Session F3C USING DESIGN, BUILD, AND TEST ... - CiteSeerX

Session F3C USING DESIGN, BUILD, AND TEST PROJECTS TO TEACH ENGINEERING 1

Donald F. Elger, 2 Steven W. Beyerlein, and 3 Ralph S. Budwig

Abstract  The design, build and test (DBT) project was created with the idea that the best way to learn engineering is by doing engineering. The primary goal of a DBT project is to provide students with an experience that is fun, motivating and educational. In addition, a DBT project is designed to be easy to implement. The preeminent feature of a DBT project is the extensive use of science, math, and calculations to guide design efforts prior to construction. Key factors in designing an effective DBT project are (1) selecting an appealing topic that is amenable to simple prototype construction, (2) using metrics to define the project goal, (3) instituting a mentoring culture, (4) involving substantial mathematical modeling, (5) guiding students using iteration cycles, (6) motivating students by using competition and public presentation, and (7) continuously improving a project by collecting project resources. Index Terms  concept of iteration, math modeling, mentoring, performance metrics, scaleable mini-projects

INTRODUCTION Design, build and test projects were developed for application in engineering courses at the pre-college through junior levels. Two simplified examples of DBT problem statements are listed below. Save-the-Citizens: Design a model rocket that flies to a height of 90 meters while carrying the maximum number of citizens (navy beans). Build the resulting design without using any commercial rocket parts except for the motor, which must be an Estes® B4-4 motor. Man-in-the-Box: Soldiers in combat sometimes need to work without creating a thermal signature (i.e. heat transfer to the surrounding environment). Design a container to house a soldier plus his or her electronic instruments. Thermal energy from the soldier and instruments will be idealized using a 100 W light bulb. The container must have a volume less than 1.0 ft 3 and the interior air should remain at 20 o C for 20 minutes. Furthermore, there must not be any heat transfer to ambient. In all DBT projects, students construct and test their designs. Project scoring is based on the quality of the engineering approach and on the performance of the design relative to the design goals. ________________________________ 1 2 3

When the first DBT projects were used in the classroom (about ten years ago), the responses from both students and professors were very positive. Since that time, many DBT projects have been used. Based on these experiences, we have developed a model of an effective DBT project. The aim of this paper is to introduce this model, highlighting key aspects of the pedagogy. There is much literature on the design process and on design pedagogy [1]-[5]. Wankat and Oreovicz [1] identify a wide variety of approaches for teaching design. Dym and Little [2] stress the value of a project-oriented introduction to modern design theory. Evans [3] emphasizes the benefits of exposing freshman to open-ended design problems. Wales et al. [4],[5] present a structured decision making approach called “guided design.” In addition, there are a number of traditional types of design projects; for example, balsa wood structure projects in the freshman year and capstone design projects in the senior year. Finally, there are a variety of national design contests ranging from hybrid electric future trucks to submarines. While the DBT project uses elements from many of the existing types of projects, it has evolved into a unique type of experience. A distinguishing feature of a DBT project is the extensive use of science and math to guide design efforts prior to construction.

DBT PROJECT GOALS A DBT project is designed to be fun and motivating, meaning that it increases student self-confidence and interest in learning as well as engineering. Additionally, a DBT project is designed to help support educational objectives. Therefore, a DBT project should include traditional subject matter such as Newton’s second law, solution of differential equations, and fluid drag. Furthermore, a DBT project should include a major component of math modeling, and may include aspects of engineering practice such as engineering drawing, teamwork, personal documentation and communication skills. A DBT project is also designed to be easy to implement. The implementation goal is met when a project is transferable, sustainable, and scaleable. Scaleable means that a DBT project can be scaled in size (one week, twoweek, etc.) so that a professor can fit the project into his or her syllabus. In addition, a project is scaleable when it can

Donald F. Elger, University of Idaho, Mechanical Engineering Dept, EPB324H, Moscow, ID 83844--0902, [email protected] Steven W. Beyerlein, University of Idaho, Mechanical Engineering Dept, EPB324E, Moscow, ID 83844-0902, [email protected] Ralph S. Budwig, University of Idaho, Mechanical Engineering Dept, EPB324K, Moscow, ID 83844-0902, [email protected]

0-7803-6424-4/00/$10.00 © 2000 IEEE October 18 - 21, 2000 Kansas City, MO 30 th ASEE/IEEE Frontiers in Education Conference F3C-9

