Biomechanical Engineering Commons^™

Towards Improving Computational Modeling Of The Lumbar Spine - Impact Of Material Properties And Laminotomy On Spinal Biomechanics, Isaac K. Kumi

Mechanical & Aerospace Engineering Theses & Dissertations

Spinal ligaments play a crucial role in maintaining the mechanical stability of the lumbar spine. These dense, collagenous tissues not only resist excessive motion but also distribute loads between spinal components to protect neural structures. Traditionally, the mechanical response of ligaments has been modeled using linear elastic assumptions, which treat the tissue as having a constant stiffness regardless of loading history. While this simplifies analysis, it fails to capture the time-dependent behaviors, such as creep, stress relaxation, and hysteresis, that are characteristic of biological tissues.

Viscoelastic modeling may provide a more physiologically accurate representation by incorporating both elastic and viscous …

Inter-Cellular Forces Modulate Cell-Ecm Traction Forces, Zaria Booth

Mechanical & Aerospace Engineering Theses & Dissertations

Epithelial cells are among the most abundant cell types in the human body, making up sheets of epithelial tissues that cover the linings of organs and body cavities. Cellular adhesion and force transmission across epithelial tissues are crucial in maintaining tissue integrity and ensuring proper tissue regeneration. Defects in cellular force transmission have been found in various diseases, including cancer. Force transmission at cell-cell and cell-ECM junctions drive cell survival and development. It has been previously shown that changes in cell-ECM traction directly modulates forces at cell-cell contacts. In this study, we aim to determine the effects of perturbations in …

Machine Learning Approach To Activity Categorization In Young Adults Using Biomechanical Metrics, Nathan Q. C. Holland

Mechanical & Aerospace Engineering Theses & Dissertations

Inactive adults often have decreased musculoskeletal health and increased risk factors for chronic diseases. However, there is limited data linking biomechanical measurements of generally healthy young adults to their physical activity levels assessed through questionnaires. Commonly used data collection methods in biomechanics for assessing musculoskeletal health include but are not limited to muscle quality (measured as echo intensity when using ultrasound), isokinetic (i.e., dynamic) muscle strength, muscle activations, and functional movement assessments using motion capture systems. These assessments can be time consuming for both data collection and processing. Therefore, understanding if all biomechanical assessments are necessary to classify the activity …

Computational Analysis And Design Optimization Of Convective Pcr Devices, Jung Il Shu

Mechanical & Aerospace Engineering Theses & Dissertations

Polymerase Chain Reaction (PCR) is a relatively novel technique to amplify a few copies of DNA to a detectable level. PCR has already become common in biomedical research, criminal forensics, molecular archaeology, and so on. Many have attempted to develop PCR devices in numerous types for the purpose of the lab-on-chip (LOC) or point-of-care (POC). To use PCR devices for POC lab testing, the price must be lower, and the performance should be comparable to the lab devices. For current practices with the existing methods, the price is pushed up higher partially due to too much dependence on numerous developmental …

Understanding The Mechanical Behavior Of Costal Cartilage At Their Curved Exterior Surface Via A Tactile Sensor With A Built-In Probe For Distributed-Deflection Detection, Jiayue Shen

Mechanical & Aerospace Engineering Theses & Dissertations

This dissertation is aimed to determine the mechanical properties at the exterior surface of costal cartilages (CC) and examine how they vary with the cartilage length and the anatomical sites of CC in the ribcage via conformal indentation testing which is built upon a tactile sensor for distributed-deflection detection. The sensor entails a rectangular Polydimethylsiloxane (PDMS) microstructure sensing-plate integrated with a 5 ×1 transducer array with 0.75mm spatial resolution underneath and a built-in probe of 0.5mm×5mm×3mm above. By pressing the sensor against the exterior surface of a CC tissue with a pre-defined indentation pattern, the sensor conforms to the curved …

The Effect Of Bone And Ligament Morphology Of Ankle Joint Loading In The Neutral Position, Jinhyuk Kim

Mechanical & Aerospace Engineering Theses & Dissertations

Computational modeling of joints is used to investigate the effect of injuries, to plan surgeries, and to answer questions about joints that cannot be answered experimentally. Existing models of the ankle joint are moving toward being able to model specific patients, however, they do not include all of the anatomy (e.g., bones and/or ligaments) and have restrictive boundary conditions. These simplification in anatomy are made to minimize pre-processing and computation time. Because biomechanical modeling is increasingly focused on the implementation of patient specific cases, the effects of including more anatomical structures and determining how they affect the model results is …

Validation Of Open Chain Model During Kinematic Analysis Of Joint Mobilization Of The Foot: An In Vitro Study, Anthony Ross Mcnally

