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  1. Friction surfacing is a solid-state metal deposition technique suitable for a wide range of metallic materials. This technique results in coatings on surfaces for joining purposes or surface modification applications such as wear and corrosion performance improvements. In this study, a novel approach in friction surfacing is utilized in which the consumable tool deposits material from its side instead of the end of the tool, which has been employed in conventional friction surfacing. Frictional heat enables plastic deformation, which results in the depositing of the consumable material on the substrate surface. The process is carried out at temperatures below the melting point of the consumable material, resulting in a solid-state deposition process. In the current study, scanning electron microscopy and energy dispersive spectroscopy have been employed for the characterization of the interfaces and coatings. The results of this study exhibited that there is no elemental diffusion between the tool and substrate materials at the interface, showing that the process temperature was low enough to prevent plasticizing of the substrate surface.
  2. Friction surfacing technique is a thermo-mechanical approach for metallic deposition, suitable for a broad range of materials and applications. Friction surfacing can be employed for various industrial purposes such as coating, welding, repairing defective parts, surface hardening, and improving corrosion performance. In this technique, frictional heat generated at the interface of the consumable tool and substrate results in a severe plastic deformation at the end of the rod, enabling the deposition of a consumable material on the substrate surface. In this investigation, a novel method in friction surfacing, lateral friction surfacing, is employed to deposit the aluminum coatings. In this novel approach, the side of the consumable tool is pressed against the surface of the substrate, and the material transfer happens from the lateral surface of the tool. This technique provides extremely thin and smooth deposits, which are more consistent compared to the conventional approach of friction surfacing. Moreover, this technique enables fabricating of deposits in lower temperatures, lessening the thermal impacts on the microstructures and mechanical properties of the deposits. In this investigation plates of 1018 mild steel were partially coated with various aluminum alloys and corroded in an accelerated corrosion test chamber. The corrosion performance of the partiallymore »coated sample was evaluated by mass loss measurement. It was found that AA5086 offered the most corrosion protection. After 13 cycles of GM9540P test, equivalent to approximately 3½ years exposure at a mild/moderate marine site in Hawaii, almost all of the deposited aluminum was consumed.« less
  3. Additive manufacturing (AM) processes present designers with creative freedoms beyond the capabilities of traditional manufacturing processes. However, to successfully leverage AM, designers must balance their creativity against the limitations inherent in these processes to ensure the feasibility of their designs. This feasible adoption of AM can be achieved if designers learn about and apply opportunistic and restrictive design for AM (DfAM) techniques at appropriate stages of the design process. Researchers have demonstrated the effect of the order of presentation of information on the learning and retrieval of said information; however, there is a need to explore this effect within DfAM education. In this paper, we explore this gap through an experimental study involving 195 undergraduate engineering students. Specifically, we compare two variations in DfAM education: (1) opportunistic DfAM followed by restrictive DfAM, and (2) restrictive DfAM followed by opportunistic DfAM, against only opportunistic DFAM and only restrictive DfAM training. These variations are compared through (1) differences in participants’ DfAM self-efficacy, (2) their self-reported DfAM use, and (3) the creativity of their design outcomes. From the results, we see that only students trained in opportunistic DfAM, with or without restrictive DfAM, present a significant increase in their opportunistic DfAM self-efficacy. However,more »all students trained in DfAM – opportunistic, restrictive, or both – demonstrated an increase in their restrictive DfAM self-efficacy. Further, we see that teaching restrictive DfAM first followed by opportunistic DfAM results in the generation of ideas with greater creativity – a novel research finding. These results highlight the need for educators to accountfor the effects of the order of presenting content to students, especially when educating students about DfAM.« less
  4. Psychological safety has been shown to be a consistent, generalizable, and multilevel predictor of outcomes in performance and learning across fields. While work in this field has suggested that psychological safety can impact the creative process, particularly in the generation of ideas and in the discussions surrounding idea development, there has been limited investigations of psychological safety in the engineering domain. Without this knowledge we do not know when to fostering psychological safety in a team environment is most important. This study provides the first attempt at answering this question through an empirical study with 53 engineering design student teams over the course of a 4- and 8-week design project. Specifically, we sought to identify the role of psychological safety on the number and quality (judged by goodness) of ideas generated. In addition, we explored the role of psychological safety on ownership bias and goodness in the concept screening process. The results of the study identified that while psychological safety was not related to the number of ideas a team developed, it was positively related to the quality (goodness) of the ideas developed. In addition, while no relationship was found between psychological safety and ownership bias during concept screening, themore »results showed that teams with high psychological safety selected a higher percentage of their team members ideas.« less
