1、TIA/EIA TELECOMMUNICATIONS SYSTEMS BULLETIN ITM-7 Characterization of Fiber Strip Damage by Dynamic Tensile Testing TSB62-7 APRIL 2000 TELECOMMUNICATIONS INDUSTRY ASSOCIATION Representing the telecommunications indushy in association with the Electronic Industries Aiance Elsctronk Industrias- Allian
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6、a or information useful to the technical community, and represent approaches to good engineering practices that are suggested by the formulating committee. This Bulletin is not intended to preclude or discourage other approaches that similarly represent good engineering practice, or that may be acce
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8、d update this Bulletin rom time to time as may be occasioned by changes in technology, industry practice, or government regulations, or for other appropriate reasons. (From Project No. 361 8, formulated under the cognizance of the TIA FO-6.6 Subcommittee on Fibers and Materials.) Published by TELECO
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10、79) International (303-397-7956) All rights reserved Printed in U.S.A. TINE IA-TSB-62-7 ITM-7 Characterization of fiber strip damage by dynamic tensile testing Contents Section Fiqure 1 2 3 4 5 6 Annex A Foreword Introduction Normative references Apparatus Sampling and specimens Procedu re Calculati
11、ons or interpretation of results Documentation Fi ber- holding fixture Strip length for end-stripping Strip length for center-stripping Fiber mounted on holding fixture Tensile test setup for end-stripping Tensile test setup for center-stripping Comparison with IEC and ITU Paqe iii 1 2 2 3 5 9 9 10
12、I TINEIA-TSB-62-7 rhis page left blank. II TINE IA-TSB-62-7 ITM-7 Characterization of fiber strip damage by dynamic tensile testing Foreword This Informative Test Method comes from TIA Project No. 3618, and was formulated under the cognizance of TIA FO-6.6, Subcommittee on Optical Fibers, and of FO-
13、6.6.8, Working Group on Fiber Reliability This ITM is part of the series of informative test methods included within TINEIA-TSB-62. There is one informative annex. Keywords: fiber stripping, fiber splicing . 111 TINEIA-TSB-62-7 rhis page left blank. IV TINE IA-TSB-62-7 ITM-7 Characterization of fibe
14、r strip damage by dynamic tensile testing 1 Introduction 1.1 Intent This method characterizes the tensile strength of stripped optical fiber. The results of this test provide an indication of the mechanical damage that is attributable to the stripping operation. 1.2 Scope An ideal coating removal pr
15、ocedure should be able to remove the protective coating without damaging the surface of the glass fiber with a nick or scratch. Practical stripping tools and/or stripping procedures (abbreviated to ?strippers?) may produce surface flaws that increase in size and weaken with stress and humidity, ther
16、eby lowering the tensile strength of the fiber, and increasing the risk of fiber failure. 1.3 Stripping methods Fiber coatings may be removed with a stripper or with a chemical solution. For most field applications the coating is removed from the end of the fiber (end-strip) with a stripper. Center-
17、stripping entails removing a length of coating while leaving the fiber coating intact on both sides of the stripped portion. Many mechanical and most chemical strippers may be capable of center-stripping. Center-stripped fiber is relatively easier to load and test without doing additional damage. Se
18、lection of the test method depends upon the information desired. technique, large coatings Design - operator 1.4 Variables Fiber strip damage depends on the fiber coating, the stripper (design, condition, age), wiping (dry wipe, wet wipe, number of wipes), and operator skill. 1 TINEIA-TSB-62-7 1.5 F
19、ailure modes Potential failure modes tested by this method include, but are not limited to: 0 Fiber breakage 0 Reduction in fiber tensile strength 2 Normative references Test requirements may include, but are not limited to, the most recent editions of the following references: FOTP-28 (EIMIA-455-28
20、C) Measuring dynamic strength and fatigue parameters of optical fibers by tension FOTP-I 78 (ElMIA-455-1 78B) Measurement of strip force required for mechanically removing coatings from optical fibers 3 Apparatus 3.1 Test Equipment Unless otherwise specified, equipment requirements shall be as speci
