Identifying Alternate Resources and Adjusting Expectations for Senior Design Projects During the COVID-19 Pandemic of 2020.

In March 2020, the COVID-19 pandemic required capstone design course instructors to transition to online learning. Student project teams were denied access to resources needed to construct and test prototypes scheduled to be delivered to project sponsors and clients at the end of the semester. Face-to-face collaboration was replaced with virtual team meetings. At Marquette University, efforts to identify (1) barriers to completing projects, (2) potential alternate prototyping resources, (3) adjustments to expectations of teams, and (4) changes to course deliverable requirements were completed. The results of these activities, the thought process used to guide students through the search for alternate resources, and final outcomes of student projects along with a discussion of what was learned from this experience are presented.

A Student-Centered Learning Approach to Design for Manufacturability: Meeting the Needs of an Often-Forgotten Customer.

A hands-on learning module was implemented at Marquette University in 2012 to teach biomedical engineering students about basic manufacturing processes, lean manufacturing principles, and design for manufacturability. It incorporates active and student-centered learning as part of in-class assembly line simulations. Since then, it has evolved from three class periods to five. The module begins with two classroom presentations on manufacturing operations and electronics design, assembly, and testing. Students then participate in an in-class assembly line simulation exercise where they build and test an actual product per written work instructions. They reflect on this experience, and suggest design and process changes to improve the assembly line process and quality, save time, and reduce cost and waste. At the end of the module students implement their suggested design and process improvements and repeat the exercise to determine the impact of their improvements. They learn of the importance of Design for Manufacturability, well-written work instructions, process design, and designing a product not only for the end user, but also for the assemblers and inspectors. Details of the module, and its implementation and assessment are presented along with student feedback and faculty observations.

Lessons Learned from a 10-Year Collaboration Between Biomedical Engineering and Industrial Design Students in Capstone Design Projects.

Engineers and industrial designers have different approaches to problem solving. Both place heavy emphasis on identification of customer needs, manufacturing methods, and prototyping. Industrial designers focus on aesthetics, ergonomics, ease of use, manufacturing methods, and the user's experience. They tend to be more visual and more concerned with the interaction between users and products. Engineers focus on functionality, performance requirements, analytical modeling, and design verification and validation. They tend to be more analytical and more concerned with the design of internal components and product performance. Engineers and industrial designers often work together on project teams in industry. Collaboration between the two groups on senior capstone design projects can teach each to respect and value the unique contributions each brings to the project team, result in improved design solutions, and help prepare students for future collaboration in industry. Student feedback and lessons learned by faculty and students from a ten-year collaboration between engineering and industrial design students from Marquette University and the Milwaukee Institute of Art and Design, respectively, are presented. Students learned to communicate with people in other disciplines, appreciate the complementary skills of each discipline, and value different approaches to problem solving.

Active learning in capstone design courses.

There is a growing trend to encourage students to take a more active role in their own education. Many schools are moving away from the sage on the stage to the guide on the side model where the instructor is a facilitator of learning. In this model, the emphasis is more on learning and less on teaching, and it requires instructors to incorporate more active and student-centered learning methods into their courses. These methods include collaborative, cooperative, problem-based, and project-based learning.

Preparing students for capstone design [Senior Design].

The senior capstone design course is the culmination of the previous three years of the undergraduate curriculum. The goal of this course is to develop students' communication (oral and written), interpersonal, teamwork, analytical, design, and project management skills through a team-based design experience. Students learn about the product-development process and gain experience solving open-ended problems. Capstone design courses give students insight into what it is like to work as an engineer.

Making the transition from technologist to manager.

To prepare for the transition to management, technical personnel must (1) develop their administrative, communication, and interpersonal skills; (2) learn to delegate, and (3) learn management principles and concepts. This last activity can be accomplished through in-house management training programs, on-the-job training, or formal management degree programs. These activities will help increase the chances for success among technical personnel making the transition into management in a clinical or industrial setting.

