Stress Concentration in Snap Ring Grooves Jon Shelley Doug Hogge.
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Transcript of Stress Concentration in Snap Ring Grooves Jon Shelley Doug Hogge.
Stress Concentration in Snap Ring Grooves
Jon Shelley
Doug Hogge
Description of Project
Description of Project
Create a Model to Determine Stress in a Snap Ring Groove
Calculate Stress Concentration Factor Create Graph Showing Stress Concentration Compare Results to Actual Snap Ring Groove
Dimensions
Method Used to Accomplish Project
Macro File
Results File
Model – Macro File
!IMPORT PARAMETERSPARRES, CHANGE,ring,exp,
!Keypointsk,1,0,0k,2,0,lk,3,OD/2,lk,4,OD/2,t/2+r
!Material PropertiesMP, EX, 1, 30.00000E+06MP, NUXY, 1,0.27
!Mesh ConstraintsLESIZE,8, , ,12,0, , , ,1 ames,2
!Boundary Conditions and LoadsSFL,8,PRES,-FYload,
!Solve Model/SOLU SOLVE
!Retrieve Outputnsort,s,y*get,syMax,sort,0,max
!Save Output to a File/output,ring,post,,
!Exit Macro File/EXIT,NOSAVE,,,
Model-Geometry
OD (1”- 4”) Ratio (1.02 – 1.1) Height (2”)
Radius (0.005” – 0.015”) Gap (0.1”)
Model-Mesh Original
Elements (53-400) Nodes (200-1,517)
Refined Elements (1,649-10,132) Nodes (5,140 – 31,005)
Mapped and Free Mesh
Model-Boundary Conditions Surface Load Axisymmetric Element Symmetry about X-Axis
Model Verification
Model Verification Radius vs. Stress
0
10000
20000
30000
40000
50000
60000
70000
80000
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5
Radius
Str
es
s
Original
Refined
Original – (1 hr) Refined – (7 hrs)
Two Models – (0.5% - 1%) Original vs. Refined – (2% - 11%)
FEA Results
Stress Concentration Factor
nom
Kt max
reducednom A
P
2
2
id
Areduced
Loadod
P2
2
LoadRatioKt
2max
DOE
Outside Diameter13 Values (1” – 4”)
Radius4 Values (0.005” 0.007” 0.01” 0.015”)
Ratio of Outside to Inside Diameter9 Values (1.02 – 1.1)
Total of 468 Runs
DOE Results
DOE Stress Results
0
10,000
20,000
30,000
40,000
50,000
60,000
70,000
80,000
90,000
100,000
0 50 100 150 200 250 300 350 400 450 500
Run Number
Str
ess
Stress Increase as Radius Decreases Ratio Increase OD Increases
Stress Concentration PlotStress Concentration of A Snap Ring Groove R=0.007"
0
1
2
3
4
5
6
7
0 0.001 0.002 0.003 0.004 0.005 0.006 0.007 0.008 0.009
Radius/Inside Diameter
Kt
Str
es
s C
on
ce
ntr
ati
on
1.02
1.03
1.04
1.05
1.06
1.07
1.08
1.09
1.1
Comparison to Actual Values
ratio od r Chart Kt Calculated SyMax Ansys SyMax Ansys Kt Error1.0504 1 0.005 3.3 36411.62347 36,650 3.322 -0.6534081821.0549 1.5 0.005 4.1 45621.25016 44,458 3.995 2.549053681.0627 2 0.005 4.8 54207.82603 52,996 4.693 2.2356661721.0495 2.5 0.005 4.9 53974.99156 52,668 4.781 2.4213094251.0409 3 0.005 4.8 52011.07065 52,471 4.842 -0.8839643971.0410 3.5 0.005 5.1 55272.72122 56,167 5.182 -1.6170341461.0357 4 0.005 5.2 55782.60446 56,079 5.228 -0.532200925
1.0504 1 0.01 2.7 29791.3283 28,572 2.590 4.0914869051.0549 1.5 0.01 3.21 35718.10073 35,738 3.212 -0.0561879491.0627 2 0.01 3.9 44043.85865 42,297 3.745 3.9662252631.0495 2.5 0.01 3.8 41858.15672 42,044 3.817 -0.4434339591.0409 3 0.01 3.95 42800.77689 41,891 3.866 2.1255382671.0410 3.5 0.01 4.05 43893.04333 44,734 4.128 -1.9165603731.0357 4 0.01 4 42909.69574 44,667 4.164 -4.096053885
Error Between Actual and Calculated Values (0.05% - 4.09%)
Conclusion
Refined model produced less variation but increased processor time
Ansys can be used as a powerful tool for design studies Model should be compared with actual data From our results equations could be found to calculate stress
concentration in snap ring grooves