Journal of Biomechanical Engineering This is an RSS file. You can use it to subscribe to this data in your favourite RSS reader or to display this data on your own website or blog.

Instability of Incompatible Bilayered Soft Tissues and the Role of Interface Conditions
Mechanical stability analysis is instructive in explaining biological processes like morphogenesis, organogenesis, and pathogenesis of soft tissues. Consideration of the layered, residually stressed structure of tissues, requires accounting for the joint effects of interface conditions and layer incompatibility. This paper is concerned with the influence of imposed rate (incremental) interface conditions (RICs) on critical loads in soft tissues, within the context of linear bifurcation analysis. Aiming at simplicity, we analyze a model of bilayered isotropic hyperelastic (neo-Hookean) spherical shells with residual stresse...
Source: Journal of Biomechanical Engineering - July 27, 2019 Category: Biomedical Engineering Source Type: research

Indirect Traumatic Optic Neuropathy Induced by Primary Blast: A Fluid –Structure Interaction Study
Current knowledge of traumatic ocular injury is still limited as most studies have focused on the ocular injuries that happened at the anterior part of the eye, whereas the damage to the optic nerve known as traumatic optic neuropathy (TON) is poorly understood. The goal of this study is to understand the mechanism of the TON following the primary blast through a fluid –structure interaction model. An axisymmetric three-dimensional (3D) eye model with detailed orbital components was developed to capture the dynamics of the eye under the blast wave. Our numerical results demonstrated a transient pressure elevation in both...
Source: Journal of Biomechanical Engineering - July 27, 2019 Category: Biomedical Engineering Source Type: research

Flow Dynamics in the Aortic Arch and Its Effect on the Arterial Input Function in Cardiac Computed Tomography
This study employs computational modeling in a patient-specific aorta to investigate mixing and dispersion of contrast in the aortic arch (AA) and to compa re the TDCs in the coronary ostium and the descending aorta. Here, we examine the validity of the use of TDC in the descending aorta as a surrogate for the AIF. Computational fluid dynamics (CFD) was used to study hemodynamics and contrast dispersion in a CTA-based patient model of the aorta. Variat ions in TDC between the aortic root, through the AA and at the descending aorta and the effect of flow patterns on contrast dispersion was studied via postprocessing of the ...
Source: Journal of Biomechanical Engineering - July 15, 2019 Category: Biomedical Engineering Source Type: research

On the Influence of the Shoulder Kinematic Chain on Joint Kinematics and Musculotendon Lengths During Wheelchair Propulsion Estimated From Multibody Kinematics Optimization
In this study, shoulder kinematics and MT lengths obtained from four shoulder kinematic chains (open-loop thorax-clavicle-scapula-humerus (M1), closed-loop with contact ellipsoid (M2), scapula rhythm from regression equations (M3), and a single ball-and- socket joint between the thorax and the humerus (M4) were compared. Right-side shoulder kinematics from seven subjects were obtained with 34 reflective markers and a scapula locator using an optoelectronic motion capture system while propelling on a MWC simulator. Data were processed based on the four models. The results showed the impact of shoulder kinematic chains on al...
Source: Journal of Biomechanical Engineering - July 13, 2019 Category: Biomedical Engineering Source Type: research

Evaluating Plastic Deformation and Damage as Potential Mechanisms for Tendon Inelasticity Using a Reactive Modeling Framework
In this study, we evaluated these potential mechanisms of tendon inelasticity by using a recently developed reactive inelasticity model (RIE), which is a structurally inspired continuum mechanics framework that models tissue inelasticity based on the molecular bond kinetics. Using RIE, we formulated two material models, one specific to plastic deformation and the other to damage. The models were independently fit to published macroscale experimental tensile tests of rat tail tendons. We quantified the inelastic effects and compared the performance of the two models in fitting the mechanical response during loading, relaxat...
Source: Journal of Biomechanical Engineering - July 13, 2019 Category: Biomedical Engineering Source Type: research

Evaluation of Force Sensing Resistors for the Measurement of Interface Pressures in Lower Limb Prosthetics
Understanding the pressure distributions at the limb-socket interface is essential to the design and evaluation of prosthetic components for lower limb prosthesis users. Force sensing resistors (FSRs) are employed in prosthetics research to measure pressure at this interface due to their low cost, thin profile, and ease of use. While FSRs are known to be sensitive to many sources of error, few studies have systematically quantified these errors using test conditions relevant to lower limb prosthetics. The purpose of this study was to evaluate FSR accuracy for the measurement of lower limb prosthetics interface pressures. T...
Source: Journal of Biomechanical Engineering - July 13, 2019 Category: Biomedical Engineering Source Type: research