21、fied in clause 3 of FOTP- 28. 3.2 Strain Rate Use a tensile tester capable of imparting a constant strain rate of 2.5 to 5.0 %/min., without jerking, to the fiber under test. 3.3 Fiber holding fixture for end-strip method Mount the test fiber on a fiber holding fixture, typically made of paper, cons
22、truction paper, cardboard, or poster board, as shown in Figure 1. The holding fixture allows stress to be transferred to the fiber without producing damage by gripping stripped fiber. It must be made of material that allows the fiber to be glued to it and that can be cut. 2 TINE IA-TSB-62-7 7 20mmx3
23、0mm i cut-out i i, a 90mm Figure 1 - Fiber-holding fixture -A- 40 mm . 4 Sampling and specimens 4.1 Representative specimens: fiber and stripper The specimens shall be representative of both the fiber and the stripper under test. 4.2 Strip length The fiber surface area subjected to possible strip da
24、mage is proportional to the strip length. Fiber strip length (before cleaving) is influenced by the following factors: The amount of stripped fiber required by the splicing system (after cleaving the fiber to I engt h) 0 The minimum length of fiber required for cleaving Stripper restrictions Operato
25、r stripping techniques Typical strip lengths before cleaving range from 50 mm to 100 mm. The amount of stripped fiber (after cleaving) required by most splicing equipment/devices is typically in the range of 8 mm to 20 mm. This test is affected by the length of stripped fiber that can fail; this is
26、the gage length. The amount of fiber that must be stripped to produce a given gage length depends on whether 3 TINEIA-TSB-62-7 25 mm for end-stripping or center-stripping is done. For both cases, unless otherwise required, use the gage lengths as given by FOTP-I 78: Coating type gage length (mm) un
27、buff e red buffered 30 f 3.0 15 f 1.5 4.2.1 End strip For the end-strip method, one must consider the amount of stripped fiber required for gluing or adhering onto the fiber holding fixture. Typically, the minimum length required is about 25 mm. A 55 mm strip length, as indicated n Figure 2, with 25
28、 mm for gluing to the holding fixture and 30 mm for the gage length is typically required for unbuffered fiber. I Figure 2 - Strip length for end-stripping 4.2.2 Center strip For the center-strip method a nominal 30 mm strip length, as shown in Figure 3, produces the required gage length for 250 pm
29、nominal coating diameter. 4 TINE IA-TSB-62-7 735 mm -7 30 mm rL500 mm -7 coated fiber stripped fiber Figure 3 - Strip length for center-stripping 4.3 Stripping attempts The number of strip passes required to remove the coating shall be specified. In some cases it is not possible to remove coating la
30、yer in one continuous length. In these cases it may be necessary to remove them in shorter segments. The number of segments shall be specified. Typical stripping requirements are: Unbuffered Coating The coating of a fiber with a nominal 250 pm coating shall be removed in one continuous ope rat ion u
31、n less otherwise stated. Coating/Buffering Larger than 250 pm The buffering of 500 pm to 900 pm (nominal) tight buffered cables (not separately strippable) can be removed by operations applied to a number of smaller sections. For some separately strippable bufferings, after removal of the outer buff
32、ering, the 250 pm coating (inner protective layer) shall be removed in one pass. Single vs. multiple passes. 5 Procedure 5.1 Hazards This method may involve hazardous materials, operations, and equipment. This method does not purport to address all of the safety problems associated with its use. It
33、is the responsibility of the user of this method to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. 5 TINEIA-TSB-62-7 Wear eye glasses at all times when the fiber is being tested to protect against shards of broken glass. Addi
34、tional protective shields around the regions where fiber failure can occur are recommended. 5.2 Test condition The test environment shall be 23 OC f 2 OC and 50 Yo f 5 Yo relative humidity. 5.3 Equipment calibration Calibrate the tensile test transducer and load cell before each series of tests or a
35、s dictated by a documented calibration schedule according to the procedures of FOTP-28. 5.4 Stripping and wiping Perform the stripping per clauses 4.2, 4.3 and the stripper instructions. Unless otherwise required for mechanical stripping, wipe the stripped fiber once with a moist alcohol pad. Note:
