1、 The following commercial specification is adopted from the military document. Revision A included all known accepted revisions, amendments, notices, and Department of Defense (DoD) engineering changes previously developed for this item. Revisions B and forward include changes adopted by DoD and Ind
2、ustry to reflect technology and design evolution. STRENGTH AND ELONGATION, BREAKING; TEXTILE WEBBING, TAPE AND BRAIDED ITEMS The Parachute Industry Association makes this document available for use by Industry and Government organizations that wish to apply this specification to their products. 1. S
3、COPE 1.1 Scope. This method is intended for determining the breaking strength and elongation of textile webbing, tape and braided items. 2. TEST SPECIMEN 2.1 Test Specimen. The specimen shall be a single length of 54 inches (1372mm) and the full width of the material as received. 3. NUMBER OF DETERM
4、INATIONS 3.1 Number of determinations. Unless otherwise specified in the procurement document, five specimens shall be tested from each sample unit. 4. APPARATUS 4.1 Apparatus. The machine shall consist of three main parts: a. Straining mechanism. b. Clamps. c. Load and elongation recording mechanis
5、m(s). 4.1.1 Straining mechanism. A machine wherein the specimen is held by two clamps and subjected to strain by a uniform movement of the pulling clamp. 4.1.1.1 Unless otherwise specified in the procurement document, the machine shall be PIA-TEST METHOD-4108D 26 January 2015 Superseding PIA-TEST ME
6、THOD-4108C 21 October 2011 DISTRIBUTION STATEMENT: All Rights Reserved. No Part of this publication may be reproduced without prior written permission from Parachute Industry Association. Additional copies may be purchased on-line from PIA Specifications and Products at: . Copyright Protected: Do No
7、t Copy!PIA-TEST METHOD-4108D adjusted so that the pulling clamp shall have a uniform speed of 3.0 +1.0 inches (76 +25mm) per minute. 4.1.2 Clamps. 4.1.2.1 Split drum. Unless otherwise specified in the procurement document, the machine shall have two clamps, split drum type as shown in FIGURE 1. The
8、width of the clamps shall be greater than the width of the specimen being tested. The distance between the clamps (gage length) shall be 10 +1/2 inches (254mm +13mm) center to center. 4.1.2.2 Flat surface clamps. When clamps are specified other than split drum type the machine shall have two clamps
9、with two jaws on each clamp. Each jaw face shall have a flat, smooth gripping surface. The design shall be such that one gripping surface or jaw may be an integral part of the rigid frame of the clamp or be fastened to allow a slight vertical movement while the other gripping surface or jaw shall be
10、 completely movable. Unless otherwise specified the dimension of the jaws parallel to the application of the load shall measure one inch (25mm) and the dimension of the jaws perpendicular to this direction shall be greater than the width of the specimen being tested. All edges, which might cause a c
11、utting action, shall be rounded to a radius not greater than 1/64 inch (0.4mm). The test specimen shall be a minimum of 6 inches (152mm). The pulling clamp shall have a uniform speed 12 +0.5 inches (305 +13mm) per minute. Unless otherwise specified, the distance between the jaws (gage length) shall
12、be 3 inches (76mm) at the start of the test. 4.1.3 Load recording mechanism(s). Calibrated chart, dial or scale to indicate applied load. Unless otherwise specified for load determination, the machine shall be adjusted or set so that the maximum load required to break the specimen shall remain indic
13、ated on the calibrated chart, dial or scale after the specimen has ruptured. 4.1.4 Capacity. The machine shall be of such capacity that the maximum load required to break the specimen shall be not greater than 85 percent or less than 15 percent of the rated capacity. 4.1.5 Machine efficiency. The er
14、ror of the machine shall not exceed 2 percent for loads up to and including 50 pounds (223N) and shall not exceed 1 percent for loads greater than 50 pounds (223N). 5. PROCEDURE 5.1 Preparation of specimen. 5.1.1 Unless otherwise specified in the procurement document, the specimens tested shall be c
15、onditioned and tested under standard conditions in accordance with Section 4 of this Standard. 5.1.2 When it is required that the elongation of the specimen shall be determined, two fine ink marks shall be placed on the specimen spaced five inches (127mm) apart. The marks shall be placed in such a m
16、anner that neither mark is closer than 1-1/2 inches (38mm) to each Page 2 of 5 Copyright Protected: Do Not Copy!PIA-TEST METHOD-4108D clamp when the specimen is mounted in the clamps. 5.2 The specimen. The specimen shall be placed in the clamps of the machine with the long dimension parallel to the
17、application of the load. When measurement of elongation is required a preload of 1 percent or a specific load required by the applicable procurement document shall be applied to the specimen as it is placed in the clamps and the two, fine ink marks shall not be closer than 1-1/2 inches (38mm) to eit
18、her clamp. 5.3 Breaking strength. Force shall be applied to the specimen at such a rate that the clamp through which the force is applied will move at a rate of 3.0 +1.0 inches (76 +25mm) per minute until the specimen is ruptured. After rupture of the specimen, the maximum load shall be read from th
19、e dial, scale or chart and the value recorded. 5.4 Elongation. Elongation shall be determined on the-same specimen being tested for breaking strength. The equipment will be stopped and the distance between the two fine ink marks measured with calipers at the load level specified in the applicable pr
20、ocurement document and recorded. The use of mechanical or electronic extensometers designed for determining elongation are acceptable alternatives. 5.5 Slippage. If a specimen slips between the clamps, breaks in or at the edges of the clamps, or if for any reason attributable to faulty technique, an
21、 individual measurement falls markedly below the average test result for the sample unit, such result shall be discarded and another specimen shall be tested. 6. REPORT 6.1 The breaking strength of the sample unit shall be the average of the results obtained from the five specimens tested and shall
22、be reported separately as follows: Breaking strength Reported to nearest 0-500 lbs (0-2220N) 1 lb (1N) 501 and up (2221N and up) 5 lbs (10N) 6.2 The elongation of the sample unit shall be the average of the specimens tested and shall be reported to the nearest 1.0 percent. The report shall state tha
23、t elongation was measured at break or at the load specified. 6.3 Each individual value use to calculate the average shall also be reported. 6.4 Note type of clamp used (see 4.1.2) (THIS SPACE LEFT INTENTIONALLY BLANK) Page 3 of 5 Copyright Protected: Do Not Copy!PIA-TEST METHOD-4108D FIGURE 1 * Page
24、 4 of 5 Copyright Protected: Do Not Copy!PIA-TEST METHOD-4108D Notice: This document has been adopted from the original Mil-Spec of the same number, and is being maintained as a commercial specification by the Parachute Industry Association. Orders, inquires and comments should be addressed to PIA,
25、Specification Committee via e-mail at: or to our website at: . Copyright 2005-2015 Parachute Industry Association. Disclaimer: This document is published by the PIA to provide technical and engineering standards that can be used as reference by all those who may benefit from them. The use of this
26、document is entirely voluntary, and its applicability and suitability for any particular use, including any patent or trademark infringement arising there from, is the sole responsibility of the user. The original government document was scanned. The PIA reviews each technical publication periodically, at which time it may be reaffirmed, revised, or canceled. The PIA invites your written comments and suggestions. Page 5 of 5 Copyright Protected: Do Not Copy!
