1
(Paper presented at American Society of Engineering Education Illinois/Indiana Sectional Conference,
29 March 2001, Purdue University, W. Lafayette, IN)
DESIGN-BUILD-TEST PROJECT TEAMS THAT INCORPORATE
ENGINEERING AND TECHNOLOGY STUDENTS
Alten F. Grandt, Jr1 and William A. Watkins2
1
School of Aeronautics and Astronautics, 1282 Grissom Hall, Purdue University, W. Lafayette, IN 479071282, 765-494-5141, grandt@ecn.purdue.edu
2
Department of Aviation Technology, Purdue University, W. Lafayette, IN 47905, 765-494-0362,
wawatkins@tech.purdue.edu
Abstract—This paper reviews the authors’ efforts to provide
inter-disciplinary teamwork experiences to students in the
Purdue University School of Aeronautics and Astronautics
and the Department of Aviation Technology.
Senior
undergraduates from two separate classes in these
engineering and technology departments are matched on
cross-class project teams that involve designing, building,
and testing simple mechanical components. This designbuild-test experience is provided in the context of an
industrial setting where ad hoc multi-disciplinary teams are
created to accomplish a specific task. These cross-class
projects have been conducted annually since the fall
semester of 1995, and are planned to continue in the future.
It is felt that these projects provide students with an
appreciation for the value of interdisciplinary teamwork by
simulating many issues associated with industrial teams. It
is suggested that faculty in other disciplines may wish to
provide their students with similar cross department
teamwork activities.
Index Terms—Design-Build-Test, interdisciplinary teams,
design education, design projects.
INTRODUCTION
Modern industrial management systems have found
that multi-disciplinary project teams provide synergism that
leads to lower costs, improved quality, better delivery
performance, and better overall customer satisfaction [1]. In
addition to promoting more pride of ownership by the
employee, significant improvements in the development
process occur when all project disciplines are included
during the planning stages. While team projects are
common in engineering and technology classes, course
prerequisites often lead to homogeneous teams that limit
interactions between students with significantly different
backgrounds and career goals. Thus, it is difficult for a
single class to simulate teams with the broad technical
diversity encountered industry. To address this problem, the
authors team senior students from an aerospace engineering
design class (AAE 454, Design of Aerospace Structures)
with students from the Department of Aviation Technology
(AT 490D Advanced Aircraft Structures and Repair). Each
class has its own separate objectives and prerequisites, but
shares responsibility for one cross-class project.
The design-build-test (DBT) project is chosen to be
beyond the scope of either class, but within the combined
skills of the two sets of students. Although the two classes
weigh the team projects differently with respect to the final
course grade, each team member receives the same project
grade. This procedure provides the unusual condition where
student grades in one department depend, in part, on the
performance of students in another department. Such a
situation is not uncommon in industry, however, where
individual rewards often depend on the performance of other
organizations.
Moreover, since students have other
assignments and requirements for their home class, they gain
a better appreciation for the context of ad hoc crossdisciplinary teams in the workforce.
The aerospace engineering (AAE) students have a
strong background in strength of materials, failure criteria,
aerospace materials, structural design, and stress analysis
gained by two prerequisite courses in aerospace structural
analysis and design. While some engineering students also
have exposure to finite element structural analysis, most
have not yet completed a course in this subject. The aviation
technology (AT) student prerequisite is a junior level course
in advanced aircraft materials and processes. That course
introduces the basic principles of statics, strength of
materials, controlling material strength, and laboratory
experience with advanced techniques for riveted and welded
joints and basic machining processes. Typically several AT,
and some AAE students, will also have machine shop
experience external to the university.
DESCRIPTION OF DESIGN-BUILD-TEST
PROJECTS
The cross-class assignments entail designing,
fabricating, and testing a minimum weight and cost structure
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subject to several specified constraints. The authors form
teams and issue a formal RFP by the end of the second or
third week of the 16 week semester. The teams are given
several weeks to prepare a formal design proposal that
satisfies the given RFP requirements. This “design” consists
of documented materials selection, stress analyses,
preparation of engineering and assembly drawings, and
development of production process sheets for all
manufacturing activities. The teams are given a budget to
purchase materials (typically $100 – $150 provided by
industrial sponsors) from a material supplier’s catalog. This
procedure defines the available materials and product forms
that can be used for the project, and also forces consideration
of both price and product availability.
Following acceptance of the proposal by the
instructors (including revisions), materials are ordered and
the teams build the components in the Aviation Technology
machine shops. Labor rates are established for machine
tools, and each team is required to record actual machine
time, leading to another component of production cost. The
final products are tested in the School of Aeronautics and
Astronautics Fatigue and Fracture Laboratory.