36、Wiping the last 25 mm may be needed to ensure that the adhesive bonds well to the glass. Note - stripping speed and wiping speed and force may affect the results. Characterize these and report them in Section 7. 5.5 Mounting and loading the test sample, end-stripped fiber Caution - It is recommended
37、 that the specimens be tested within 10 minutes after the protective coating has been removed to minimize fiber degradation resulting from exposure to air. One method is to strip one specimen and test it immediately before stripping the next specimen. 5.5.1 End-stripped fiber Mount the stripped fibe
38、r sample on the fiber holding fixture as shown in Figure 4. Attach the fiber to the fiber holding fixture with a suitable adhesive. After the adhesive has set, transfer the whole assembly to the tensile test apparatus. The fixture protects the fiber from handling damage during this process. Avoid to
39、uching the gage length portion with anything to prevent additional damage. Mount the assembly in the fixed jaws of the test apparatus as in Figure 5. Clamp the jaws onto the adhesive beads to spread the clamping stress over a wide area. Bring the moveable jaws of the apparatus into place and attach
40、them to the adhesive bead at the other end of the holding fixture. Cut the fiber holding fixture at the dotted line, and apply the load to the fiber. 6 TINE IA-TSB-62-7 stripped fiber . I 5 t I+ _ + _ 55 mm _ + I I I I I I I I I I coated/buffered i i If- 25 mm-3 fiber I / ,o /. i i cut at dashed lin
41、es i / / / / ad hesive Figure 4 - Fiber mounted on holding fixture gripping jaws Figure 5 7 TINEIA-TSB-62-7 5.5.2 Center-stripped fiber The length of the fiber test sample shall be sufficient to secure the fiber ends, consistent with the requirements of FOTP-28. Wrap the fiber ends around the capsta
42、ns and secure them as in Figure 6. capstans I I Tensile Tester - coated fiber - stripped fiber Figure 6 -Tensile test setup for center-stripped fiber 5.7 Tensile load Start the test apparatus and apply the load to the test fiber at a constant strain rate of 2.5 to 5.0 % per minute. Record the load a
43、t which the fiber breaks. 5.8 Post-test inspection Remove the specimen from the test apparatus and inspect for fiber that may have been broken by the tensile testers jaws (fiber jaw-breaks). Discard any results of jaw-breaks. If required, repeat the tests for additional specimens. 8 TINE IA-TSB-62-7
44、 6 Calculations or interpretation of results Calculations are required in clause 7.1 .I2 for the breaking strengths and in clause 7.2.9 for the Weibull distribution of the breaking strength. Refer to FOTP-28 for details. 7 Documentation 7.1 Report the following information for each characterization.
45、 7.1 .I Date of test. 7.1.2 Population identification and history. 7.1.3 Stripper identification, and its condition. 7.1.4 Wiping procedure (number of wipes, dry/wet, type of wipe used). 7.1.5 ITM number, and whether end-stripping or center-stripping was used. 7.1.6 Number of strips per fiber. 7.1.7
46、 Nominal strain rate(s). 7.1.8 Sample or specimen identification, and number tested. 7.1.9 Preconditioning environment and time. 7.1 .IO Test environment. 7.1 .I 1 Method of stress calculation. 7.1 .I2 Maximum, minimum, mean, median, and standard deviation of breaking strengths. 7.2 for review upon
47、request: For nonmilitary applications, this information need not be reported but shall be available 7.2.1 Fiber manufacture date. 7.2.2 Fiber diameter information. 7.2.3 Coating characteristic information, including Eo for silica (if taken into account). 7.2.4 Method of stretching the fiber. 7.2.5 M
48、ethod for measuring failure load. 7.2.6 Method of distinguishing capstan failures. 7.2.7 Weibull plot, Weibull parameters md and So, and method of calculation. 9 TINEIA-TSB-62-7 7.3 for each test. United States military applications require that the following information also be reported 7.3.1 Test
49、personnel. 7.3.2 Test equipment used and date of latest calibration. 10 TINE IA-TSB-62-7 Annex A (informative) Comparison with IEC and ITU A.l Introduction One of TIAS policy objectives is to promote, whenever possible, the worldwide harmonization of fiber-optic standards. Committee FO-6 therefore requires that all new and revised ITMs contain an informative annex comparing the ITM to any counterpart in the International Electrotechnical Commission (IEC) and the International Telecommunication Union (ITU). This covers documents in print, and those in draft o
