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Design Project. Marisa Bernal Neysa Alicea Ang é lica B á ez Beatriz Ramos. What would you do…. if you loose any of your limbs?. Outline. Design Purpose Applications Engineering Considerations Uniqueness Challenges Areas of Opportunities New Techniques. Prosthetic Leg. LINER. - PowerPoint PPT Presentation
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Marisa BernalNeysa Alicea
Angélica BáezBeatriz Ramos
if you loose any of your limbs?
OutlineDesignPurposeApplicationsEngineering ConsiderationsUniquenessChallengesAreas of OpportunitiesNew Techniques
Prosthetic LegLINER
FEET
SOCKET
KNEE
Socket
PurposeImprove the design of the prosthesis socket,
making it more comfortable for the user, and thus improving the quality of life of people with disabilities.
ApplicationsFor medical purposes, related to athletes
with disabilities.
Engineering ConsiderationsUse impact analysis in our calculationsUse the safest approximations for our design
Proper material selection
Material CharacteristicsLightweight low densityStiff high Elastic Modulus
Minimize
Maximize
Material Characteristics
Material CharacteristicsMaterial Possibilities
WoodTechnical CeramicsCompositesCarbon Fiber Reinforced Plastics (CFRP)
Carbon Fiber Reinforced Plastic (CFRP)Density: 1.8 g/ccModulus of Elasticity: 225 GPa Sut: 3800 Mpa
UniquenessA prosthesis has to be designed to fit the
needs of a specific person.It is customized for each user
ChallengeConsider that the product is a medical deviceConvert our project to shapes that we can
analyze with the concept learned in class
Material Selection
Static Loads Analysis
Static Load AnalysisFor this analysis we used the following
equations and obtained the shown values.
28.115m
KN
I
My
262.4
2
3
m
KN
A
V
EICxC
xCqxx
1
26)( 32
21
3
)(x 2.68 x 10-6m= 2.6 x 10-3mm
Dynamic Load Analysis
Dynamic Load AnalysisImpact Load
Maximum Elongation
M=mass v=velocity at impact L=length E=Elastic Modulus A=area
Dynamic Load AnalysisImpact Load
Maximum stress
E = Elastic Modulus δmax = maximum elongation L = length
Dynamic Load AnalysisWe calculated the values of:
=3195.38KN = = 128.69MPa =
Using stress concentrator factor Kf = 1.5 = 192.95MPa = 192.95MPa
We calculated the fatigue strength: = 0.4 SUT =1520MPa
amplitudePmeanP
meanamplitude
SCamplitude,
SCmean,
'fS'fS
Dynamic Load AnalysisStress concentration factors:
MPaS
S
K
K
K
K
K
f
f
yreliabilit
retermperatu
surface
load
size
5.497
)620.0)(1)(7841.0)(85.0)(792.0(
620.0
1
7841.0
85.0
792.0
Dynamic Load AnalysisUsing Modified Goodman theory to calculate
the safety factor:
28.2
3800
95.192
5.497
95.19211
,,
MPa
MPa
MPa
MPan
UTf S
mvm
S
avm
Component lifeAproximated it to the behavior of aluminum
a=19922.54, b= -0.2815N = 1.3 x 107 cycles
Sm
Sf
5 x 1081.3 x 107
Sm
Areas of OpportunityAssumed values were used since data for our
material was not availableDesign uniqueness.
A different analysis is needed for each person
New KnowledgeReinforce teamwork skillsLoads distribution in prosthetic devicesImpact loads
Any Questions???