Engineering Commons^™

Design, Material And Surgical Assembly Effects On Fretting Corrosion Behavior Of Modular Tapers In Orthopedic Implants, David Pierre

Dissertations - ALL

Mechanically assisted crevice corrosion (MACC) has become a significant problem in the orthopedic device industry, particularly in modular devices with metal-on-metal (MoM) tapered interfaces. Oxide film abrasion, leading to fretting corrosion in the presence of a crevice, accelerates the corrosion process and in some instances may lead to failure of the implant. Failure is defined as the need for revision surgery. The basic processes of oxide film abrasion and repassivation, and the associated effects (chemical, transport, mechanical and electrical) of these processes have been well described and studied over time.

Despite these advancements, there is much that is still not …

The Effects Of Simulated Inflammatory Conditions On The Corrosion And Fretting Corrosion Of Cocrmo Alloy, Yangping Liu

Dissertations - ALL

In vivo corrosion of CoCrMo alloy and its potential adverse effects on the body have been recognized as major concerns in recent years. While the underlying concepts of general and mechanically-assisted corrosion have been well documented, recent report of inflammatory cell-induced corrosion (ICIC) of CoCrMo alloy challenged traditional understanding of the relationship between biology and corrosion of hip implants. To better understand the role biology may play in the corrosion of CoCrMo-based implants, this study explored the mechanism of ICIC on CoCrMo alloy and investigated how simulated inflammatory (SI) conditions affected the electrochemistry, oxide film and fretting corrosion behavior of …

The Economy Of Preventive Maintenance Of Concrete Bridges Due To Corrosion, Haotian Zhang

Dissertations - ALL

The current practice for physical evaluation and delayed maintenance of deteriorated concrete bridge is fundamentally wrong. This research presents a new approach for the evaluation of the condition states of steel reinforced concrete bridge members, which is based on their chemical conditions instead of the physical deficiencies such as cracks and delamination. Using the proposed chemical based inspection approach, a more effective and economic preventive maintenance plan could be achieved. The available non-destructive evaluation (NDE) methods and preventive maintenance measure are identified. Since the chloride induced corrosion is the major factor that dictates the service life of the steel reinforced …

Effect Of Severe Corrosion On Lateral Strength Of Square Rc Bridge Columns, Sara Sotoud

Dissertations - ALL

Corrosion of reinforcing steel bars is the primary durability problem that causes degradation of reinforced concrete structures located in aggressive environments. Severe corrosion of steel bars decreases the lateral load-carrying capacity of reinforced concrete members, causes loss in the mechanical properties of reinforcement and cross-sectional area of steel bars and concrete cover, bond deterioration, reduces anchorage of steel bars, and decreases the confinement by transverse reinforcement. Consequently, corrosion results in drop in the lateral strength of columns. Therefore, studying response of corroded reinforced concrete columns subjected to lateral loads is necessary.

According to the Federal Highway Administration (FHWA) report in …

Interactions Between Inflammatory Cells And Cocrmo Alloy Surfaces Under Simulated Inflammatory Conditions, Huiyu Shi

Dissertations - ALL

Metallic biomaterials continue to be the primary materials for medical devices because of their excellent physical and mechanical properties especially for certain implants which need high strength (hip, spinal, shoulder, knee etc.). However there is no perfect material to meet all the requirements of a medical device. Metallic biomaterials are prone to corrosion and wear which has been associated with implant failure (osteolysis, aseptic loosening, pseudo tumor etc.) This study focused on investigating how inflammatory cells interact with CoCrMo alloy surfaces under simulated inflammatory conditions (H2O2 treatment). It is hypothesized that the presence of Reactive Oxygen Species (ROS) in cell …

Novel Methods And Self-Reinforced Composite Materials For Assessment And Prevention Of Fretting Corrosion In Modular Tapers, Eric S. Ouellette

Dissertations - ALL

Novel methods for assessing the electrochemical and micromechanical performance of modular tapers were evaluated, and self-reinforced composite materials were developed for their potential to prevent the onset of mechanically assisted corrosion in modular taper devices.

A study of the seating and taper locking mechanics of modular taper samples was conducted, and the effect on taper engagement strength of seating load, loading rate, taper moisture, and taper design/material combination was studied. The load-displacement behavior was captured during seating, and the subsequent pull off load was correlated to seating displacement, seating energy, and seating load. The primary factor affecting taper engagement strength …