involving undergraduate engineering students in design of

Proceedings of the 2002 American Society for Engineering Education Annual Conference & Exposition Copyright © 2002, American Society for Engineering Education

Session 1566

INVOLVING UNDERGRADUATE ENGINEERING STUDENTS

IN DESIGN OF AN AFFORDABLE MODEL LABORATORY

Bijan Sepahpour The College of New Jersey Department of Engineering

Ewing, New Jersey 08628-0718 Tel. 609.771.3463

[email protected]

ABSTRACT A promising model for involving undergraduate engineering students in design of experiments and fabrication of their associated apparatuses is proposed. It is a proven fact that students learn better and retain more information by doing rather than hearing or observing. Some also learn best when they are allowed to discover on their own. Due to the influence of the ABET 2000 Criteria, all engineering students must develop the ability to design and conduct experiments, analyze and interpret data, and communicate the results effectively. Many undergraduate engineering programs suffer from lack of equipment/apparatus for experimentation. Commercial units are very costly and generally not exactly custom tailored for the specific needs of certain topics in a course. This model may be incorporated into a typical four-year undergraduate engineering curriculum to successfully address many of such concerns. In their laboratory-oriented courses, student groups are encouraged to design meaningful experiments. In this process, the coordinator may be able to discover those students with a high level of interest and enthusiasm. Some of these student-proposed experiments may be expanded/fine tuned into conceivable and practical entities. Several such experiments and their associated apparatuses that have been successfully conceived through the proposed approach are briefly discussed. These case studies range from a simple and yet quite an ingenious experiment to those that are novel and not commercially available. Elements of Group Dynamics and the instrumental role of the coordinator in recognizing the capabilities and limitations of each group and his/her necessary willingness to spend the time for provision of guidance at the critical stages are discussed.

I - INTRODUCTION This paper describes the parameters involved in the generation of an exemplary and yet affordable undergraduate laboratory designed for conducting experiments in Mechanics of Materials and Dynamics of Machinery. The central role of the undergraduate students and the instrumental role of the coordinator in achieving this task are discussed.


As of now, fourteen (14) experiments and their seventeen (17) associated apparatuses are being developed under this plan. Upon completion of the design, fabrication and full testing of these proposed experiments, a comprehensive information package may be generated for national dissemination. As a package, they may lay the foundation for a starting laboratory course or selectively, each of them may be added to the existing archives of experiments at many undergraduate engineering programs. Enthusiastic undergraduate students have been participating in the implementation processes of research, design and development necessary for materializing all components of the Model Laboratory. Their understanding of group dynamics and appreciation for cost-effective and superior designs has been enhanced. Partial support of NSF (which started from spring of 2002) has increased the momentum of the efforts that started in 1998 for creation of the State of the Art Laboratory. Successful implementation of this project will result in several measurable outcomes including:

1. Generation of comprehensive blueprints for fabrication of apparatuses necessary for precision

experimentation in the areas of Mechanics of Materials and Dynamics of Machinery. 2. Creation of detailed laboratory manuals-ready for distribution to students. 3. A well thought out and comprehensive plan for putting together an affordable model laboratory

that successfully addresses the fundamental requirements of undergraduate laboratories in mechanical and civil engineering as well as engineering technology programs.

4. Enhancement of capabilities of future engineers/educators by their involvement in the processes of research, design and development and group dynamics.

5. Creation of a National Data Bank for submission and distribution of all information necessary for putting together an affordable model laboratory that may successfully address the fundamental requirements of undergraduate experimentation in mechanics of materials and dynamics of machinery.

Collaboration with colleagues may further enhance the quality of the proposed model laboratory, which may then be considered for adaptation and implementation on a national scale. II - THE PROBLEM With the start of the new millennium and expected global competition in nearly all aspects of technology, the issue of the quality of undergraduate education delivered to future engineers/educators has hardly ever been as pronounced. In this highly information technology (IT) driven era, the challenge for engineering schools and their educators is to provide the needed brain power and innovation not only to information-based companies, but also to those that operate in what we might call the “old economy”- the companies that make “things” rather than just move information. [1]


The Accreditation Board for Engineering and Technology (ABET) places heavy emphasis on the quality of undergraduate education by scrutinizing all facets of such programs nationwide under its 2000 criteria. One of the important aspects of any engineering discipline is the degree of involvement of the graduates with hands on experimentation and the ability to design and conduct experiments. Laboratory apparatus is generally expensive due to low production levels and specialized features. Further, to avoid demonstration (rather than experimentation), in larger class sizes, multiple numbers of the same apparatus are usually required for controlling time constraints. One of the major contributing factors in making engineering programs expensive is the cost of the apparatus and equipment required for experimentation. Recent enrollment figures at smaller engineering programs have challenged their survival. The models of administrations of colleges and smaller universities for allocation of the budget are (usually) heavily influenced by the enrollment figures at each of the departments. The combined effects of these factors may pose some significant difficulties for low-budget programs in terms of justification of the cost. Consequently, students may be deprived from being sufficiently exposed to important concepts such as verification of engineering theories through experimentation, interpretation and analysis of data and gaining sufficient background for designing experiments.

III - A POTENTIAL SOLUTION The necessary and sufficient conditions for creating meaningful laboratory components of engineering courses and programs may be described as:

1. Availability of laboratory coordinators with high levels of dedication, enthusiasm and know-how,

2. Availability of the required space, 3. Availability of the apparatus and equipment required for conducting experiments.

