Collaborative Efforts in Engineering and Technology Education

Transcription

1 Collaborative Efforts in Engineering and Technology Education R. Sterkenburg, D.L. Stanley & J. Lampe Purdue University Abstract - Over the last two years, Mechanical Engineering (ME) and Aviation Technology (AT) students at Purdue University have been collaborating and competing in several aviation related design-build projects. This paper will describe three such projects: The Personal lifting vehicle (PLV), the lighter than air vehicle (Blimp), and the Hovercraft. Elements of collaboration, competition, and design-build strategies were utilized in an effort to increase student motivation. In the first project students of ME and AT worked together to design and build a Personal Lifting Vehicle (PLV); a prototype was built but the team was unable to satisfactorily resolve some control problems with the vehicle. For the second project a design was chosen that could more realistically be achieved, and the effort was to culminate in a race between the two design blimps. The element of competition greatly improved the motivation of the students and both teams successfully constructed and raced the 12 feet long radio controlled blimps. For the third project one team of ME students and a combined team of AT and ME students competed. The teams were tasked with the design and manufacture of a full-scale one-person hovercraft. Both teams successfully built a hovercraft, but only the hovercraft of the combined AT/ME team was tested. The ME hovercraft was not tested due to safety concerns. These projects have created considerable interest among faculty members from other departments within the University, some of who have expressed a desire to participate in future projects of the type. Suggestions have also been made that collaborative competitions might be conducted in the future between teams from Purdue University and other universities here and abroad. Introduction Due to the evolution of engineering science research beginning in the 1960s, the emphasis of engineering education became more strongly biased towards the science of engineering, and away from the application of engineering (McMaster & Matsch, 1996; Hayes & Wheelwright, 1984) 1 That shift in emphasis coincided with a reduction in engineering curricula that had focused on application related design activities. Prior to that time, undergraduate engineering programs were typically of five-year duration, with 170 or more credit hours. In response to considerations of economy and declining enrollment, universities were forced to reduce credit hours and program length. Courses eliminated during this time typically included the application-based laboratory classes, which, in the short term, allowed engineering to fall in line with the program lengths of other disciplines. Unfortunately, the long-term impact of these decisions was to be largely negative for engineering graduates. Observing this, McMaster and Match said that Too few of our engineering graduates have an adequate understanding of how Page

2 to manufacture anything. Fewer still seem to understand the process of large-scale, complex system integration which characterizes so much of what we do in our industry, and it has become increasingly clear to us in industry that the curricula in most of the major universities in the United States overemphasize engineering science at the expense of engineering practice. (Bokulich, Gehm, & Hessler, 2001). 2 The findings of several studies, new ABET requirements and feedback from industry advisory boards support these observations and indicate a broad concern that graduating engineers are not prepared to enter the workforce. Faculty members of Mechanical Engineering (ME) and Aviation Technology (AT) share some of these concerns, and have discussed ways to approach these problems. One method originated from a desire among faculty members to develop means by which to motivate students in a ME senior design course. The AT department was chosen to simulate a manufacturing division, and the projects were to reflect current aerospace design and manufacturing processes. Collaborative work between the two groups would be important in order to accomplish the objectives. The aerospace industry is highly competitive and most aircraft acquisitions are decided in a competition with only one winner, so it is important for students to become familiar with this pressure. In general, then, elements of both collaboration and competition were to be the focal points of this initiative. The personal lifting vehicle (PLV) 3 Design objective: develop a vehicle that is relatively inexpensive to operate, will fit in a standard two-car garage, and is useful for daily transportation much like a motorcycle. The students were to design a ½-scale radio controlled prototype of the PLV, and prove that the concept could work. A group of 20 engineering students were divided into five teams for the design effort: ducted fans, airframe, drive train, engine, and stability control. The schedule called for students to meet and work within their groups three times per weeks; once a week, all five groups were to meet and discuss the overall progress toward the vehicle design. The design stage was to be of 8-weeks duration. The budget allotted $500 to purchase parts and materials, and the ME machine shop and the composites and materials laboratories in the AT department were available for the fabrication effort. The AT students were involved from the beginning of the design phase, and they organized a workshop to introduce the ME students to basic composites and aluminum manufacturing processes and also assisted in manufacturing parts and components as the detailed design phases were completed. A major setback occurred during the design phase when the stability and controls group reported that it was impossible to design a stable vehicle. Their calculations indicated that utilization of two fans in the vehicle design would result in an inherently unstable and uncontrollable vehicle. Many members of the other teams - including faculty advisors - disagreed, and it was decided to build the vehicle to prove that the concept would work or not. At the end of the semester the PLV was completely assembled and prepared for ground testing. Unfortunately, during the initial ground tests, incorrect procedures were followed with respect to the operation of the 2-stroke engine, resulting in significant engine damage. Insufficient time and money remained to rebuild the engine in the allotted time, and the project was terminated at that point. Page

