E3 and Aperture Joints

cypriotcamelUrban and Civil

Nov 29, 2013 (4 years and 1 month ago)

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E3 and Aperture Joints

Bill Slauson

et alia

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Distr ibution Statement D: Distr ibution author ized to DoD and DoD contr actor s only, Cr itical Technology (02 May 2006). Other U
.S.

r equests shall be r efer r ed to the Pr ogr am Executive Office, Sur face Str ike / DD(X) pr ogr am Office.

Destr oy by any means that will pr event disclosur e of contents or r econstr uction of document

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Use or disclosur e of pr oprietar y infor mation or data contained in this document is subject to the r estr iction on the fir st pa
ge
of the document.

Topics on Aperture Joints


Review NGSS designs


Graphics are from Rich Foedinger’s
presentations


Review analysis


Analysis by Cyrus Tau


Summarize future efforts

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Use or disclosur e of pr oprietar y infor mation or data contained in this document is subject to the r estr iction on the fir st pa
ge
of the document.

Type 6 Joint, General E3 Approach

1.
Resistance weld 316L SS strip (inlay) to inner 200x200 SS mesh before
panel lay
-
up


For HF antennas, resistance weld SS strip to outer SS mesh


2.
Abrade (sand
-
blast) resin from inlaid strip (or 40x40 mesh)

3.
Install SS aperture frame (bonded, bolted 6
-
3.3) or EMI clip (6
-
1.3)

4.
Resistive weld mesh overlay (40x40 or 100x100) to inlaid SS strip and SS
frame (6
-
3.3) or SS clip (or backing plate
--
6
-
1.3)

5.
Apply fiberglass overlay

6.
Use gel
-
infused conductive gasket between antenna and frame or clip

316 SS strip
welded to
200x200 mesh

40x40 (or 100x100) SS mesh
overlay R
-
welded to SS strip
and SS frame or backing plate

sealant

316L SS frame (6
-
3.3)
or EMI clip (6
-
1.3)

fiberglass overlay

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Use or disclosur e of pr oprietar y infor mation or data contained in this document is subject to the r estr iction on the fir st pa
ge
of the document.

Type 6
-
1.3 Modified Phase 3 Baseline

clad bimetal washer (Al
1100, 316L SS) +
laminated SS shim stack

0.750 inch diameter
A
-
286 bolts,
beehive sealant

316L SS strip
resistance welded to
inner 200x200 mesh
prior to infusion,
expose SS strip and
R
-
weld 40x40 or
100x100 mesh to strip
and SS backing plate

316L SS
backing plate

beehive sealant
over fasteners

EMI Clip, 0.020”
316L SS

fillet seal

composite sandwich
panel with machined,
tapered core

antenna
flange

gel
-
infused,
wire
-
mesh
conductive
gasket

fiberglass
overlay

high density
balsa core

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Use or disclosur e of pr oprietar y infor mation or data contained in this document is subject to the r estr iction on the fir st pa
ge
of the document.

EMI Clip Phase 3 Baseline (1A)

CRES Sheet,

with clearance
holes for shims

Backing plate

Adhesive bond the CRES clip
to the ship’s mount flange.

Blue Line Indicates:

a)
Exposed 40 X 40 mesh, or

b)
Wide CRES strip, seam
welded to 200 X 200 mesh
prior to infusion, or

c)
Perforated sheet

Shim

Gel
-
Infused
wire gasket

Antenna

Bi
-
metal Washer

Composite

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Use or disclosur e of pr oprietar y infor mation or data contained in this document is subject to the r estr iction on the fir st pa
ge
of the document.

EMI Clip with Resistive Welding (1B)

CRES Sheet,

with clearance
holes for shims

Adhesive bond the CRES clip to
the ship’s mount flange.

Shim

Gel
-
Infused
Wire Gasket

Antenna

Bi
-
metal
Washer

Composite

Separate washers,
or backing plate

Weld mesh

CRES Strip welded to 200
X 200 mesh pre
-
infusion

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Use or disclosur e of pr oprietar y infor mation or data contained in this document is subject to the r estr iction on the fir st pa
ge
of the document.

Type 6
-
1.3 Joint Variants


Composite laminate build
-
up
at flange (0.71 inch)



Machined, tapered, high
density (16 pcf) balsa core in
joint region




.020 inch thick EMI clip over
composite flange




316L SS backing plate



2
-
D plane strain FEA models
in progress

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ge
of the document.