Assuming that the first two of these conditions are in place, strategies for satisfying the last condition must be developed. To best utilize the available space with the minimum required apparatus and equipment, the cost factors must be brought under control. Computer software and hardware prices are continuously dropping; making the major ingredients of the necessary laboratory equipment attractively affordable. Cougar and McFadden state that “if the automobile industry had been able to advance its technology as rapidly as the computer industry, a Rolls-Royce would cost $2.50 and would get 2 million miles per gallon!” [2] Unfortunately, such is not the case for the required apparatus. Even for non-profit organizations, materials, components and machining costs are unavoidable. The high cost of such products may be explained by the following two main factors: 1. The limited number of orders,

2. Significantly higher Design Costs built into the final cost.


However, if blueprints of the designs of the apparatus are available, a significant decrease may be expected in the final cost. Such designs and blueprints may be generated in-house in collaboration with undergraduate students. Prototypes of such units may be constructed and tested to ensure the high quality and reliability of the suggested designs. Potential fabrication of the tested designs may also be conceived at the facilities of such programs. Enthusiastic engineering students, the machinists and technicians of the department may collaborate with the coordinator in achieving such a task. Comprehensive blueprints of the designs along with their corresponding laboratory manuals may be distributed to all engineering programs. Engineering faculty at other institutions may consider adopting this model and joining forces to create a large Data Bank for compilation of the results of their valuable efforts. IV - LABORATORY COURSES AND THE IMPORTANCE OF THEIR SEQUENCE Laboratory experimentation is a critical final link for a thorough understanding of scientific and engineering theories. Every possible effort should be made not to deprive the future engineers/educators from this vital component of their education. Many colleagues involved in the teaching and conducting of laboratory courses subscribe to this ancient Chinese proverb:

"When I hear, I forget - When I see, I remember - When I do, I understand." Traditionally, laboratories are employed in such a manner that the students conduct the corresponding experiments of certain theories one or two semesters after they have had exposure to them. In this way, experiments related to several subjects may be “packaged” in a single laboratory course. The major advantage in this approach is “presumably” the elimination of all synchronizing activities required in a mixed lecture-lab course and greater development of measurement theory. However, the main disadvantage is the loss of “the two-way street” through which the theory and the experimentation simultaneously enrich understanding by supporting each other. Recognizing this dilemma, we (at the College of New Jersey - TCNJ) have tried to bring the best of the two worlds together and minimize the loss in the previous model. [3] To achieve such an idealized environment, the following five major questions/difficulties should be addressed:

1. What material should be covered in each of the courses in the sequence? 2. How much time should be allocated on a weekly basis? 3. Where should these courses be placed in the body of the 8-semesters? 4. How many lab courses are necessary? 5. How many credits should be allocated for each of the courses?

It is highly desirable to maintain the integrity of “the two-way street” approach. Therefore, every effort should be made to maintain the close proximity of lecture-laboratory material. The number of


courses should be decided based on the need for synchronization with the lecture materials of the courses. The courses should meet weekly for one 2 ½ -3 hour session in the 14-week semesters. The following table displays the order in which the mechanical laboratory courses (at TCNJ) are placed in the program along with their relations to other supporting courses.

SUPPORTING COURSES

COURSE

YEAR TAKEN

TERM TAKEN TAKEN PRIOR TAKEN CONCURRENTLY

MECH. LAB. I

2

2

· PHYSICS I & II · TECH. WRITING · STATICS · COMPUTER

PROGRAMMING · DIFF. EQS.

· MECHANICS OF MATERIALS · MATERIAL SCIENCE · PROBABILITY · DYNAMICS

MECH. LAB. II

3

2

· THERMO. I · NUMERICAL ANALYSIS · ADVANCED MATH. I

· THERMO. II · FLUID MECHANICS · ADVANCED MATH. II

MECH. LAB. III

4

1

· MECHANICAL ENGINEERING

ELECTIVE I

· HEAT TRANSFER · CONTROL SYSTEMS

MECH. LAB. IV

4

2

· MECHANICAL DESIGN ANALYSIS · MECHANICAL

ENGINEERING ELECTIVE II

· COMPUTER AIDED DESIGN · DIGITAL CIRCUITS AND MICROPROCESSORS · MECHANICAL

ENGINEERING ELECTIVE III

Table 1: Sequence of the four laboratory courses and their relationship with lecture courses

V - INVOLVING STUDENTS Engineering students at TCNJ take their first Mechanical Laboratory course simultaneously with the Mechanics of Materials course in the second semester of their sophomore year. Students, in groups of three-four are charged with the task of designing an experiment that examines the validity of a physical law/engineering principle/formula or a technique/approach that measures a certain quantity. This requirement is carefully matched with the theoretical content of the two interdependent courses.


In this process, the coordinator will be able to discover groups/students with high level of interest and enthusiasm. Some of these proposed experiments may be expanded/fine tuned into meaningful and affordable entities. Alternatively, the coordinator may discover the need for a certain experiment, define the problem for a group of interested students/class and collaborate with them in the brainstorming, prototyping, testing and conceiving the final unit. This trend may continue through the second, third and the final laboratory course. In exceptional cases, the efforts of the student(s) may be justifiable for credits towards an independent study course or even a senior design project. Incorporation of design all through an engineering curriculum provides opportunities for young engineers to recognize their full potential and increase their confidence level significantly. Thus, they would be better prepared to meet the most critical demands of today’s industry. [4] The proposed model would provide opportunities for undergraduate students to get involved in the process of design and development of both the experiments and the associated apparatuses. This would be a process through which the serious students may develop a much deeper appreciation of the subject matter as well as the design and development process in a realistic environment. Equally important, it would enhance their chances for receiving Research/ Teaching Assistantship or Full Scholarships in graduate engineering programs. The following case studies reflect on the promising nature of this approach/model. VI - CASE STUDIES 1. Universal Combined Stress Apparatus (UCSA) and an Example of Team Work While most commercially available apparatuses provide data for a single type of load, no such educational apparatus for generation of (simultaneous) Combined Stresses existed. Creation of such an apparatus would be a remarkable addition to the engineering laboratories at any inst itution. This unique apparatus and experiment is designed to investigate the state of stresses in combined loading scenarios. Eight (8) Rectangular Rosette Strain Gauges are strategically installed on two different sections of the specimen (6061-T6 Aluminum Tubing with 1/8" wall, 3.75" O.D. and 42" Length/Height) to generate 24 strain readings leading to the values of the corresponding eight (8) Principal Stresses and Maximum Shear Stresses. Specifically, it is designed for:

1. Generation of incremental precision torque for application of pure torque, 2. Generation of incremental bending moment in the X-Y plane, 3. Generation of incremental bending moment in the Z-Y plane,

4. Any combination of the loads available in steps 1, 2, and 3 resulting in a combined loading / combined stress situation.

The tested apparatus consistently returns results with high level of accuracy and precision when compared to expected theoretical values. Appendix A-1 contains photographs of the completed “Universal Combined Stress Apparatus.” Appendix A-2 contains samples of stress data generated using the “UCSA” for eight (8) stress elements during different loading scenarios. Three engineering students (Kevin Olesky, Carl Janetti and Patrick Carroll) collaborated with the


coordinator in nearly all phases of the project; Design and Fabrication of the "UCSA". These three students got fully exposed to the entire spectrum of the project - from First Draft to the Final Production and Comprehensive Testing of the device. They started their involvement in spring of 1998 and continued until the end of summer of 1999. Their high level of enthusiasm, dedication and voluntary base contributions was rewarded by the Department’s Service Award in May of 1999. The two laboratory assistants, Daniel Snyder and Michael Mancino and another volunteer student- Jenny Castellano provided additional support in the processes of brainstorming, design, modeling, fabrication, instrumentation, data collection and computer programming. Alexander Michalchuk, the department technician and machinist provided guidance in the fabrication process and performed machining on more demanding components. The coordinator took over the task of installing the Rosette gauges on the non-flat surface of the specimen. Michael Mensch, the department technician, provided assistance in the fine soldering of the electrical network. Estimated Price of this apparatus (should it be commercially available) is well over $30,000. Total material and component costs were kept well under $3,000. Of course, the time factor involved in the design and fabrication of this unit should not be overlooked. 2. Springs and their Applications in Design of Experiments This outstanding experiment was designed in collaboration with sophomore engineering students in Mech. Lab. I. The main idea was to utilize springs in verification of the deformation of Non-Prismatic Bars. More importantly, the student designers, their classmates (and future peers) come to realize that "it is quite possible to utilize simple components in design of experiments that may verify and visualize a relatively difficult theory." The laboratory handout for this highly affordable experiment is placed in "Appendix B." 3. Stresses in a Truss Frame This experiment enables the undergraduate students to measure the stresses and forces in different members of a truss frame / bridge. Linear strain gauges are installed at critical locations of the apparatus. Both symmetric and non-symmetric loads are applied to the unit. A second unit (in the upside – down configuration) may be examined by a different group of students simultaneously. Design and manufacturing of this unit has posed many interesting challenges. The first prototype suffered from the buckling effect. The initial design was primarily dominated by the following two criteria. First, the thickness of the section was chosen based on the assumption that a maximum load of 30 lb. may be applied to the unit using only conventional methods of application of loads. Second, to establish reliable values of the corresponding stresses and forces, the cross sections of the Truss Members must be chosen such that they experience meaningful and appreciable levels of strain. This valuable failure lesson encouraged both the coordinator and the collaborating students to design a High Mechanical Advantage Loader (HMAL) to lift the first constraint of the initial design while


maintaining or potentially improving on the second constraint. With the birth of HMAL – 200 (described in Appendix D), a second prototype was attempted with the necessary modifications and improvements. The Truss Frame is successfully designed and constructed. The unit displays appreciable deformations under several loading scenarios. The experience gained in this process has been quite valuable both for the coordinator and the collaborating student designers. Design and manufacture of another experiment and apparatus - "Stresses in an I – Beam," will benefit substantially from the valuable lessons learned in this exercise. A photograph of the unit is placed in Appendix C. This Photograph also displays the ingeniously designed HMAL that may easily be manufactured by an average machinist. In this case, it was machined by the students under the supervision of the coordinator . In different applications, this unit may safely apply loads up to 300 lbs. Two entirely different groups of students were involved in two different semesters. While the second group built on the work of the first and nearly completed the task, it was truly the first (presumably the failing group) that contributed to the major goals of the task. 4. The Thin-Walled Pressure Vessel Contributions of two engineering students made it possible to repair, calibrate and fully test a Thin-Walled Cylindrical Pressure Vessel that was donated to the department. This "gifted horse" was not in working condition. The gauges were damaged and the fluid’s quality was in question. The manufacturer of the unit is no longer in business. The commercial value of such an apparatus (provided by other companies) is about $ 8,000+. In collaboration with the coordinator, Richard Gallagher and Thomas Ronge’ brought this fantastic apparatus back to life. The total cost of the repair was less than $500. The experiments for this outstanding device are well documented by the two students and the test results have consistently returned a respectable level of accuracy when compared with expected theoretical values. Equally important, the process of rejuvenation of the unit enabled the team to completely understand the characteristics of its outstanding design and realizing that if desired, it would be possible to fabricate a similar unit with minimal cost so that an additional group of students conducts the experiment simultaneously. The experiment enables the student to investigate the validity of the basic equations of stress in Thin-Walled Cylindrical Pressure Vessels. An added feature to the experiment is the application of torque to the vessel. Upon pressurizing the unit and applying torque, the following critical information may be generated:

1. Circumferential Stresses 3. Principal Stresses 2. Longitudinal Stresses 4. Maximum Shear Stresses


While some of the collaborating students have already graduated, they have left their legacy on the outcomes of these units and their associated experiments. It is critical to note that the most important outcome of this approach is not necessarily the generation of affordable apparatuses and experiments. Rather, it is the involvement of students in a cooperative learning environment through which they enhance their design capabilities and improve their group dynamics skills. VII - ADDITIONAL EXPERIMENTS Continuous brainstorming and incubation effects of this approach/model may result in the inception of additional experiments. Table 2, on the next page shows the CURRENT status of the listed experiments in terms of their:

· Design, · Material and Component Cost / One Unit, · Required Fabrication Time and Degree of Difficulty.

Upon completion of the design, fabrication and full testing of these proposed experiments, a full information package may be generated for national dissemination. As a package, they may lay the foundation for a starting laboratory course or selectively, each may be added to the existing archives of experiments at many undergraduate engineering programs. A condensed description of each of the fourteen (14) experiments and the associated seventeen (17) apparatuses (listed in Table 2), is presented in "Appendix D." This package provides additional information on:

· Equipment Requirement, · Fabrication Requirement,

· Optional Interface with LabVIEW. VIII - INTERFACE WITH LabVIEW LabVIEW is a state of the art instrumentation / controls software package designed for diversified engineering applications. It is possible and desirable to interface some of the apparatuses in this package with this powerful and user-friendly package. Currently, the department of engineering at TCNJ has dedicated a computer for this project. This unit has the LabVIEW card installed on it and the coordinator and the collaborating students have successfully demonstrated the possibility of interfacing the Universal Combined Stress Apparatus with LabVIEW. However, during this process, it was recognized that only three of the 24 inputs might be interfaced at one time. An equipment package with the capability of handling 24 simultaneous inputs and outputs should be designed to control this deficiency.


#

EXPERIMENT

/ APPARATUS

DEGREE OF DIFFICULTY IN DESIGN (SCALE OF 1 ñ 10 )

DESIGN STATUS

COST OF MATERIAL

AND COMPON.

PER UNIT *

RECOMM- ENDED

QUANTITY

FABRICATION & ASSEMBLY TIME /1 UNIT

*

FABRICATION & ASSEMBLY TIME/2 UNITS

*

DEGREE OF DIFFICULTY IN FABRIC. (SCALE OF 1 ñ 10 )

1

UNIVERSAL FRAME

7

95 %

$ 950

2

4

6

NA

2

UNIVERSAL SUPPORTS

5

95 %

$ 150/ SET

2 SETS

25

40

5

3

HIGH MECH. ADV. LOADER

8

95 %

$ 350

2

25

40

6

4

DATA ANALYSIS

8

95 %

$ 50

1 SET

4

NA

NA

5

MOMENT OF INERTIA

7

95 %

$ 150

1 SET

8

NA

3

6

DEFORM. OF NON-PRISMAT. BARS

7 ½

95 %

$ 250

2

12

20

5

7

COMBINED STRESSES

9 ½

95 %

$ 2700

ONE

120

NA

8

8

STRESSESIN A TRUSS FRAME

8 ½

85 %

$ 1350

2

35

55

8

9

STRESSES IN AN IñBEAM

7

85 %

$ 850

2

20

35

6

10

THIN-WALLED PRESSURE VESSEL

7 ½

80 %

$ 1850

2

35

55

8

11

BUCKLING OF COLUMNS

9

70 %

$ 550

2

30

45

8

12

EXCEPTIONAL LOADS IN DEFLECTION

8

70 %

$ 850

ONE SET

45

NA

7

13

IMPENDING MOTION

5

70 %

$ 450

2

30

45

7

14

COEFFICIENT OF KINETIC FRICTION

9 ½

40 %

$ 2300

ONE

45

NA

8

15

DIFFERENTIAL PULLEYS

8

40 %

$ 950

ONE SET

30

NA

7

16

MECH. ADV. & MOTION OF GEAR TRAINS

9 ½

60 %

$ 2500

2

40

65

8

17

MECH. ADV. & MOTION OF BELT DRIVES

8

40 %

$ 850

2

25

40

6

* A CONSERVATIVE ESTIMATE. TABLE 2. The Proposed Experiments/Apparatuses and their corresponding Characteristics in Terms of Cost, Required Fabrication Time and Degree of Difficulty in Design and Fabrication.


IX - DESIGN CONSIDERATIONS "Everything must be made as simple as possible, but not simpler." (Albert Einstein) The following criteria should be incorporated in the design of the associated apparatuses:

· Safety · Simplicity in Fabrication · Affordability · Use of Reliable Sources for Components · Durability · Use of Non-Corrosive and Aesthetically Pleasing Materials · Simplicity of Operation · No use of Discontinued Parts/Components X - THE TIME FACTOR Both the coordinator and the collaborating students may learn a great deal about the design and the manufacturing processes involved in the generation of such experiments and devices. They develop time management skills and practical group dynamics experience. However, this valuable learning experience may only be gained with a considerable time factor and this trend would (at least partially) continue as teams of graduating students relinquish their position for members of the next year's class. The collaborating teams of students, the coordinator and the departmental technicians (at TCNJ) have already succeeded in the design and fabrication of the first eight (8) of the seventeen targeted items (listed in Table 2). They are determined and quite optimistic to successfully complete the bulk of the remaining experiments and the associated apparatuses within the next eighteen months. This estimate, of course, would not have been realistic without the support of both TCNJ and NSF in terms of provision of time for the coordinator and some students, material and equipment. Table 3 displays the main parameters involved for successfully addressing the requirements of such an approach. The practical experience gained so far in this plan has led to the following estimates of the percentage of the allocated time for each phase. The last column reflects the estimated time required for successful generation of the remaining nine experiments and the associated apparatuses (listed in Table 2).