When
possible, the specimens are loaded to destruction to
determine the ultimate load capability and to identify “weak
links” in the structure. The destructive test provides the
opportunity to analyze the failure mode, and determines if
the component was “over” or “under” designed. The teams
then prepare a final report and presentation that assesses
their design’s strengths and weaknesses, identifies
components that needed additional strengthening, and
discusses potential areas for weight savings.
The Fall 2000 project is summarized schematically
in Figure 1a. The goal here was to design a cantilever beam
that would be bolted to the test machine at one end and to a
lever at the other end through specified bolt-hole patterns. A
1000 lb force was to be applied to the lever without causing
permanent deformation in the beam or allowing the free end
of the lever to deflect more than 2 inches. The member was
then to be unloaded, checked for permanent deformation,
and reloaded to failure, where it must withstand 1500 lbs
without total collapse. The beam was to be a specified
length and to have a cross section that fit within a 6 x 8 inch
triangular envelope. It was also to contain a watertight
compartment with access panels that could be opened and
closed within 10 minutes to store a “black box” of specified
dimensions. Students were also judged on their ability to
minimize component weight and costs (both purchased
materials and manufacturing labor), and on the quality of
manufacture.
A photograph of the 2000 class DBT projects is
given in Figure 1b. Although these members may appear
similar at first sight, they are actually quite different in
construction details and performance, attesting to the
different design approaches followed by individual teams.
The beam weights, for example, varied between 5 lbs-4 oz
and 6 lb-13 oz, while the failure loads ranged between 280
lbs and 1710 lbs. Purchase price for component materials
ran from $108.64 to $153.50, while the manufacturing costs
(measured in machine tool time) varied between 20 and 59
hours. Although only one of the five teams satisfied all of
the specified design constraints, two others came very close
to meeting all RFP requirements.
Other DBT projects employed in previous years
are summarized in Table 1. They also typically require the
components to withstand a 1000 lb force without exceeding
some specified elastic deflection, and then to resist a final
1500 lb force without complete collapse. The 1995 project
simulated a landing gear actuating structure, while the 1996
class considered a thin-walled stringer reinforced beam
subjected to three-point bending and/or torsion. The
adjustable mechanism of the 1995 project was to fit within a
given storage box and was to accurately position one point
when two other points were moved a fixed distance. The
1996 project involved a beam that was to fit within a given
enclosure and to provide internal access for a “black box” of
specified dimensions.
The 1997-1999 DBT projects are versions of the
2000 cantilever beam project described previously. These
beams typically involved two or three “bends” between the
fixed and free ends, leading to several joints between the
various segments of the beam. Geometric requirements
specified an envelope for the maximum component
dimensions, located the mounting and loading points, and
required that the beams be disassembled into smaller
components for storage. This disassembly had to be
accomplished with “standard shop tools” within ten minutes.
DISCUSSION OF RESULTS
As discussed previously in connection with the
2000 DBT project, the student teams exhibit a wide variation
in performance. Typically some will produce structures that
fail to meet the RFP’s loading or geometric requirements,
and others will construct “heavy” components that are
significantly over-built. Usually, however, at least one team
will manufacture a light-weight structure that satisfies the
RFP requirements.
Some groups demonstrate strong interactions
between the engineers and technologists, while other teams
appear to operate in the “throw it over the wall mode” with
the engineers and technologists performing individual tasks
more or less independently. The latter approach often results
in finger pointing when a deadline was missed or something
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went wrong. It is felt, however, that these “failures in
communication” do provide a valuable learning experience.
There are a number of other student team issues
that simulate real world industrial experience. It is not
always possible, for example, to have the same team size
and mix of engineers and technologists. In addition, the
frequent need to modify the teams to accommodate students
who add or drop the course during the first weeks of the
semester gives experience with the impact of company
mergers or lay-offs. These changing resources are a fact of
life that the students will encounter in industry.
teamwork (and problems associated with team breakdown).
The authors plan to continue similar cross-class laboratory
projects in the future, and offer these suggestions to others
who are interested in pursuing similar projects.
1.
2.
Another serendipitous consequence of the disparity
in team composition arose in 1997 when an industrial
sponsor provided a $300 prize for the best DBT team. It was
necessary to have technology students serve on more than
one team to achieve the desired mix of engineering and
technology expertise that semester, leading to an apparently
unfair financial advantage for the technology students. It
was pointed out to the students, however, than this situation
frequently arises in industry when a particular company may
join two or more competing teams to bid on a RFP. The
potential inequities of that situation require formal industrial
teaming agreements to deal with issues of proprietary
information. Thus, it was decided to have the student teams
prepare written teaming agreements that dealt with the
responsibilities and restrictions imposed on students who
were members of more than one DBT team. This exercise
turned out to be an excellent educational experience, and the
requirement to prepare teaming agreements amongst
individual students has been repeated in subsequent years.
