Fibre optic interconnecting devices and passive components - Basic test and measurement procedures - Part 2-24: Tests - Screen testing of ceramic alignment split sleeve by stress application

IEC 61300-2-24:2010 identifies weaknesses in a ceramic alignment split sleeve which could lead to early failure of the component. This second edition constitutes a technical revision. Specific technical changes involve the addition of a dimension example of the reference gauge and the plate for the ceramic sleeve and a commonly used ceramic alignment sleeve for the 1,25 mm ceramic sleeve.

Dispositifs d'interconnexion et composants passifs à fibres optiques - Méthodes fondamentales d'essais et de mesures - Partie 2-24: Essais - Essai de sélection du manchon d'alignement fendu en céramique par l'application de contrainte

La CEI 61300-2-24:2010 est d'identifier, dans un manchon d'alignement fendu en céramique, les faiblesses susceptibles d'entraîner une défaillance précoce du composant. Cette seconde édition constitue une révision technique. Les modifications techniques spécifiques concernent l'ajout d'un exemple de dimension du calibre de référence et de la pastille pour manchon en céramique, ainsi qu'un manchon d'alignement en céramique couramment utilisé comme manchon en céramique de 1,25 mm.

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Status
Published
Publication Date
20-Apr-2010
Current Stage
PPUB - Publication issued
Start Date
21-Apr-2010
Completion Date
21-Apr-2010
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IEC 61300-2-24
Edition 2.0 2010-04
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Fibre optic interconnecting devices and passive components – Basic test and
measurement procedures –
Part 2-24: Tests – Screen testing of ceramic alignment split sleeve by stress
application
Dispositifs d'interconnexion et composants passifs à fibres optiques –
Méthodes fondamentales d'essais et de mesures –
Partie 2-24: Essais – Essai de sélection du manchon d'alignement fendu en
céramique par l'application de contrainte
IEC 61300-2-24:2010
---------------------- Page: 1 ----------------------
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---------------------- Page: 2 ----------------------
IEC 61300-2-24
Edition 2.0 2010-04
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Fibre optic interconnecting devices and passive components – Basic test and
measurement procedures –
Part 2-24: Tests – Screen testing of ceramic alignment split sleeve by stress
application
Dispositifs d'interconnexion et composants passifs à fibres optiques –
Méthodes fondamentales d'essais et de mesures –
Partie 2-24: Essais – Essai de sélection du manchon d'alignement fendu en
céramique par l'application de contrainte
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CODE PRIX P
ICS 33.180.20 ISBN 978-2-88912-460-2
® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale
---------------------- Page: 3 ----------------------
– 2 – 61300-2-24 © IEC:2010
CONTENTS

FOREWORD ........................................................................................................................... 3

1 Scope ............................................................................................................................... 5

2 General description .......................................................................................................... 5

3 Apparatus ......................................................................................................................... 5

4 Procedure ........................................................................................................................ 7

5 Details to be specified ...................................................................................................... 7

Annex A (informative) Static fatigue for zirconia alignment sleeve .......................................... 8

Bibliography .......................................................................................................................... 15

Figure 1 – Apparatus used for screen testing of a ceramic alignment sleeve ........................... 6

Figure A.1 – Model of time-varying proof stress for a zirconia sleeve .................................... 10

Figure A.2 – Calculated contour lines of gauge retention force and working stress

along with inner and outer diameter of a zirconia sleeve ....................................................... 11

Figure A.3 – Calculated general relationship between s /s and t , satisfying 0,1 FIT

p a e

for 20 years use .................................................................................................................... 12

Figure A.4 – Calculated failure probability of screened zirconia sleeves along with

working time ......................................................................................................................... 12

Figure A.5 – Measured and calculated strength distribution of 2,5 mm zirconia sleeves

(comparison between sleeves, extended proof tested or not) ................................................ 13

Figure A.6 – Measured strength distribution of 1,25 mm zirconia sleeves (comparison

between sleeves, extended proof tested or not) .................................................................... 14

Table 1 – Dimension example of the reference gauge and the plate for the ceramic

sleeve ..................................................................................................................................... 6

Table 2 – Dimension example of a commonly used ceramic alignment sleeve ......................... 7

Table A.1 – Measured static fatigue parameters for zirconia sleeves .................................... 11

---------------------- Page: 4 ----------------------
61300-2-24 © IEC:2010 – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
______________
FIBRE OPTIC INTERCONNECTING
DEVICES AND PASSIVE COMPONENTS –
BASIC TEST AND MEASUREMENT PROCEDURES –
Part 2-24: Tests –
Screen testing of ceramic alignment
split sleeve by stress application
FOREWORD

1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising

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9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of

patent rights. IEC shall not be held responsible for identifying any or all such patent rights.