# Type of Activity %

Time Estimated Required

Time (Hours) 1 Brainstorming and Design of the Experiments and the Apparatuses 25 500-550 2 Selection of Components and Identification of Suitable Sources 5 100-125 3 Fabrication and Compilation of Notes on Best Machining Approach 25 500-550 4 Instrumentation and Interfacing 10 175-225 5 Testing, Calibration, Generation of Data and Measure of Accuracy 10 175-225 6 Generation of Technical Drawings of each of the Apparatuses 15 275-325 7 Generation of Laboratory Manual for the Experiments 10 175-200

Total: 1900 - 2200 Hours Table 3: Estimated Break Down of the Time required for completion of the project


XI - THE ROLL OF THE COORDINATOR AND HIS/HER EXPECTATIONS The role of the coordinator in the success of each of the collaborating groups of students is instrumental. He/she should consider and where/when applicable, incorporate the following parameters:

1. Form groups whose members complement each other, 2. Establish the level of (your) expectations (clearly define the objectives of the task), 3. Discuss the tools and resources that are available and should be utilized by the team, 4. Recognize the pros and cons of smaller groups Vs larger groups, 5. Recognize the capabilities and limitations of each group, 6. Challenge each (unique) team at a level that they may succeed, 7. Respect their efforts and time and let them know that what they do is valuable, 8. Spend time with each group and provide guidance at the critical stages, 9. Consider failures as the price for future success, 10. Accept the possibility that you may have underestimated the time and energy required for

completing a certain project, 11. Accept the possibility that your suggested approach to the group may be impractical, 12. Accept the fact that many students may have better solutions than yours, 13. Projects may be rolled over to the next group to continue the work or revisited at next

laboratory courses, 14. Practice and encourage all team members to exercise good group dynamics, 15. Interact with them at personal level and it may help to buy them lunch once in a while.

XII - MERITS AND DRAWBACKS There is no question that the ability to acquire Standardized and Tested laboratory equipment has a good number of major advantages. But for those of us who are deprived of such luxury, these advantages are relatively meaningless. Companies such as TecQuipment (HI-TECH), Edmund Scientific, Armfield, Didactec (FEEDBACK Inc.), gunt Hamburg (ECHOSCAN Inc.), ecp (Educational Control Products) certainly produce a large array of high quality equipment. However, they are not non-profit organizations and they are (justifiably) forced to charge their customers as other companies do. These companies certainly have the know-how and the staff necessary for generating equipment that is (probably) well beyond the scope of what is proposed here. When possible, such equipment should be obtained from such sources. For the proposed experiments in the current package, there are two areas that may be problematic; the problem of in-house machining and installation of the strain gauges. Measurement Group Inc. provides free of charge one-week educational programs for training educators in Applications of Strain Measuring Systems in Stress Analysis. They have also created educational videotapes designed for installation of gauges at a nominal charge of $ 120. For the machining issue, there are many feasible alternatives where there are no on site technicians/machinists or students who can


accomplish the task. Certainly, laboratory coordinators must be willing to control the logistical problems of this approach. Should the grant move on to the upper phases, an article or a short regional workshop may assist the willing coordinators to better control these parameters and develop their own effective strategies relative to their individual environment.

XIII - WHAT'S TO COME - THE NSF COMPONENT NSF has recognized the potential value of the package that may be distributed at the national level. This support (at the Proof of Concept Phase) has started since January of 2002 and continues for a period of one year. There are two main objectives in this phase of the project. First, to continue work on the remaining proposed experiments and second, to investigate the feasibility of moving into the next phase. During the Proof of Concept Phase of the project, a trial package of three-four of the units will be generated and then distributed to several institutions to test the feasibility of the plan. The information and input gathered in this phase will enable the coordinator and the collaborating students to make the provisions necessary for further improvements. Should this process be successful, then the project may move to Full Development Phase and then potentially to National Dissemination. Should the project prove itself, there would be several possibilities that may be considered for dissemination of the results. Some may be listed as:

1. Use of a compact disc to contain all the information necessary for creation of the model laboratory and outlines of the experiments.

2. Creation of national web-sites for storing all the information mentioned in choice 1. 3. Conducting workshops to inform the enthusiastic laboratory coordinators about the

availability of such a source and encouraging them to build on it. 4. Presentations and publications at national level.

XIV - OUTCOMES AND CLOSURE A promising model for involving undergraduate engineering students in design of experiments and the associated apparatuses has been proposed. Through the process of exercising the proposed model, fourteen experiments and seventeen apparatuses are being developed at TCNJ. Upon completion of the design, fabrication and full testing of these proposed experiments, a comprehensive information package may be generated for national dissemination. As a package, these experiments may lay the foundation for a starting laboratory course or selectively, each may be added to the existing archives of experiments at many undergraduate engineering programs. Students have been playing a central role in the generation of these experiments. And during their collaboration with other team members and the coordinator, their capabilities in design and research enhances. Collaboration with other colleagues may further enhance the quality of the proposed model laboratory, which may then be considered for adaptation and implementation at national scale.


