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1. 3D-Printed Laboratory Equipment for Vibrations and Control Theory Courses: Pendulum, Cantilever Beam, and Rectilinear System

   https://doi.org/10.1115/IMECE2021-69866  

   Garcia, Martin ; Estrada, Benji ; Lucier, Elizabeth ; Tekes, Coskun ; Utschig, Tris ; Tekes, Ayse ( November 2021 , ASME 2021 International Mechanical Engineering Congress and Exposition)

   Learning by doing has proven to have numerous advantages over traditionally taught courses in which the instructor teaches the topic while students remain passive learners with little engagement. Although laboratories give hands-on opportunities for undergraduate mechanical engineering students, they have to wait for a semester for the lab course for instance the prerequisite of the vibrations and control laboratory is the mechanical vibrations course. Since the nature of the dynamics branch consisted of dynamics, vibrations, and control theory courses are highly mathematical, students struggle comprehending the introduced topic and relate the theory to its real-world application area. Furthermore, it’s almost impossible for an instructor to bring the existing educational laboratory equipment to the class since they are bulky and heavy. The advents in manufacturing technology such as additive manufacturing bring us more opportunities to build complex systems new materials.

   This study presents the design, development, and implementation of low-cost, 3D printed vibratory mechanisms to be utilized in mechanical vibrations, control theory courses along with their associated laboratories. A pendulum, cantilever beam integrated with springs, and a rectilinear system consisted of two sliding carts, translational springs, and a scotch yoke mechanism are designed. The main parts of the mechanisms are 3D printed using polylactic acid (PLA), polyethylene terephthalate glycol (PETG), and thermoplastic polyurethane (TPU).

    

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2. Learning by Doing in the Dynamics and Mechanical Vibrations Courses Using 3D Printed Equipment

   https://doi.org/10.1115/IMECE2022-94180  

   Tran, Thuong ; Tran, Tinh ; Tran, Kevin ; Oun, Karena ; Tekes, Ayse ( October 2022 , ASME 2022 International Mechanical Engineering Congress and Exposition)

   Limited resources available to the engineering faculty and students impede student learning and deep understanding of the material that is presented in the dynamics and mechanical vibrations courses. Active learning practices such as learning by doing is an effective way to not only build a solid foundation in knowledge but also help students develop engineering skills. However, these courses are mainly taught in a traditional manner and many students struggle in connecting the theory to its real-world application and lose interest. Although mechanical engineering students get more hands-on opportunities in the laboratories, they take vibrations and control laboratories in the following semesters since vibrations is a pre-requisite for these labs. To address this issue, we designed 3 low-cost, compact, and portable laboratory equipment and fabricated them using 3D printing technology. The first equipment is a 3-pendulum system with different lengths and tip loads that can be utilized in the engineering dynamics course. While the second equipment is a 2 DOF compliant vibration isolator consisting of flexible beams, masses, and a linear actuator, the third equipment is a non-linear cantilever beam to be utilized in the vibrations courses and their associated laboratories.

    

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3. Impact of 3D-printed laboratory equipment in vibrations and controls courses on student engineering identity, motivation, and mindset

   https://doi.org/10.1177/03064190231205013  

   Utschig, Tris ; Tekes, Ayse ; Linden, Maureen ( October 2023 , International Journal of Mechanical Engineering Education)

   This paper describes the implementation of innovative 3D-printed laboratory equipment linked to inquiry-based learning activities designed to improve learning, increase engineering identity and motivation, and foster a growth mindset in students taking undergraduate level mechanical vibrations courses, control theory courses, and associated laboratories. These innovative designs create new opportunities for hands-on learning, are low-cost, portable, and can be adapted for use in multiple science and engineering disciplines. The learning activities are based on the POGIL model, which has been used across a variety of disciplines including engineering. We describe the features of three separate devices (spring-connected sliding carts, compliant parallel arms with fixed-free ends and a slider mass, and a pendulum with variable tip load) implemented using a quasi-experimental approach with 510 duplicated students across three semesters during the COVID-19 pandemic in multiple lecture courses and laboratory sections. We also present an assessment of impact based on descriptive statistical analyses of survey data for student-reported learning gains and pre-post paired comparison tests on validated instruments measuring perceptions of engineering identity, engineering motivation, and growth mindset. Further, we conducted a student focus group and include salient instructor observations. Results show most students participating in the learning activities using these devices report that it supported their learning “a lot” or “a great deal.” In addition, on six of seven surveyed learning outcomes, most students reported feeling confident enough to complete them on their own or even teach them to someone else. Our data did not show a measurable impact on engineering identity, engineering motivation, or growth mindset, though it does suggest further investigation is merited.