International Standard IEC 61300-2-24 has been prepared by subcommittee 86B: Fibre optic

interconnecting devices and passive components, of IEC technical committee 86: Fibre optics.

This second edition replaces the first edition published in 1999. This second edition

constitutes a technical revision. Specific technical changes involve the addition of a

dimension example of the reference gauge and the plate for the ceramic sleeve and a

commonly used ceramic alignment sleeve for the 1,25 mm ceramic sleeve.

This bilingual version, published in 2011-04, corresponds to the English version.

---------------------- Page: 5 ----------------------
– 4 – 61300-2-24 © IEC:2010
The text of this standard is based on the following documents:
FDIS Report on voting
86B/2967/FDIS 86B/3014/RVD

Full information on the voting for the approval of this standard can be found in the report on

voting indicated in the above table.

This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.

A list of all parts of IEC 61300 series, published under the general title, Fibre optic

interconnecting and passive components – Basic test and measurement procedures, can be

found on the IEC website.

The committee has decided that the contents of this publication will remain unchanged until

the stability date indicated on the IEC web site under "http://webstore.iec.ch" in the data

related to the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.

IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates

that it contains colours which are considered to be useful for the correct

understanding of its contents. Users should therefore print this document using a

colour printer.
---------------------- Page: 6 ----------------------
61300-2-24 © IEC:2010 – 5 –
FIBRE OPTIC INTERCONNECTING
DEVICES AND PASSIVE COMPONENTS –
BASIC TEST AND MEASUREMENT PROCEDURES –
Part 2-24: Tests –
Screen testing of ceramic alignment
split sleeve by stress application
1 Scope

The purpose of this part of IEC 61300 is to identify weaknesses in a ceramic alignment split

sleeve which could lead to early failure of the component.
2 General description

Ceramic alignment sleeves are important components often used in the adaptor of plug-

adaptor-plug optical connector sets. By using the method described, the component is

subjected to a proof stress greater than would be experienced under normal service

conditions. This enables weak products to be screened out.
3 Apparatus

The apparatus and arrangement necessary to perform this screening procedure are shown in

Figure 1. The material needed consists of the following:

a) a reference gauge made of ceramic with a sleeve-holding section, a tapered section and a

stress-applying section. The diameter of each section is dependent on the dimensions of

the product being screened. The length of the sleeve-holding section and the stress-

applying section should be greater than the component being tested;

b) plates A and B, each having a clearance hole in the centre to allow the plate to move a

sample of a ceramic alignment split sleeve on the reference gauge.
---------------------- Page: 7 ----------------------
– 6 – 61300-2-24 © IEC:2010
Figure 1 – Apparatus used for screen testing of a ceramic alignment sleeve

Table 1 shows the dimension of the reference gauge and the plate for the ceramic split sleeve.

A dimension of the stress-applying section diameter (E) is shown for a commonly used

ceramic alignment sleeve in Table 2.
Table 1 – Dimension example of the reference gauge and the plate for
the ceramic sleeve
Reference For 1,25 mm gauge For 2,5 mm gauge Notes
Dimension Dimension
mm mm
NOTE 2
A 9 14
B 5 5
NOTE 2
C 9 14
NOTE 1
D – –
E 1,259 0 ± 0,000 5 2,515
F – – NOTE 3
G 20 20
H 2 2
NOTE 1 This diameter should be less than the inner diameter of the split sleeve.
NOTE 2 Surface finish in this area Ra = 0,2 mm.
NOTE 3 Dimension F should be greater than dimension E, and less than sleeve ØD.
---------------------- Page: 8 ----------------------
61300-2-24 © IEC:2010 – 7 –
Table 2 – Dimension example of a commonly used ceramic
alignment sleeve
Items For 1,25 mm For 2,5 mm
Dimension Dimension
mm mm
Length 6,8 10,1
Outer diameter 1,62 3,2
Inner diameter (ref.) 1,246 2,49
Split section width 6,8 10,1
4 Procedure

This test should be carried out under a 23 °C ± 2 °C environmental temperature condition.