3 Although the end result was not as planned, many things were learned as a result of these efforts, some of which are detailed below. Student motivation: This is a quality that is difficult to evaluate, particularly without baseline measurements for comparison. Student surveys conducted indicated that nearly all students thought that it was important to learn more about manufacturing processes, but in reality only a small number of the students involved in the overall project put forth the lion s share of the effort required to complete the manufacturing stages. Lessons learned The PLV was a unique and innovative design, but excessively complex and work intensive for a one-semester course. Students without practical application and manufacturing experience may produce designs that are impractical, excessively time intensive, expensive to manufacture, or simply will not work in the real world. As a result, students learned through their experience with the manufacturing process that they must have some fundamental understanding of the manufacturing processes before they can design effectively. The ratio of ME students to AT was too large, which resulted in insufficient practical input and experience for the design and fabrication stages During the manufacturing processes, students came to realize that they often lacked necessary knowledge of material properties and elements required for detailed drawings, for instance. The results showed up in the fabrication stages, with re-work required, and slipped deadlines, the result. Students came to realize that at critical junctures, for instance at the testing phase for this project, close attention must be paid to procedures. Those with expertise in an area must be consulted; otherwise the entire effort is jeopardized. Improvements in elements of collaboration might help address this issue in the future. In a project of this type, students required about three to five weeks to make the transition from acting simply as a student on a class project to becoming an engineer for a major initiative.time required for this process must be factored into projects of this type. Another very important lesson for all was that every problem might not have an assessable solution, given the resources available. Such determinations should be addressed as early as possible in any initiative. Also, it is important to note that the resolution of some problems may not found on the drawing board or in software applications, but through practical experience. That is why experiences of this type are so beneficial, even when the original objectives are not achieved. Lighter than air vehicle (blimp) Increased student motivation was one of the original goals at the onset of the ME/AT collaboration, and it was felt that this goal was not realized. In order to better address this goal it Page

4 was decided to have ME and AT teams compete against each other in the design and manufacturing of a lighter than air vehicle (blimp). Design objective: To design and manufacture a blimp for a race inside the Amory building at Purdue University. Criteria for the contest required that the blimp be capable of lifting a 50 g weight from the ground while in flight. Both teams were given a budget of $500 with which to purchase weather balloons, electrical motors and helium for the project. Although teams were required to buy the same balloons and motors, choices for selection of other project materials and hardware were unrestricted. The teams were allowed access to the ME machine shop and the AT materials laboratory to obtain materials and to fabricate parts and assemble the vehicle. The students established the race rules during a meeting at the beginning of the semester. Decisions regarding team organization and design philosophy were to be made by the teams. The AT team employed an open, consensus approach to the design phase. Three weeks were required for this initial stage, as they evaluated existing designs and made predictions for lift and propulsion based on available materials and components. Having settled on a design, they made assembly drawings and prepared to fabricate the vehicle. The building phase required eleven weeks and the flight-testing two weeks. The students finished the project on time for the race. The mechanical engineering students used a more traditional engineering approach; they divided the team into propulsion, airframe, lift and control teams based on standard industry practice. Eight weeks were required for the design phase, which included a detailed design study of the vehicle, including drawings and models and a critical design review with a formal presentation of their findings. Although they struggled with the building process, the design was innovative and creative thinking afforded them some significant advantages. Gearboxes were installed to increase torque and lower RPM, which allowed for the use of larger propellers, resulting in higher thrust and increased speed. Race day The race was planned in the Amory at Purdue University, and a large number of people showed up to watch. A racetrack was established in accordance with the race rules, and both faculty members served as judges. The AT blimp was built with emphasis on control to improve the capability for lifting the weight, while the engineering team built their vehicle for speed. Both vehicles got of to a good start and, as expected, the ME blimp was fast but suffered control problems. Surprisingly, the AT team lost control of the blimp for unknown reasons, which then hit the ground resulting in the loss of a propeller. The ME team required many attempts to pick up the weight but Page