    

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4. 3D Printed Skin‐Interfaced UV‐Visible Hybrid Photodetectors

   https://doi.org/10.1002/advs.202201275  

   Ouyang, Xia ; Su, Ruitao ; Ng, Daniel Wai Hou ; Han, Guebum ; Pearson, David R. ; McAlpine, Michael C. ( July 2022 , Advanced Science)

   Photodetectors that are intimately interfaced with human skin and measure real‐time optical irradiance are appealing in the medical profiling of photosensitive diseases. Developing compliant devices for this purpose requires the fabrication of photodetectors with ultraviolet (UV)‐enhanced broadband photoresponse and high mechanical flexibility, to ensure precise irradiance measurements across the spectral band critical to dermatological health when directly applied onto curved skin surfaces. Here, a fully 3D printed flexible UV‐visible photodetector array is reported that incorporates a hybrid organic‐inorganic material system and is integrated with a custom‐built portable console to continuously monitor broadband irradiance in‐situ. The active materials are formulated by doping polymeric photoactive materials with zinc oxide nanoparticles in order to improve the UV photoresponse and trigger a photomultiplication (PM) effect. The ability of a stand‐alone skin‐interfaced light intensity monitoring system to detect natural irradiance within the wavelength range of 310–650 nm for nearly 24 h is demonstrated.

    

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5. Creating and Assessing an Upper Division Additive Manufacturing Course and Laboratory to Enhance Undergraduate Research and Innovation

   https://doi.org/10.18260/1-2--30124  

   Maloney, Patricia A ; Li, Bingbing ; Zhang, Meng ; Cong, Weilong ( June 2018 , 2018 ASEE Annual Conference & Exposition)

   This NSF IUSE project is on the Exploration and Design Tier and the Engaged Student Learning Track. It is aimed at better preparing the country’s professional workforce in the renaissance of U.S. skilled manufacturing by creating new personnel proficient in additive manufacturing (AM). AM is mainstream; it has the potential to bring jobs back to the U.S. and add to the nation’s global competitiveness. AM is the process of joining materials to make objects from 3D data in a layer upon layer fashion. The objectives are to develop, assess, revise, and disseminate an upper division course and laboratory, “Additive Manufacturing,” and to advance undergraduate and K-12 student research and creative inquiry activities as well as faculty expertise at three diverse participating universities: Texas Tech, California State-Northridge, and Kansas State. This research/pedagogical team contains a mechanical engineering professor at each university to develop and teach the course, as well as a sociologist trained in K-12 outreach, course assessment, and human subjects research to accurately determine the effects on K-12 and undergraduate students. The proposed course will cover extrusion-based, liquid-based, and powder-based AM processes. For each technology, fundamentals, applications, and advances will be discussed. Students will learn solutions to AM of polymers, metals, and ceramics. Two lab projects will be built to provide hands-on experiences on a variety of state-of-the-art 3D printers. To stimulate innovation, students will design, fabricate, and measure test parts, and will perform experiments to explore process limits and tackle real world problems. They will also engage K-12 students through video demonstrations and mentorship, thus developing presentation skills. Through the project, different pedagogical techniques and assessment tools will be utilized to assess and improve engineering education at both the undergraduate and K-12 levels through varied techniques: i) undergraduate module lesson plans that are scalable to K-12 levels, ii) short informational video lessons created by undergraduates for K-12 students with accompanying in-person mentorship activities at local high schools and MakerSpaces, iii) pre- and post-test assessments of undergraduates’ and K-12 participating students’ AM knowledge, skills, and perceptions of self-efficacy, and iv) focus groups to learn about student concerns/learning challenges. We will also track students institutionally and into their early careers to learn about their use of AM technology professionally. 

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