AC 2007-945: The converging-diverging approach to design in the sophomore engineering clinic

The Sophomore Engineering Clinic at Rowan University is a two-semester sequence intended to teach engineering design and communication. Historically, the course has been taught with semester-long projects, one in the fall and one in the spring. An example from the fall 2003 and 2004 semesters was the Hoistinator project. Student teams of 4-5 were challenged to build a crane that could lift at least 420 pounds, using no more than 75 cubic inches of aluminum and 50 cubic inches of plastic. Teams would receive a score that was directly proportional to the amount of weight lifted, and inversely proportional to the amount of material used. The project was successful in many respects but there was room for improvement in the student's overall approach to the design problem. Students were generally successful at using statics to predict their crane's performance, but the cranes they designed and built were generally not well optimized. Many student teams chose a basic design quickly and after investigating few, if any, alternatives, and in many cases important decisions were made without a quantitative analysis. During the fall of 2005, the faculty team addressed this shortcoming by 1) establishing a sequence of design projects that increases in complexity, and 2) presenting a converging-diverging approach to design, modeled after a paper by Dym, et. al.1 Rather than a semester-long project, the faculty provided a four week project on designing bottle rockets followed by a 10-week version of the Hoistinator project. Students were required to document their approach to these problems in detail, showing specific evidence of divergent design and convergent design and specific rationale for the final decisions resulting from these processes. A comparative assessment demonstrated that the new approach had a substantial and lasting impact on student design skills: fall 2005 students not only performed better on the Hoistinator project than earlier cohorts, but also performed significantly better on a spring 2006 Sophomore Engineering Clinic project that was essentially unmodified from previous years. This paper will explain the convergent-divergent design model, provide a description of the design projects, and present in detail the comparative assessments of the effectiveness of this approach compared to prior offerings of Sophomore Engineering Clinic that did not explicitly incorporate the convergingdiverging design model.