Teaching and Learning Engineering Design: A PBL Approach Nagaraj Ekabote1, Krishnaraja G Kodancha2 Automobile Engineering Department, BVB College of Engineering and Technology 1
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Abstract Teaching engineering design in early semesters of the mechanical science engineering is becoming a need to enhance student’s cognitive levels. Most of the foreign universities were practicing new pedagogies to teach engineering design to their students effectively. Project-based learning (PBL) is one of the pedagogy, which is popular due to its effectiveness in teaching the engineering design through course projects. Here an effort is made to adopt PBL with slight modifications by introducing the common problem to the third semester of Automobile engineering students. Engineering design process is followed to solve the problem of carrying LPG cylinder within a house. Five groups worked on this problem separately and produced five unique designs and fabricated working prototypes. This not only increased the student’s cognitive levels but also increased their competency in engineering design. With the help of this pedagogical method we are able to reasonably address ABET criteria’s 3a, 3d, 3e, 3g and 3i program outcomes. Keywords: Engineering design, project-based learning (PBL), ABET criteria. 1. Introduction Design engineering is one of the main streams in mechanical science engineering discipline. To meet the ABET criteria the curriculum should require design as a core course [1]. Efforts have been made to meet the ABET criteria, by introducing capstone projects and mini projects in the final and pre-final year of engineering respectively. The students and instructors face problems in implementing the design process methodologically through capstone and mini projects. This clearly shows a gap in understanding of the effective design process. This is in accordance with Duston et al. [2]. Because of which our graduates never ready for the industry, where the challenges are immense in the design field. Hence there is a strong need of relooking into the curriculum of mechanical science engineering. Introduction of the engineering design course, in the first or second year of engineering gives the flavor of design as a process rather than only calculations [3]. The efforts were made to teach design process effectively by bringing course projects. Course projects or Project-based learning (PBL) enhanced the student learning and bridge the gap [4]. According to Dym and Little [4], PBL in early semester of the engineering as a pedagogical tool to teach engineering design practiced by many universities. The course engineering design addresses hard problems because these problems are ill structured. Engineering design will be learned by doing [4]. Since the course engineering design needs practical exposure, PBL is ideal to apply. As per our best knowledge, the earlier contributed papers on PBL demand to increase the competency to the next level due to the need of the present scenario. As more engineers graduate every year, industries demand for high standards especially in competitiveness of the students.
Hence in order to bridge the identified gap, an attempt has been made to apply PBL to engineering design theory in three phases within a semester by posing a common project problem to all the student groups. The following section explains the methodology, three phases of PBL, results, discussion and conclusions in detail. 2. Methodology Engineering design has been defined in many ways by many researchers in recent past. Here we adopted a definition given by the Dym and little [5] as “Engineering Design is a systematic, intelligent process in which designers generate, evaluate and specify designs for devices, systems or processes whose form(s) and function(s) achieve clients’ objectives and users’ needs while satisfying a specific set of constraints”. Moreover engineering design is a thoughtful process which can be understood by young designers’ effectively through course projects. The engineering design course is being taught in our institute for 3rd semester Automobile engineering students with PBL. The process/model considered for engineering design in the course is shown in Fig.1. Problem Statement
Revised Problem Statement
Conceptual Design
Manufacturing Drawing
Fabrication
Design Communication
Fig.1. Engineering Design Process
Total of five groups were made out of twenty students and given a common problem, of social concern. The constraint put on the group of students were money and time for improvement in competency in the design field. Each team should come up with an innovative conceptual design and working prototype during three months of duration which is spread in 3 phases. The course was of 4 hours/week, in which 2 hours was of theory and rest was tutorial. In the tutorial interaction with students were held, where the doubts on using certain design related decision making tools were discussed. Students have to show weekly progress to the course instructor and take the guidance from anyone viz. other staff members, fabricator, sales persons etc. The engineering social problem was chosen in such way that the students should be able to apply the fundamental engineering subjects studied so far and demonstrate the knowledge gained in engineering design theory. In the present study the social problem chosen was to “Obtain a conceptual design and fabricate a device which is useful to move the gas cylinder from one place to another place within house with minimum human effort.” 2.1 Phase 1 In the first step students were made to perform individually and submit the soft copy of the work done within five weeks immediately after defining the problem statement by the course instructor. Each student first studies the problem through rigorous literature survey which they have been assigned and the copy should follow the flow shown in Fig.2. Here student define the objectives and constraints for the given problem with the knowledge gained in the theory. Based upon the literature survey the student will able to redefine the problem statement. For the objectives defined earlier students develop the metrics to measure the same in the final stage of the conceptual design. Morphological chart is to obtain alternate solutions for the problem posed. Here for the set of functions, student writes the means and obtain the alternatives by different
combinations for each function as shown in Table: 01. Finally one feasible solution will be selected among the alternatives generated by the student, and model that by using software. The model should contain the main dimensions and name of the parts. Typical solid edge model created by one of the students is shown in Fig.3. Literature Survey
Feasible Conceptual Design
Functions
Defining Objectives and constraints Revised Problem Statement Developing Objective Tree
Table : 01 Morphological Chart