The electrochemical and mechanical behavior of passivated and TiN/AlN-coated CoCrMo and Ti6Al4V alloys.

The mechanical and electrochemical behavior of the surface oxides of CoCrMo and Ti6Al4V alloys during fracture and repassivation play an important role in the corrosion of the taper interfaces of modular hip implants. This behavior was investigated in one group of CoCrMo and Ti6Al4V alloy samples passivated with nitric acid and another group coated with a novel TiN/AlN coating. The effects of mechanical load and sample potential on peak currents and time constants resulting from fracture of the surface oxide or coating, and the effects of mechanical load on scratch depth were investigated to determine the mechanical and electrochemical properties of the oxides or coating. The polarization behavior of the samples after fracture of the oxide or coating was also investigated. CoCrMo had a stronger surface oxide and higher interfacial adhesion strength, making it more resistant to fracture than Ti6Al4V. If undisturbed, the oxide on the surface of Ti6Al4V significantly reduced dissolution currents at a wider range of potentials than CoCrMo, making Ti6Al4V more resistant to corrosion. The TiN/AlN coating had a higher hardness and modulus of elasticity than CoCrMo and Ti6Al4V. It was much less susceptible to fracture, had a higher interfacial adhesion strength, and was a better barrier to ionic diffusion than the surface oxides on CoCrMo and Ti6Al4V. The coating provided increased corrosion and fretting resistance to the substrate alloys.

In vitro corrosion testing of modular hip tapers.

The in vivo fretting behavior of modular hip prostheses was simulated to determine the effects of material combination and a unique TiN/AlN coating on fretting and corrosion at the taper interface. Fretting current, open-circuit potential (OCP), and quantities of soluble debris were measured to determine the role of mechanically assisted crevice corrosion on fretting and corrosion of modular hip tapers. Test groups consisting of similar-alloy (Co-Cr-Mo head/Co-Cr-Mo neck), mixed-alloy (Co-Cr-Mo head/Ti-6Al-4V neck), and TiN/AlN-coated mixed-alloy modular hip taper couples were used. Loads required to initiate fretting were similar for all test groups and were well below loads produced by walking and other physical activities. Decreases in OCP and increases in fretting current observed during long-term cyclic loading were indicative of fretting and corrosion. Current measured after cessation of cyclic loading suggests that once the conditions for crevice corrosion are established, corrosion can continue in the absence of loading. The chemical, mechanical, and electrochemical measurements, along with microscopic inspections of the taper surfaces indicate that the fretting and corrosion behavior of similar- and mixed-alloy taper couples are similar and that the coated samples are more resistant to fretting and corrosion. The results of this study clearly indicate the role of mechanical loading in the corrosion process, and support the hypothesis of mechanically assisted crevice corrosion.

A multicenter retrieval study of the taper interfaces of modular hip prostheses.

A multicenter retrieval analysis of 231 modular hip implants was done to investigate the effects of material combination, metallurgic condition, flexural rigidity, head and neck moment arm, neck length, and implantation time on corrosion and fretting of modular taper surfaces. Scores for corrosion and fretting were assigned to medial, lateral, anterior, and posterior quadrants of the necks, and proximal and distal regions of the heads. Neck and head corrosion and fretting scores were found to be significantly higher for mixed alloy versus similar alloy couples. Moderate to severe corrosion was observed in 28% of the heads of similar alloy couples and 42% of the heads of mixed alloy couples. Differences in corrosion scores were observed between components made from the same base alloy, but of different metallurgic conditions. Corrosion and fretting scores tended to be higher for heads than necks. Implantation time and flexural rigidity of the neck were predictors of head and neck corrosion and head fretting. The results of this study suggest that in vivo corrosion of modular hip taper interfaces is attributable to a mechanically-assisted crevice corrosion process. Larger diameter necks will increase neck stiffness and may reduce fretting and subsequent corrosion of the taper interface regardless of the alloy used. Increasing neck diameter must be balanced, however, with the resulting loss of range of motion and joint stability.