The procedure is as follows.

a) Insert plate A into the reference gauge and set it at the fixed end of the reference gauge.

b) Moisten the inside surface of a ceramic split sleeve sample with distilled water (for

example using a cotton bud). Only touch the sleeve with suitable tools.

c) The sample sleeve is inserted onto the sleeve-holding part and set just in front of the

tapered part of the reference gauge.

d) Insert plate B into the left-hand side of the sample sleeve and move the sample sleeve

onto the stress-applying part until the sample sleeve touches plate A (within approximately

1 s).
e) The sample sleeve should be held for 3 s under the stressed state.

f) After 3 s, stress applied to the sample sleeve is removed by moving plate A to the left-

hand side (within approximately 1 s).

g) In the course of the procedure from d) to f), samples without damage (breakage or crack)

should be selected as acceptable sleeves.
5 Details to be specified

The following details shall be specified depending on the sample sleeve size in the detail

specification:
- diameter of sleeve-holding part of reference gauge (ØD);
- diameter of stress-applying part of reference gauge (ØE);
- length of sleeve-holding part (A) and stress-applying part (C);
- diameter of the center hole of plates A and B (ØF);
- deviations from test procedure.
---------------------- Page: 9 ----------------------
– 8 – 61300-2-24 © IEC:2010
Annex A
(informative)
Static fatigue for zirconia alignment sleeve
A.1 Prediction of failure probability by static fatigue

This annex applies primarily to 2,5 mm zirconia alignment sleeves supported by references [1]

to [5] . For 1,25 mm zirconia sleeves, a comprehensive analysis is referenced [6] and the

strength distribution is shown in Figure A.6. Micro-cracks essentially exist on the surface or

inside of ceramics. Therefore, fracture due to static fatigue occurs in ceramics under lower

stress than the characteristic strength of the materials because of crack propagation in

ceramic materials [1] [2].

Assurance of reliable optical fibre connections requires the prediction of failure probability of

the zirconia sleeves under working stress needed to align the ferrules.

Assuming aligned ferrules of optical connectors, the zirconia sleeves are allowed to stand

under a constant stress, as working stress s . Based on the theories of Weibull statistics and

slow crack growth for brittle materials, cumulative failure probability F of the zirconia sleeves

suffering from working stress is given by the following equation:
1 m
ln = ln s t + lng (A.1)
a a
1- F N -1
with
g º
m / (N-2)
s b
b º
2 (N -2)
(N - 2) AY K
where
t is the working time during which the working stress s is applied;
a a

m, V and s are the Weibull modulus, effective volume, and normalization constant to

e 0
express the failure probability by the Weibull statistics theory, respectively;
Y is the geometry constant;
K is the critical stress intensity factor;
A and N are crack propagation constants of the brittle materials [2].
—————————
Figures in square brackets refer to the Bibliography.
---------------------- Page: 10 ----------------------
61300-2-24 © IEC:2010 – 9 –

These crack propagation constants depend on environmental conditions such as temperature,

humidity, atmosphere, and material characteristics. Therefore, if m, N and g values are

estimated, the static fatigue life time of sleeves is predicted. The N value is estimated by the

dynamic fatigue test that measures the strength of a sleeve corresponding variable of the

proportional increased stress coefficient s' in MPa/s. On the other hand, the relationship

between F, strength s of sleeves and s' is given by executing the sleeve destructive test.

The slope m and the intercept lns are estimated from equation (A.2).
(N +1) /(N -1)
ln = m ln + ln g (A.2)
1/(N -2)
1- F
{(N +1)s ¢}
A.2 Reliability improvement by proof test

In order to improve the reliability of the zirconia sleeve against fracture due to static fatigue, a

proof test that initially eliminates weak zirconia sleeves by applying a greater stress (called

proof stress) than the working stress is effective. Fatigue also occurs under the proof stress.

