Transcript Friction_Review.ppt

Peer Review
NSTX TF Hub Assembly
Friction Coating
Requirements
Testing
Calculation Update
Implementation
C Neumeyer
10/27/04
Friction Coating for Hub/Box Interface
Hub/Box
Interface
Hub/Box
Attachment
Studs
Potting
Joint must not slip under applied EM loads
Outer Layer Loads Are Design Drivers
Flex Link loads updated out to r = 24”
Moment
Flateral
(lbf)
7379
dR from effective
point of
application to flag
inboard edge
(in)
4.3
(in-lbf)
31719
Outer
Layer
Link
Total Per
Outer
Layer
Flag/Link
Inner
Layer Flag
2575
15.1
38934
9955
7.1
70653
1845
4.3
7930
Inner
Layer
Link
Total Per
Inner
Layer
Flag/Link
Total from
All Turns
644
13.8
9734
2489
6.2
17663
Fvertical
Outer
Layer Flag
268775
Moment
(lbf)
3174
dR from effective
point of
application to flag
inboard edge
(in)
8.9
Outer
Layer
Link
Total per
Outer
Layer
Flag/Link
Inner
Layer Flag
1899
18.8
35767
5074
12.6
64053
1979
9.1
18061
Inner
Layer
Link
Total per
Inner
Layer
Flag/Link
Total from
All Turns
1330
19.0
25200
3039
14.2
43261
Outer
Layer Flag
(in-lbf)
28286
13.0
158233
2056400
Friction Shear (frs) at Interface Must Exceed Load
w/adequate Safety Factor
In-Plane Reaction to Moment
Out-of-Plane Reaction to Lateral Load
F_ frs
r
M_ em
F_ frs
F_frs ~ f*M_em/r/2
f = load fraction to frs
Approx. 42% per FEA
F_frs ~ f*F_em/2
Assume f = 100%
Max Single Surface
Radial Shears at Hubto-box Interface
(Total load along face in lbs)
For 6kG TF-loading with max
moment (70000 in-lbs)
SOFT – 3479 lbs (Run 54ng)
EOFT – 4569 lbs (Run 65nb)
In both cases, the maximum hubto-box shear surface is the one
away from the plasma
Courtesy Irv Zatz
Design Load and Safety Factor
Net load per interface is resultant of in-plane and out-of-plane at 6kG….
F frs_ IP  4569lbf
F frs_ OOP  2537lbf
F frs_ NET  F frs_ IP 2  F frs_ OOP 2  5226lbf
Average Box Stud compression force with three bolts ….

Fnormal  3*5500 16500lbf
Desired Friction Coefficient for SF = 2 ….