Session F3C be matched to the educational objectives of different courses, even though the topics differ and the educational levels of the students differ. For example, the save-thecitizens project can be scaled for use in a class at the prefreshman level (summer camp), a class at the sophomore level (dynamics) and a class at the junior level (fluid mechanics). A project is sustainable when it can be used many different times, thereby eliminating the need to constantly develop new projects. A project is transferable when one professor can develop the project and another professor can use the project, thereby eliminating much of the original developmental work. Our DBT projects are designed for implementation in courses at the junior level and below. This includes engineering science courses with heavy technical content as well as courses that focus on enhancing professional skills,

including application software usage, technical communication, team dynamics, and design methodology. There are several constraints. A project must be safe. A project must also be practical in terms of the amount of resources (time and money) consumed. The DBT project should require a realistic time commitment from students, it must complement a typical syllabus, and it should require an acceptable preparation time by the professor.

DBT PROJECT M ODEL Fig. 1 illustrates our model of a DBT project. The boxes shown illustrate the common elements that we incorporate in each new DBT project. A complete discussion of each topic in Fig. 1 is beyond the scope of a single paper. Here, we overview what we believe are the more important elements.


Session F3C Project Selection Before a DBT project is developed, a theme is selected. Themes are chosen to match subject matter being taught in a course. Themes are also chosen based on their intrinsic appeal. For example, the “save-the-citizens” project appeals to the fascination that most of us have with rocket flight. The “man-in-the-box” project is based on an army project, and this project can be made very appealing by introducing some of the real-world issues. A DBT project is selected so prototypes can be built quickly and at a low cost. For example, students can build prototype rockets for the save-the-citizens project in a short time (0.5 to 3 hr) at a low cost (less than $1.00, excluding the motor). Also, we design a project to promote creativity. For example, in the save-the-citizens project, students were required to build their rocket designs without commercial parts. The result was that students created an amazing variety of different rocket designs, most of which could not have been built with off-the-shelf parts. When students are assigned a DBT project, we communicate that design performance will be measured using one or more metrics. For example, the performance score P for the save-the-citizens project is defined as:

P = M 1 × M 2 ×100 In this equation, M1 is a metric which has a value of 1.0 if the rocket travels exactly to an altitude of 90 m. If a rocket flies too high or too low, the value of M1 decreases according to a Gaussian distribution. The metric M2 is given by M2 =m/(63 g), where m is the mass of navy beans carried by the rocket. Use of performance metrics is very important. This focuses students on the design goals, and it provides a concrete measure of design quality. The performance score promotes friendly competition between teams, and has proven to be very popular with students. Use of metrics provides a way for a professor to tailor the project to reinforce his or her educational objectives. For example, metric M1 was selected because it focuses students on designing with an engineering model as opposed to design by trial and error. Alternatively, metric M2 focuses students on fin design, aerodynamic stability, and topics like boundary layer that are related to design for low drag. To reuse a DBT project, we modify the metrics. For example, this semester we are reusing the save-the-citizens project. To reuse the project, we are changing the size of the rocket motor and changing the second metric to M2 = t/(15 s), where t is the time from launch to landing. Modifying the second metric will focus the students on parachute design and remove the focus from the topic of low-drag design. The design issues will be quite different, and the students will not be able to simply copy the work done last semester. For the professor, most of the developmental work is completed because he or she can use the resources developed from previous semesters. In addition, the issue of

