Fine wires and cables play a critical role in the design of medical devices and subsequent treatment of a large array of medical diagnoses. Devices such as guide wires, catheters, pacemakers, stents, staples, functional electrical stimulation systems, eyeglass frames and orthodontic braces can be comprised of wires with diameters ranging from 10s to 100s of micrometres. Reliability is paramount as part of either internal or external treatment modalities. While the incidence of verified fractures in many of these devices is quite low, the criticality of these components requires a strong understanding of the factors controlling the fracture and fatigue behaviour. 1,2 Additionally, optimisation of the performance and reliability of these devices necessitates characterisation of the fatigue and fracture properties of its constituent wires. A review of cable architecture and stress states experienced during testing is followed by an overview of the effects of changes in material composition, microstructure, processing and test conditions on fracture and fatigue behaviour of wire and cable systems used in biomedical applications. The review concludes with recommendations for future work.

During her time at CWRU, she has mentored numerous high school and undergraduate student research projects that have focused on the mechanical characterization of wires used in biomedical applications. Her dissertation research investigates the effects of inclusions on the fatigue life of superelastic Nitinol fine wire and she is also involved in projects evaluating the reliability of implantable electrodes and characterizing the fatigue behavior of dental archwires. Janet is an active member of ASTM International, serving on E04 Metallurgy, E08 Promoting Technical Standards Education in Engineering AbstractThe United States Standards Strategy, the framework developed by the American National Standards Institute (ANSI) to guide the U.S. standards system, recognizes the need for standards education programs as a high priority and recommends initiatives that address the significance and value of standards.To this intent, a novel workshop was developed in partnership with the library and the School of Engineering to raise the level of awareness of technical standards and standards usage on campus. The effort was a result of a campus-wide collaboration that provided a low-cost method of introducing technical standards and providing a foundation to develop a series of online tools accessible to the campus community. The event featured guest speakers representative of six major national and international standards bodies in addition to faculty, staff and students. The panels provided discussions on the background of the various types of standards and industries impacted, the development and implementation of these documents, the ways in which students and faculty can become more familiar with these documents and the benefit to becoming actively involved with standards organizations. The presentations and question-and-answer sessions provided a venue to learn about technical standards and to talk about ways to improve standards education within the campus community. The event was well received as shown by strong attendance and follow up to online materials continues to show activity five months following the event.This paper summarizes the implementation of the workshop, its impact, and strategies to further improve standards education on campus.

Dental archwires are used to treat patients with malocculusion by producing forces on the teeth to move them into an aligned position. To achieve movement with minimal patient discomfort and provide appropriate formability for clinicians to implement the archwires, the material must be able to accommodate a large range of deflection and endure constant forces without plastically deforming [1]. Shape memory alloy (SMA) development has contributed to the advancement of orthodontic treatment by providing excellent strain recovery and lower stiffness than traditional stainless steel wires while maintaining good formability. Furthermore, nickel-free materials such as beta titanium alloys, with properties between the stainless steels and SMA provides treatment flexibility for the clinicians and an alternative for patients with nickel sensitivity, a concern common in SMA alloys, such as Nitinol. The bending stiffness of these materials in archwires has been well documented in literature; however, little information exists on the fatigue behavior.Nitinol (NiTi), stainless steel (SS) and beta titanium (Beta Ti) archwires with round and rectangular cross sections were evaluated in tension and fully-reversed (i.e. R = -1), flex bending fatigue under ambient conditions at 1 Hz. Cyclic strain was calculated for various mandrel sizes and compared to work by Benini [2]. Scanning electron microscopy was used to identify characteristic features associated with the failure mode and note trends in low cycle fatigue (LCF) and high cycle fatigue (HCF) regimes.Tension results showed characteristic stress/strain curves for all materials, noting the presence of a stress plateau in the NiTi archwire. Ultimate tensile strength (UTS) and modulus of elasticity were greatest for the SS archwires followed by Beta Ti then NiTi. Fatigue behavior for all materials displayed improvements in fatigue life with an increase in mandrel size and decrease in cyclic strain. Under LCF/high strain and HCF/low strain regimes, the NiTi exhibited longer cyclic life than the Beta Ti and SS as seen in Figure 1. Fractography of all materials showed ductile behavior with LCF samples exhibiting rougher features and larger regions of rapid fracture compared to HCF samples as seen in Figure 2.Tension data was clearly delineated among the materials providing archwire options that are strong and stiff when small amounts of tooth movement are needed (SS), elastic when larger malocclusions exist (NiTi) or an intermediate (Beta Ti). The NiTi wires exhibited the greatest fatigue life across the LCF and HCF regimes. Future work should investigate correlations between the fatigue data and in vivo use [3].

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