Type 6
-
3.3 Bonded Joint

EA9395
structural
adhesive

0.750” diameter
A
-
286 bolts,
beehive sealant

316 SS strip
resistance welded
to 200x200 mesh,
40x40 (or
100x100) mesh
overlay resistance
welded to strip
and steel channel,
fiberglass overlay

3/8” 316L SS
frames

sealant (fill cavities
and fillet seal corners)

sealant

composite
sandwich
panel

antenna
flange

overspray with
sealant

overspray
with sealant

fay seal or gel
-
infused wire gasket

weld frames

clad bimetal
washer (Al
1100/316L SS) +

laminated CRES
shim stack,

gel
-
infused wire
gasket w/ 316L or
Monel mesh

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Use or disclosur e of pr oprietar y infor mation or data contained in this document is subject to the r estr iction on the fir st pa
ge
of the document.

Type 6
-
3.3 Bonded Joints


Composite laminate build
-
up
at joint region


Stainless steel frame
bonded to composite panel
(EA9395 structural adhesive)


“Under/under” mount to
antenna flange


Gussets as required


Corrosion risk

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Use or disclosur e of pr oprietar y infor mation or data contained in this document is subject to the r estr iction on the fir st pa
ge
of the document.

Type 6
-
3.3 Bolted Joint, Over
-
under Design

SCI V/E based
structural putty

0.750” diameter A
-
286
bolts, beehive sealant

316L SS frame

316L SS frame

beehive sealant
over fasteners

sealant

sealant

composite
sandwich
panel

antenna flange

sealant

316 SS strip
resistance welded
to 200x200 mesh,
40x40 (or
100x100) mesh
overlay resistance
welded to strip
and steel channel,
fiberglass overlay

clad bimetal washer
(Al 1100, 316L SS) +

laminated CRES
shim stack

0.50” diameter A
-
286
bolts, beehive sealant

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Use or disclosur e of pr oprietar y infor mation or data contained in this document is subject to the r estr iction on the fir st pa
ge
of the document.

Type 6
-
3.3 Bolted Joints


Composite laminate build
-
up to
0.5 inch max. each skin (resin
infusion constraint) at joint
region


0.375 inch thick stainless steel
frames bolted to composite
deckhouse using 0.5 inch
diameter bolts


“Under/under” mount to
antenna flange


Over
-
plate (non
-
continuous) for
VSR (SPY
-
4), SPY
-
3 (except top
edge) with gussets as required


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Use or disclosur e of pr oprietar y infor mation or data contained in this document is subject to the r estr iction on the fir st pa
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of the document.

Analysis with MicroStripes


Model joint cross
-
section in
detail


Apply boundary conditions


Illuminate with plane wave E
i


Monitor field just beyond gap
E
g


Transfer “impedance” is
Z
T
= 377*E
g
*d/(2*E
i
)


Match slot model to detailed
3
-
D results

E
g

E
i

d

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of the document.

Previous Type 6
-
3.2 Joint Modeled


AvDec 60 mils, 0.22 S/m (excluding bolts)

E
-
GLASS DOUBLER

AVDEC CONDUCTIVE GASKET

ANTENNA

CRES MESH


ALUMINUM FRAME


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of the document.

Calculated Transfer Impedance


Before
optimization:


1k
-

1 MHz:

Z
T

= 8.6 m
W
-
m


1
-
20 MHz:

Z
T

= 10 m
W
-
m


20

300 MHz:
Z
T

= 34

m
W
-
m


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Use or disclosur e of pr oprietar y infor mation or data contained in this document is subject to the r estr iction on the fir st pa
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of the document.

Detailed vs. Compact Slot Model


Detailed model with
AvDec conductive
gasket (
s

= 0.22 S/m)

Optimized compact
model with slot Z
T

=
50 m
W
-
m (
s

= 20 S/m)


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Use or disclosur e of pr oprietar y infor mation or data contained in this document is subject to the r estr iction on the fir st pa
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of the document.

Use of Compact Joint Models


Include joints of all antennas in model of whole ship


Include representative cables, including shields


Include door/hatch/scuttle joints


Include vent/intake/uptake joints


Calculate induction from lightning attachment


Calculate induction from EMP

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Use or disclosur e of pr oprietar y infor mation or data contained in this document is subject to the r estr iction on the fir st pa
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of the document.

Update of Analysis


Current analysis is out of date


Type 6
-
3.2 analyzed


Standard AvDec gasket used in model


Designs changed to 6
-
1.3 and 6
-
3.3


Detailed cross
-
sectional drawings not yet available


Drawings will be imported directly into MicroStripes


Gaskets will be Dow (Geltec) or new AvDec


Both will be new designs


Bulk resistivity changes with compression; use worst
case

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Use or disclosur e of pr oprietar y infor mation or data contained in this document is subject to the r estr iction on the fir st pa
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of the document.

Additional Analysis, Tests


Update model below 300 MHz


Model current joint design


Include new Dow or AvDec gasket


Model joint leakage above 300 MHz


MIL
-
STD
-
464 EM environments


Only localized fields can be estimated because of computer and
MicroStripes limits


Test modified phase
-
3 panel with aperture (6059)


Panel still available


Similar to type 6
-
1.3 joint