However, the proof test conditions should be decided in order to take into consideration

fatigue during the proof test [3] [4].
s applied to the zirconia changes
When the proof test is performed, the proof stress

trapezoidally along with time as shown in Figure A.1. In this figure, stress change is defined

as follows:
: s (t) = s't
0 < t £ t
t < t £ t +t : s (t) = s
l l p p
t +t < t £ t +t +t : s (t) = s -s't
l p l p u p
where
s´ = s / t = s / t
p l p u

The cumulative failure probability F after proof testing is given by equation (A.3):

m /(N -2)
é p ù
(N - 2)/(N - 2)
ì ü
1 p
(N -2) (N -2) / m
N p p
ê ú
( )
ln = ln s t + z d - z d + ln g (A.3)
í ý
a a
1- F ê ú
î þ
ë û
with
1/(N -2)
æ p ö
z º s t
ç ÷
p e
è ø
æ ö
1/(N -2)
p ç b ÷
d º º
ç ÷
1/(N -2)
g p
ç ÷
è ø
---------------------- Page: 11 ----------------------
– 10 – 61300-2-24 © IEC:2010
g º
m /(N -2)
m p
s b
t + t
u l
t º t +
e p
N + 1
where N and b are N and b value under the proof test environment, respectively.
p p
Proof
t t t
l p u
stress
0 Test time
IEC 1489/99
Figure A.1 – Model of time-varying proof stress for a zirconia sleeve
A.3 Method of proof test
A.3.1 Stress design for zirconia alignment sleeve

Figure A.2 shows calculated contour lines of the gauge retention force f and working stress

s along with inner and outer diameters of a zirconia sleeve. Modelling the zirconia sleeve as

a curved beam, the gripping force and the working stress are calculated analytically. In

calculation, length, maximum static frictional coefficient and Young's modulus of the zirconia

sleeve are 11,4 mm, 0,1 and 196 GPa, respectively. Considering operational difficulty and a

low yield rate in proof testing, proof stress shall be kept as small as possible. For example, as

the maximum gauge retention force and the maximum working stress satisfies the above-

mentioned condition and the safety coefficient of around 10 against zirconia characteristic

strength of 1 200 MPa respectively, the outer diameter of zirconia sleeve is designed with a

value of 3,2 mm. From Figure A.2, the maximum working stress with a 3,2 mm outer diameter

becomes 130 MPa (gauge retention force is 3,9 N, inner diameter is 2,490 mm).
---------------------- Page: 12 ----------------------
61300-2-24 © IEC:2010 – 11 –
Dimensions in millimetres
2,500
65 MPa
2,0 N
2,495
2,490
130 MPa
2,485
Gauge retention force
3,9 N Working stress
2,480
3,0 3,1 3,2 3,3 3,4
Outer diameter of sleeve
IEC 1490/99

Figure A.2 – Calculated contour lines of gauge retention force and working stress along

with inner and outer diameter of a zirconia sleeve
A.3.2 Conditions for proof test

Ordinarily, components for switchboard and transmission equipment require very low failure

probability (for example under 0,1 FIT during 20 years). In order to decide proof test

conditions that make a zirconia sleeve satisfy required failure probability, parameters m, N,

N , g and g in equation (A.3) shall be estimated. Table A.1 shows these estimated

p p
parameters using 3 mol % Y O -ZrO sleeves. According to equation (A.3), by using
2 3 2

parameters in Table A.1, a general relationship between s /s and t , satisfying 0,1 FIT

p a e
during 20 years use, is shown in Figure A.3.
Table A.1 – Measured static fatigue parameters for zirconia sleeves
Parameters 25 °C in water 85 °C in water
m 5,5 to 7,1 5,5 to 6,3
N or N 28 to 40 22 to 35
–43,3 to –53,9 –40,7 to –47,8
In g or In g
Inner diameter of sleeve
---------------------- Page: 13 ----------------------
– 12 – 61300-2-24 © IEC:2010
4,0
3,5
3,0
2,5
2,0
Test time t (arbitrary unit)
IEC 1491/99
Figure A.3 – Calculated general relationship between s /s and t ,
p a e
satisfying 0,1 FIT for 20 years use

Working and proof test environments are assumed as 85 °C in water and 25 °C in water

respectively. From Figure A.3, “T ” is the time for s /s » 2,7, which is almost saturated against t .

e p a e

Failure probability of zirconia sleeves, which are screened on the condition s /s » 2,7, t =

p a e

T , and 0,1 FIT reference along with working time t are shown in Figure A.4. It is clear that

e a

the proof test ensures the failure probability under 0,1 FIT during 20 years of use.

