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Alan W. Eberhardt,1 R. Justin Lesley1
Tina G. Oliver,2 Rose N. Scripa3
Biomedical Engineering,1 Mechanical Engineering,2 Material Science & Engineering3
University of Alabama at Birmingham
Birmingham, AL
Appropriate Technology in an Introductory Engineering Design Experience
Outline
• Undergraduate Designs to Aid Disabled• NSF & NCIIA activities• SIFAT, Engineers w/o Borders &
Zambia• EGR 200 design project• Appropriate technology constraints• Engineering design tools• Assessments and Results
• student & faculty perspectives
• NSF RAPD funding • 13 years +
• Projects to aid children & adults (in Alabama) with various disabilities• Senior Design• EGR 100, 200
• BME, MSE, ME
Undergraduate Design Projects for People with Disabilities
New direction:Appropriate technologies
• NCIIA funding – 2 years• Partner with EWB using appropriate technologies• Senior design projects for disabled in developing
countries• Peru – all terrain crutch• Zambia – bamboo wheelchair
UAB Engineers w/o Borders + SIFAT (Servants in Faith and Technology)
• SIFAT: Christian nonprofit that provides training in self-help programs for a needy world.
• EWB + SIFAT building a training facility in Zambia
• Opportunity for reproduction of devices designed by UAB students
EGR 200 Intro to Engineering
• Course is for 2nd year transfer students (pre-BME, -ME, -CE etc)
• Majority from 2-year community colleges
• 2 sections of ~50 students
• Topics: Reverse engineering, team projects, oral & written
communication +
5 week design project
Design Project:Crutches using appropriate technology
Crutches for men, women and children of Zambia
Zambia• One of the poorest countries
in the world
• 87% of total population live on less than $2 USD per day
• Health problems abound…
Ex. Infection leads to amputation… war torn neighbors
Design Constraints
• Appropriate materials• Bamboo poles, string, glue, leather,
cloth scraps, burlap• Appropriate technology
• Hand tools only (saws, files, vises, hand drill)
• No power tools or expensive machining equipment
• Time: 5 weeks (end of term)
Schedule – Fall 2010
Class Date Activity
1 10/29 Introduction to problem
2 11/5 Lab Safety, SOE Design Lab visit, Brainstorm designs
3 11/12 Project work* – materials list due by end of class
4 11/19 Project work* - continued
X 11/26 Thanksgiving holiday
5 12/3 Project work*, stress analysis
6 12/10 Oral presentations/reports & completed crutches due
* class time to work in teamsSOE Design Lab/computer labs
Design Contest
• Crutch designs judged for “Best Engineered Device” based on Final Presentation + Final Report
Winning team gets dinner at Dreamland Bar-B-Q
• “Best engineered” based on use of engineering tools in design• Computer aided drawing• Free body diagrams, force/moment calcs• Stress and buckling analysis• Material description – engineering properties
Drawing
• Discuss the range from hand sketching to Pro-E CAD• Intro to Pro-E demo, some students taking Pro-E
course
Statics, Equilibrium & FBD’s
SF = 0
Action-reaction (Newton’s 3rd)
SM = 0
Ex. Civil War era crutch
1. Underarm piece
P
P
P
M
Mechanics of Solidsaka, Stress and Strain
• Fundamental concepts of stress and strain can be illustrated by considering a “prismatic bar” (straight structural member with constant cross section) that is loaded by axial forces P at the ends
• Material failure is often a function of stress or strain (not just the force applied)
Stress - strain curve:Engineering materials
In elastic zone, s = Ee
“Hooke’s Law”
Material selection/analysis
• CES Edupak software
• On EGR computers:• Programs
• Engineering software• CES
• Properties of bamboo• Modulus• Failure strength• Joining techniques
Column Buckling
• Pcrit = p2 EI/Le2
Note: The effective length Le depends on the boundary conditions
Important!Allocated class time for project work
• SOE Design Lab• Tables for teams
with materials (bamboo, string, glue, etc)
• Hand saws/drills, files…
• Instructor + grad student (Lesley) circulating & advising…
Rubric circulated
Level 5 Level 3 Level 1
Background
Background review is thorough and provides sufficient information regarding the need for design, Engineers w/o
Borders, potential benefactors, etc.
Background review is somewhat lacking and
does not provide sufficient information regarding the
need for design, Engineers w/o Borders,
potential benefactors, etc.
No background review is provided.
Problem Statement &
Design Constraints
Problem statement concise and based on background review.
Design constraints are complete.
Problem statement neither concise nor based
on background review. DC’s incomplete
No problem statement provided.
Drawings
Excellent drawings that involve use of computer
aided design (CAD) software and include labels & dimensions
Fair drawings that involve use of traditional drafting tools with some labels &
dimensions
No drawings included
Free body diagrams
Excellent free body diagrams with correct
calculations of forces and moments in crutch sub-
structures
Some free body diagrams with attempted
calculations of forces and moments in crutch sub-
structures
No FBDs
Calculations
Stress and buckling calculations completed
correctly for crutch sub-structures
Stress and buckling calculations attempted for
some crutch sub-structures
No calculations included
Material descriptions
Bamboo/sisal fiber/wood glue material
descriptions included with comparison to
calculated stresses to ensure safe design
Material descriptions included without
comparison to calculated stresses to ensure safe
design
No material descriptions
Presentation (slides,
mechanics, etc)
Outstanding Pretty Good Lousy
Paper (grammar,
headings, etc)
Outstanding Pretty Good Lousy
Students told how they would be graded
= how judged for contest….
Results & student learning outcomes:
• All design teams completed their projects (19)
• Student ownership & satisfaction was remarkable (personal best for freshman experience)
• Students comments: “understand what it means to design … what engineers do… feel prepared & excited for next level courses…”
• Many signed up for UAB Engineers w/o Borders
Benefits from the teaching end
• Costs are low• $500 covered two sections of ~50
students• Materials purchased a priori &
provided• Bamboo, string, glue, leather, burlap
• Facilities are simple• Hand tools (saws, files, hand drills,
vises) • Projects are safe
• No special training needed…
Acknowledgments
• National Science Foundation (NSF RAPD)
• National Collegiate Inventors and Innovators Alliance (NCIIA)
• UAB School of Engineering• Dreamland BBQ
Thank you!