ACKNOWLEGMENTS The author wishes to thank all of the students who have made significant contributions to the progress of this project. He also wishes to thank Alexander Michalchuk and Michael Mensch for their support and dedication to the project. He thanks the continuous support of the College of New Jersey for implementing the rigorous tasks of this project. He also thanks NSF for its support in adding momentum and generating continuity to the progress of the project. REFERENCES 1. Dan McGraw, "Engineers & the New Economy", ASEE PRISM, November, 1999, Pg. 16-20. 2. Cougar, J. D., and F. R. McFadden, First Course in Data Processing, Wiley. New York 1981. 3. Tebbe, P. A. and Sepahpour, B., " The Challenges of an Integrated Laboratory Course Sequence", Proceedings of

A.S.E.E. 2001 National Conference, Albuquerque, NM, June 2001, Session: 1566. 4. Miller, J. W. / Sepahpour, B., "Design in the Engineering Curriculum", Proceedings of A.S.E.E. 1995 National

Conference, Anaheim, CA, July 1995, Vol. 1 (1995), Pg.: 2591-2596. BIJAN SEPAHPOUR Bijan Sepahpour is an Associate Professor of Mechanical Engineering at the College of New Jersey. He is a Registered Professional Engineer and is actively involved in the generation of design-oriented exercises and development of laboratory apparatus and experiments in the areas of mechanics of materials and dynamics of machinery for undergraduate engineering programs. Professor Sepahpour is an active member of ASME and ASEE and has published in the proceedings of these societies. He has degrees from the College of New Jersey and New Jersey Institute of Technology.

APPENDECIES

APPENDIX: A-1

Photographs of the completed “Universal Combined Stress Apparatus.” APPENDIX: A-2

Samples of Stress Data generated using the "Universal Combined Stress Apparatus." APPENDIX: B A preliminary Laboratory handout for the Experiment of "Deformation of Non-Prismatic Bars." APPENDIX: C "High Mechanical Advantage Loader" acting on the "Truss Frame." APPENDIX: D

Condensed Description of the Fourteen (14) Experiments and their Associated Apparatuses. APPENDIX: E "Universal Frame", "Sinusoidal Load" and Springs Experiment. APPENDIX: F

A potential Laboratory Manual for "Determination of Coefficient of Kinetic Friction Experiment."


APPENDIX: A-1

Photographs of the completed “Universal Combined Stress Apparatus.”


APPENDIX: B A potential Laboratory handout for the Experiment of:

Deformation of Non-Prismatic Bars

(SPRINGS AND THEIR APPLICATIONS IN DESIGN OF EXPERIMENTS)

Form groups of three (Min.) or four (Max.) for this exercise.

Using the seven available springs of equal length and diameter, the frame, the indicators and the scales on the frame, the hangers and the loads; design an experiment that may examine/address/confirm the following situations: 1. Establish the stiffness of each of the springs. Note that some of these springs show no trace of deformation up

until a certain load applied. Comment and provide reasons for this condition. (i.e.: can you generate a linear/non-linear/other relationship between loads and deformations by plotting your findings and make certain conclusions?)

2. Identify the springs with identical "K"s and examine the deformation of springs:

A- In Parallel B- In Series

(Make a DRAWING of each case.) C- Do the experimental results confirm the theoretical results? D- What is the Electrical Analog of this part of the experiment?

3. Correlate the results of step 2 with PRISMATIC BARS in Uniaxial loading.

[i.e.: using proper combination of springs (in series/parallel/both), show (experimentally) that

Delta = F L / AE holds and discuss how the change in "Delta" is directly proportional to F & L and inversely proportional to A & E.] Draw the different combinations and TABULATE the results in an organized manner.

4. Using the results of the previous steps, arrange for spring combinations to show (experimentally) that Delta = Sum ( Fi Li / Ai Ei ) holds. Discuss and TABULATE the results. 5. Using a similar approach to steps 3 &4, generate (at least one more) experimental approach to show the

validity of a known/unknown relationship. 6. Discuss your overall findings in this experiment and propose means to make improvements in all aspects of

this exercise. 7. Prepare a professional report using the guidelines of the instructor.


APPENDIX: C

High Mechanical Advantage Loader acting on the Truss Frame.


APPENDIX: D Condensed Description of the Fourteen (14) Experiments and their Associated Apparatuses

1. Universal Frame (UF - 400)

A multi-purpose frame designed based on commercially available extruded aluminum with specific sections to support

the components of the apparatuses listed as #s: 6, 8, 9, 11, and 15. The load capacity of the unit is 400 lb. with a factor of

safety of 2.2 (in quasi-static mode). A photograph of the unit is placed in Appendix E.

Fabrication Requirements: NONE (Assembly required.)

2. Universal Supports (US – 300)

A set of supports for simulation of simply supported (with rollers on either end) as well as fixed/clamped ends used

in conjunction with the apparatuses listed as #s: 8, 9 and 11. The load capacity of each support is over 300 lb. with a factor

of safety of 2.5 (in quasi-static mode) and may be located at any location of the vertical or horizontal members of UF – 400.

Fabrication Requirements: Average Machining Skills

3. High Mechanical Advantage Loader (HMAL – 200)

For applications where required magnitude of load is considerably high. This system may generate different symmetric

and non-symmetric point loads. The loader may apply in excess of 200 lb. by two 10-lb. loads (one at each end). The

flexibility in design of the unit allows for adjustment of height and locations of the applied loads. Safety has been the primary

consideration in the design of this unit. Accidental drop of a 10 lb. load is considerably less catastrophic than drop of a 100

lb. load. If necessary / desired, the unit can generate up to 300 lb. with a factor of safety of 1.95 (in quasi-static mode).