0,1 FIT
s / s » 3
p a
t = T
-9 e e
-10
1 10 100
0,1
Working time t in years
IEC 1492/99
Figure A.4 – Calculated failure probability of screened zirconia
sleeves along with working time
Failure probability, log F
Stress ratio s /s
p a
20 years
---------------------- Page: 14 ----------------------
61300-2-24 © IEC:2010 – 13 –
A.3.3 Experimental verification of proof test

Applying the above-mentioned theory for the proof test to real zirconia sleeves, improvement

of reliability is experimentally verified. The assumed working time is around 20 years,

therefore the verification in a practical environment entails considerable difficulties.

Consequently, by performing two kinds of comparison between theory and experiment, validity

of the proof test is confirmed.
A.3.4 Strength distribution after proof test

Effective elimination of weak sleeves by proof test is experimentally verified. Destroying

screened sleeves that just passed the proof test, by a proportional increased stress s', with a

cumulative failure probability F of the screened sleeves is given by equation (A.4):

m /(n -2)
é p ù
N +1
ì p ü
ê ú
1 ï N -2 ï
f p m
ln = ln + z - z + lng (A.4)
êí ý ú
1- F s (N +1)
r p
ï ï
ê ú
î þ
ë û

Figure A.5 shows measured strength distribution of 2,5 mm zirconia sleeves and calculated

results using equation (A.4). To emphasize the efficiency of the proof test, a 1 000 MPa proof

stress s and 10 s of testing time t , t and t were adopted as the proof test conditions. The

p p u l

calculation was carried out using the values of m = 7,1, N = 34 and ln g = –53,9. The

p p

constants m, N and ln g were estimated by previously mentioned dynamic fatigue test and

p p

destructive test conditions. According to the strength distribution of Figure A.5, it is clear that

the reliability of zirconia sleeves is considerably improved by proof testing which eliminates

initially weak sleeves. The measured and calculated distributions agree well, therefore, the

validity of the theory is proved. Figure A.6 shows measured strength distribution of 1,25 mm

zirconia sleeves using specified proof test conditions shown in Table A.1.
Screened sleeve
Original sleeve
Calculated
6,0 6,4 6,8 7,2 7,6 8,0
Strength ln s (MPa)
IEC 1493/99

Figure A.5 – Measured and calculated strength distribution of 2,5 mm zirconia sleeves

(comparison between sleeves, extended proof tested or not)
Cumulative failure probability lnln (1/1-F)
---------------------- Page: 15 ----------------------
– 14 – 61300-2-24 © IEC:2010
Original sleeve
Screened sleeve
Strength ln s (MPa)
IEC 607/10
Figure A.6 – Measured strength distribution of 1,25 mm zirconia sleeves
(comparison between sleeves, extended proof tested or not)
A.4 Conclusion

The gauge retention force of the zirconia sleeve has been prescribed as between 2,0 N

and 3,9 N bearing in mind its practical application.

Concerning fracture prevention of zirconia ceramics due to static fatigue, it has been clarified

that the proof test, which initially eliminates weak sleeves by applying a greater stress than

the working stress, assures sufficient strength reliability under high temperature and humidity

environments (under 0,1 FIT during 20 years use). The conditions for proof testing have been

derived theoretically and the validity of the test has been confirmed experimentally. The

adequate proof stress is about three times larger than the actual stress [5], [6].

Cumulative failure probability lnln (1/1-F)
---------------------- Page: 16 ----------------------
61300-2-24 © IEC:2010 – 15 –
Bibliography

[1] ABE, H., KAWAI, M., KANNO, T. and SUZUKI, K., Engineering ceramics, Gihodo Pub.

Co., p.167-188, 1984 (in Japanese).

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...

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