IPC-TM-650 EN 2022 试验方法-- - 第397页

Figure 9 Aluminum Clam ping Plate Provided with T apped Holes fo r the Pres sure Block and a Thermocouple Well IPC-TM-650 Page 17 o f 25 Number 2.5.5.5 Subject Stripline Test for Permittivity and Loss Tangent (Dielectric…

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Figure 6 Base Cover Board with Copper Foil Ground Plane
Figure 7 Detail of the Supplied Launcher Body, Omni-Spectra Part No. 2070-5068-02 or Equivalent
IPC-TM-650
Page 15 of 25
Number
2.5.5.5
Subject
Stripline
Test
for
Permittivity
and
Loss
Tangent
(Dielectric
Constant
and
Dissipation
Factor)
at
X-Band
Date
3/98
Revision
C
3,4
diameter
holes,
4
places,
use
base
plate
as
template
上
76.2
IPC-2555-6
Nominal
thickness
of
specimens
Machine
0.025
less
than
minimum
thickness
specimen
11.1
area
left
clad
with
foil
12.7
area
left
unmachined
15.1
J
Note:
Replace
the
#1—72
flat
head
screws
supplied
with
the
launcher
with
#1
—
72
cap
screws
cut
to
a
length
of
6.35
mm
plus
specimen
nominal
thickness.
Use
these
to
fasten
the
launcher
body
(2
required)
between
the
base
plates.
IPC-2555-7
Figure 9 Aluminum Clamping Plate Provided with Tapped Holes for the Pressure Block and a Thermocouple Well
IPC-TM-650
Page 17 of 25
Number
2.5.5.5
Subject
Stripline
Test
for
Permittivity
and
Loss
Tangent
(Dielectric
Constant
and
Dissipation
Factor)
at
X-Band
Date
3/98
Revision
C
IPC-2555-9
Tabulated values of ƒ(x) are given in Table 7-1.
7.1.5
For the bend specimens calculate G
Q
[=] kJ/m2 from
the corrected energy, U, as follows:
G
Q
= U/(BWΦ ) or G
Q
= η
e
U/(B(W - a))
Values of η
e
are given in Table 7-1. The energy calibration
factor, Φ, is defined as:
Φ = C/(dC/d(A/W))
and
be computed from the following:
Φ = (A + 18.64)/(dA/dx)
where:
A = [16x
2
/(1 - x)
2
][8.9 - 33.717x + 79.616x
2
- 112.952x
3
+
84.815x
4
- 25.672x
5
],
and:
dA/dx = [16x
2
/(1 - x)
2
][-33.717 + 159.232x - 338.856x
2
+
339.26x
3
- 128.36x
4
]
+ 16[8.9 - 33.717x + 79.616x
2
-112.952x
3
+ 84.815x
4
-
25.672x
5
]{[2x(1 - x) + 2x
2
]/(1 - x)
3
}
Values of Φ are given in Table 7-1.
7.1.6
(Reference ASTM D5045, Section 9.1.3) Check the
validity of K
Q
via the size criteria. Calculate 2.5 (K
Q
/σ
y
)
2
where
σ
y
is the yield stress. If this quantity is less than the specimen
thickness, B, the crack length, a, and the ligament (W - a),
then K
Q
is equal to K
1c
. Otherwise the test is not a valid K
1c
test.
Use of a specimen with too small a thickness, B, will
result in K
Q
being higher than the true K
1c
value while a small
(W - a) will result in a K
Q
value that is lower than the true K
1c
value. The net effect may be close to the correct K
1c
but
unfortunately in an unpredictable way, since the dependence
on B cannot be quantified.
7.1.7
For the recommended specimen dimensions of W =
2B and a/W = 0.5, all the relationships of 7.1.6 are satisfied
simultaneously. In fact, the criterion covers two limitations in
that B must be sufficient to ensure plane strain, but (W - a) has
to be sufficient to avoid excessive plasticity in the ligament. If
(W - a) is too small the test will often violate the linearity crite-
ria. If the linearity criterion is violated, a possible option is to
increase W for the same a/W and S/W ratios. Values of W/B
of up to 4 are permitted.
7.1.8
If the test result fails to meet the requirements in either
7.1.2 or 7.1.6, or both, it will be necessary to use a larger
specimen to determine K
Q
. The dimensions of the larger
specimen can be estimated on the basis of K
Q
, but generally
must be increased to 1.5 times those of the specimen that
failed to produce a valid K
1c
value.
7.2 Displacement Correction for Calculation of G
Q
(Ref-
erence ASTM D5045, Section 9.2)
Make a displacement correction for system compliance,
loading-pin penetration, and specimen compression, then cal-
culate G
1C
from the energy derived from integration of the
load versus load-point displacement curve.
7.2.1
The procedure for obtaining the corrected displace-
ment, u
c
(P), at load P from the measured displacement, u
Q
(P), is as follows: Use an un-cracked displacement correction
specimen prepared from the same material as that being
tested. Using the same testing parameters as the actual test,
load the specimen to a point at or above the fracture loads
observed during actual testing. From the load-displacement
Φ ψ η
0.450 9.14 0.274 45.8 2.00
0.455 9.27 0.272 46.7 2.00
0.460 9.41 0.269 47.6 2.01
0.465 9.55 0.266 48.5 2.01
0.470 9.70 0.263 49.5 2.02
0.475 9.85 0.260 50.4 2.02
0.480 10.00 0.257 51.4 2.03
0.485 10.16 0.254 52.5 2.03
0.490 10.32 0.252 53.5 2.03
0.495 10.48 0.249 54.7 2.03
0.500 10.65 0.246 55.8 2.03
0.505 10.82 0.243 57.0 2.03
0.510 10.99 0.241 58.2 2.04
0.515 11.17 0.238 59.4 2.04
0.520 11.36 0.236 60.7 2.04
0.525 11.54 0.233 62.1 2.04
0.530 11.74 0.230 63.5 2.04
0.535 11.94 0.228 64.9 2.04
0.540 12.14 0.225 66.4 2.04
0.545 12.35 0.223 67.9 2.04
0.550 12.56 0.220 69.5 2.05
Values calculated using A. Bakker, Compatibility Compliance and Stress
Intensity Expressions for the Standard Three-Point Bend Specimens. Paper
submitted for publication in International Journal of Fatigue and Fracture of
Engineering Materials and Structures (March 1989).
Number
2.4.52
Subject
Fracture Toughness of Resin Systems for Base Materials
Date
07/13
Revision
Page 5 of 8
IPC-TM-650
—
Table
7-1
Calibration
Factors
SENB"
S/W
=
4
a/W
fM
e
NOTE:
shall