Mechanical & Aerospace Engineering Theses & Dissertations

Joint mobilization techniques have been shown to improve dorsiflexion range of motion after ankle injury in multiple in vivo studies; however, the underlying arthrokinematic effects of this treatment still require clarification. Therefore, the purpose of this preliminary study was to determine the viability of an open kinetic chain in vitro model for applying Maitland Grade III anterior/posterior joint mobilizations to the talocrural joint while examining the osteokinematic and arthrokinematic changes at the talocrural, subtalar and hindfoot joints. Three fresh frozen cadaver lower legs had Maitland Grade III anterior-to-posterior joint mobilization applied to the talocrural joint in 2 sessions of 200 …

Implementation Of Analytical Fatigue Models Into Opensim To Predict The Effects Of Fatigue On Anterior Cruciate Ligament Loading, Michael A. Samann

Mechanical & Aerospace Engineering Theses & Dissertations

The anterior cruciate ligament (ACL) provides stability to the knee joint while performing activities such as a side step cut. Neuromuscular fatigue, a reduction in muscle force producing capabilities, alters lower extremity mechanics while performing a side step cut and may increase the risk of ACL injury, particularly in females. Musculoskeletal modeling allows for the measurement of muscle forces, which are difficult to measure in-vivo. Therefore, musculoskeletal modeling, may improve our understanding of the effects of neuromuscular fatigue on muscle force production and loading of the ACL. Therefore, the purpose of this study was to develop a musculoskeletal model which …

Micro-Scale Dielectric Spectroscopy Of Biological Cells, Arindam Ghosh

Mechanical & Aerospace Engineering Theses & Dissertations

In recent years microfluidics has become one of the most commonly used tools to investigate cellular biology and to provide a platform for novel biomedical devices. Electrical Impedance Spectroscopy (EIS) was formulated as a non-invasive and label-fi.ee method to investigate the dielectric and the structural properties of materials. Since the early 20th century, EIS and Dielectric Spectroscopy have been applied to measure the dielectric properties of biological cells and tissues. Information about the cell membrane, cytoplasm and the nucleus can be extracted by dielectric spectroscopy. This thesis focuses on the applicability of the analytical models, in particular the Maxwell-Wagner Interfacial …

Preliminary Development Of A Subject Specific Finite Element Model Of The Hindfoot, Liang Dong

Mechanical & Aerospace Engineering Theses & Dissertations

The human hindfoot is a complex structure and its medical treatment can vary from patient to patient. If physicians have access to a patient specific computer model, the optimal treatment option can be explored on the model before preforming it on the patient. The purpose of this study was to create a quasi-static finite element model and to show the stress contour in the cartilage between the bones. Ankle joint contact pressure was collected on one cadaver limb with a 40 lbs ( 178 N) axial load applied and tendon loads applied to simulate the ratio of tendon loading during …

Analysis Of Bar Deformation Under Sternum Forces During Surgical Correction Of Pectus Excavatum In Children, Rohit N. Nikam

Mechanical & Aerospace Engineering Theses & Dissertations

Pectus excavatum (PE) also known as sunken or funnel chest is the most common chest wall deformity and affects 1 in every 1,000 children. In PE patients, the middle lower portion of the sternum is depressed producing concave appearance of the anterior part of the chest wall. This problem can be corrected with minimally invasive surgery developed by Dr. Donald Nuss in 1986. A specially made steel bar is implanted to lift the sternum to its normal position. This technique has been modified several times to improve safety and effectiveness of the bar placement and removal. One of the significant …

Dynamic Model Of Sailors Descending A Navy Ship Ladder, Jonathan Coulter

Mechanical & Aerospace Engineering Theses & Dissertations

Knee moments are greater in individuals who climb Navy ship ladders than in people climbing stairs. Because it is known that people who climb stairs frequently are at greater risk for osteoarthritis and that people in the Navy report higher incidences of knee pain, it was hypothesized that the internal joint reaction forces during the sailor's descent of a ship ladder would be greater than internal joint reaction forces of gait and stair climbing. Dimensions of a commonly used Navy ship ladder were collected and a replica was constructed. The replica was instrumented to collect 3D kinematics and kinetics during …

A Novel Piezoelectric Device With Dual Functions Of Studying Biological Soft Tissues, Avin A. Jamadagni

Mechanical & Aerospace Engineering Theses & Dissertations

This thesis presents the design of a novel piezoelectric device with dual functions of studying soft biological tissues. The device consists of a central circular plate and a set of flexural beams. The flexural beams are partially covered with piezoelectric film for integrated transduction. It can function as a force sensor for measuring the mechanical behavior of a tissue sample and a load applier for mimicking physiological loads experienced by the tissue sample in vivo, while the mechanical behavior can be visually observed under a microscope simultaneously. By combining the classic theories in solid mechanics and piezoelectricity, the performance of …

