P 14042 UNACRUTCH Right Move Right Place Right

P 14042: UNA-CRUTCH Right Move, Right Place, Right Time Systems Design Review Day 2 Ana Allen Joanna Dzionara-Norsen Beverly Liriano Dan Sawicki

Agenda Tuesday Background • • • Problem Statement Summary Customer Requirements Engineering Requirements HOQ Market Analysis/ Benchmarking Functional Analysis Thursday Concept and Architecture Development Engineering Analysis • Risk Assessment • Test Plan

CONCEPT AND ARCHITECTURE DEVELOPMENT

Concepts

Initial Concepts Rev 1 Pugh Chart

Initial Concepts Rev 1 Pugh Chart (Continued) Continued

Initial Concepts Rev 2 Pugh Chart

Initial Concepts Rev 2 Pugh Chart (Continued) Continued

New Concepts Rev 3 Pugh Chart

Connective Mechanism Terms Male/ Female Connection Guide Track Pin Magnetic Clamp Rubber Snap Tupperware Snap

Concept NA • Pros: • Springs relax user tension Pin Hinge • Large surface area on single crutch • Hinge is simple to use • Cons: • Expensive • Many components • Too many steps to assemble

Concept NB Male/female mold • Pros: • Easy connection • Aesthetically pleasing Male/female mold and/or pin • Innovative design • Minimal components • Spring base • Cons: • Bulky • Potentially expensive • Magnetic Connection Magnetic

Concept NC Male/female mold • Pros: • Adjustable handle • Spring base Male/female mold • Male/female mold is an easy connection • Innovative design • Cons: • Stability • Thickness Clamp

Concept ND Guide track • Pros: • Lightweight • Revolutionary handle design • Cons: Male/female mold • Base connection is inconvenient if user is on one leg • Similar to axilla crutch Snap

Concept NE Male/female mold • Pros: • Foldable into a cane • Lightweight • Stable Pin • Cons: • Two separate bases • Not aesthetically pleasing • Pad is in contact with the ground

Concept NF Male/female mold for elbows • Pros: • Largest surface area for connection • No axillary component • Spring base • Minimal components • Cons: • Not aesthetically pleasing • Stability compromised

New Concepts Rev 4 Pugh Chart

System Architecture

ENGINEERING ANALYSIS

Engineering Analysis Overview Friction Analysis Cantilevered Beam Analysis Static Analysis

Loads: Statics Analysis of Axilla Crutch Analyzed from user recommended angles between 0° and 45°. Three Forces acting on object. Friction Force Increases as θ increases.

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: OD = 0. 47 in = 12 mm L = 0. 39 in = 10 mm Smallest dimensions at which the maximum stress from bending does not exceed the yield strength of aluminum

Static Analysis ASSUMPTIONS: Negligible out of plane loads Entire user load is on the hand grip The underarm pad is being held by a screw. P Nf ΣFy=ma=0 Σfy=-P+Nf=0 P=Nf

Static Analysis ASSUMPTIONS: Force on Dy can be neglected Cx Force Dx has a direct relation with Cx being Dx=Cx/2 Cy Dx Dy Nf ΣFy=ma=0 ΣFy=Nf-Cy=0 Nf=Cy=P

Static Analysis P BX BX By ΣFy=ma=0 ΣFy=2 By-P=0 By=P/2

Statics Analysis Ax

Static Analysis Ax Bx ASSUMPTIONS: Force on Dy can be neglected By Cy Cx Dx Dy unknown: 3 unknowns Ax, BX, Cx Equations: 3 equations ΣFy=ma=0 ΣFx=ma=0 ΣM=0

Prototype Test Plan

Risk Assessment

Action Items for Subsystem Design Phase Week 7 Week 8 Week 9 Nazareth Orthopedic Clinic Connective Mechanism Prototypes CAD Design Continue Mechanical Analysis User Interface Prototypes FEA Analysis of Prototype Continue Concept Design Experimental Friction Analysis

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?