P14042: Una -Crutch
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Transcript of P14042: Una -Crutch
P14042: UNA-CRUTCHRight Move, Right Place, Right Time
Systems Design Review Day 2Ana AllenJoanna Dzionara-NorsenBeverly LirianoDan Sawicki
Agenda
Background
• Problem Statement Summary• Customer Requirements• Engineering Requirements• HOQ• Market Analysis/ Benchmarking• Functional Analysis
Concept and Architecture Development
• Risk Assessment • Test Plan
Engineering Analysis
CONCEPT AND ARCHITECTURE DEVELOPMENT
Concepts
Initial Concepts Rev 1Pugh Chart
Initial Concepts Rev 1 Pugh Chart (Continued)
Continued
Initial Concepts Rev 2Pugh Chart
Initial Concepts Rev 2 Pugh Chart (Continued)
Continued
New Concepts Rev 3Pugh Chart
Connective Mechanism Terms
Male/ Female Connection Pin Magnetic
Rubber Snap Guide Track
Clamp Tupperware Snap
Concept NA• Pros:
• Springs relax user tension• Large surface area on single
crutch• Hinge is simple to use
• Cons:• Expensive• Many components• Too many steps to assemble
Hinge
Pin
Concept NB
• Pros:• Easy connection• Aesthetically pleasing• Innovative design• Minimal components• Spring base
• Cons:• Bulky• Potentially expensive• Magnetic Connection
Male/female mold
Male/female mold and/or pin
Magnetic
Concept NC
• Pros:• Adjustable handle• Spring base• Male/female mold is an easy
connection• Innovative design
• Cons:• Stability• Thickness
Male/female mold
Male/female mold
Clamp
Concept ND
• Pros:• Lightweight• Revolutionary handle design
• Cons:• Base connection is
inconvenient if user is on one leg
• Similar to axilla crutch
Snap
Male/female mold
Guide track
Concept NE• Pros:
• Foldable into a cane• Lightweight• Stable
• Cons:• Two separate bases• Not aesthetically pleasing• Pad is in contact with the
ground
Pin
Male/female mold
Concept NF
• Pros:• Largest surface area for
connection• No axillary component• Spring base• Minimal components
• Cons:• Not aesthetically pleasing• Stability compromised
Male/female moldfor elbows
New Concepts Rev 4Pugh Chart
System Architecture
ENGINEERING ANALYSIS
Engineering Analysis Overview
Friction Analysis
Cantilevered Beam Analysis
Static Analysis
Loads: Statics Analysis of Axilla Crutch
30.000 0.524 0.866 0.500 75.000 -129.904 150.000 129.904 75.000
θ[deg] θ[rad] cos(θ) [deg] sin(θ) [deg] Px Py P N Ff[deg] [rad] [deg] [deg] [lbf] [lbf] [lbf] [lbf] [lbf]
High μs
value to
low μs
value
Ice will result in slip the quickest!
Concrete is least likely to
slip!
Cantilevered Beam Analysis• Crutch handle modeled as a cantilevered beam with a
distributed load and external moment:
• Cross-sections considered: circular, square, hollow circular, I-beam, T-beam
• Maximum stress from bending:
L = 0.39in
L = 0.39in = 10 mm
OD = 0.47 in = 12 mm
Smallest dimensions at which the maximum stress from bending does not exceed the yield strength of aluminum
= 25 MPa = 27.6 MPa
Nf
P
ΣFy=ma=0Σfy=-P+Nf=0
P=Nf
Static AnalysisASSUMPTIONS:
Static Analysis
Nf
Dx
Cx
Cy
DyΣFy=ma=0
ΣFy=Nf-Cy=0Nf=Cy=P
ASSUMPTIONS:
Static Analysis
P
ByBy
BX BX
ΣFy=ma=0ΣFy=2By-P=0
By=P/2
Statics Analysis
Ax Ax
Static Analysis
Bx
Cx
Dx
Ax
Cy
Dy
By
unknown: 3 unknownsAx,BX,Cx
Equations: 3 equationsΣFy=ma=0ΣFx=ma=0
ΣM=0
ASSUMPTIONS:
Prototype Test Plan
Risk Assessment
Action Items for Subsystem Design Phase
Week 7
Nazareth Orthopedic Clinic
Continue Mechanical Analysis
Continue Concept Design
THANK YOU AND WE ARE NOW OPEN FOR QUESTIONS!
BACKUP SLIDE
Detailed Project Plan (Week 7)
Detailed Project Plan (Week 8-9)
Bill of Materials
Final Product Test Plan
QUESTIONS?