HMAL – 200 is required for the loading of the apparatuses listed as #s: 8, 9 and 11.

A photograph of the unit is placed in Appendix: C.


NOTE: In the Fabrication Requirements Boxes, an Average machinist is capable of working with the Lathe and Milling Machines. Using Hourly Rate as a benchmark, such a machinist is estimated to be paid about $15 - $20 per hour. The Hourly rate of an ABOVE Average machinist is estimated to be about $25 - $30


4. Data Analysis

An experiment designed for sophomores to comprehensively review the basic statistical tools used in analysis of data.

This review covers: (1) Histograms, (2) Population and Sample Mean, (3) Variance and Std. Deviation, (4) Probability, (5)

Central Tendency, (6) Error, (7) Minimum Required Number of Samples, and (8) Reliability.

Fabrication Requirements: NONE (Separation/Creation of three different sets of samples required.)

5. Moment of Inertia

This experiment allows the students to make appropriate selection and use of Linear Measurement tools to obtain the

Area Moment of Inertia of several (sets) of Round, Rectangular and S/W shapes sections and COMPARE the Strength to

Weight Ratios in each of the sets. Upon arriving at the values of these Ratios, they will discuss and justify their recommend

choices in different applications.

Mass Moment of Inertia of a commercially available pulley is next examined. A comparison of manually calculated

results is made with the Pro-Engineer generated ones. Students are challenged to provide alternative approaches for

obtaining the mass moment of inertia of such shapes.

Tools required:

1. Dial Calipers (4) 3. Micrometers (4) 2. Linear Scales (4) 4. Weight / Mass Scales (2)


6. Deformation of Non-Prismatic Bars

An experiment designed to utilize Tension Springs for examining the role of each of the parameters involved in the

equation: Delta = Sum ( Fi Li / Ai Ei ) used for obtaining the Elongation of both Prismatic and Non-Prismatic Bars.

This exercise also serves as an example (for students) to observe how they may utilize simple tools to create meaningful

and yet conceivable experiments.

A copy of the HANDOUT for this Experiment is placed in Appendix B.



7. Combined Stresses

This unique (and NOT commercially available) apparatus and experiment is designed to investigate the state of stress in

combined loading scenarios. Eight Rectangular Rosette Strain Gauges are strategically installed on two different sections of

the specimen (6061-T6 Aluminum Tubing with 1/8" wall, 3.75" O.D. and 42" Length) to generate 24 strain readings leading

to the values of the corresponding eight (8) Principal Stresses and eight (8) Maximum Shear Stresses. Specifically, it is

designed for:

1. Generation of Incremental Precision Torque for application of pure torque,

2. Generation of Incremental Bending Moment in the X-Y plane,

3. Generation of Incremental Bending Moment in the Z-Y plane,

4. Any Combination of the Loads available in steps 1, 2, and 3 resulting in a

Combined Loading / Stress Situation.

Equipment requirements:

1. Three (preferably Four) Strain Indicators (such as Micro Measurement’s P-3500) or Equivalent

2. Three (preferably Four) Multi-port Switch and Balance Units (such as Micro Measurement’s SB-10)

Fabrication Requirements: Above Average Machining Skills

Ability to Install Strain Gauges

Optional: Possible Interface with LabVIEW

8. Stresses in a Truss Frame

This experiment enables the undergraduate students to measure the stresses and forces in different members of a truss

frame / bridge. Linear strain gauges are installed at critical locations. HMAL – 200 is utilized to apply symmetric and non-

symmetric loads on the unit. A second unit (in the upside – down configuration) may be examined by a different group of

students simultaneously.


1. (UF - 400) or Equivalent

2. (US - 300) or Equivalent

3. HMAL – 200 or Equivalent

4. One Strain Indicator (such as Micro Measurement’s P-3500) or Equivalent

5. One Multi-port Switch and Balance Unit (such as Micro Measurement’s SB-10)





9. Stresses in an I – Beam

This experiment is designed to examine stresses at different locations (of span and section) of an I-beam. Rosette

strain gauges may be installed at interesting and critical locations of the beam. Several loading scenarios may be applied

(using HMAL – 200) to fully examine the signatures of stresses. To obtain appreciable and meaningful strain levels, and

control the buckling effect, the design of the I-beam calls for specific selection of materials and section properties.




3. HMAL – 200 or Equivalent

4. Two Strain Indicators (such as Micro Measurement’s P-3500) or Equivalent

5. Two Multi-port Switch and Balance Units (such as Micro Measurement’s SB-10)




10. Thin-Walled Pressure Vessel

This experiment will enable the student to investigate the validity of the basic equations of stress in Thin-Walled

Pressure Vessels. An added feature to the experiment is the application of torque to the vessel. Upon pressurizing the unit

and applying torque, the following critical information may be generated:

1. Circumferential Stresses,

2. Longitudinal Stresses,

3. Principal Stresses

4. Maximum Shear Stresses


1. Two Strain Indicators (such as Micro Measurement’s P-3500) or Equivalent

2. Two Multi-port Switch and Balance Units (such as Micro Measurement’s SB-10)



Ability to Weld Aluminum



11. Exceptional Loads in Deflection

To make the Historical experiment of Deflection of Bars / Beams more interesting and challenging, the following

sets of loads are designed and recommended:

1. Sinusoidal Load 3. Uniformly Varying Load

2. Uniformly Distributed Load 4. Mixed Loads





A photograph of the FIRST Prototype of the Sinusoidal Load placed on a Steel Beam (which is supported by US

- 300 and UF - 400) placed in Appendix E.