5 eventually succeeded. It crossed the finish line and promptly imploded. The reason for the aviation blimp failure was found to be the AM controller used. This controller had functioned well during outside test trials, but the steel structure of the Amory created some apparent interference issues, resulting in intermittent operation and control issues. Lessons learned The blimp proved to be a great one-semester project, and the element of competition greatly motivated the students. The AT team learned a valuable lesson about the importance of testing in the race environment. The Aviation team stated that the successes were a gain in knowledge of buoyancy and propulsion, making valuable contacts and friends with engineering students. Engineering students expressed great interest in a utilizing the blimp concepts for their senior design course. The disadvantage of the competition model is that the collaboration element is missing. Having several teams with combinations of AT and ME students would allow for collaborative efforts. The hovercraft Having gained experience and knowledge with the first two projects, the faculty members decided a new approach was in order for a large-scale project. The elements of competition and collaboration were to be the focus for the design of a hovercraft vehicle. One large team consisting of 25 engineering students would compete against a combined team of 4 aviation and 2 engineering students. The low number of AT students involved dictated the makeup of the teams. Given the interest and emphasis given to the collaborative elements of the project, much speculation was focused on the performance of the combined team. Design objective: To design and build a one-person hovercraft to be used in a race over land or water. Page At the beginning of the semester the leaders of both teams met to set up the competition rules. The teams were again allotted a budget of $500 and access to materials available in the ME

6 machine shop and the AT materials laboratory. Aluminum alloy was to be the primary construction material, and two 6.5 hp lawnmower engines were supplied to both teams for lifting and propulsion. Thinking back to the creative advantage the ME team had gained through the use of gearboxes on the previous project, the AT/ME team borrowed a 35 hp snowmobile engine for propulsion. The AT students in this team expressed concern with the time required with a comprehensive design approach and proposed that the team utilize existing plans available online and modify them as necessary. ME students on this team were more inclined to follow the traditional engineering approach and design the vehicle from the ground up. AT students won out at least in part due to numbers. This decision afforded the team extra time for the fabrication of the vehicle, which proved to be time consuming. As the deadline approached, this team found itself working as many as 30 or more hours per work to complete the project. Nonetheless, the hovercraft was successfully completed and tested prior to race day. The ME team followed a more traditional design phase of 8 week during which the team worked in sub-teams focused on airframe, power plant, propellers, and control issues. A complete set of detailed drawings was generated, and the building started in week 9. Due to the large number of students they made good progress, but encountered multiple manufacturing problems. The design was innovative, but presented great challenges for manufacturing. Safety concerns eventually led to cancellation of testing for this vehicle. Student motivation This project proved to be a great motivator, and was by far the most successful of the three projects. At the beginning of the project, the students of both teams were observed to react rather negatively towards each other. While the student groups operated in the same physical area, they did so generally at different times and exchanged little information. During the last two weeks both vehicles were moved to a smaller area where the teams worked side by side. During this period the students were on-task many hours often into the nighttime - and gained respect for each other during the process. They realized that the challenges were large, and that collaborative efforts were necessary. Through this time, students gained an increased understanding and appreciation of the skills and knowledge on display by both groups. The teams elected to display their completed vehicles during the annual picnic of the Aviation Department. The AT/ME team gave a demonstration of their hovercraft during this event it performed well, and was enthusiastically supported by those in attendance. Discussion turned immediately to future projects. Lessons learned To integrate both student groups, they need to work in the same area at the same time. Time dedicated to the project must be controlled. Faculty involved need to solicit support from the faculty and department in order for a project of this scale to succeed. Practical, hands-on skills are an essential part of a design-build initiative. Competition forces teams to make critical choices, particularly with respect to the design timeline. Page

7 In a team, numbers of students from different disciplines should be balanced. This has been illustrated now in two projects where one group that outnumbers another will tend to dominate the team. CONCLUSIONS It was a great experience for us to work with groups of students working on realistic projects, although time consuming and many nights at work, it was wonderful to work with self-motivated students making things happen. These projects clearly showed that engineering and technology students could benefit greatly from this type of interaction. Moreover, students develop a respect for the knowledge and skills apparent in other disciplines. Through this type of activity, engineering students may be able to gain back some of the application experience and knowledge that is missing from engineering curriculum these days. Technology students can benefit by observing the formal analytical approach that engineering students typically bring to projects of this nature. Collaboration is a key component to success in projects, while the element of competition is the great motivator. Students in aerospace disciplines must become familiar with this environment, if only because most aerospace companies work in interdisciplinary teams in a highly competitive marketplace. BIBLIOGRAPHIC INFORMATION 1. McMasters, J.H., Matsch, L.A., Desired attributes of an engineering graduate An industry perspective. 19 th AIAA Advanced Measurement and Ground Testing Technology Conference, Washington (1996). 2. Bokulich, F., Gehm, R., & Hessler, J.R., Wanted: aerospace engineers. Aerospace Engineering, 21 (4), (2001). 3. Sterkenburg, R., The personal lifting vehicle: a joint project of mechanical engineering and aviation technology at Purdue University. International conference on engineering eduction, Manchester, United Kingdom Page