  5. The capabilities of additive manufacturing (AM) open up designers’ solution space and enable them to build designs previously impossible through traditional manufacturing. To leverage AM, designers must not only generate creative ideas, but also propagate these ideas without discarding them in the early design stages. This emphasis on selecting creative ideas is particularly important in design for AM (DfAM), as ideas perceived as infeasible through the traditional design for manufacturing lens could now be feasible with AM. Several studies have discussed the role of DfAM in encouraging creative idea generation; however, there is a need to understand concept selection in DfAM. In this paper, we investigated the effect of two variations in DfAM education: 1) restrictive DfAM and 2) dual DfAM (opportunistic and restrictive) on students’ concept selection process. Specifically, we compared the creativity of the concepts generated by the students to the creativity of the concepts selected by them. Further, we performed qualitative analyses to explore the rationale provided by the students in making these design decisions. From the results, we see that teams from both educational groups select ideas of greater usefulness; however, only teams from the restrictive DfAM group select ideas of higher uniqueness and overall creativity.more »Further, we see that introducing students to opportunistic DfAM increases their emphasis on the complexity of designs when evaluating and selecting them. These results highlight the need for DfAM education to encourage AM designers to not just generate but also select creative ideas.« less
  6. Friction surfacing is an advanced technique to create solid-state deposition of wide range of materials onto a similar or dissimilar material substrate. This paper describes the study of a novel method to deposit material onto a substrate by friction surfacing. In the friction surfacing technique, the heat is generated entirely by friction. This metallic deposition technique consists of a rotating consumable tool that rubs against the surface of the substrate, and due to the frictional heat and forging generated between the tool and substrate, material is deposited onto the substrate. The material transferred from the consumable tool to the substrate occurs from the side of the tool, while in the conventional friction surfacing method, the material transfer happens from the end of the tool. In this investigation, the single and double-pass deposition of A6063 aluminum alloy onto an A36 carbon steel substrate was successfully carried out. To study the influence of the process parameters on the friction depositions, the substrate was divided into three sections, while the applying forces were varied in each section. Process parameters such as tool rotational speeds, table traverse speeds and normal force were experimented. A customized JET JMD-18 milling machine was used to carry outmore »the experiments. The influence of process parameters on the material deposition was characterized by means of roughness tester and optical microscope. The results of the study reveal that this novel method is capable to create an ultra-thin and smooth metallic deposition with excellent coverage. The material consumption during the single and double-pass deposition was evaluated, and the coating cross-section was assessed using the optical microscope.« less
  7. Additive manufacturing (AM) enables engineers to improve the functionality and performance of their designs by adding complexity at little to no additional cost. However, AM processes also exhibit certain unique limitations, such as the presence of support material, which must be accounted for to ensure that designs can be manufactured feasibly and cost-effectively. Given these unique process characteristics, it is important for an AM-trained workforce to be able to incorporate both opportunistic and restrictive design for AM (DfAM) considerations into the design process. While AM/DfAM educational interventions have been discussed in the literature, limited research has investigated the effect of these interventions on students’ use of DfAM. Furthermore, limited research has explored how DfAM use affects the performance of students’ AM designs. This research explores this gap through an experimental study with 123 undergraduate students. Specifically, participants were exposed to either restrictive DfAM or dual DfAM (both opportunistic and restrictive) and then asked to participate in an AM design challenge. The students’ final designs were evaluated for (1) performance with respect the design objectives and constraints, and (2) the use of the various aspects of DfAM. The results showed that the use of certain DfAM considerations, such as minimum featuremore »size and support material mass, successfully predicted the performance of the AM designs. Further, while the variations in DfAM education did not influence the performance of the AM designs, it did have an effect on the students’ use of certain DfAM concepts in their final designs. These results highlight the influence of DfAM education in bringing about an increase in students’ use of DfAM. Moreover, the results demonstrate the potential influence of DfAM in reducing build time and build material of the students’ AM designs, thus improving design performance and manufacturability.« less
  8. Research in additive manufacturing (AM) has increased the use of AM in many industries, resulting in a commensurate need for a workforce skilled in AM. In order to meet this need, educational institutions have undertaken different initiatives to integrate design for additive manufacturing (DfAM) into the engineering curriculum. However, limited research has explored the impact of these educational interventions in bringing about changes in the technical goodness of students’ design outcomes, particularly through the integration of DfAM concepts in an engineering classroom environment. This study explores this gap using an experimental study with 193 participants recruited from a junior-level course on mechanical engineering design. The participants were split into three educational intervention groups: (1) no DfAM, (2) restrictive DfAM, and (3) restrictive and opportunistic (dual) DfAM. The effects of the educational intervention on the participants’ use of DfAM were measured through changes in (1) participants’ DfAM self-efficacy, (2) technical goodness of their AM design outcomes, and (3) participants’ use of DfAM-related concepts when describing and evaluating their AM designs. The results showed that while all three educational interventions result in similar changes in the participants’ opportunistic DfAM self-efficacy, participants who receive only restrictive DfAM inputs show the greatest increase inmore »their restrictive DfAM self-efficacy. Further, we see that despite these differences, all three groups show a similar decrease in the technical goodness of their AM designs, after attending the lectures. A content analysis of the participants’ design descriptions and evaluations revealed a simplification of their design geometries, which provides a possible explanation for the decrease in their technical goodness, despite the encouragement to utilize the design freedom of AM to improve functionality or optimize the weight of the structure. These results emphasize the need for more in-depth DfAM education to encourage the use of both opportunistic and restrictive DfAM during student design challenges. The results also highlight the possible influence of how the design problem is stated on the use of DfAM in solving it.« less