12. Buckling of Columns

This experiment and apparatus enables the students to examine the effects of ALL parameters in the Euler’s buckling

equation [ PCR. = (pi) 2 E I / (K L) 2 ]. Specifically, it will establish that the critical load is directly proportional to the

modulus of elasticity ( E ) of the material used and the area moment of inertia ( I ), and inversely proportional to length ( L )

and end support condition (K – factor). The design of the apparatus also allows for simulation of intermediate supports to

physically observe the formation of other modes of buckling.


13. Impending Motion

This experiment and apparatus is designed to investigate:

1. Coefficient of Friction - µS of:

Steel on Steel, Aluminum on Steel, Steel on Wood, Aluminum on Wood and Wood on Wood

2. Angle of Friction

3. Impending Upward and Downward Motion

4. Multiple Sliding Surfaces



14. Coefficient of Kinetic Friction ( µK )

This experiment takes on a unique VIBRATION approach to measure the Kinetic Coefficient of Friction of several

different materials against machined steel surface. An adjustable speed motor is used to rotate two synchronized steel

rollers. The placement of bars made of different material creates the corresponding individual Simple Harmonic Motions

(SHM).

The experiment calls for creation of the appropriate free body diagram (F.B.D.) of the situation at hand and the

development of the Static / Dynamic equations required for determination of the Natural Frequency using the equation:

( X’’ + w 2 . X = 0 ).

A copy of the Potential HANDOUT for this Experiments is placed in Appendix F.


15. Differential Pulleys

This experiment will generate information on:

1. Mechanical advantage of Differential Pulleys

2. Relationship between displacement and velocity of input vs. output Loads

3. Efficiency

4. Measure of Friction


16. Mechanical Advantage and Motion of Gear Trains

This experiment enables the undergraduate students to gain a comprehensive understanding of the characteristics of gear

train systems. The use of encoders and interface with LabVIEW enhances the reliability and accuracy of the collected data.

The main objectives of the experiment are to measure and obtain:

1. Mechanical advantage of simple and compound trains

2. Relationship between displacement and velocity of input vs. output gears

3. Efficiency

4. Velocity and acceleration of the input vs. output links

5. Effect of backlash



Modularity of the apparatus will allow conversion from a simple to a compound train (or vice versa) in no more than 30 seconds. This ingenious feature eliminates any unnecessary confusion in the process of conversion and saves considerable time in comparison with some commercially available units.

Safety is of great concern in this design and experiment. The tooth sizes of the gears are selected such that even

under the extreme range of loads and velocities, no damage will be done to the fingers of (curious) students - the unit will stop motion.


1. Computer 3. LabVIEW Card (National Instrument)

2. One Terminal Block 4. LabVIEW Software (National Instrument)


17. Mechanical Advantage and Motion of Belt Drives

This experiment will generate information on:

1. Mechanical advantage of simple and compound Belt Driven Systems

2. Relationship between displacement and velocity of input vs. output links

3. Efficiency

4. Velocity and acceleration of the input vs. output links


The Unit is Modular and capable of simulating both Simple and Compound Systems. The use of encoders and

interface with LabVIEW enhances the reliability and accuracy of the collected data.


1. Computer 3. LabVIEW Card (National Instrument)

2. One Terminal Block 4. LabVIEW Software (National Instrument)



APPENDIX: E Top: Universal Frame (supporting the Sinusoidal Load and The Springs experiments).

Bottom: First Prototype of the Sinusoidal Load on a Steel Specimen


APPENDIX: F

COEFFICIENT OF KINETIC FRICTION

EQUIPMENT:

· Counter-Rotating Roller Machine · Sample Bars of Steel, Copper, Nylon, etc.

OBJECTIVE:

To measure the Kinetic Coefficient of Friction of several materials against machined steel surface. STEPS:

1. Start the variable-speed motor with CCW rotation setting. 2. Adjust the speed of the motor to the desired rate. 3. With the rollers in motion, gently place the test rod in grooved rollers. The rod(s) are

expected to perform “Simple Harmonic Motion.” 4. Measure the time for “10” or more Cycles of motion. Compute the Average value of the

Natural Frequency, and use this value to determine m k. 5. Repeat steps #3 and #4 with a different (slightly higher) speed of rollers to see if there are

any effects (due to the change in speed) on test results. 6. Repeat steps #3 and #4 with different roller spacing. 7. Repeat all steps for all specimens. 8. Read this entire paragraph before trying this step. Turn the motor off and using a very

low speed setting, turn it on for CW rotation. Observe the change in the rotation of the rollers. Place the short steel specimen on the roller and observe the change in the behavior of the motion. Place your hands near the ends of the specimen and expect it to shoot out!

REPORT:

1. Prepare a brief Technical Report, describing the purpose of the experiment, the equipment and setup used, and the procedure followed.

2. Create a Free Body Diagram (F.B.D.) of the situation at hand (steps#1 through #7) and develop the

static/dynamic equations required for determination of the Natural Frequency: ( X’’ + w 2 . X = 0 )

3. Repeat step #2 (in the report section) for the situation at step #8 in the experiment and comment on the differences in the generated equations. May one expect the physical behavior that happens in step #8 by examination of the corresponding equation?

4. Create appropriate tables reflecting the results of the experiment and compare them with a reliable (Handbook) source.

5. Discuss the potential sources of error.

6. Close your report by conclusive remarks. 7. Include the sources / references used in the report and the experiment.

involving undergraduate engineering students in design of

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