Developing Metrics for objectives
Morphological Chart
Material Used for Base and Handle
Function Means Tree
Material Used for Wheels Shape of the Wheels Mechanism to Provide Displacement
Pair-wise Comparison Chart
1 Steel
Means 2 3 Aluminum Wood
4 Plastic
Wooden
Plastic
Rubber
****
Spherical
Cylindrical
****
****
Pulling
Pushing
Electrical
****
Fig.2. Flow of Phase 1
2.2 Phase 2 Immediately after phase 1, student joins their respective group members to finalise best feasible model between them. Four members in a group mean four different models among them. The task to decide the best was solved by using tools and methods dealt during Engineering design theory classes. One of the methods is Numerical Evaluation chart, where all models were assessed to their objectives and constraints defined earlier and the marks allotted are as shown in Table: 02. In this way they arrive at feasible solution. At this stage slight modification of the selected model was allowed among the team members with justification. After finalising the conceptual design, students list out the basic manufacturing methods required for fabrication of the conceptual design along with the calculation required to justify the design. Each team have to present their progress after 4 weeks with the help of power point presentation. At this juncture the body language, quality of slides and communication skills are assessed. They have to demonstrate the selection procedure of best feasible design keeping in mind of imposed constraints. The model containing details of fabrication of the product was presented at this phase. Table : 02 Numerical Evaluation Chart
Fig.3. 3D Model of Cylinder Carrier
Model 1
Model 2
Model 3
C: Cost
√
√
X
C: Moveable
√
√
X
O: Durable
80
60
---
O: Portable
70
80
---
O: Safe
60
50
---
Total
210
190
---
2.3 Phase 3 The suggestions and improvements suggested during the phase 2 presentations by the course instructors have to be implemented in the fabrication of the product. Two weeks of time has been provided to correct and implement the suggestion. The exhibition of the product developed was made on a prescribed date and venue, where the higher semester students and the staff were invitees. Final and pre-final year students were asked to give both positive and negative criticism about working prototype. Teaching staff were also assessed the student’s decision making process, basics/fundamentals used in working of the model, explanation of the working prototype and most importantly the team work. Fig.4. shows all the five working prototypes of cylinder carriers which were demonstrated in the project exhibition.
Fig.4. Project Exhibition of Cylinder carriers
3. Discussion and Conclusions The discussion in this paper majorly contributes to the student’s learning enhancement through minor modifications in PBL. The reviews in each phase helped the students to apply fundamentals/basic knowledge to practical problems and to work in a team environment. Tutorials made the students to discuss their problems about effectiveness of the decision making tools/methods. Open-ended theme made students to realize that for any problem there are multiple solutions, which drives us to design with new concepts and new products. Students realized the importance of reframing the problem according to the needs of the users through literature survey. This is attributed to the modified pedagogy. Feedback from some potential users of the prototype were taken and tried to incorporate those, as without feedback design process will not be completed. Transfer of thought to unique prototype without violating certain objectives and constraints was successfully demonstrated through engineering design process. In a nutshell, the new pedagogical tool has been found to be effective in improving the skills like leadership while handling the project teams, persuade effectively the ideas and associated methods to the teammates and also others, personal accountability to take responsibility, goal orientation and above all interpersonal skills, which are essential characteristics of an entrepreneur. Though a quantitative analysis of the outcome in this regard has not been done by the authors, improvements have been witnessed. It is also anticipated that, the present pedagogical tool is expected to help the students in higher semesters to take active part and implement the deliverables of experiential learning of engineering design course in the miniprojects and Capstone projects. Hence it can be concluded that, finally when a student undergoes
this curriculum structure he/she is expected to be ready for undertaking entrepreneurial initiatives to help the scientific community and society. Handling large class room for these kinds of subjects is a big challenge for the course instructor. Authors feel, as long as pedagogies are modified according to geography and cultural changes the learning will enhance in a measurable quantity. The major findings in this modified pedagogy applied to engineering design are outlined as follows:1. Student’s cognitive levels enhanced in the design and fundamentals due to the involvement in the project work. Tutorials played a major role in building confidence and one to one interaction with the staff made them to explore the subject in to a new level. 2. The project problem being common, team role and effort was tremendous as the information gathered to take decisions in the project kept secretive to other batches. Since the rubrics demands unique and innovative product, this made them as a team player and leaders to take decisions in the process. 3. Student identified the social problem, formulated into the useful format and solved the same by using engineering design process, which enabled to reasonably satisfy the ABET’s 3e program outcome. And also conclusions 1 and 2 addresses ABET’s 3a, 3d, 3g and 3i program outcomes. Acknowledgement Authors gratefully acknowledge the support by beloved Students, Faculty and Staff, department of Automobile Engineering, Principal and Management of B. V. B. College of Engineering and Technology, Hubli, Karnataka. References [1] Evans, D.L., McNeill, B.W., and Beakley, G.C., “Design in Engineering Education: Past Views of Future Directions,” Journal of Engineering Education, Vol. 79, No. 4, 1990, pp. 517–522. [2] Dutson, A.J., Todd, R.H., Magleby, S.P., and Sorensen, C.D., “A Review of Literature on Teaching Design Through Project-Oriented Capstone Courses,” Journal of Engineering Education, Vol. 76, No. 1, 1997, pp. 17–28. [3] Dym, C.L., “Teaching Design to Freshmen: Style and Content,” Journal of Engineering Education, Vol. 83, No. 4, 1994, pp. 303–310. [4] Dym, C.L., and Little, L., Engineering Design: A Project-Based Introduction, 3rd ed., New York, N.Y.: John Wiley, 2003. [5] Dym, Alice, Ozgur, Daniel and Larry, “Engineering Design Thinking, Teaching, and Learning,” Journal of Engineering Education, Vol. 94, No.1, 2005, pp. 103-120.