3.
4.
5.
It is essential that project complexity matches the
technical and manufacturing capabilities of the
participants, available facilities, and semester
length.
In order to provide time for students to interact, and
experience the “give and take” of a team activity,
they should be able to begin work on the project
immediately. Thus, introduction of new concepts
needed to complete the project should be kept to a
minimum.
Frequent milestones, and other structured activities
that require team interactions early in the semester
should be encouraged to help the groups get to
know each other and to learn to work together.
Discussion of group dynamics and team building
concepts should be provided early in the semester.
Since industry recognizes that development of team
working skills often requires facilitation, facilitators
may also be helpful for student teams to learn to
work together effectively.
It may also be of interest to pair beginning students
with the upperclassmen in a given department to
provide mentoring aspects to the program.
ACKNOWLEDGEMENT
SUMMARY AND CONCLUSIONS
The cross-disciplinary projects DBT have proven to
be quite effective in providing both student groups exposure
to different aspects of structural design and manufacturing.
The AAE students, educated in stress analysis and design,
gain experience with manufacturing methods and how they
impact design.
The AT students, well versed in
manufacturing and process drawings, learn about structural
design and analysis. All students gain experience with
structural testing to demonstrate product performance,
failure analysis, and with a “cradle to grave” project that
sees paper designs fabricated and tested. Most importantly,
all students gain a better appreciation for cross-disciplinary
The DBT projects described here have been
supported by grants from the Indiana Space Grant
Consortium, Boeing North America, and by Allied Signal.
REFERENCE
[1]
Groover, M. P., Fundamentals of Modern
Manufacturing: Materials, Processes, and Systems,
Prentice-Hall, 1996, p. 977.
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Figure 1.a. Schematic description of 2000 design-build-test project design requirements
Fall 2000 AAE 454/AT 490 DBT Project
Goal: design/build/test cantilever beam AB
Constraints:
y
“free” end
“fixed” end
– Bolt fixed end (A) to test machine
– Load through lever bolted to free end (B)
– Point C deflect < 2 inch when 1000 lb force
P applied at C
– Withstand 1500 lb force P without collapse
– Cross section fit within 6” x 8” triangular
envelope
– “Black box” to be contained within beam
• “Protected from the elements”
• Install black box/seal access panels
within 10 minutes
– Minimize weight and costs
– AAE/AT student team project
Schedule
–
–
–
–
1 September RFP issued
Week 2 October: preliminary design review
Week 13 November: projects due/tested
Week 11 December: final presentations
x
B
A
Loading fixture
z
“beam” member
C
P
Outer envelope for
beam cross section
y
“Black box”
6 in.
z
8 in
4 holes @ 0.50 in. dia
Bolt hole
pattern at ends
A and B
Points
A or B
2.00 in.
Figure 1. b Photograph of resulting components
2.00 in.
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Table 1 Summary of AAE 454/AT 490 Design-Build-Test Projects
Year
Number
of
teams
Description
1995
6
Mechanical
linkage
1996
3
1997
4
Thin-walled
beam loaded in
3-point bending
or torsion
L-shaped
cantilever beam
loaded in
bending and
torsion
1998
5
1999
4
2000
5
Z-shaped
cantilever beam
loaded in
bending and
torsion
Three segment
(3-D) cantilever
beam loaded in
bending and
torsion
Cantilever beam
loaded in
bending and
torsion
Constraints
Comments
Failure
criteria
Geometric
Other
Elastic
deflection,
yield, buckle,
fatigue
Elastic
deflection,
yield, buckle,
fatigue
Elastic
deflection,
yield, buckle
Move point to
specific location,
fit in box for
storage
Maximum outer
envelope
dimensions
specified
Outer envelope
and attachment
holes specified
Minimum weight,
cost
Elastic
deflection,
yield, buckle
Outer envelope
and attachment
holes specified
Minimum weight,
cost, disassemble in
specified time limit
Elastic
deflection,
yield, buckle
Outer envelope
and attachment
holes specified
Minimum weight,
cost, disassemble in
specified time limit
Elastic
deflection,
yield, buckle
Outer envelope
and attachment
holes specified
Minimum weight,
cost, contain
internal storage
AT students on
multiple teams
Minimum weight,
cost, provide
internal storage
Minimum weight,
cost, disassemble
for storage in
specified time limit
AT students on 2
teams.
Teaming
agreement for
prize money
AT students on 2
teams