Development and Assessment of a Microcomputed Tomography Compatible Five Degrees-of-Freedom Knee Joint Motion Simulator
Currently available knee joint kinematic tracking systems fail to nondestructively capture the subtle variation in joint and soft tissue kinematics that occur in native, injured, and reconstructed joint states. Microcomputed tomography (CT) imaging has the potential as a noninvasive, high-resolution kinematic tracking system, but no dynamic simulators exist to take advantage of this. The purpose of this work was to develop and assess a novel micro-CT compatible knee joint simulator to quantify the knee joint's kinematic and kinetic response to clinically (e.g., pivot shift test) and functionally (e.g., gait) relevant loadi...
Source: Journal of Biomechanical Engineering - July 13, 2019 Category: Biomedical Engineering Source Type: research

Embolus Analog Trajectory Paths Under Physiological Flowrates Through Patient-Specific Aortic Arch Models
Atrial fibrillation (AF) is the most common irregular heartbeat among the world's population and is a major contributor to cardiogenic embolisms and acute ischemic stroke (AIS). However, the role AF flow plays in the trajectory paths of cardiogenic emboli has not been experimentally investigated. A physiological simulation system was designed to analyze the trajectory patterns of bovine embolus analogs (EAs) (n = 720) through four patient-specific models, under three flow conditions: steady flow, normal pulsatile flow, and AF pulsatile flow. It was seen that EA trajectory paths were proportional to the percentage flow...
Source: Journal of Biomechanical Engineering - July 13, 2019 Category: Biomedical Engineering Source Type: research

In Vivo Layer-Specific Mechanical Characterization of Porcine Stomach Tissue Using a Customized Ultrasound Elastography System
This paper presents in vivo mechanical characterization of the muscularis, submucosa, and mucosa of the porcine stomach wall under large deformation loading. This is particularly important for the development of gastrointestinal pathology-specific surgical intervention techniques. The study is based on testing the cardiac and fundic glandular stomach regions using a custom-developed compression ultrasound elastography system. Particular attention has been paid to elucidate the heterogeneity and anisotropy of tissue response. A Fung hyperelastic material model has been used to model the mechanical response of each tissue la...
Source: Journal of Biomechanical Engineering - July 11, 2019 Category: Biomedical Engineering Source Type: research

Fluid –Structure Interaction and In Vitro Analysis of a Real Bileaflet Mitral Prosthetic Valve to Gain Insight Into Doppler-Silent Thrombosis
Prosthetic valve thrombosis (PVT) is a serious complication affecting prosthetic heart valves. The transvalvular mean pressure gradient (MPG) derived by Doppler echocardiography is a crucial index to diagnose PVT but may result in false negatives mainly in case of bileaflet mechanical valves (BMVs) in mitral position. This may happen because MPG estimation relies on simplifying assumptions on the transvalvular fluid dynamics or because Doppler examination is manual and operator dependent. A deeper understanding of these issues may allow for improving PVT diagnosis and management. To this aim, we used in vitro and fluid –...
Source: Journal of Biomechanical Engineering - July 11, 2019 Category: Biomedical Engineering Source Type: research

The Effects of Personalized Versus Generic Scaling of Body Segment Masses on Joint Torques During Stationary Wheelchair Racing
In this study, athlete-specific mass segment inertial parameters of the head and neck, torso, upper arm, forearm, hand, thigh, shank, and feet for five elite wheelchair athletes were calculated using dual-energy X-ray absorptiometry (DXA) scans. These were compared against commonly used anthropometrics parameters of data presented in the literature. A computational biomechanical simulation of wheelchair propulsion using the upper extremity dynamic model inopensim assessed the sensitivity of athlete-specific mass parameters using Kruskal –Wallis analysis and Spearman correlations. Substantial between-athlete body mass dis...
Source: Journal of Biomechanical Engineering - July 11, 2019 Category: Biomedical Engineering Source Type: research

Anchor Hole Placement for Bankart Repairs and Its Interaction With Variable Size Hill –Sachs Defects-Minimizing Risk of Glenoid Rim Fractures
This study used finite element modeling techniques to investigate the risk of fracture of the glenoid rim in relation to variable sized Hill–Sachs defects impacting on the anterior glen oid edge with suture anchor holes placed in varying positions. The distribution of Von Mises (VM) stresses and the factor of safety (FOS) for each of the configurations were calculated. The greatest peak in VM stresses was generated when the glenoid was loaded with a small Hill–Sachs lesion. The V M stresses were lessened and the FOS increased (reducing likelihood of failure) with increasing size of the Hill–Sachs lesion. Placement of...
Source: Journal of Biomechanical Engineering - July 11, 2019 Category: Biomedical Engineering Source Type: research