Development Of A Technique To Diagnose Subtalar Joint Instability, Ajaya Dhakal

Mechanical & Aerospace Engineering Theses & Dissertations

Most patients escape diagnosis of subtalar joint instability for years before treatment. Therefore, a clinically relevant technique to diagnose subtalar joint instability will improve its management. Towards this goal, a six degree of freedom positioning and loading device was developed to apply physiologic loads to the hindfoot. Because the ideal loading configuration to detect subtalar joint instability is unknown, the device was designed to apply rotational and translational forces simultaneously. Specifically, plantarflexion/dorsiflexion, inversion/eversion, and internal/external rotation can be applied individually or as coupled motions along with an anterior/posterior drawer. Kinematic data were collected from calcaneus, talus and tibia using a …

Experimental Analysis And Modeling Validation Of A Knee Brace In Shock Mitigation, Manish Prakash Dhekane

Mechanical & Aerospace Engineering Theses & Dissertations

An experimental setup simulating the dynamic environment in a high sea state is developed for the lower extremities to study the mitigation of shock impact. A single degree of freedom machine is equipped with six linear induction motors to produce impact acceleration ranging from 0.5G to 4G. The experiments are carried out along the dummy leg by using two configurations, one without a knee brace and one with a knee brace. Force and acceleration data is collected using a data acquisition system.

To develop the analytical model of the same experimental setup, the knee brace and dummy leg were scanned …

The Effect Of Hans Device On Brain Pressure Values In Finite Element Brain Models, Mihir M. Jawale

Mechanical & Aerospace Engineering Theses & Dissertations

A parametric study of behavior of different brain material properties when exposed to a mid-high severity pulse is presented. Few studies have considered brain pressure as a parameter to study the effect of change of brain material properties. Specifically pressure and strain values in the frontal and posterior fossa and occipital region of the brain are investigated for mid-high severity pulse.

The brain model is composed of several parts modeled as hexahedral elements and with different material properties. A parametric study of several material types of brain is conducted using MAthematical DYnamic MOdel (MADYMO). Initially only the finite element (FE) …

Shaken Baby Syndrome: Retinal Hemorrhaging. A Biomechanical Approach To Understanding The Mechanism Of Causation, Steven Alex Hans

Mechanical & Aerospace Engineering Theses & Dissertations

Shaken Baby Syndrome (SBS) is a form of abuse where typically an infant, age six months or less, is held and shaken. There may or may not be direct impact associated with this action. Further, there is very little agreement on the actual mechanism of SBS. Clinical studies are limited in showing the exact mechanism of injury and only offer postulations and qualitative descriptions. SBS has received much attention in the media, has resulted in a great deal of litigation and can be the source of unfounded accusations. Therefore, it is necessary to try to quantify the forces that may …

Distal Placement Of An End-To-Side Bypass Graft Anastomosis A 3-D Computational Study, John Robert Di Cicco

Mechanical & Aerospace Engineering Theses & Dissertations

A three-dimensional computational fluid dynamics study of blood flow through stenotic arteries has been conducted. Flow phenomena, such as separation regions and turbulence, can be found distal to an arterial stenosis. Frequently, a bypass graft using an end-to-side technique is attached to a stenotic artery to restore adequate blood flow. However, a significant percentage of these grafts fail after thirty postoperative days due to intimal hyperplasia development around the distal anastomosis. Moreover, aberrant wall shear rates have been implicated as a factor in the development of intimal hyperplasia. Thus, the present study examines whether placement of the distal end of …

An Experimental Study Of An Advanced Polymeric Material For Use In Total Knee Replacements Including Gait Analysis Of Mobile Knee Bearings, Lisa Ann Scott

Mechanical & Aerospace Engineering Theses & Dissertations

The primary objectives of this research were to clinically examine the New Jersey Low Contact Stress (LCS)™ Rotating Platform and Meniscal knee bearing systems and to investigate the tribological properties of a new polymer for potential application in total joint replacement. Thus, clinical studies were performed on subjects having the LCSTM Rotating Platform knee bearing and subjects having the LCS™ meniscal knee bearing. The results indicated that there was a statistically significant difference in the braking force for both implant groups when compared to a control group. There was also a statistically significant difference noted for the LCS™ Rotating Platform …

Synthesis Of An Efficient Band Mechanism For Robots And Prosthetic Devices, Run Chen Zhou

Mechanical & Aerospace Engineering Theses & Dissertations

A noncircular pulley has been applied to improve the system efficiency of an electrical-powered elbow prosthesis. The dynamics of the motor and the prosthetic arm have been incorporated into the kinematic synthesis relationships for determining the pulley profile that maximizes the efficiency of the elbow prosthesis.

The nonlinear dynamic equations have been solved by the code Differential Equation (DE) while determining the motor power and efficiency which are the criteria in the nonlinear programming problem. The optimal design variables for determining the pulley profile along with some simulation results have been obtained from an optimization program (based on the Generalized …