and strain information were hoped to be obtained more efficiently, but current methods were not effective enough when they were used to analyze responses of human head neck complex to long duration undulate accelerations...
April 2018: Computer Methods in Biomechanics and Biomedical Engineering
Nolwenn Fougeron, Pierre-Yves Rohan, Aurélien Macron, Christophe Travert, Hélène Pillet, Wafa Skalli
Several Finite Element (FE) models of the pelvis have been developed to comprehensively assess the onset of pathologies and for clinical and industrial applications. However, because of the difficulties associated with the creation of subject-specific FE mesh from CT scan and MR images, most of the existing models rely on the data of one given individual. Moreover, although several fast and robust methods have been developed for automatically generating tetrahedral meshes of arbitrary geometries, hexahedral meshes are still preferred today because of their distinct advantages but their generation remains an open challenge...
April 2018: Computer Methods in Biomechanics and Biomedical Engineering
Ori Hazan, Leonid Sternik, Dar Waiss, Michael Eldar, Oshrit Hoffer, Orly Goitein, Rafael Kuperstein, Eli Konen, Zehava Ovadia-Blechman
Invagination is an innovative technique for closing the left atrial appendage (LAA) to reduce the risk of thrombi formation. The influence of LAA invagination on the flow fields in the atria was investigated based on a computational fluid dynamics. The simulation results demonstrated that the novel invagination process can eliminate low velocities (blood stasis) and low shear rate and thus decrease the risk of thrombus formation during atrial fibrillation. This innovative technique may enhance the clinical treatment of patients with atrial fibrillation by improving the atrial flow field while lowering the risk of creating emboli...
March 2018: Computer Methods in Biomechanics and Biomedical Engineering
George P Huang, Hongtao Yu, Zifeng Yang, Ryan Schwieterman, Bryan Ludwig
One-dimensional (1D) simulation of the complete vascular network, so called THINkS (Total Human Intravascular Network Simulation) is developed to investigate changes of blood flow characteristics caused by the variation of CoW. THINkS contains 158 major veins, 85 major arteries, and 77 venous and 43 arterial junctions. THINkS is validated with available in vivo blood flow waveform data. The overall trends of flow rates in variations of the CoW, such as the missing anterior cerebral artery (missing-A1) or missing posterior cerebral artery (missing-P1), are confirmed by in vivo experimental data...
March 2018: Computer Methods in Biomechanics and Biomedical Engineering
Léo Savonnet, Xuguang Wang, Sonia Duprey
Being seated for long periods, while part of many leisure or occupational activities, can lead to discomfort, pain and sometimes health issues. The impact of prolonged sitting on the body has been widely studied in the literature, with a large number of human-body finite element models developed to simulate sitting and assess seat-induced discomfort or to investigate the biomechanical factors involved. Here, we review the finite element models developed to investigate sitting discomfort or risk of pressure sores...
March 2018: Computer Methods in Biomechanics and Biomedical Engineering
Yun He, Istabrak Hasan, Ludger Keilig, Dominik Fischer, Luisa Ziegler, Marcus Abboud, Gerhard Wahl, Christoph Bourauel
This study combines finite element method and animal studies, aiming to investigate tissue remodelling processes around dental implants inserted into sika deer antler and to develop an alternative animal consuming model for studying bone remodelling around implants. Implants were inserted in the antlers and loaded immediately via a self-developed loading device. After 3, 4, 5 and 6 weeks, implants and surrounding tissue were taken out. Specimens were scanned by μCT scanner and finite element models were generated...
March 2018: Computer Methods in Biomechanics and Biomedical Engineering
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