parachute design will provide a new technical challenge to keep the professor from getting bored with the project. Mentoring Culture To facilitate a positive experience, we use cooperative learning activities and coaching techniques to encourage student design efforts. In fact, we deliberately suppress criticism in our classrooms and strive to create an environment in which student teams learn by doing. We allow students to fail, and then move on in their next design iteration. For many students, this is their first real design experience and we hope to communicate the affective assurance that “you can do this, and you will do an excellent job.” We do not lecture students on how to do things, rather we give them just enough information so that they can successfully experience self-discovery. We value innovative design efforts and approaches, and we do not prescribe a single method they must follow. At the same time, we structure the project so students regularly reflect on and improve their unique approaches to design. Because project reflection involves higher-order thinking skills, it is valuable to structure this to highlight out important details. We periodically ask students to identify strengths in their design process and challenge them to explain why these are valuable. Likewise, we also ask them to identify areas for greatest improvement and challenge them to explain how to implement their ideas. These reflective exercises are done in a variety of contexts—in journals, in team meetings, and in quick rounds of oral reports to the entire class. Dramatic improvement in reflective thinking is often observed throughout our DBT projects. Application of Education DBT projects feature the extensive use of science and math to guide design efforts prior to construction. The math modeling effort is substantial. We want students to learn how to apply mathematics to a complex problem that does not have a right answer. Furthermore, we want students to begin gaining a perspective on what can and cannot be modeled. Some of the strategies we use for guiding math modeling are (1) teaching the art of estimation, (2) teaching how to simplify a complex problem into a series of simple problems, (3) structuring the problem using the concept of iteration (next section), (4) giving students a “base-case” computer model, and (5) assessing each design against the math model prediction. In the case of the Save the Citizens project, we first help students construct a constant acceleration model that includes only rocket thrust and gravity. Next, we have them compare their height predictions with the performance of a first generation prototype. Throughout the project, we encourage them to increase the complexity of their math models to match the sophistication of their current prototype. We require each team to compile a portfolio comparing each


Session F3C generation of model predictions with data on actual prototype performance. In addition to math modeling, DBT projects are designed to involve other skills such as personal documentation and engineering drawing. Indeed, students report that the opportunity to apply material from their education is one of the most favorable aspects of the DBT project. Concept of Iteration To invent an airplane, the Wright brothers followed a systematic approach. In 1899, they designed a biplane kite, built it, tested it and learned from this experience. In 1900, they designed a glider, and repeated the construction, testing and learning cycle. After a number of design, build and test cycles, their efforts culminated with the first successful manned flight on December 17, 1903. We label the systematic approach of the Wright brothers as the “concept of iteration.” Designing a rocket that can achieve a high performance score in the save-the-citizens contest is extremely challenging, even for an experienced engineer. Thus, we structure the project using the concept of iteration. The first generation design uses a kit so students can learn the practical aspects of rocketry. The second design iteration involves a rocket built without any commercial parts. While most of these second-generation rockets are not flight worthy, students learn about key design issues. The thirdgeneration rockets typically fly along a variety of paths, most of which are not straight up, and they often crash dramatically due to recovery system failure. In later iterations, many students discover that physical understanding and math modeling can dramatically improve their results. The last few design iterations produce some truly awesome rockets. Math modeling is structured with the concept of iteration. For example, the first-generation math model may involve the equations of projectile motion. The secondgeneration math model may include integration of Newton’s second law and the inclusion of a constant drag force. Subsequent generations of the math model may include advanced topics such as variable drag force, variable mass, numerical integration of Newton’s second law, calculation of the center of pressure, prediction of drag, etc. The concept of iteration is an excellent way to teach engineering because it will work on real-world problems. Furthermore, this approach reduces anxiety and procrastination because it provides a natural way for starting a project and then making steady progress. We have found that using this concept eliminates the problem that is expressed when we hear students say “I have no idea of what to do.” Public Presentation We have found that students are motivated by the inherent fun and competitive challenge of a DBT project.

To heighten this excitement, we announce at the beginning of the project that the final designs will be presented to the public. Public presentation provides ownership of projects and is an excellent venue for celebrating collective achievement. We have experimented with several types of public presentations: design competitions, poster sessions, oral presentations, and refereed panel presentations. They have all been very well received by students and by faculty. In engineering science courses we often use just one form of final presentation. In professional skills courses, we frequently combine multiple forms of technical communication. We have found that a design competition coupled with a 10-15 minute Powerpoint presentation and a one-hour design show for peers, upperclassmen, and other faculty is an effective mix. Resources Each time we implement a DBT project, we collect materials. These materials, which we label as resources, improve the next project implementation (in a future class) by either improving the quality, reducing our efforts or both. Resources are items such as a report describing how to measure rocket altitude, a computer model to predict the drag coefficient, a handout on predicting parachute drag, a videotape illustrating a safe launch procedure, or a web page documenting different prototype concepts along with fabrication details. Resources dramatically reduce the effort needed for implementation of a DBT project. Resources also provide a way to transfer a DBT project from one professor to another. Good resources are the key to scaling a project to fit into a given class. By controlling which resources are provided to students, the professor can control the focus of a project and the time required by students to be successful.