2 * 5226
COFSF 2 
 0.633
16500lbf
Grit-Surfaced Sample
from Braziler Technology, Inc
Test Fixture
•
The test fixture consisted of a floating
clamp with a load cell to measure the
clamping load. Right view
•
Bottom end view of grit sample
between two sacrificial clamping
blocks
Measured COF ~ 0.6
Sample Grit
060/080
Break Away Peak Force
Run 1
lbf 140.00
Run 2
lbf 120.00
Run 3
lbf 120.00
Run 4
lbf 100.00
Average
lbf 120.00
Std Dev
lbf 16.33
Static Coefficient of
Friction
Test Runs
No. Box Bolts
Force/Bolt
Area
Pressure
Sample Width
Clamp Height
Sample Surface Area
Clamp Force
Clamp Pressure
Friction Coefficient
No. Surfaces
Shear Force to Slip
Handle Dia
Handle Area
Handle Stress
Avg
lbf
sq in
psi
in
in
sq in
lbf
psi
lbf
in
sq in
psi
0.61
060/080
SS Strip
141.00
127.00
103.00
141.00
128.00
17.93
45.50
0.65
0.23
• Tests on coated SS ~ 0.6
• Tests on uncoated SS ~ 0.2
45.50
• Coating provides 3x improvement
3.00
3.00
3.00
5000.00 5000.00 5000.00
15.40
15.40
15.40
974.03
974.03 974.03
0.225
0.225
0.337
0.500
0.500
0.500
0.113
0.113
0.169
99.00
99.00
99.00
880.00
880.00 587.54
0.61
0.65
0.23
2.00
2.00
2.00
120.00
128.00
45.50
0.115
0.115
0.115
0.010
0.010
0.010
11558.88 12329.48 4382.74
Courtesy Tom Kozub
Calculation
With
Coating
Without
Coating
COF for Coated Plates
0.600
0.200
0.200
At 6 kG
Total In Plane EM Moment
% In Plane Load to Hub/Box Shear
Moment Arm to Interface
In Plane Shear Load per Interface
Total Out Of Plane EM Load
Out Of Plane Shear Load per Interface
6
70653
42%
3.25
4569
5073
2537
6
70653
42%
3.25
4569
5073
2537
6
70653
42%
3.25
4569
5073
2537
Field Strength kG
6.00
4.50
3.56 kG
In Plane Load
Out Of Plane Load
4569
2537
2570
1902
1607 lbf
1504 lbf
Resultant Load
5226
3198
2201 lbf
Min Bolt Tension
Avg. Bolt Tension
Max. Bolt Tension
3900
5500
6500
3900
5500
6500
3900 lbf
5500 lbf
6500 lbf
7020
9900
11700
2340
3300
3900
2340 lbf
3300 lbf
3900 lbf
1.34
1.89
2.24
0.73
1.03
1.22
1.06
1.50
1.77
Min Resistance to Load
Avg Resistance to Load
Max Resistance to Load
Min. FS Friction Resultant
Avg. FS Friction Resultant
Max. FS Friction Resultant
kG
in-lbf
in
lbf
lbf
lbf
Courtesy Mike Kalish
Implementation
• Two prospective vendors identified, and samples received from each…
Braziler Technology, Inc, East Windsor CT
White Engineering Surfaces Corporation, Newtown PA
• President of Brazilier has been very cooperative…
-answered many questions
-Appears very interested to develop product
-Visited PPPL
-Researched options and came up with preferred scheme using diamond grit
abrasive with resin binder (non-conductive and non-magnetic)
• Included White on bidder’s list but do not know much about capability
Highlights of SOW for Coating
• Surface coating shall consist of a diamond grit with waterproof heat resistant resin
binder, or other binder material as may be proposed by subcontractor in writing and
approved by PPPL in writing. Abrasive shall be grit size in the range 60-80 based on
the Coated Abrasives Manufacturers Institute (CAMI) standards. Materials shall be
non-conductive and non-magnetic.
• Two 1/2” SS sample plates supplied by PPPL shall be coated and returned to PPPL
for test
• PPPL may elect to proceed with the production run at any time, independent of the
status of the samples, based on schedule considerations.
Eight Surfaces to be Coated
Top Assemblies
Bottom Assemblies
• Surface coating shall not exceed 0.015” thickness based on 8 measurements per disk
located 90 degrees apart on ID and OD, before and after coating
Note: actual delta dimension hub to box will be <= 15 mils depending on extent to which
diamond grit bites into SS. This will reduce the potting thickness on the middle disk side
Potential Issues
1) Samples tested used “electroless nickel” binder, not identical to resin-based binder
-final COF could be different
2) Substrate material of samples used unknown material, not 304SS
-final COF could be different
3) Present plans call for assembly of boxes, potting, detachment, testing, and re-assembly
- impact of multiple compressions on coating is unknown, although Braziler thinks
it will not be a problem
- final COF could be different
- fit-up and seating during re-assembly could be impacted by presence of coating
•Testing of sample parts in advance of committing to coating of actual
parts would reduce risk of “gotcha’s”
•Sandblasting would probably be required to remove coating if it is found undesirable