STUDENT ASSESSMENT Save-the-citizens is our most recent DBT project. In the past year, it has been implemented in three classes: Engineering Design (sophomore level, 40 students), Fluid Mechanics (junior level, 25 students), and a two-week summer camp (high school, 40 students). Assessment data are comprised of written reflections in student journals and reports. We make a point to summarize the best individual and team discoveries at the end of each DBT project. We compile these in a 1-2 page handout that we share with our students as well as our colleagues. Students profit from reviewing examples of high quality responses composed by their peers and faculty appreciate the concise, insightful format. DBT Projects Are Fun and Motivating The student feedback about DBT projects is typically very positive. Below are some quotes from student reports. Note that our comments are added in italic.


Session F3C “In conclusion, our rocket did very well and was very successful. We learned that engineering can be a lot of fun, and that we can accomplish things we never expected.” Fun and success are two important features of the DBT experience. "The project reminded us that engineering is an art, as much as a science. It also emphasized that there is no substitute for dedication and hard work. In the end it convinced me that engineering is just a whole lot of fun." A nice perspective from a sophomore. “All in all, we had a great team and achieved great heights in both altitude and knowledge.” The team experience is an important part of a DBT project. DBT Projects Are Educational When students learn from their experiences, we find the results very exciting. Below we have selected some student comments that reflect their learning. Again, our comments are in italic. "An area for improvement was to do more background research before picking the rocket features.” Locating and learning information during design is a very valuable skill. "We should have brainstormed more. We found a design that we liked and before we reasoned out all of its implications, we decided that it was the way to go. Our maple seed recovery system (i.e. on descent, the rocket spun like a maple seed) was cool, but it didn't end up being very practical given the scoring criteria." Don’t lock onto your first design idea; considering alternative designs is very important. “Most likely, the first prototype will not even come close to being flight worthy ….” The importance of early prototyping cannot be overemphasized. “Our team learned the hard way that our parachute was not large enough” Figure out the design before construction. “We learned a great deal from our rocketry design project. First and foremost, we were able to learn from our mistakes—to which, at times, it seemed there was no bound.” Engineers get stuck and make plenty of mistakes, it goes with the territory. However, the idea is to learn from our mistakes and grow our design process. These students are on track!

“Nothing is more frustrating than coming up with an almost perfect design that cannot be built.” Consider fabrication issues during the design process. “We learned to successfully substitute a math model for a real-life situation and make predictions based on that model.” Eureka—An essential skill of engineering!

CONCLUSIONS The DBT concept facilitates purposeful design of a miniproject. DBT projects integrate math modeling and handson experimentation in a fashion that is both fun and educational for students and professors alike. A comprehensive discussion of the math modeling and rocket prototyping associated with the Save the Citizens project is planned for a companion paper. Recent NSF support will also allow us to incorporate wind tunnel testing related to this project. We expect that this will add a new an exciting dimension to DBT projects. DBT projects appear to be sustainable, transferable and scaleable. They have been successfully implemented in a variety of different class settings at the University of Idaho. Judging from the diversity of mathematical models, hardware prototypes, and design insights collected in all settings, the DBT project is a very effective way to apply engineering education and to enhance professional skills. Especially in introductory classes, we believe that DBT projects serve as an excellent retention tool as well as an integrative tool. We intend to explore these connections further in future FIE and ASEE papers.

REFERENCES [1]

Wankat, P.C., and Oreovicz, F.S., Teaching Engineering, McGraw Hill: New York, pp. 168-179, 1993.

[2]

Dym, C.L., and Little, P., Engineering Design: A Project Based Introduction, Wiley: New York, 2000.

[3]

Evans, D.L., McNeill, B.W., and Beakley, G.C., “Capstone Design for Engineering Freshman,” Proceeding: Innovation in Undergraduate Engineering Education Conference, Engineering Foundation, New York, 45, 1990.

[4]

Wales, C.E., and Stager, R.A., Guided Design, West Virginia Center for Guided Design: Morgantown, 1977.

[5]

Wales, C.E., Nardi, A.H., Stager, R.A., Thinking Skills: Making a Choice, West Virginia Center for Guided Design: Morgantown, 1987.


Session F3C USING DESIGN, BUILD, AND TEST ... - CiteSeerX

Session F3C USING DESIGN, BUILD, AND TEST ... - CiteSeerX

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